Introduce `DefPathData::AnonAssocTy`.

PR #137977 changed `DefPathData::TypeNs` to contain `Option<Symbol>` to
account for RPITIT assoc types being anonymous. This commit changes it
back to `Symbol` and gives anonymous assoc types their own variant. It
makes things a bit nicer overall.

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_ty_utils/src/assoc.rs b/compiler/rustc_ty_utils/src/assoc.rs
index b7684e85d41..9520d948f51 100644
--- a/compiler/rustc_ty_utils/src/assoc.rs
+++ b/compiler/rustc_ty_utils/src/assoc.rs
@@ -252,7 +252,7 @@ fn associated_type_for_impl_trait_in_trait(
     assert_eq!(tcx.def_kind(trait_def_id), DefKind::Trait);
 
     let span = tcx.def_span(opaque_ty_def_id);
-    // No name because this is a synthetic associated type.
+    // No name because this is an anonymous associated type.
     let trait_assoc_ty = tcx.at(span).create_def(trait_def_id, None, DefKind::AssocTy);
 
     let local_def_id = trait_assoc_ty.def_id();
@@ -305,7 +305,7 @@ fn associated_type_for_impl_trait_in_impl(
         hir::FnRetTy::DefaultReturn(_) => tcx.def_span(impl_fn_def_id),
         hir::FnRetTy::Return(ty) => ty.span,
     };
-    // No name because this is a synthetic associated type.
+    // No name because this is an anonymous associated type.
     let impl_assoc_ty = tcx.at(span).create_def(impl_local_def_id, None, DefKind::AssocTy);
 
     let local_def_id = impl_assoc_ty.def_id();