More cleanup

Author: Aaron1011

chalk-solve/src/clauses/builtin_traits.rs

@@ -34,7 +34,7 @@ pub fn add_builtin_program_clauses<I: Interner>(
             WellKnownTrait::Copy => copy::add_copy_program_clauses(db, builder, &trait_ref, ty),
             WellKnownTrait::Clone => clone::add_clone_program_clauses(db, builder, &trait_ref, ty),
             WellKnownTrait::FnOnce | WellKnownTrait::FnMut | WellKnownTrait::Fn => {
-                fn_family::add_fn_trait_program_clauses(db, builder, trait_ref.trait_id, ty)
+                fn_family::add_fn_trait_program_clauses(db, builder, trait_ref.trait_id, self_ty)
             }
             // Drop impls are provided explicitly
             WellKnownTrait::Drop => (),
@@ -55,7 +55,7 @@ pub fn add_builtin_assoc_program_clauses<I: Interner>(
             let interner = db.interner();
             let self_ty = AliasTy::Projection(proj.clone()).self_type_parameter(interner);
             let trait_id = db.well_known_trait_id(well_known).unwrap();
-            fn_family::add_fn_trait_program_clauses(db, builder, trait_id, self_ty.data(interner));
+            fn_family::add_fn_trait_program_clauses(db, builder, trait_id, self_ty);
         }
         _ => {}
     }

chalk-solve/src/clauses/builtin_traits/fn_family.rs

@@ -17,11 +17,11 @@ pub fn add_fn_trait_program_clauses<I: Interner>(
     db: &dyn RustIrDatabase<I>,
     builder: &mut ClauseBuilder<'_, I>,
     trait_id: TraitId<I>,
-    ty: &TyData<I>,
+    self_ty: Ty<I>,
 ) {
-    match ty {
+    let interner = db.interner();
+    match self_ty.data(interner) {
         TyData::Function(fn_val) => {
-            let interner = db.interner();
             let (binders, orig_sub) = fn_val.into_binders_and_value(interner);
             // Take all of the arguments except for the last one, which
             // represents the return type
@@ -43,9 +43,7 @@ pub fn add_fn_trait_program_clauses<I: Interner>(
                 }),
             );
 
-            let self_ty = Ty::new(interner, ty);
-
-            let tupled_sub = Substitution::from(interner, vec![self_ty, tupled]);
+            let tupled_sub = Substitution::from(interner, vec![self_ty.clone(), tupled]);
             // Given a function type `fn(A1, A2, ..., AN)`, construct a `TraitRef`
             // of the form `fn(A1, A2, ..., AN): FnOnce<(A1, A2, ..., AN)>`
             let new_trait_ref = TraitRef {