diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 0a65d74bb5bd1b4800044223cb1b9d43a0f5b802..867844e9e122007d8d6e9d59692a552401a87733 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -675,30 +675,41 @@ namespace views template<typename _Tp> inline constexpr empty_view<_Tp> empty{}; - struct _Single + namespace __detail { template<typename _Tp> - [[nodiscard]] + concept __can_single_view + = requires { single_view<decay_t<_Tp>>(std::declval<_Tp>()); }; + } // namespace __detail + + struct _Single + { + template<__detail::__can_single_view _Tp> constexpr auto - operator()(_Tp&& __e) const + operator() [[nodiscard]] (_Tp&& __e) const noexcept(noexcept(single_view<decay_t<_Tp>>(std::forward<_Tp>(__e)))) { return single_view<decay_t<_Tp>>(std::forward<_Tp>(__e)); } }; inline constexpr _Single single{}; + namespace __detail + { + template<typename... _Args> + concept __can_iota_view = requires { iota_view(std::declval<_Args>()...); }; + } // namespace __detail + struct _Iota { - template<typename _Tp> - [[nodiscard]] + template<__detail::__can_iota_view _Tp> constexpr auto - operator()(_Tp&& __e) const + operator() [[nodiscard]] (_Tp&& __e) const { return iota_view(std::forward<_Tp>(__e)); } template<typename _Tp, typename _Up> - [[nodiscard]] + requires __detail::__can_iota_view<_Tp, _Up> constexpr auto - operator()(_Tp&& __e, _Up&& __f) const + operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const { return iota_view(std::forward<_Tp>(__e), std::forward<_Up>(__f)); } }; @@ -796,13 +807,21 @@ namespace views namespace views { + namespace __detail + { + template<typename _Tp, typename _Up> + concept __can_istream_view = requires (_Up __e) { + basic_istream_view<_Tp, typename _Up::char_type, typename _Up::traits_type>(__e); + }; + } // namespace __detail + template<typename _Tp> struct _Istream { template<typename _CharT, typename _Traits> - [[nodiscard]] constexpr auto - operator()(basic_istream<_CharT, _Traits>& __e) const + operator() [[nodiscard]] (basic_istream<_CharT, _Traits>& __e) const + requires __detail::__can_istream_view<_Tp, remove_reference_t<decltype(__e)>> { return basic_istream_view<_Tp, _CharT, _Traits>(__e); } }; diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc index 2dd17113536954ec4ddfd21e16f622f709141943..0d2eaf1d0c2f89f70c008a843862d3e9c5f8f62e 100644 --- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc +++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc @@ -110,6 +110,15 @@ test06() VERIFY( std::ranges::equal(v3, w3) ); } +template<auto iota = std::views::iota> +void +test07() +{ + // Verify SFINAE behavior. + static_assert(!requires { iota(nullptr); }); + static_assert(!requires { iota(nullptr, nullptr); }); +} + int main() { @@ -119,4 +128,5 @@ main() test04(); test05(); test06(); + test07(); } diff --git a/libstdc++-v3/testsuite/std/ranges/istream_view.cc b/libstdc++-v3/testsuite/std/ranges/istream_view.cc index 26f109fdeaa3ea16387d69dc0045cc7d91591759..cc1c3e006b97507ae70f49713aa2e62b4c4afd7a 100644 --- a/libstdc++-v3/testsuite/std/ranges/istream_view.cc +++ b/libstdc++-v3/testsuite/std/ranges/istream_view.cc @@ -115,6 +115,17 @@ test07() VERIFY( sum == 10 ); } +template<class T, class U> +concept can_istream_view = requires (U u) { views::istream<T>(u); }; + +void +test08() +{ + // Verify SFINAE behavior. + struct S { }; + static_assert(!can_istream_view<S, std::istringstream>); +} + int main() { @@ -125,4 +136,5 @@ main() test05(); test06(); test07(); + test08(); } diff --git a/libstdc++-v3/testsuite/std/ranges/single_view.cc b/libstdc++-v3/testsuite/std/ranges/single_view.cc index 063caeb87852d11a1b93d3ce442c3cac04385f7d..38a3946ca43c9a45acd66833bad25ec7a6ddac35 100644 --- a/libstdc++-v3/testsuite/std/ranges/single_view.cc +++ b/libstdc++-v3/testsuite/std/ranges/single_view.cc @@ -111,6 +111,18 @@ test06() auto y = std::views::single(std::move(obj)); } +template<auto single = std::views::single> +void +test07() +{ + // Verify SFINAE behavior. + struct uncopyable { + uncopyable(); + uncopyable(const uncopyable&) = delete; + }; + static_assert(!requires { single(uncopyable{}); }); +} + int main() { test01(); @@ -119,4 +131,5 @@ int main() test04(); test05(); test06(); + test07(); }