From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1888) id 1664F3858D20; Thu, 9 Mar 2023 18:35:26 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1664F3858D20 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1678386926; bh=jqna5S5faHiF9LcUDN+ZraRDBo+D48hU9TlnDyjnJ7w=; h=From:To:Subject:Date:From; b=djs/0QxawQqkrvd9D4TDj4Onq/vLzR01pZXRgnhAB27hmBHKfnCVGf4qJgQvho38D oR29UTv3x2k/GNohGrfWdjgGYyJnTnEa5uDQQjdYCvOFZeq9UN+bTivNrHkm+TPUQH IkfbVwhKS9tkw7P9+ia6nUaqVdp2z5qsPqmYCcz4= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Patrick Palka To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r13-6560] libstdc++: Make views::single/iota/istream SFINAE-friendly [PR108362] X-Act-Checkin: gcc X-Git-Author: Patrick Palka X-Git-Refname: refs/heads/master X-Git-Oldrev: c6232ba229a4fcd453b50f11351fcbd35296809c X-Git-Newrev: 95827e1b9f7d5dd5a697bd60292e3876a7e8c15c Message-Id: <20230309183526.1664F3858D20@sourceware.org> Date: Thu, 9 Mar 2023 18:35:26 +0000 (GMT) List-Id: https://gcc.gnu.org/g:95827e1b9f7d5dd5a697bd60292e3876a7e8c15c commit r13-6560-g95827e1b9f7d5dd5a697bd60292e3876a7e8c15c Author: Patrick Palka Date: Thu Mar 9 13:35:04 2023 -0500 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/iota_view.cc (test07): New test. * testsuite/std/ranges/istream_view.cc (test08): New test. * testsuite/std/ranges/single_view.cc (test07): New test. Diff: --- libstdc++-v3/include/std/ranges | 39 ++++++++++++++++------ .../testsuite/std/ranges/iota/iota_view.cc | 10 ++++++ libstdc++-v3/testsuite/std/ranges/istream_view.cc | 12 +++++++ libstdc++-v3/testsuite/std/ranges/single_view.cc | 13 ++++++++ 4 files changed, 64 insertions(+), 10 deletions(-) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 0a65d74bb5b..867844e9e12 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -675,30 +675,41 @@ namespace views template inline constexpr empty_view<_Tp> empty{}; - struct _Single + namespace __detail { template - [[nodiscard]] + concept __can_single_view + = requires { single_view>(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>(std::forward<_Tp>(__e)))) { return single_view>(std::forward<_Tp>(__e)); } }; inline constexpr _Single single{}; + namespace __detail + { + template + concept __can_iota_view = requires { iota_view(std::declval<_Args>()...); }; + } // namespace __detail + struct _Iota { - template - [[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 - [[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 + concept __can_istream_view = requires (_Up __e) { + basic_istream_view<_Tp, typename _Up::char_type, typename _Up::traits_type>(__e); + }; + } // namespace __detail + template struct _Istream { template - [[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> { 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 2dd17113536..0d2eaf1d0c2 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 +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 26f109fdeaa..cc1c3e006b9 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 +concept can_istream_view = requires (U u) { views::istream(u); }; + +void +test08() +{ + // Verify SFINAE behavior. + struct S { }; + static_assert(!can_istream_view); +} + 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 063caeb8785..38a3946ca43 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 +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(); }