[Bug libstdc++/101263] non-propagating-cache::emplace-deref missing constexpr

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101263

--- Comment #8 from CVS 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:2c564e813c0626802e5bfb066c094933d5e6a774

commit r12-4448-g2c564e813c0626802e5bfb066c094933d5e6a774
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Oct 15 14:49:21 2021 +0100

    libstdc++: Make non-propagating-cache fully constexpr [PR101263]

    libstdc++-v3/ChangeLog:

            PR libstdc++/101263
            * include/std/ranges (__cached): New wrapper struct.
            (__non_propagating_cache): Use __cached for contained value.
            (__non_propagating_cache::_M_emplace_deref): Add constexpr. Use
            std::construct_at instead of placement new.
            * testsuite/std/ranges/adaptors/join.cc: Check constexpr works.