On Sat, 2 Oct 2021, 13:50 Daniel Krügler via Libstdc++, <
libstd...@gcc.gnu.org> wrote:
> Am Fr., 1. Okt. 2021 um 21:57 Uhr schrieb Jonathan Wakely via
> Libstdc++ <libstd...@gcc.gnu.org>:
> >
> > Implement the changes from P2162R2 (as a DR for C++17).
> >
> > Signed-off-by: Jonathan Wakely <jwak...@redhat.com>
> >
> > libstdc++-v3/ChangeLog:
> >
> > PR libstdc++/90943
> > * include/std/variant (__cpp_lib_variant): Update value.
> > (__detail::__variant::__as): New helpers implementing the
> > as-variant exposition-only function templates.
> > (visit, visit<R>): Use __as to upcast the variant parameters.
> > * include/std/version (__cpp_lib_variant): Update value.
> > * testsuite/20_util/variant/visit_inherited.cc: New test.
> >
> > Tested powerpc64le-linux. Committed to trunk.
> >
>
> I'm wondering why the first __as overload is not noexcept as well (or
> asking it the other way around: Why different exception-specifications
> are used for the different overloads):
>
> + // The __as function templates implement the exposition-only
> "as-variant"
> +
> + template<typename... _Types>
> + constexpr std::variant<_Types...>&
> + __as(std::variant<_Types...>& __v)
> + { return __v; }
>
Probably just an oversight, I'll check again and fix it. Thanks!
