[PATCH] PR libstdc++/80939 Remove unmeetable constexpr specifiers

[Jonathan Wakely]

On 02/06/17 12:19 -0700, Tim Shen wrote:
>On Fri, Jun 2, 2017 at 6:07 AM, Jonathan Wakely wrote:
>> As the PR points out, we aren't qualifying calls to __ref_cast, and
>> have 'constexpr' on function templates that can never be usable in
>> constant expressions.
>
>Apology for the constexpr trolling, but that was not intentional. :)
>
>I'm curious why no tests break. Is it because constexpr in a template
>function is a no-op instead of a hard error, when the function
>definition is not constexpr?
>
>The patch looks good.

Committed to trunk (I'll backport it to gcc-7-branch some time too).