diff options
Diffstat (limited to 'compiler/rustc_ty_utils/src')
| -rw-r--r-- | compiler/rustc_ty_utils/src/opaque_types.rs | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/compiler/rustc_ty_utils/src/opaque_types.rs b/compiler/rustc_ty_utils/src/opaque_types.rs index 3b313edea6f..4a7263d0ccd 100644 --- a/compiler/rustc_ty_utils/src/opaque_types.rs +++ b/compiler/rustc_ty_utils/src/opaque_types.rs @@ -223,7 +223,10 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> { } // Skips type aliases, as they are meant to be transparent. // FIXME(type_alias_impl_trait): can we require mentioning nested type aliases explicitly? - ty::Alias(ty::Free, alias_ty) if alias_ty.def_id.is_local() => { + ty::Alias(ty::Free, alias_ty) if let Some(def_id) = alias_ty.def_id.as_local() => { + if !self.seen.insert(def_id) { + return; + } self.tcx .type_of(alias_ty.def_id) .instantiate(self.tcx, alias_ty.args) @@ -256,16 +259,16 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> { return; } - let impl_args = alias_ty.args.rebase_onto( + let alias_args = alias_ty.args.rebase_onto( self.tcx, impl_trait_ref.def_id, ty::GenericArgs::identity_for_item(self.tcx, parent), ); - if self.tcx.check_args_compatible(assoc.def_id, impl_args) { + if self.tcx.check_args_compatible(assoc.def_id, alias_args) { self.tcx .type_of(assoc.def_id) - .instantiate(self.tcx, impl_args) + .instantiate(self.tcx, alias_args) .visit_with(self); return; } else { |