[Sema] RuntimeMetadata: Supress attr inference for local types

Author: xedin

lib/Sema/TypeCheckAttr.cpp

@@ -7391,7 +7391,7 @@ GetRuntimeDiscoverableAttributes::evaluate(Evaluator &evaluator,
 
   auto *NTD = dyn_cast<NominalTypeDecl>(decl);
   // Attribute inference is only possible from protocol conformances.
-  if (!NTD || isa<ProtocolDecl>(NTD))
+  if (!NTD || isa<ProtocolDecl>(NTD) || NTD->getDeclContext()->isLocalContext())
     return copyAttrs(attrs);
 
   // Gather any attributes inferred from (explicit) protocol conformances

test/IRGen/runtime_attributes.swift

@@ -209,3 +209,8 @@ struct FlagWithAvail {
 @FlagWithAvail
 @available(macOS, obsoleted: 100.0)
 func attrIsHigherThanFunc() {}
+
+func test_local_type_with_protocol_conformance() {
+  // CHECK-NOT: define hidden swiftcc void @"$s18runtime_attributes41test_local_type_with_protocol_conformanceyyF9LocalTest{{.*}}"
+  struct LocalTest : Ignored {} // Ok but attribute is not inferred.
+}

test/type/runtime_discoverable_attrs.swift

@@ -153,3 +153,7 @@ class MembersWithAvailability {
   @available(macOS, introduced: 100.0)
   var prop: Int { get { 0 } } // Ok
 }
+
+func test_local_types_with_conformances() {
+  struct X : Flagged {}
+}