3 files changed, 44 insertions, 9 deletions
diff --git a/clang/lib/ARCMigrate/ObjCMT.cpp b/clang/lib/ARCMigrate/ObjCMT.cpp
index dd210264582..ab4aa0e0850 100644
--- a/clang/lib/ARCMigrate/ObjCMT.cpp
+++ b/clang/lib/ARCMigrate/ObjCMT.cpp
@@ -250,17 +250,22 @@ ClassImplementsAllMethodsAndProperties(ASTContext &Ctx,
       if (Property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
         continue;
       DeclContext::lookup_const_result R = IDecl->lookup(Property->getDeclName());
-      if (R.size() == 0)
-        return false;
-      for (unsigned I = 0, N = R.size(); I != N; ++I) {
-        if (ObjCPropertyDecl *ClassProperty = dyn_cast<ObjCPropertyDecl>(R[0])) {
-          if (ClassProperty->getPropertyAttributes()
-              != Property->getPropertyAttributes())
-            return false;
-          if (!Ctx.hasSameType(ClassProperty->getType(), Property->getType()))
+      if (R.size() == 0) {
+        // Relax the rule and look into class's implementation for a synthesize
+        // or dynamic declaration. Class is implementing a property coming from
+        // another protocol. This still makes the target protocol as conforming.
+        if (!ImpDecl->FindPropertyImplDecl(
+                                  Property->getDeclName().getAsIdentifierInfo()))
+          return false;
+      }
+      else if (ObjCPropertyDecl *ClassProperty = dyn_cast<ObjCPropertyDecl>(R[0])) {
+          if ((ClassProperty->getPropertyAttributes()
+              != Property->getPropertyAttributes()) ||
+              !Ctx.hasSameType(ClassProperty->getType(), Property->getType()))
             return false;
-        }
       }
+      else
+        return false;
     }
   // At this point, all required properties in this protocol conform to those
   // declared in the class.
diff --git a/clang/test/ARCMT/objcmt-protocol-conformance.m b/clang/test/ARCMT/objcmt-protocol-conformance.m
index 2ad8a659fae..3ef2eff13f2 100644
--- a/clang/test/ARCMT/objcmt-protocol-conformance.m
+++ b/clang/test/ARCMT/objcmt-protocol-conformance.m
@@ -46,3 +46,18 @@
 - (id) Meth1: (double) arg { return 0; }
 @end
 
+// Test5 - conforms to P3 because it implement's P3's property.
+@protocol P3
+@property (copy) id Prop;
+@end
+
+@protocol P4
+@property (copy) id Prop;
+@end
+
+@interface Test5 : NSObject<P3>
+@end
+
+@implementation Test5
+@synthesize Prop=_XXX;
+@end
diff --git a/clang/test/ARCMT/objcmt-protocol-conformance.m.result b/clang/test/ARCMT/objcmt-protocol-conformance.m.result
index 71fa3b1b06d..11bf7847280 100644
--- a/clang/test/ARCMT/objcmt-protocol-conformance.m.result
+++ b/clang/test/ARCMT/objcmt-protocol-conformance.m.result
@@ -46,3 +46,18 @@
 - (id) Meth1: (double) arg { return 0; }
 @end
 
+// Test5 - conforms to P3 because it implement's P3's property.
+@protocol P3
+@property (copy) id Prop;
+@end
+
+@protocol P4
+@property (copy) id Prop;
+@end
+
+@interface Test5 : NSObject<P3, P4>
+@end
+
+@implementation Test5
+@synthesize Prop=_XXX;
+@end