https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113763
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #2) > I think that ctor is constexpr since https://wg21.link/N3471 > Does that have some feature test macro? That was long before we started using feature test macros. > If not, should we use constexpr conditionally for C++14 and const otherwise? Yes.
