Fix 48631_neg test in _GLIBCXX_VERSION_NAMESPACE mode

[Jonathan Wakely]

On Tue, 28 Sept 2021 at 21:21, François Dumont via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On 27/09/21 11:06 pm, Jonathan Wakely wrote:
> > On Mon, 27 Sept 2021 at 21:26, François Dumont via Libstdc++
> > <libstdc++@gcc.gnu.org> wrote:
> >> Here is a small patch to fix a test which fails in
> >> _GLIBCXX_VERSION_NAMESPACE mode.
> >>
> >> IMHO it would be better to avoid putting <type_traits> content in
> >> versioned namespace, no ?
>
> No opinion on this, you prefer to use consistently the versioned namespace ?

I haven't though about it in much detail, but I think it's safer to
keep them in the versioned namespace.

Can we be sure that we'd never need to make any incompatible changes
to anything in that header? It seems likely, but I'm not entirely
confident.


> >> There is of course more work to do, so for now here is the simpler approach.
> >>
> >> Ok to commit ?
> > Leaving the pattern ending with just "struct" isn't very useful.
> > Wouldn't it be better to do:
> >
> > // { dg-prune-output "no type named 'type' in" }
> >
> > or just:
> >
> > // { dg-prune-output "enable_if" }
> >
> > ?
> >
> > Either of those is OK to commit.
>
> Done with "enable_if"

Thanks.