objc: err on a property designated both atomic and
nonatomic. // rdar://10260017


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141580 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 727c7b8..df95396 100644
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -1744,6 +1744,13 @@
       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
   }
 
+  if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
+      (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
+      Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
+        << "atomic" << "nonatomic";
+      Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
+  }
+
   // Warn if user supplied no assignment attribute, property is
   // readwrite, and this is an object type.
   if (!(Attributes & (ObjCDeclSpec::DQ_PR_assign | ObjCDeclSpec::DQ_PR_copy |