Remove the (ignored) -Wreceived-is-weak diagnostic.

We kept this around for a while since Xcode 6 and earlier had a build
setting for this warning. It was removed in Xcode 7 so there should be
no need for this warning now.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@266938 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticGroups.td

@@ -286,8 +286,6 @@ def : DiagGroup<"overflow">;
 def ForwardClassReceiver : DiagGroup<"receiver-forward-class">;
 def MethodAccess : DiagGroup<"objc-method-access">;
 def ObjCReceiver : DiagGroup<"receiver-expr">;
-// FIXME: Remove this when Xcode removes the warning setting.
-def : DiagGroup<"receiver-is-weak">;
 def OperatorNewReturnsNull : DiagGroup<"new-returns-null">;
 def OverlengthStrings : DiagGroup<"overlength-strings">;
 def OverloadedVirtual : DiagGroup<"overloaded-virtual">;

test/SemaObjC/iboutlet.m

-// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -Wno-objc-root-class -Wreceiver-is-weak -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
-// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -fobjc-arc -Wno-objc-root-class -Wreceiver-is-weak -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
+// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -Wno-objc-root-class -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
+// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -fobjc-arc -Wno-objc-root-class -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
 // rdar://11448209
-// rdar://20259376
 
 #define READONLY readonly