https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93983
Bug ID: 93983
Summary: std::filesystem::path is not concept-friendly
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: lyberta at lyberta dot net
Target Milestone: ---
#include <concepts>
#include <filesystem>
struct Foo
{
Foo(const std::filesystem::path& p);
};
static_assert(std::copyable<Foo>);
Error:
In file included from <source>:1:
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/bits/stl_iterator_base_types.h:
In instantiation of 'struct std::iterator_traits<Foo>':
/opt/compiler-explorer/gcc-trunk-20200229/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 = Foo; _Iter_traits =
std::iterator_traits<Foo>]'
/opt/compiler-explorer/gcc-trunk-20200229/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 =
Foo]'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/bits/fs_path.h:115:29:
required from 'struct
std::filesystem::__cxx11::__detail::__constructible_from<Foo, void>'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:138:12:
required from 'struct std::__and_<std::__not_<std::is_void<Foo> >,
std::filesystem::__cxx11::__detail::__constructible_from<Foo, void> >'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:143:12:
required from 'struct std::__and_<std::__not_<std::is_same<Foo,
std::filesystem::__cxx11::path> >, std::__not_<std::is_void<Foo> >,
std::filesystem::__cxx11::__detail::__constructible_from<Foo, void> >'
/opt/compiler-explorer/gcc-trunk-20200229/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 = Foo; _Tp2 = void]'
/opt/compiler-explorer/gcc-trunk-20200229/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 = Foo; _Require =
<missing>]'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:901:30:
required from 'struct std::__is_constructible_impl<Foo, Foo>'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:906:12:
required from 'struct std::is_constructible<Foo, Foo>'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:3107:25:
required from 'constexpr const bool std::is_constructible_v<Foo, Foo>'
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/concepts:139:30:
required from here
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/concepts:139:30:
error: the value of 'std::is_constructible_v<Foo, Foo>' is not usable in a
constant expression
139 | = destructible<_Tp> && is_constructible_v<_Tp, _Args...>;
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/concepts:44,
from <source>:1:
/opt/compiler-explorer/gcc-trunk-20200229/include/c++/10.0.1/type_traits:3107:25:
note: 'std::is_constructible_v<Foo, Foo>' used in its own initializer
3107 | inline constexpr bool is_constructible_v =
| ^~~~~~~~~~~~~~~~~~
