meh

Author: lcnr

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -145,9 +145,21 @@ pub(crate) fn handle_opaque_type_uses<'tcx>(
             scc_values: &scc_values,
         });
 
-        hidden_type.ty =
-            infcx.infer_opaque_definition_from_instantiation(opaque_type_key, hidden_type);
-        root_cx.add_concrete_opaque_type(opaque_type_key.def_id, hidden_type);
+        let ty = infcx.infer_opaque_definition_from_instantiation(opaque_type_key, hidden_type);
+
+        // TODO this doesn't seem to help
+        if !tcx.use_typing_mode_borrowck() {
+            if let ty::Alias(ty::Opaque, alias_ty) = ty.kind()
+                && alias_ty.def_id == opaque_type_key.def_id.to_def_id()
+                && alias_ty.args == opaque_type_key.args
+            {
+                continue 'entry;
+            }
+        }
+        root_cx.add_concrete_opaque_type(
+            opaque_type_key.def_id,
+            OpaqueHiddenType { span: hidden_type.span, ty },
+        );
     }
 
     if !unexpected_hidden_regions.is_empty() {