Index: lib/Sema/SemaExprObjC.cpp
===================================================================
--- lib/Sema/SemaExprObjC.cpp
+++ lib/Sema/SemaExprObjC.cpp
@@ -2000,10 +2000,16 @@
   }
 
   // Look for the matching setter, in case it is needed.
-  Selector SetterSel =
-    SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
-                                            PP.getSelectorTable(),
-                                           &propertyName);
+  Selector SetterSel;
+  if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(
+          &propertyName, ObjCPropertyQueryKind::OBJC_PR_query_class)) {
+    SetterSel = PD->getSetterName();
+  } else {
+    SetterSel =
+      SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
+                                             PP.getSelectorTable(),
+                                             &propertyName);
+  }
 
   ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
   if (!Setter) {