PR libstdc++/80762 avoid ambiguous __constructible_from<void, void>

Ensure we don't try to instantiate __is_constructible_from<void, void>,
because there are two partial specializations that are equally good
matches.

	PR libstdc++/80762
	* include/bits/fs_path.h (path::_Path): Use remove_cv_t and is_void.
	* include/experimental/bits/fs_path.h (path::_Path): Likewise.
	* testsuite/27_io/filesystem/path/construct/80762.cc: New test.
	* testsuite/experimental/filesystem/path/construct/80762.cc: New test.

From-SVN: r267056
This commit is contained in:
Jonathan Wakely 2018-12-12 16:13:43 +00:00 committed by Jonathan Wakely
parent 5da5fefeeb
commit 6b7c0b5559
5 changed files with 70 additions and 2 deletions

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@ -1,3 +1,11 @@
2018-12-12 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/80762
* include/bits/fs_path.h (path::_Path): Use remove_cv_t and is_void.
* include/experimental/bits/fs_path.h (path::_Path): Likewise.
* testsuite/27_io/filesystem/path/construct/80762.cc: New test.
* testsuite/experimental/filesystem/path/construct/80762.cc: New test.
2018-12-12 Jakub Jelinek <jakub@redhat.com>
P0595R2 - is_constant_evaluated

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@ -110,7 +110,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
template<typename _Tp1, typename _Tp2 = void>
using _Path = typename
std::enable_if<__and_<__not_<is_same<_Tp1, path>>,
std::enable_if<__and_<__not_<is_same<remove_cv_t<_Tp1>, path>>,
__not_<is_void<_Tp1>>,
__constructible_from<_Tp1, _Tp2>>::value,
path>::type;

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@ -125,7 +125,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
template<typename _Tp1, typename _Tp2 = void>
using _Path = typename
std::enable_if<__and_<__not_<is_same<_Tp1, path>>,
std::enable_if<__and_<__not_<is_same<typename remove_cv<_Tp1>::type,
path>>,
__not_<is_void<_Tp1>>,
__constructible_from<_Tp1, _Tp2>>::value,
path>::type;

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@ -0,0 +1,29 @@
// Copyright (C) 2018 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
// <http://www.gnu.org/licenses/>.
// { dg-options "-std=gnu++17" }
// { dg-do compile { target c++17 } }
#include <filesystem>
using std::filesystem::path;
static_assert( !std::is_constructible_v<path, void> );
static_assert( !std::is_constructible_v<path, volatile path> );
static_assert( !std::is_constructible_v<path, volatile path&> );
static_assert( !std::is_constructible_v<path, const volatile path> );
static_assert( !std::is_constructible_v<path, const volatile path&> );

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@ -0,0 +1,28 @@
// Copyright (C) 2018 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
// <http://www.gnu.org/licenses/>.
// { dg-do compile { target c++11 } }
#include <experimental/filesystem>
using std::experimental::filesystem::path;
static_assert( !std::is_constructible<path, void>::value, "" );
static_assert( !std::is_constructible<path, volatile path>::value, "" );
static_assert( !std::is_constructible<path, volatile path&>::value, "" );
static_assert( !std::is_constructible<path, const volatile path>::value, "" );
static_assert( !std::is_constructible<path, const volatile path&>::value, "" );