From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 4ADB93858D39; Tue, 11 Jan 2022 15:17:37 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4ADB93858D39 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r12-6483] libstdc++: Make copyable-box completely constexpr (LWG 3572) X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: 06bc1b0c539e3a60692d7432d15e701c38610f80 X-Git-Newrev: d2dc5305d87f4e6a1b861f59164c124636e2b69d Message-Id: <20220111151737.4ADB93858D39@sourceware.org> Date: Tue, 11 Jan 2022 15:17:37 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Jan 2022 15:17:37 -0000 https://gcc.gnu.org/g:d2dc5305d87f4e6a1b861f59164c124636e2b69d commit r12-6483-gd2dc5305d87f4e6a1b861f59164c124636e2b69d Author: Jonathan Wakely Date: Tue Jan 11 14:11:46 2022 +0000 libstdc++: Make copyable-box completely constexpr (LWG 3572) This LWG issue was approved at the October 2021 plenary and can be implemented now that std::optional is fully constexpr. libstdc++-v3/ChangeLog: * include/std/ranges (ranges::__detail::__box): Add constexpr to assignment operators (LWG 3572). * testsuite/std/ranges/adaptors/filter.cc: Check assignment of a view that uses copyable-box. Diff: --- libstdc++-v3/include/std/ranges | 5 ++-- .../testsuite/std/ranges/adaptors/filter.cc | 28 ++++++++++++++++++++++ 2 files changed, 31 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index c90d33c89fb..780a3633417 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -109,7 +109,8 @@ namespace ranges // _GLIBCXX_RESOLVE_LIB_DEFECTS // 3477. Simplify constraints for semiregular-box - __box& + // 3572. copyable-box should be fully constexpr + constexpr __box& operator=(const __box& __that) noexcept(is_nothrow_copy_constructible_v<_Tp>) requires (!copyable<_Tp>) @@ -124,7 +125,7 @@ namespace ranges return *this; } - __box& + constexpr __box& operator=(__box&& __that) noexcept(is_nothrow_move_constructible_v<_Tp>) requires (!movable<_Tp>) diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc index b8d081e1d5e..ed5a01ca595 100644 --- a/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc @@ -140,6 +140,33 @@ test06() static_assert(!requires { views::all | filter; }); } +constexpr bool +test07() +{ + struct Pred + { + constexpr Pred() { } + constexpr Pred(const Pred&) { } + constexpr Pred(Pred&&) { } + // These make it non-copyable, so non-copyable-box will provide + // assignment. + Pred& operator=(const Pred&) = delete; + Pred& operator=(Pred&&) = delete; + + bool operator()(int i) const { return i < 10; } + }; + + int i = 0; + ranges::filter_view v(views::single(i), Pred{}); + // LWG 3572. copyable-box should be fully constexpr + v = v; + v = std::move(v); + + return true; +} + +static_assert( test07() ); + int main() { @@ -150,4 +177,5 @@ main() test05(); test05(); test06(); + test07(); }