https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113068
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:4f54e656788be3268dd45eb036447464a937fae9 commit r14-6668-g4f54e656788be3268dd45eb036447464a937fae9 Author: Patrick Palka <ppa...@redhat.com> Date: Mon Dec 18 18:05:36 2023 -0500 libstdc++: Make ranges::to closure objects SFINAE-friendly [PR112802] This also happens to fix composition of these closure objects. PR libstdc++/112802 PR libstdc++/113068 libstdc++-v3/ChangeLog: * include/std/ranges (__detail::_To::operator()): Add constraints. (__detail::_To2::operator()): Likewise. * testsuite/std/ranges/conv/1.cc (test_sfinae): New test. (test_composition): New test.