From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1888) id A86BE3858C50; Sat, 29 Apr 2023 14:04:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A86BE3858C50 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1682777043; bh=KUGWAnVLah6tQ9yQq1ypqrvHTKZVAZUpGM4695hZgYw=; h=From:To:Subject:Date:From; b=OEzZcYhb2nvQM2v3uoGnS29jpry8jnWTrSOTGAlZN4xpIRjj2Ss9NWsT1b9Rr0cEJ TxcW2JgBAmtSIRP3mbW9CW2+wh9w0/pXf5Dc83KaT2TwXfa6o3XB/1Ji4y5Mgiu6Nu 5Br61x10GAlR3OwonL9KIiCKjhM9VRZBW6Fswd6o= 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 r12-9496] libstdc++: Make views::single/iota/istream SFINAE-friendly [PR108362] X-Act-Checkin: gcc X-Git-Author: Patrick Palka X-Git-Refname: refs/heads/releases/gcc-12 X-Git-Oldrev: 1539af7fe0d77e8b56cb58bd757c304833b3bac3 X-Git-Newrev: 7d0cddced0ff101f5f59ceb2a45e7f145ff973ac Message-Id: <20230429140403.A86BE3858C50@sourceware.org> Date: Sat, 29 Apr 2023 14:04:03 +0000 (GMT) List-Id: https://gcc.gnu.org/g:7d0cddced0ff101f5f59ceb2a45e7f145ff973ac commit r12-9496-g7d0cddced0ff101f5f59ceb2a45e7f145ff973ac 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/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) Diff: --- libstdc++-v3/include/std/ranges | 39 ++++++++++++++++------ .../testsuite/std/ranges/iota/iota_view.cc | 10 ++++++ .../testsuite/std/ranges/iota/lwg3292_neg.cc | 1 + libstdc++-v3/testsuite/std/ranges/istream_view.cc | 12 +++++++ 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 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)); } }; @@ -791,13 +802,21 @@ 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 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 +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 +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 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 +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(); }