From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 829833861802; Mon, 29 Mar 2021 20:04:02 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 829833861802 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 r10-9601] libstdc++: Define converting assignment operator for std::move_iterator X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/releases/gcc-10 X-Git-Oldrev: 253751d1115710f5f150656fb13705282076a987 X-Git-Newrev: e3eb2a4f4ec789a7c22cd7fbb4fce42761684a60 Message-Id: <20210329200402.829833861802@sourceware.org> Date: Mon, 29 Mar 2021 20:04:02 +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: Mon, 29 Mar 2021 20:04:02 -0000 https://gcc.gnu.org/g:e3eb2a4f4ec789a7c22cd7fbb4fce42761684a60 commit r10-9601-ge3eb2a4f4ec789a7c22cd7fbb4fce42761684a60 Author: Jonathan Wakely Date: Tue Jun 9 22:16:24 2020 +0100 libstdc++: Define converting assignment operator for std::move_iterator As clarified by LWG 3265, std::move_iterator is supposed to have an assignment operator that converts from a different specialization of std::move_iterator, which performs an assignment. That has always been missing from libstdc++, so assigning a different type actually performs a converting construction, then an assignment. This is non-conforming for the (fairly contrived) case where the converting assignment is well-formed but the converting construction is not. * include/bits/stl_iterator.h (move_iterator::operator=): Define. * testsuite/24_iterators/move_iterator/dr3265.cc: New test. (cherry picked from commit 733167f9d5ca5b9417559b7362d91e967be95a01) Diff: --- libstdc++-v3/include/bits/stl_iterator.h | 8 ++++ .../testsuite/24_iterators/move_iterator/dr3265.cc | 51 ++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h index 429df10c190..d950e896928 100644 --- a/libstdc++-v3/include/bits/stl_iterator.h +++ b/libstdc++-v3/include/bits/stl_iterator.h @@ -1328,6 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION move_iterator(const move_iterator<_Iter>& __i) : _M_current(__i.base()) { } + template + _GLIBCXX17_CONSTEXPR + move_iterator& operator=(const move_iterator<_Iter>& __i) + { + _M_current = __i.base(); + return *this; + } + #if __cplusplus <= 201703L _GLIBCXX17_CONSTEXPR iterator_type base() const diff --git a/libstdc++-v3/testsuite/24_iterators/move_iterator/dr3265.cc b/libstdc++-v3/testsuite/24_iterators/move_iterator/dr3265.cc new file mode 100644 index 00000000000..05327e979ac --- /dev/null +++ b/libstdc++-v3/testsuite/24_iterators/move_iterator/dr3265.cc @@ -0,0 +1,51 @@ +// Copyright (C) 2020 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// . + +// { dg-do compile { target c++11 } } + +#include + +struct Iter +{ + using iterator_category = std::forward_iterator_tag; + using value_type = int; + using pointer = int*; + using reference = int&; + using difference_type = std::ptrdiff_t; + + Iter(); + + // Construction from int* is not valid: + Iter(int*) = delete; + + // Assignment from int* is valid: + Iter& operator=(int*); + + Iter& operator++(); + Iter operator++(int); + int& operator*() const; + int* operator->() const; + + template friend bool operator==(Iter, Iter); +}; + +void test01() +{ + std::move_iterator m; + int i = 0; + m = std::make_move_iterator(&i); // Should use assignment not construction +}