diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index 05c3bc7..6375d91 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -1274,9 +1274,7 @@
     
     // Check that type of property and its ivar are type compatible.
     if (PropType != IvarType) {
-      // A readonly property is allowed to be a sub-class of the ivar type.
-      if (!property->isReadOnly() ||
-          CheckAssignmentConstraints(PropType, IvarType) != Compatible) {
+      if (CheckAssignmentConstraints(PropType, IvarType) != Compatible) {
         Diag(PropertyLoc, diag::error_property_ivar_type, property->getName(),
             Ivar->getName());
         return 0;
diff --git a/test/SemaObjC/property-9.m b/test/SemaObjC/property-9.m
new file mode 100644
index 0000000..b83291a
--- /dev/null
+++ b/test/SemaObjC/property-9.m
@@ -0,0 +1,38 @@
+// RUN: clang -fsyntax-only -verify %s
+
+typedef signed char BOOL;
+@protocol NSObject  - (BOOL)isEqual:(id)object; @end
+
+@interface NSObject <NSObject> {} @end
+
+@interface _NSServicesInContextMenu : NSObject {
+    id _requestor;
+    NSObject *_appleEventDescriptor;
+}
+
+@property (retain, nonatomic) id requestor;
+@property (retain, nonatomic) id appleEventDescriptor;
+
+@end
+
+@implementation _NSServicesInContextMenu
+
+@synthesize requestor = _requestor, appleEventDescriptor = _appleEventDescriptor;
+
+@end
+
+@class NSString;
+
+@protocol MyProtocol
+- (NSString *)stringValue;
+@end
+
+@interface MyClass : NSObject {
+  id  _myIvar;
+}
+@property (readwrite, retain) id<MyProtocol> myIvar;
+@end
+
+@implementation MyClass
+@synthesize myIvar = _myIvar;
+@end