https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93983
Paco Arjonilla <pacoarjonilla at yahoo dot es> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pacoarjonilla at yahoo dot es --- Comment #4 from Paco Arjonilla <pacoarjonilla at yahoo dot es> --- I got this error too. This is the code: #include <filesystem> #include <concepts> struct A { A() = default; A(A const&) = default; A & operator = (A const&) = default; A(std::filesystem::path); // This line triggers the error. }; static_assert(std::semiregular<A>); There is no reason why an extra constructor would affect the semiregularity of a type. $> g++ -std=c++20 In file included from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/compare:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_pair.h:65, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_algobase.h:64, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/char_traits.h:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/string:40, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/stdexcept:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/system_error:41, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_fwd.h:35, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/filesystem:44, from <source>:1: /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_iterator_base_types.h: In instantiation of 'struct std::iterator_traits<A>': /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:84:11: required by substitution of 'template<class _Iter, class _Iter_traits> using __is_path_iter_src = std::__and_<std::__or_<std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char8_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, wchar_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char16_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char32_t> >, std::is_base_of<std::input_iterator_tag, typename _Iter_traits::iterator_category> > [with _Iter = A; _Iter_traits = std::iterator_traits<A>]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:91:5: required by substitution of 'template<class _Iter> std::filesystem::__cxx11::__detail::__is_path_iter_src<_Iter> std::filesystem::__cxx11::__detail::__is_path_src(_Iter, int) [with _Iter = A]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:115:29: required from 'struct std::filesystem::__cxx11::__detail::__constructible_from<A, void>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:138:12: required from 'struct std::__and_<std::__not_<std::is_void<A> >, std::filesystem::__cxx11::__detail::__constructible_from<A, void> >' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:143:12: required from 'struct std::__and_<std::__not_<std::is_same<A, std::filesystem::__cxx11::path> >, std::__not_<std::is_void<A> >, std::filesystem::__cxx11::__detail::__constructible_from<A, void> >' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:119:11: required by substitution of 'template<class _Tp1, class _Tp2> using _Path = typename std::enable_if<std::__and_<std::__not_<std::is_same<typename std::remove_cv< <template-parameter-1-1> >::type, std::filesystem::__cxx11::path> >, std::__not_<std::is_void<typename std::remove_pointer<_Tp>::type> >, std::filesystem::__cxx11::__detail::__constructible_from<_Tp1, _Tp2> >::value, std::filesystem::__cxx11::path>::type [with _Tp1 = A; _Tp2 = void]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:219:7: required by substitution of 'template<class _Source, class _Require> std::filesystem::__cxx11::path::path(const _Source&, std::filesystem::__cxx11::path::format) [with _Source = A; _Require = <missing>]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:901:30: required from 'struct std::__is_constructible_impl<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:906:12: required from 'struct std::is_constructible<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:3091:25: required from 'constexpr const bool std::is_constructible_v<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/concepts:139:30: required from here /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/concepts:139:30: error: the value of 'std::is_constructible_v<A, A>' is not usable in a constant expression 139 | = destructible<_Tp> && is_constructible_v<_Tp, _Args...>; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/move.h:57, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/nested_exception.h:40, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/exception:148, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/stdexcept:38, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/system_error:41, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_fwd.h:35, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/filesystem:44, from <source>:1: /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:3091:25: note: 'std::is_constructible_v<A, A>' used in its own initializer 3091 | inline constexpr bool is_constructible_v = | ^~~~~~~~~~~~~~~~~~ ASM generation compiler returned: 1 In file included from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/compare:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_pair.h:65, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_algobase.h:64, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/char_traits.h:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/string:40, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/stdexcept:39, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/system_error:41, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_fwd.h:35, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/filesystem:44, from <source>:1: /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/stl_iterator_base_types.h: In instantiation of 'struct std::iterator_traits<A>': /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:84:11: required by substitution of 'template<class _Iter, class _Iter_traits> using __is_path_iter_src = std::__and_<std::__or_<std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char8_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, wchar_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char16_t>, std::is_same<typename std::remove_const<typename _Iter_traits::value_type>::type, char32_t> >, std::is_base_of<std::input_iterator_tag, typename _Iter_traits::iterator_category> > [with _Iter = A; _Iter_traits = std::iterator_traits<A>]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:91:5: required by substitution of 'template<class _Iter> std::filesystem::__cxx11::__detail::__is_path_iter_src<_Iter> std::filesystem::__cxx11::__detail::__is_path_src(_Iter, int) [with _Iter = A]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:115:29: required from 'struct std::filesystem::__cxx11::__detail::__constructible_from<A, void>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:138:12: required from 'struct std::__and_<std::__not_<std::is_void<A> >, std::filesystem::__cxx11::__detail::__constructible_from<A, void> >' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:143:12: required from 'struct std::__and_<std::__not_<std::is_same<A, std::filesystem::__cxx11::path> >, std::__not_<std::is_void<A> >, std::filesystem::__cxx11::__detail::__constructible_from<A, void> >' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:119:11: required by substitution of 'template<class _Tp1, class _Tp2> using _Path = typename std::enable_if<std::__and_<std::__not_<std::is_same<typename std::remove_cv< <template-parameter-1-1> >::type, std::filesystem::__cxx11::path> >, std::__not_<std::is_void<typename std::remove_pointer<_Tp>::type> >, std::filesystem::__cxx11::__detail::__constructible_from<_Tp1, _Tp2> >::value, std::filesystem::__cxx11::path>::type [with _Tp1 = A; _Tp2 = void]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_path.h:219:7: required by substitution of 'template<class _Source, class _Require> std::filesystem::__cxx11::path::path(const _Source&, std::filesystem::__cxx11::path::format) [with _Source = A; _Require = <missing>]' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:901:30: required from 'struct std::__is_constructible_impl<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:906:12: required from 'struct std::is_constructible<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:3091:25: required from 'constexpr const bool std::is_constructible_v<A, A>' /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/concepts:139:30: required from here /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/concepts:139:30: error: the value of 'std::is_constructible_v<A, A>' is not usable in a constant expression 139 | = destructible<_Tp> && is_constructible_v<_Tp, _Args...>; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/move.h:57, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/nested_exception.h:40, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/exception:148, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/stdexcept:38, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/system_error:41, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/bits/fs_fwd.h:35, from /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/filesystem:44, from <source>:1: /opt/compiler-explorer/gcc-trunk-20200321/include/c++/10.0.1/type_traits:3091:25: note: 'std::is_constructible_v<A, A>' used in its own initializer 3091 | inline constexpr bool is_constructible_v = | ^~~~~~~~~~~~~~~~~~