From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1888) id 9E83D385DC1F; Thu, 1 Feb 2024 20:03:56 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9E83D385DC1F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1706817836; bh=jWYvgBI50tV6aFk3QBNGGZaGehfkGwoa9IKhrA4ClQU=; h=From:To:Subject:Date:From; b=FdDz2cS8NCceLg4Z3q4uUsFcQj0c8cnrCl620au18kHJ/ptQO8Bgo02ChW6AkXMsS hxTSWh8viY4LP3q4L/8m05yd6HINXQQx9OBj6tvqJivPNxEWvvKohs+RrbAgrAOD3n Eo6k6VhjIOZHVsLT4RLn9k4jMq1+QA/+OsRs8Jtw= 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 r14-8709] libstdc++/pair: Factor out const-assignability helper for C++20 X-Act-Checkin: gcc X-Git-Author: Patrick Palka X-Git-Refname: refs/heads/master X-Git-Oldrev: b14209715e659f6d3ca0f9eef9a4851e7bd6e373 X-Git-Newrev: 87d162383ed68c55311a55784f6b40e979945c00 Message-Id: <20240201200356.9E83D385DC1F@sourceware.org> Date: Thu, 1 Feb 2024 20:03:56 +0000 (GMT) List-Id: https://gcc.gnu.org/g:87d162383ed68c55311a55784f6b40e979945c00 commit r14-8709-g87d162383ed68c55311a55784f6b40e979945c00 Author: Patrick Palka Date: Thu Feb 1 14:56:02 2024 -0500 libstdc++/pair: Factor out const-assignability helper for C++20 This is consistent with std::tuple's __const_assignable helper, and will be useful for implementing the new pair::operator= overloads from P2165R4. libstdc++-v3/ChangeLog: * include/bits/stl_pair.h (pair::_S_const_assignable): Define, factored out from ... (pair::operator=): ... the constraints of the const overloads. Reviewed-by: Jonathan Wakely Diff: --- libstdc++-v3/include/bits/stl_pair.h | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h index acd0c7b58f91..b81b479ad43a 100644 --- a/libstdc++-v3/include/bits/stl_pair.h +++ b/libstdc++-v3/include/bits/stl_pair.h @@ -404,6 +404,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return false; } + template + static constexpr bool + _S_const_assignable() + { + if constexpr (is_assignable_v) + return is_assignable_v; + return false; + } + template static constexpr bool _S_nothrow_assignable() @@ -468,8 +477,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Copy assignment operator (const) constexpr const pair& operator=(const pair& __p) const - requires is_copy_assignable_v - && is_copy_assignable_v + requires (_S_const_assignable()) { first = __p.first; second = __p.second; @@ -479,8 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Move assignment operator (const) constexpr const pair& operator=(pair&& __p) const - requires is_assignable_v - && is_assignable_v + requires (_S_const_assignable()) { first = std::forward(__p.first); second = std::forward(__p.second); @@ -491,8 +498,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template constexpr const pair& operator=(const pair<_U1, _U2>& __p) const - requires is_assignable_v - && is_assignable_v + requires (_S_const_assignable()) { first = __p.first; second = __p.second; @@ -503,8 +509,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template constexpr const pair& operator=(pair<_U1, _U2>&& __p) const - requires is_assignable_v - && is_assignable_v + requires (_S_const_assignable<_U1, _U2>()) { first = std::forward<_U1>(__p.first); second = std::forward<_U2>(__p.second);