diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 74d22e7..e60cd63 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1746,6 +1746,10 @@
       return;
     }
   }
+  else {
+    S.Diag(D->getLocation(), diag::warn_nsobject_attribute);
+    return;
+  }
   D->addAttr(::new (S.Context) ObjCNSObjectAttr(Attr.getRange(), S.Context));
 }