[Bug libstdc++/121956] tuple-or-pair to just tuple part was missed from P2165R4

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121956

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:0c762f79a9e7bbd8d8fc5e639d53e43d9e331299

commit r16-3911-g0c762f79a9e7bbd8d8fc5e639d53e43d9e331299
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Sep 16 13:41:20 2025 +0100

    libstdc++: Fix missing change to views::pairwise from P2165R4 [PR121956]

    ranges::adjacent_view::_Iterator::value_type should have been changed by
    r14-8710-g65b4cba9d6a9ff to always produce std::tuple, even for the
    N == 2 views::pairwise specialization.

    libstdc++-v3/ChangeLog:

            PR libstdc++/121956
            * include/std/ranges (adjacent_view::_Iterator::value_type):
            Always define as std::tuple<T, N>, not std::pair<T, T>.
            * testsuite/std/ranges/adaptors/adjacent/1.cc: Check value type
            of views::pairwise.

    Reviewed-by: Patrick Palka <ppalka@redhat.com>