Re: [C++ Patch] PR 51312

[Jason Merrill <jason at redhat dot com>]

On 08/07/2014 09:58 AM, Paolo Carlini wrote:
> Also, I was thinking earlier today that conceptually the check pasted
> above should check cases different from the cases handled by
> perform_implicit_conversion_flags, thus, eg, *not* handle enum27.C,
> because it's an hard error, isn't our standard (and suppressible)
> narrowing diagnostic. Seems more correct to use it only to diagnose that
> the internally computed next enumerator overflows. See what I mean?

-Wno-narrowing should prevent an error on enum27; the narrowing 
conversion makes it not a converted constant expression, so the 
initializer is ill-formed.  This probably needs some tweaking in the 
constexpr code.

And we should use the same code path for explicit and implicit values.

Jason