From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: "Daniel Krügler" <daniel.kruegler@gmail.com>
Cc: Jonathan Wakely <jwakely@redhat.com>,
"libstdc++" <libstdc++@gcc.gnu.org>,
gcc-patches List <gcc-patches@gcc.gnu.org>
Subject: Re: [committed] libstdc++: Allow visiting inherited variants [PR 90943]
Date: Sun, 3 Oct 2021 10:07:13 +0100 [thread overview]
Message-ID: <CAH6eHdQHHXCr9xb9bgC4EwOpz47+2HG6z2+LyT-DH1Yw-DU=zg@mail.gmail.com> (raw)
In-Reply-To: <CAGNvRgCuPz52iQiL=__iJ1QfyXRRAH+wD42NKCcxxLrjy5xKAw@mail.gmail.com>
On Sat, 2 Oct 2021, 13:50 Daniel Krügler via Libstdc++, <
libstdc++@gcc.gnu.org> wrote:
> Am Fr., 1. Okt. 2021 um 21:57 Uhr schrieb Jonathan Wakely via
> Libstdc++ <libstdc++@gcc.gnu.org>:
> >
> > Implement the changes from P2162R2 (as a DR for C++17).
> >
> > Signed-off-by: Jonathan Wakely <jwakely@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!
next prev parent reply other threads:[~2021-10-03 9:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 19:42 Jonathan Wakely
2021-10-02 12:49 ` Daniel Krügler
2021-10-03 9:07 ` Jonathan Wakely [this message]
2021-10-04 14:26 ` Jonathan Wakely
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