Remove FnCtxt::impl_self_ty

src/test/ui/issues/issue-18446.stderr

@@ -7,7 +7,7 @@ LL |     x.foo();
    |     | multiple `foo` found
    |     help: disambiguate the method call for candidate #2: `T::foo(&x)`
    |
-note: candidate #1 is defined in an impl for the type `dyn T`
+note: candidate #1 is defined in an impl for the type `(dyn T + 'a)`
   --> $DIR/issue-18446.rs:9:5
    |
 LL |     fn foo(&self) {}

src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.stderr

@@ -20,12 +20,12 @@ error[E0034]: multiple applicable items in scope
 LL |     let z = x.foo();
    |               ^^^ multiple `foo` found
    |
-note: candidate #1 is defined in an impl of the trait `internal::X` for the type `_`
+note: candidate #1 is defined in an impl of the trait `internal::X` for the type `T`
   --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:43:9
    |
 LL |         fn foo(self: Smaht<Self, u64>) -> u64 {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: candidate #2 is defined in an impl of the trait `nuisance_foo::NuisanceFoo` for the type `_`
+note: candidate #2 is defined in an impl of the trait `nuisance_foo::NuisanceFoo` for the type `T`
   --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:70:9
    |
 LL |         fn foo(self) {}

src/test/ui/suggestions/suggest-assoc-fn-call-with-turbofish.stderr

@@ -11,7 +11,7 @@ LL |     x.default_hello();
    |     help: use associated function syntax instead: `GenericAssocMethod::<i32>::default_hello`
    |
    = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
-note: the candidate is defined in an impl for the type `GenericAssocMethod<_>`
+note: the candidate is defined in an impl for the type `GenericAssocMethod<T>`
   --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:4:5
    |
 LL |     fn default_hello() {}