Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td	(revision 195354)
+++ include/clang/Basic/DiagnosticSemaKinds.td	(working copy)
@@ -1796,9 +1796,6 @@
   ":requires exactly %1 arguments}1">;
 def err_attribute_too_many_arguments : Error<
   "attribute takes no more than %0 argument%s0">;
-def err_suppress_autosynthesis : Error<
-  "objc_requires_property_definitions attribute may only be specified on a class"
-  "to a class declaration">;
 def err_attribute_too_few_arguments : Error<
   "attribute takes at least %0 argument%s0">;
 def err_attribute_invalid_vector_type : Error<"invalid vector element type %0">;
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp	(revision 195354)
+++ lib/Sema/SemaDeclAttr.cpp	(working copy)
@@ -2116,6 +2116,11 @@
 
 static void handleArcWeakrefUnavailableAttr(Sema &S, Decl *D, 
                                             const AttributeList &Attr) {
+  if (!isa<ObjCInterfaceDecl>(D)) {
+    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_decl_type)
+      << Attr.getName() << ExpectedObjectiveCInterface;
+    return;
+  }
   D->addAttr(::new (S.Context)
              ArcWeakrefUnavailableAttr(Attr.getRange(), S.Context,
                                        Attr.getAttributeSpellingListIndex()));
@@ -2137,7 +2142,8 @@
 static void handleObjCRequiresPropertyDefsAttr(Sema &S, Decl *D,
                                                const AttributeList &Attr) {
   if (!isa<ObjCInterfaceDecl>(D)) {
-    S.Diag(Attr.getLoc(), diag::err_suppress_autosynthesis);
+    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_decl_type)
+      << Attr.getName() << ExpectedObjectiveCInterface;
     return;
   }
   
Index: test/SemaObjC/arc-unavailable-for-weakref.m
===================================================================
--- test/SemaObjC/arc-unavailable-for-weakref.m	(revision 195354)
+++ test/SemaObjC/arc-unavailable-for-weakref.m	(working copy)
@@ -90,3 +90,5 @@
 __attribute__((objc_arc_weak_reference_unavailable(1)))	// expected-error {{'objc_arc_weak_reference_unavailable' attribute takes no arguments}}
 @interface I3
 @end
+
+int I4 __attribute__((objc_arc_weak_reference_unavailable)); // expected-error {{'objc_arc_weak_reference_unavailable' attribute only applies to Objective-C interfaces}}
Index: test/SemaObjC/default-synthesize-3.m
===================================================================
--- test/SemaObjC/default-synthesize-3.m	(revision 195354)
+++ test/SemaObjC/default-synthesize-3.m	(working copy)
@@ -37,7 +37,7 @@
 @interface Deep(CAT)  // expected-error {{attributes may not be specified on a category}}
 @end
 
-__attribute ((objc_requires_property_definitions)) // expected-error {{objc_requires_property_definitions attribute may only be specified on a class}} 
+__attribute ((objc_requires_property_definitions)) // expected-error {{'objc_requires_property_definitions' attribute only applies to Objective-C interfaces}}
 @protocol P @end
 
 // rdar://13388503