Merge pull request #489 from ferd/maybe_expr_unsupported

Add known problem for unsupported maybe expression

Author: erszcz

.github/workflows/build-and-test.yml

@@ -9,11 +9,11 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Erlang ${{matrix.otp}}
     strategy:
       matrix:
-        otp: ['22.3.4.20', '23.3.4.7', '24.3.4.4']
+        otp: ['23.3.4.7', '24.3.4.4', '25.1.2']
     steps:
       - uses: actions/checkout@v2
       - uses: erlef/setup-beam@v1

.github/workflows/proptests.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Erlang ${{matrix.otp}}
     strategy:
       matrix:

.github/workflows/publish-to-hex.yml

@@ -5,7 +5,7 @@ on:
 
 jobs:
   publish:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
       - name: Check Out

.github/workflows/self-check.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Erlang ${{matrix.otp}}
     strategy:
       matrix:

Makefile

@@ -32,6 +32,8 @@
 .PHONY: all
 all: app escript
 
+ERL_OPTS = -enable-feature maybe_expr
+
 # Compilation
 
 erls = $(wildcard src/*.erl)
@@ -143,7 +145,7 @@ end
 endef
 
 eunit: compile-tests
-	erl -noinput -pa ebin -pa test -eval \
+	erl $(ERL_OPTS) -noinput -pa ebin -pa test -eval \
 	 '$(erl_run_eunit), halt().'
 
 cli-tests: bin/gradualizer test/arg.beam

rebar.config

@@ -4,7 +4,10 @@
           {deps,
            [
             {proper, {git, "https://github.com/proper-testing/proper.git", {branch, "master"}}}
-           ]}
+           ]},
+          %% see the maybe expression fail;
+          %% the VM also needs to be configured to load the module
+          {erl_opts, [{feature,maybe_expr,enable}]}
          ]}
  ]}.
 

src/gradualizer_fmt.erl

@@ -362,6 +362,12 @@ format_type_error({form_check_timeout, Form}, Opts) ->
                              [form_info(Form),
                               format_location(Form, verbose, Opts)])
        end]);
+format_type_error({unsupported_expression, Anno, Expr}, Opts) ->
+    io_lib:format(
+      "~sThe ~s expression~s is not supported yet~n",
+      [format_location(Anno, brief, Opts),
+       atom_to_list(element(1, Expr)),
+       format_location(Anno, verbose, Opts)]);
 format_type_error({Location, Module, ErrorDescription}, Opts)
   when is_integer(Location) orelse is_tuple(Location),
        is_atom(Module) ->

src/typechecker.erl

@@ -1903,7 +1903,12 @@ do_type_check_expr(Env, {'try', _, Block, CaseCs, CatchCs, AfterBlock}) ->
           end,
     {normalize({type, erl_anno:new(0), union, [Ty, TyC, TyS]}, Env)
     ,VB
-    ,constraints:combine([Cs1,Cs2,Cs3,Cs4])}.
+    ,constraints:combine([Cs1,Cs2,Cs3,Cs4])};
+
+%% Maybe - value-based error handling expression
+%% See https://www.erlang.org/eeps/eep-0049
+do_type_check_expr(Env, {'maybe', Anno, [{maybe_match, _, _LHS, _RHS}]} = MaybeExpr) ->
+    erlang:throw({unsupported_expression, Anno, MaybeExpr}).
 
 %% Helper for type_check_expr for funs
 -spec type_check_fun(env(), _) -> {type(), env(), constraints:constraints()}.

test/known_problems/should_pass/any_doesnt_have_type_none_should_pass.erl

@@ -1,5 +1,7 @@
 -module(any_doesnt_have_type_none_should_pass).
 
+-export([f/2]).
+
 -type type() :: abstract_type().
 
 -type abstract_type() :: af_tuple_type().

test/known_problems/should_pass/fun_subtyping.erl

@@ -1,6 +1,6 @@
 -module(fun_subtyping).
 
--compile([export_all, nowarn_export_all]).
+-export([return_fun_intersection/0]).
 
 -spec return_fun_intersection() -> fun((number()) -> number()).
 return_fun_intersection() -> fun number/1.

test/known_problems/should_pass/list_concat_op_should_pass.erl

@@ -2,9 +2,7 @@
 
 -export([nil_concat_op_elem_gives_elem/0,
          nonempty1_concat_op_elem_gives_improper/0,
-         nonempty2_concat_op_elem_gives_improper/0,
-         nil_concat_op_nonempty_gives_proper/0,
-         nonempty_concat_op_nonempty_gives_proper/0]).
+         nonempty2_concat_op_elem_gives_improper/0]).
 
 -spec nil_concat_op_elem_gives_elem() -> b.
 nil_concat_op_elem_gives_elem() ->
@@ -23,14 +21,6 @@ nonempty2_concat_op_elem_gives_improper() ->
 %% improper_concat_op_elem_gives_badarg() ->
 %%     [a|b] ++ c.
 
--spec nil_concat_op_nonempty_gives_proper() -> [atom()].
-nil_concat_op_nonempty_gives_proper() ->
-    [] ++ [a].
-
--spec nonempty_concat_op_nonempty_gives_proper() -> [atom()].
-nonempty_concat_op_nonempty_gives_proper() ->
-    [a,b] ++ [c].
-
 %% See list_op_should_fail.
 %% -spec improper_concat_op_nonempty_gives_badarg() -> none().
 %% improper_concat_op_nonempty_gives_badarg() ->

test/known_problems/should_pass/maybe_expr.erl

@@ -0,0 +1,18 @@
+-module(maybe_expr).
+
+-ifdef(OTP_RELEASE).
+-if(?OTP_RELEASE >= 25).
+-if(?FEATURE_AVAILABLE(maybe_expr)).
+
+-feature(maybe_expr, enable).
+
+-export([syntax/0]).
+
+syntax() ->
+    maybe
+        ok ?= ok
+    end.
+
+-endif. %% FEATURE_AVAILABLE
+-endif. %% OTP >= 25
+-endif. %% OTP_RELEASE

test/known_problems/should_pass/refine_mismatch_using_guard_bifs.erl

@@ -1,8 +1,7 @@
 -module(refine_mismatch_using_guard_bifs).
 
 -export([refine_by_guards_1/1,
-         refine_by_guards_2/1,
-         refine_literals_by_guards/1]).
+         refine_by_guards_2/1]).
 
 -spec refine_by_guards_1(atom() | pos_integer() | float() |
                          binary() | tuple() | [any()] |
@@ -24,10 +23,3 @@ refine_by_guards_2(X) when is_boolean(X) -> ok;
 refine_by_guards_2(X) when is_list(X)    -> ok;
 refine_by_guards_2(X) when is_port(X)    -> ok;
 refine_by_guards_2(X)                    -> X.
-
--spec refine_literals_by_guards(banana | 0 | {} | [] | pid()) -> pid().
-refine_literals_by_guards(X) when is_atom(X)    -> self();
-refine_literals_by_guards(X) when is_integer(X) -> self();
-refine_literals_by_guards(X) when is_tuple(X)   -> self();
-refine_literals_by_guards(X) when is_list(X)    -> self();
-refine_literals_by_guards(X)                    -> X.

test/should_pass/list_concat_op_pass.erl

@@ -4,7 +4,9 @@
          nonempty1_concat_fun_elem_gives_improper/0,
          nonempty2_concat_fun_elem_gives_improper/0,
          nil_concat_fun_nonempty_gives_proper/0,
+         nil_concat_op_nonempty_gives_proper/0,
          nonempty_concat_fun_nonempty_gives_proper/0,
+         nonempty_concat_op_nonempty_gives_proper/0,
          proper_concat_fun_proper_gives_proper/0]).
 
 -spec nil_concat_fun_elem_gives_elem() -> b.
@@ -23,10 +25,18 @@ nonempty2_concat_fun_elem_gives_improper() ->
 nil_concat_fun_nonempty_gives_proper() ->
     erlang:'++'([], [a]).
 
+-spec nil_concat_op_nonempty_gives_proper() -> [atom()].
+nil_concat_op_nonempty_gives_proper() ->
+    [] ++ [a].
+
 -spec nonempty_concat_fun_nonempty_gives_proper() -> [atom()].
 nonempty_concat_fun_nonempty_gives_proper() ->
     erlang:'++'([a,b], [c]).
 
+-spec nonempty_concat_op_nonempty_gives_proper() -> [atom()].
+nonempty_concat_op_nonempty_gives_proper() ->
+    [a,b] ++ [c].
+
 -spec proper_concat_fun_proper_gives_proper() -> [integer()].
 proper_concat_fun_proper_gives_proper() ->
     erlang:'++'(generate_list(), generate_list()).

test/should_pass/type_refinement_pass.erl

@@ -1,6 +1,17 @@
 -module(type_refinement_pass).
 
--compile([export_all, nowarn_export_all]).
+-export([basic_type_refinement/1,
+         getenv/1,
+         int_literals_1/1, int_literals_2/1, int_literals_3/1,
+         disjoint_stuff_1/1, disjoint_stuff_2/1, disjoint_stuff_3/1, disjoint_stuff_4/1,
+         var_pat/2,
+         nil_elimination/1,
+         tuple_union/1,
+         tuple_union_2/1,
+         beside_match_all/2,
+         beside_singleton/2,
+         refine_bound_var_by_guard_bifs/1,
+         refine_literals_by_guards/1]).
 
 %% Test that Value is not considered to be string() | false.
 -spec basic_type_refinement(string()) -> string().
@@ -81,3 +92,10 @@ refine_bound_var_by_guard_bifs(X) ->
         is_pid(X)     -> ok;
         true          -> X
     end.
+
+-spec refine_literals_by_guards(banana | 0 | {} | [] | pid()) -> pid().
+refine_literals_by_guards(X) when is_atom(X)    -> self();
+refine_literals_by_guards(X) when is_integer(X) -> self();
+refine_literals_by_guards(X) when is_tuple(X)   -> self();
+refine_literals_by_guards(X) when is_list(X)    -> self();
+refine_literals_by_guards(X)                    -> X.

test/test.erl

@@ -57,7 +57,10 @@ gen_should_fail() ->
 gen_known_problem_should_pass() ->
     map_erl_files(
       fun(File) ->
-              ?_assertNotEqual(ok, safe_type_check_file(File))
+              {ok, Forms} = gradualizer_file_utils:get_forms_from_erl(File, []),
+              ExpectedErrors = typechecker:number_of_exported_functions(Forms),
+              ReturnedErrors = length(safe_type_check_file(File, [return_errors])),
+              ?_assertEqual(ExpectedErrors, ReturnedErrors)
       end, "test/known_problems/should_pass").
 
 % Test succeeds if Gradualizer crashes or if it does type check.
@@ -85,8 +88,11 @@ map_erl_files(Fun, Dir) ->
     [{filename:basename(File), Fun(File)} || File <- Files].
 
 safe_type_check_file(File) ->
+    safe_type_check_file(File, []).
+
+safe_type_check_file(File, Opts) ->
     try
-        gradualizer:type_check_file(File)
+        gradualizer:type_check_file(File, Opts)
     catch
         _:_ -> crash
     end.