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 <r...@gcc.gnu.org>: https://gcc.gnu.org/g:2c564e813c0626802e5bfb066c094933d5e6a774 commit r12-4448-g2c564e813c0626802e5bfb066c094933d5e6a774 Author: Jonathan Wakely <jwak...@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.