Discovered because of: https://bugs.llvm.org/show_bug.cgi?id=38235
It seems to me that a scoped enum should NOT be an integral constant expression
without a cast, so this seems like a sensical change.
Attributes that check for an integer parameter simply use this function to
ensure that they have an integer, so it was previously allowing a scoped enum.
Also added a test based on Richard's feedback to ensure that case labels still work.
Differential Revision: https://reviews.llvm.org/D49599
llvm-svn: 337585
Erich Keane