https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119742
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- Also, do we want to make this change? --- a/libstdc++-v3/include/std/bitset +++ b/libstdc++-v3/include/std/bitset @@ -720,7 +720,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER namespace __bitset { -#if _GLIBCXX_HOSTED +#ifdef __cpp_lib_bitset // ...construct from string_view + template<typename _CharT> + using __string = std::basic_string_view<_CharT>; +#elif _GLIBCXX_HOSTED template<typename _CharT> using __string = std::basic_string<_CharT>; #else It's cheaper to instantiate basic_string_view than basic_string, so it seems useful.