Pass the diagnostic in for better error messages.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@178120 91177308-0d34-0410-b5e6-96231b3b80d8
Fix testcase to add expected note.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@178122 91177308-0d34-0410-b5e6-96231b3b80d8