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libstdc++: Simplify filesystem::path SFINAE constraints
This replaces the filesystem::__detail::_Path SFINAE helper with two separate helpers, _Path and _Path2. This avoids having one helper which tries to check two different sets of requirements. The _Path helper now uses variable templates instead of a set of overloaded functions to detect specializations of basic_string or basic_string_view. The __not_<is_void<remove_pointer_t<_Tp1>> check is not necessary in C++20 because iterator_traits<void*> is now empty. For C++17 replace that check with a __safe_iterator_traits helper with partial specializations for void pointers. Finally, the __is_encoded_char check no longer uses remove_const_t, which means that iterators with a const value_type will no longer be accepted as arguments for path creation. Such iterators resulted in undefined behaviour anyway, so it's still conforming to reject them in the constraint checks. * include/bits/fs_path.h (filesystem::__detail::__is_encoded_char): Replace alias template with variable template. Don't remove const. (filesystem::__detail::__is_path_src): Replace overloaded function template with variable template and specializations. (filesystem::__detail::__is_path_iter_src): Replace alias template with class template. (filesystem::__detail::_Path): Use __is_path_src. Remove support for iterator pairs. (filesystem::__detail::_Path2): New alias template for checking InputIterator requirements. (filesystem::__detail::__constructible_from): Remove. (filesystem::path): Replace _Path<Iter, Iter> with _Path2<Iter>. * testsuite/27_io/filesystem/path/construct/80762.cc: Check with two constructor arguments of void and void* types.
This commit is contained in:
Jonathan Wakely
parent
804254edb4
commit
988b853f9c
@ -1,3 +1,20 @@
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2020-05-23 Jonathan Wakely <jwakely@redhat.com>
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* include/bits/fs_path.h (filesystem::__detail::__is_encoded_char):
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Replace alias template with variable template. Don't remove const.
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(filesystem::__detail::__is_path_src): Replace overloaded function
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template with variable template and specializations.
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(filesystem::__detail::__is_path_iter_src): Replace alias template
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with class template.
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(filesystem::__detail::_Path): Use __is_path_src. Remove support for
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iterator pairs.
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(filesystem::__detail::_Path2): New alias template for checking
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InputIterator requirements.
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(filesystem::__detail::__constructible_from): Remove.
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(filesystem::path): Replace _Path<Iter, Iter> with _Path2<Iter>.
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* testsuite/27_io/filesystem/path/construct/80762.cc: Check with two
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constructor arguments of void and void* types.
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2020-05-21 Matthias Kretz <kretz@kde.org>
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* testsuite/Makefile.am: Remove dup target_triplet and set tool,
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@ -73,58 +73,87 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
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namespace __detail
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{
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template<typename _CharT>
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using __is_encoded_char = __is_one_of<remove_const_t<_CharT>,
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char,
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inline constexpr bool __is_encoded_char = false;
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template<>
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inline constexpr bool __is_encoded_char<char> = true;
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#ifdef _GLIBCXX_USE_CHAR8_T
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char8_t,
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template<>
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inline constexpr bool __is_encoded_char<char8_t> = true;
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#endif
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#if _GLIBCXX_USE_WCHAR_T
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wchar_t,
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template<>
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inline constexpr bool __is_encoded_char<wchar_t> = true;
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#endif
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char16_t, char32_t>;
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template<typename _Iter,
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typename _Iter_traits = std::iterator_traits<_Iter>>
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using __is_path_iter_src
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= __and_<__is_encoded_char<typename _Iter_traits::value_type>,
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std::is_base_of<std::input_iterator_tag,
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typename _Iter_traits::iterator_category>>;
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template<>
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inline constexpr bool __is_encoded_char<char16_t> = true;
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template<>
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inline constexpr bool __is_encoded_char<char32_t> = true;
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#if __cpp_concepts >= 201907L
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template<typename _Iter>
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static __is_path_iter_src<_Iter>
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__is_path_src(_Iter, int);
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template<typename _CharT, typename _Traits, typename _Alloc>
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static __is_encoded_char<_CharT>
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__is_path_src(const basic_string<_CharT, _Traits, _Alloc>&, int);
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template<typename _CharT, typename _Traits>
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static __is_encoded_char<_CharT>
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__is_path_src(const basic_string_view<_CharT, _Traits>&, int);
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template<typename _Unknown>
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static std::false_type
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__is_path_src(const _Unknown&, ...);
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template<typename _Tp1, typename _Tp2>
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struct __constructible_from;
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using __safe_iterator_traits = std::iterator_traits<_Iter>;
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#else
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template<typename _Iter>
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struct __constructible_from<_Iter, _Iter>
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: __is_path_iter_src<_Iter>
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struct __safe_iterator_traits : std::iterator_traits<_Iter>
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{ };
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// Protect against ill-formed iterator_traits specializations in C++17
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template<> struct __safe_iterator_traits<void*> { };
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template<> struct __safe_iterator_traits<const void*> { };
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template<> struct __safe_iterator_traits<volatile void*> { };
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template<> struct __safe_iterator_traits<const volatile void*> { };
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#endif
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template<typename _Iter_traits, typename = void>
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struct __is_path_iter_src
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: false_type
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{ };
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template<typename _Iter_traits>
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struct __is_path_iter_src<_Iter_traits,
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void_t<typename _Iter_traits::value_type>>
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: bool_constant<__is_encoded_char<typename _Iter_traits::value_type>>
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{ };
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template<typename _Source>
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struct __constructible_from<_Source, void>
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: decltype(__is_path_src(std::declval<_Source>(), 0))
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{ };
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inline constexpr bool __is_path_src
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= __is_path_iter_src<iterator_traits<decay_t<_Source>>>::value;
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template<typename _Tp1, typename _Tp2 = void>
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using _Path = typename
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std::enable_if<__and_<__not_<is_same<remove_cv_t<_Tp1>, path>>,
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__not_<is_void<remove_pointer_t<_Tp1>>>,
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__constructible_from<_Tp1, _Tp2>>::value,
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path>::type;
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template<>
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inline constexpr bool __is_path_src<path> = false;
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template<>
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inline constexpr bool __is_path_src<volatile path> = false;
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template<>
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inline constexpr bool __is_path_src<void*> = false;
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template<>
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inline constexpr bool __is_path_src<const void*> = false;
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template<>
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inline constexpr bool __is_path_src<volatile void*> = false;
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template<>
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inline constexpr bool __is_path_src<const volatile void*> = false;
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template<typename _CharT, typename _Traits, typename _Alloc>
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inline constexpr bool
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__is_path_src<basic_string<_CharT, _Traits, _Alloc>>
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= __is_encoded_char<_CharT>;
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template<typename _CharT, typename _Traits>
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inline constexpr bool
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__is_path_src<basic_string_view<_CharT, _Traits>>
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= __is_encoded_char<_CharT>;
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// SFINAE constraint for Source parameters as required by [fs.path.req].
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template<typename _Tp>
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using _Path = enable_if_t<__is_path_src<_Tp>, path>;
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// SFINAE constraint for InputIterator parameters as required by [fs.req].
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template<typename _Iter, typename _Tr = __safe_iterator_traits<_Iter>>
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using _Path2 = enable_if_t<__is_path_iter_src<_Tr>::value, path>;
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template<typename _Source>
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static _Source
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@ -227,7 +256,7 @@ namespace __detail
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{ _M_split_cmpts(); }
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template<typename _InputIterator,
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typename _Require = __detail::_Path<_InputIterator, _InputIterator>>
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typename _Require = __detail::_Path2<_InputIterator>>
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path(_InputIterator __first, _InputIterator __last, format = auto_format)
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: _M_pathname(_S_convert(__first, __last))
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{ _M_split_cmpts(); }
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@ -241,8 +270,8 @@ namespace __detail
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{ _M_split_cmpts(); }
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template<typename _InputIterator,
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typename _Require = __detail::_Path<_InputIterator, _InputIterator>,
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typename _Require2 = __detail::__value_type_is_char<_InputIterator>>
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typename _Require = __detail::_Path2<_InputIterator>,
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typename _Req2 = __detail::__value_type_is_char<_InputIterator>>
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path(_InputIterator __first, _InputIterator __last, const locale& __loc,
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format = auto_format)
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: _M_pathname(_S_convert_loc(__first, __last, __loc))
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@ -268,7 +297,7 @@ namespace __detail
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{ return *this = path(__source); }
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template<typename _InputIterator>
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__detail::_Path<_InputIterator, _InputIterator>&
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__detail::_Path2<_InputIterator>&
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assign(_InputIterator __first, _InputIterator __last)
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{ return *this = path(__first, __last); }
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@ -295,7 +324,7 @@ namespace __detail
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}
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template<typename _InputIterator>
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__detail::_Path<_InputIterator, _InputIterator>&
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__detail::_Path2<_InputIterator>&
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append(_InputIterator __first, _InputIterator __last)
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{
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_M_append(_S_convert(__first, __last));
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@ -315,7 +344,7 @@ namespace __detail
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operator+=(_Source const& __x) { return concat(__x); }
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template<typename _CharT>
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__detail::_Path<_CharT*, _CharT*>&
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__detail::_Path2<_CharT*>&
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operator+=(_CharT __x);
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template<typename _Source>
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@ -328,7 +357,7 @@ namespace __detail
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}
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template<typename _InputIterator>
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__detail::_Path<_InputIterator, _InputIterator>&
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__detail::_Path2<_InputIterator>&
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concat(_InputIterator __first, _InputIterator __last)
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{
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_M_concat(_S_convert(__first, __last));
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@ -695,7 +724,7 @@ namespace __detail
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* @relates std::filesystem::path
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*/
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template<typename _InputIterator,
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typename _Require = __detail::_Path<_InputIterator, _InputIterator>,
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typename _Require = __detail::_Path2<_InputIterator>,
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typename _CharT
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= __detail::__value_type_is_char_or_char8_t<_InputIterator>>
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inline path
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@ -1000,7 +1029,7 @@ namespace __detail
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}
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template<typename _CharT>
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inline __detail::_Path<_CharT*, _CharT*>&
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inline __detail::_Path2<_CharT*>&
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path::operator+=(_CharT __x)
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{
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auto* __addr = std::__addressof(__x);
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@ -37,3 +37,9 @@ static_assert( !std::is_constructible_v<path, const volatile void*> );
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static_assert( !std::is_constructible_v<path, void*&> );
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static_assert( !std::is_constructible_v<path, void* const&> );
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static_assert( !std::is_constructible_v<path, const void* const&> );
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static_assert( !std::is_constructible_v<path, void, void> );
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static_assert( !std::is_constructible_v<path, void*, void*> );
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static_assert( !std::is_constructible_v<path, const void*, void*> );
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static_assert( !std::is_constructible_v<path, volatile void*, void*> );
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static_assert( !std::is_constructible_v<path, const volatile void*, void*> );
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