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author | Patrick Palka <ppalka@redhat.com> | 2023-03-09 13:35:04 -0500 |
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committer | Patrick Palka <ppalka@redhat.com> | 2023-04-29 09:46:06 -0400 |
commit | 7d0cddced0ff101f5f59ceb2a45e7f145ff973ac (patch) | |
tree | b50af43c88b406ecbf3a787058f8f518354e69d4 | |
parent | 1539af7fe0d77e8b56cb58bd757c304833b3bac3 (diff) | |
download | gcc-7d0cddced0ff101f5f59ceb2a45e7f145ff973ac.tar.gz |
libstdc++: Make views::single/iota/istream SFINAE-friendly [PR108362]
PR libstdc++/108362
libstdc++-v3/ChangeLog:
* include/std/ranges (__detail::__can_single_view): New concept.
(_Single::operator()): Constrain it. Move [[nodiscard]] to the
end of the function declarator.
(__detail::__can_iota_view): New concept.
(_Iota::operator()): Constrain it. Move [[nodiscard]] to the
end of the function declarator.
(__detail::__can_istream_view): New concept.
(_Istream::operator()): Constrain it. Move [[nodiscard]] to the
end of the function declarator.
* testsuite/std/ranges/iota/lwg3292_neg.cc: Prune "in
requirements" diagnostic.
* testsuite/std/ranges/iota/iota_view.cc (test07): New test.
* testsuite/std/ranges/istream_view.cc (test08): New test.
* testsuite/std/ranges/single_view.cc (test07): New test.
(cherry picked from commit 95827e1b9f7d5dd5a697bd60292e3876a7e8c15c)
-rw-r--r-- | libstdc++-v3/include/std/ranges | 39 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc | 10 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/std/ranges/iota/lwg3292_neg.cc | 1 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/std/ranges/istream_view.cc | 12 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/std/ranges/single_view.cc | 13 |
5 files changed, 65 insertions, 10 deletions
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 3e71ecb32b7..443fe65da92 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -671,30 +671,41 @@ 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)); } }; @@ -791,13 +802,21 @@ 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 a4825021d1d..cf8ec7e9ae0 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/iota/lwg3292_neg.cc b/libstdc++-v3/testsuite/std/ranges/iota/lwg3292_neg.cc index a6c73813804..373bdfe270b 100644 --- a/libstdc++-v3/testsuite/std/ranges/iota/lwg3292_neg.cc +++ b/libstdc++-v3/testsuite/std/ranges/iota/lwg3292_neg.cc @@ -38,3 +38,4 @@ test01() // { dg-prune-output "no match" } // { dg-prune-output "deduction failed" } // { dg-prune-output "constraint failure" } +// { dg-prune-output "in requirements" } diff --git a/libstdc++-v3/testsuite/std/ranges/istream_view.cc b/libstdc++-v3/testsuite/std/ranges/istream_view.cc index 37fde30a4a4..95de016ed67 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 ba9e2f91850..9d5662841b4 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(); } |