[Sema] RuntimeMetadata: Make sure that attrs on unavailable extensions always have a type

Author: xedin

lib/Sema/TypeCheckAttr.cpp

@@ -7629,8 +7629,19 @@ GetRuntimeDiscoverableAttributes::evaluate(Evaluator &evaluator,
 }
 
 void TypeChecker::checkReflectionMetadataAttributes(ExtensionDecl *ED) {
+  auto &ctx = ED->getASTContext();
   auto *extendedType = ED->getExtendedNominal();
 
+  // If extension has any reflection metadata attributes, trigger the
+  // request to set their types.
+  for (auto *attr : ED->getRuntimeDiscoverableAttrs()) {
+    (void)evaluateOrDefault(
+        ctx.evaluator,
+        CustomAttrTypeRequest{attr, ED->getDeclContext(),
+                              CustomAttrTypeKind::RuntimeMetadata},
+        nullptr);
+  }
+
   for (auto *protocol : ED->getLocalProtocols()) {
     forEachCustomAttribute<RuntimeMetadataAttr>(
         protocol, [&](CustomAttr *attr, NominalTypeDecl *attrType) {
@@ -7640,7 +7651,6 @@ void TypeChecker::checkReflectionMetadataAttributes(ExtensionDecl *ED) {
                     return extendedType->getRuntimeDiscoverableAttrTypeDecl(
                                typeAttr) == attrType;
                   })) {
-            auto &ctx = protocol->getASTContext();
             ctx.Diags.diagnose(ED->getLoc(), diag::type_does_not_conform,
                                ED->getExtendedType(),
                                protocol->getDeclaredInterfaceType());

test/ModuleInterface/custom_reflection_metadata_attr.swift

@@ -18,7 +18,7 @@ public class BaseClass {}
 public class TestClass : BaseClass {}
 
 // CHECK: @available(*, unavailable)
-// CHECK-NEXT: @Flag extension CRM.TestClass {
+// CHECK-NEXT: @CRM.Flag extension CRM.TestClass {
 // CHECK-NEXT: }
 
 @available(*, unavailable)