Handle impl-trait-in-assoc-types separately from type-alias-impl-trait

Author: oli-obk

compiler/rustc_ty_utils/src/opaque_types.rs

@@ -233,6 +233,9 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
                 self.visit_opaque_ty(alias_ty);
             }
             ty::Alias(ty::Projection, alias_ty) => {
+                if let CollectionMode::TypeAliasImplTraitTransition = self.mode {
+                    return ControlFlow::Continue(());
+                }
                 // This avoids having to do normalization of `Self::AssocTy` by only
                 // supporting the case of a method defining opaque types from assoc types
                 // in the same impl block.

tests/ui/generic-associated-types/issue-88595.rs

@@ -20,5 +20,4 @@ impl<'a> A<'a> for C {
 
     fn a(&'a self) -> Self::B<'a> {} //~ ERROR: non-defining opaque type use in defining scope
     //~^ ERROR: non-defining opaque type use in defining scope
-    //~| ERROR: non-defining opaque type use in defining scope
 }

tests/ui/generic-associated-types/issue-88595.stderr

@@ -10,19 +10,6 @@ note: for this opaque type
 LL |     type B<'b> = impl Clone;
    |                  ^^^^^^^^^^
 
-error: non-defining opaque type use in defining scope
-  --> $DIR/issue-88595.rs:21:23
-   |
-LL |     fn a(&'a self) -> Self::B<'a> {}
-   |                       ^^^^^^^^^^^ generic argument `'a` used twice
-   |
-note: for this opaque type
-  --> $DIR/issue-88595.rs:19:18
-   |
-LL |     type B<'b> = impl Clone;
-   |                  ^^^^^^^^^^
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
 error: non-defining opaque type use in defining scope
   --> $DIR/issue-88595.rs:21:35
    |
@@ -37,5 +24,5 @@ LL | impl<'a> A<'a> for C {
 LL |     type B<'b> = impl Clone;
    |            ^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 

tests/ui/type-alias-impl-trait/multi-error.rs

@@ -16,7 +16,6 @@ impl Foo for () {
     type Baz = impl Sized;
     fn foo() -> (Self::Bar<u32>, Self::Baz) {
         //~^ ERROR non-defining opaque type use
-        //~| ERROR non-defining opaque type use
         ((), ())
         //~^ ERROR expected generic type parameter
     }

tests/ui/type-alias-impl-trait/multi-error.stderr

@@ -10,28 +10,15 @@ note: for this opaque type
 LL |     type Bar<T> = impl Sized;
    |                   ^^^^^^^^^^
 
-error[E0792]: non-defining opaque type use in defining scope
-  --> $DIR/multi-error.rs:17:17
-   |
-LL |     fn foo() -> (Self::Bar<u32>, Self::Baz) {
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ argument `u32` is not a generic parameter
-   |
-note: for this opaque type
-  --> $DIR/multi-error.rs:15:19
-   |
-LL |     type Bar<T> = impl Sized;
-   |                   ^^^^^^^^^^
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
 error[E0792]: expected generic type parameter, found `u32`
-  --> $DIR/multi-error.rs:20:9
+  --> $DIR/multi-error.rs:19:9
    |
 LL |     type Bar<T> = impl Sized;
    |              - this generic parameter must be used with a generic type parameter
 ...
 LL |         ((), ())
    |         ^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0792`.

tests/ui/type-alias-impl-trait/non-defining-method.rs

@@ -15,7 +15,6 @@ impl Foo for () {
     type Bar<T> = impl Sized;
     fn foo() -> Self::Bar<u32> {}
     //~^ ERROR non-defining opaque type use
-    //~| ERROR non-defining opaque type use
     //~| ERROR expected generic type parameter, found `u32`
     fn bar<T>() -> Self::Bar<T> {}
 }

tests/ui/type-alias-impl-trait/non-defining-method.stderr

@@ -10,19 +10,6 @@ note: for this opaque type
 LL |     type Bar<T> = impl Sized;
    |                   ^^^^^^^^^^
 
-error[E0792]: non-defining opaque type use in defining scope
-  --> $DIR/non-defining-method.rs:16:17
-   |
-LL |     fn foo() -> Self::Bar<u32> {}
-   |                 ^^^^^^^^^^^^^^ argument `u32` is not a generic parameter
-   |
-note: for this opaque type
-  --> $DIR/non-defining-method.rs:15:19
-   |
-LL |     type Bar<T> = impl Sized;
-   |                   ^^^^^^^^^^
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
 error[E0792]: expected generic type parameter, found `u32`
   --> $DIR/non-defining-method.rs:16:32
    |
@@ -31,6 +18,6 @@ LL |     type Bar<T> = impl Sized;
 LL |     fn foo() -> Self::Bar<u32> {}
    |                                ^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0792`.