AST: Clean up TypeBase::isOpenedExistentialWithError()

Author: slavapestov

include/swift/AST/Types.h

@@ -6689,17 +6689,6 @@ inline bool TypeBase::isOpenedExistential() const {
   return isa<OpenedArchetypeType>(T);
 }
 
-inline bool TypeBase::isOpenedExistentialWithError() {
-  if (!hasOpenedExistential())
-    return false;
-
-  CanType T = getCanonicalType();
-  if (auto archetype = dyn_cast<OpenedArchetypeType>(T)) {
-    return archetype->getExistentialType()->isExistentialWithError();
-  }
-  return false;
-}
-
 inline bool TypeBase::canDynamicallyBeOptionalType(bool includeExistential) {
   CanType T = getCanonicalType();
   auto isArchetypeOrExistential = isa<ArchetypeType>(T) ||

lib/AST/Type.cpp

@@ -1113,6 +1113,19 @@ bool TypeBase::isExistentialWithError() {
   return layout.isExistentialWithError(getASTContext());
 }
 
+bool TypeBase::isOpenedExistentialWithError() {
+  if (auto archetype = getAs<OpenedArchetypeType>()) {
+    auto errorProto = getASTContext().getErrorDecl();
+    if (!errorProto) return false;
+
+    for (auto protoDecl : archetype->getConformsTo()) {
+      if (protoDecl == errorProto || protoDecl->inheritsFrom(errorProto))
+        return true;
+    }
+  }
+  return false;
+}
+
 bool TypeBase::isStdlibType() {
   if (auto *NTD = getAnyNominal()) {
     auto *DC = NTD->getDeclContext();