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re PR libstdc++/77537 (pair constructors do not properly SFINAE) 

PR libstdc++/77537
	Implement LWG 2729 for pair.
	* include/bits/stl_pair.h (_PCC): New.
	(_ConstructiblePair, _ImplicitlyConvertiblePair):
	Turn into static member functions of _PCC.
	(_MoveConstructiblePair, _ImplicitlyMoveConvertiblePair): Likewise.
	(_PCCP): New.
	(pair(const _T1&, const _T2&)): Adjust.
	(_PCCFP): New.
	(pair(const pair<_U1, _U2>&)): Adjust.
	(pair(_U1&&, const _T2&)): Likewise.
	(pair(const _T1&, _U2&&)): Likewise.
	(pair(_U1&&, _U2&&)): Likewise.
	(pair(pair<_U1, _U2>&&)): Likewise.
	(operator=(const pair&)): Make conditionally deleted.
	(operator=(pair&&)): Make conditionally suppressed.
	(operator=(const pair<_U1, _U2>&)): Constrain.
	(operator=(pair<_U1, _U2>&&): Likewise.
	* include/std/type_traits (__nonesuch): New.
	* testsuite/20_util/pair/traits.cc: New.

From-SVN: r240322
This commit is contained in:
Ville Voutilainen 2016-09-21 19:48:35 +03:00 committed by Ville Voutilainen
parent d43b4ccc37
commit f524d5b34a
4 changed files with 260 additions and 86 deletions
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23
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,26 @@
2016-09-21 Ville Voutilainen <ville.voutilainen@gmail.com>
PR libstdc++/77537
Implement LWG 2729 for pair.
* include/bits/stl_pair.h (_PCC): New.
(_ConstructiblePair, _ImplicitlyConvertiblePair):
Turn into static member functions of _PCC.
(_MoveConstructiblePair, _ImplicitlyMoveConvertiblePair): Likewise.
(_PCCP): New.
(pair(const _T1&, const _T2&)): Adjust.
(_PCCFP): New.
(pair(const pair<_U1, _U2>&)): Adjust.
(pair(_U1&&, const _T2&)): Likewise.
(pair(const _T1&, _U2&&)): Likewise.
(pair(_U1&&, _U2&&)): Likewise.
(pair(pair<_U1, _U2>&&)): Likewise.
(operator=(const pair&)): Make conditionally deleted.
(operator=(pair&&)): Make conditionally suppressed.
(operator=(const pair<_U1, _U2>&)): Constrain.
(operator=(pair<_U1, _U2>&&): Likewise.
* include/std/type_traits (__nonesuch): New.
* testsuite/20_util/pair/traits.cc: New.
2016-09-20 Ville Voutilainen <ville.voutilainen@gmail.com>
PR libstdc++/77619

222
libstdc++-v3/include/bits/stl_pair.h
View File

@ -88,52 +88,95 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Concept utility functions, reused in conditionally-explicit
// constructors.
// See PR 70437, don't look at is_constructible or
// is_convertible if the decayed types are the same to
// is_convertible if the types are the same to
// avoid querying those properties for incomplete types.
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ConstructiblePair()
template <bool, typename _T1, typename _T2>
struct _PCC
{
return __and_<__or_<is_same<typename decay<_T1>::type,
typename decay<_U1>::type>,
is_constructible<_T1, const _U1&>>,
__or_<is_same<typename decay<_T2>::type,
typename decay<_U2>::type>,
is_constructible<_T2, const _U2&>>>::value;
template <typename _U1, typename _U2>
static constexpr bool _ConstructiblePair()
{
return __and_<is_constructible<_T1, const _U1&>,
is_constructible<_T2, const _U2&>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ImplicitlyConvertiblePair()
template <typename _U1, typename _U2>
static constexpr bool _ImplicitlyConvertiblePair()
{
return __and_<__or_<is_same<typename decay<_T1>::type,
typename decay<_U1>::type>,
is_convertible<const _U1&, _T1>>,
__or_<is_same<typename decay<_T2>::type,
typename decay<_U2>::type>,
is_convertible<const _U2&, _T2>>>::value;
return __and_<is_convertible<const _U1&, _T1>,
is_convertible<const _U2&, _T2>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _MoveConstructiblePair()
template <typename _U1, typename _U2>
static constexpr bool _MoveConstructiblePair()
{
return __and_<__or_<is_same<typename decay<_T1>::type,
typename decay<_U1>::type>,
is_constructible<_T1, _U1&&>>,
__or_<is_same<typename decay<_T2>::type,
typename decay<_U2>::type>,
is_constructible<_T2, _U2&&>>>::value;
return __and_<is_constructible<_T1, _U1&&>,
is_constructible<_T2, _U2&&>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ImplicitlyMoveConvertiblePair()
template <typename _U1, typename _U2>
static constexpr bool _ImplicitlyMoveConvertiblePair()
{
return __and_<__or_<is_same<typename decay<_T1>::type,
typename decay<_U1>::type>,
is_convertible<_U1&&, _T1>>,
__or_<is_same<typename decay<_T2>::type,
typename decay<_U2>::type>,
is_convertible<_U2&&, _T2>>>::value;
return __and_<is_convertible<_U1&&, _T1>,
is_convertible<_U2&&, _T2>>::value;
}
template <bool __implicit, typename _U1, typename _U2>
static constexpr bool _CopyMovePair()
{
using __do_converts = __and_<is_convertible<const _U1&, _T1>,
is_convertible<_U2&&, _T2>>;
using __converts = typename conditional<__implicit,
__do_converts,
__not_<__do_converts>>::type;
return __and_<is_constructible<_T1, const _U1&>,
is_constructible<_T2, _U2&&>,
__converts
>::value;
}
template <bool __implicit, typename _U1, typename _U2>
static constexpr bool _MoveCopyPair()
{
using __do_converts = __and_<is_convertible<_U1&&, _T1>,
is_convertible<const _U2&, _T2>>;
using __converts = typename conditional<__implicit,
__do_converts,
__not_<__do_converts>>::type;
return __and_<is_constructible<_T1, _U1&&>,
is_constructible<_T2, const _U2&&>,
__converts
>::value;
}
};
template <typename _T1, typename _T2>
struct _PCC<false, _T1, _T2>
{
template <typename _U1, typename _U2>
static constexpr bool _ConstructiblePair()
{
return false;
}
template <typename _U1, typename _U2>
static constexpr bool _ImplicitlyConvertiblePair()
{
return false;
}
template <typename _U1, typename _U2>
static constexpr bool _MoveConstructiblePair()
{
return false;
}
template <typename _U1, typename _U2>
static constexpr bool _ImplicitlyMoveConvertiblePair()
{
return false;
}
};
#endif
@ -186,16 +229,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
pair(const _T1& __a, const _T2& __b)
: first(__a), second(__b) { }
#else
// Shortcut for constraining the templates that don't take pairs.
using _PCCP = _PCC<true, _T1, _T2>;
template<typename _U1 = _T1, typename _U2=_T2, typename
enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
&& _ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
enable_if<_PCCP::template
_ConstructiblePair<_U1, _U2>()
&& _PCCP::template
_ImplicitlyConvertiblePair<_U1, _U2>(),
bool>::type=true>
constexpr pair(const _T1& __a, const _T2& __b)
: first(__a), second(__b) { }
template<typename _U1 = _T1, typename _U2=_T2, typename
enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
&& !_ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
enable_if<_PCCP::template
_ConstructiblePair<_U1, _U2>()
&& !_PCCP::template
_ImplicitlyConvertiblePair<_U1, _U2>(),
bool>::type=false>
explicit constexpr pair(const _T1& __a, const _T2& __b)
: first(__a), second(__b) { }
@ -207,16 +257,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
#else
// Shortcut for constraining the templates that take pairs.
template <typename _U1, typename _U2>
using _PCCFP = _PCC<!is_same<_T1, _U1>::value
|| !is_same<_T2, _U2>::value,
_T1, _T2>;
template<typename _U1, typename _U2, typename
enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
&& _ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
enable_if<_PCCFP<_U1, _U2>::template
_ConstructiblePair<_U1, _U2>()
&& _PCCFP<_U1, _U2>::template
_ImplicitlyConvertiblePair<_U1, _U2>(),
bool>::type=true>
constexpr pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
template<typename _U1, typename _U2, typename
enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
&& !_ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
enable_if<_PCCFP<_U1, _U2>::template
_ConstructiblePair<_U1, _U2>()
&& !_PCCFP<_U1, _U2>::template
_ImplicitlyConvertiblePair<_U1, _U2>(),
bool>::type=false>
explicit constexpr pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
@ -226,75 +286,67 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// DR 811.
template<typename _U1, typename
enable_if<_ConstructiblePair<_T2, _T2, _T2, _T2>()
&& _MoveConstructiblePair<_T1, _T2, _U1, _T2>()
&& _ImplicitlyConvertiblePair<_T2, _T2, _T2, _T2>()
&& _ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _T2>(),
enable_if<_PCCP::template
_MoveCopyPair<true, _U1, _T2>(),
bool>::type=true>
constexpr pair(_U1&& __x, const _T2& __y)
: first(std::forward<_U1>(__x)), second(__y) { }
template<typename _U1, typename
enable_if<_ConstructiblePair<_T2, _T2, _T2, _T2>()
&& _MoveConstructiblePair<_T1, _T2, _U1, _T2>()
&& (!_ImplicitlyConvertiblePair<_T2, _T2, _T2, _T2>()
|| !_ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _T2>()),
enable_if<_PCCP::template
_MoveCopyPair<false, _U1, _T2>(),
bool>::type=false>
explicit constexpr pair(_U1&& __x, const _T2& __y)
: first(std::forward<_U1>(__x)), second(__y) { }
template<typename _U2, typename
enable_if<_ConstructiblePair<_T1, _T1, _T1, _T1>()
&& _MoveConstructiblePair<_T1, _T2, _T1, _U2>()
&& _ImplicitlyConvertiblePair<_T1, _T1, _T1, _T1>()
&& _ImplicitlyMoveConvertiblePair<_T1, _T2,
_T1, _U2>(),
enable_if<_PCCP::template
_CopyMovePair<true, _T1, _U2>(),
bool>::type=true>
constexpr pair(const _T1& __x, _U2&& __y)
: first(__x), second(std::forward<_U2>(__y)) { }
template<typename _U2, typename
enable_if<_ConstructiblePair<_T1, _T1, _T1, _T1>()
&& _MoveConstructiblePair<_T1, _T2, _T1, _U2>()
&& (!_ImplicitlyConvertiblePair<_T1, _T1, _T1, _T1>()
|| !_ImplicitlyMoveConvertiblePair<_T1, _T2,
_T1, _U2>()),
enable_if<_PCCP::template
_CopyMovePair<false, _T1, _U2>(),
bool>::type=false>
explicit pair(const _T1& __x, _U2&& __y)
: first(__x), second(std::forward<_U2>(__y)) { }
template<typename _U1, typename _U2, typename
enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
&& _ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _U2>(),
enable_if<_PCCP::template
_MoveConstructiblePair<_U1, _U2>()
&& _PCCP::template
_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
bool>::type=true>
constexpr pair(_U1&& __x, _U2&& __y)
: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
template<typename _U1, typename _U2, typename
enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
&& !_ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _U2>(),
enable_if<_PCCP::template
_MoveConstructiblePair<_U1, _U2>()
&& !_PCCP::template
_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
bool>::type=false>
explicit constexpr pair(_U1&& __x, _U2&& __y)
: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
template<typename _U1, typename _U2, typename
enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
&& _ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _U2>(),
enable_if<_PCCFP<_U1, _U2>::template
_MoveConstructiblePair<_U1, _U2>()
&& _PCCFP<_U1, _U2>::template
_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
bool>::type=true>
constexpr pair(pair<_U1, _U2>&& __p)
: first(std::forward<_U1>(__p.first)),
second(std::forward<_U2>(__p.second)) { }
template<typename _U1, typename _U2, typename
enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
&& !_ImplicitlyMoveConvertiblePair<_T1, _T2,
_U1, _U2>(),
enable_if<_PCCFP<_U1, _U2>::template
_MoveConstructiblePair<_U1, _U2>()
&& !_PCCFP<_U1, _U2>::template
_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
bool>::type=false>
explicit constexpr pair(pair<_U1, _U2>&& __p)
: first(std::forward<_U1>(__p.first)),
@ -304,7 +356,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
pair&
operator=(const pair& __p)
operator=(typename conditional<
__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>::value,
const pair&, const __nonesuch&>::type __p)
{
first = __p.first;
second = __p.second;
@ -312,7 +367,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
pair&
operator=(pair&& __p)
operator=(typename conditional<
__not_<__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>>::value,
const pair&, const __nonesuch&>::type __p) = delete;
pair&
operator=(typename conditional<
__and_<is_move_assignable<_T1>,
is_move_assignable<_T2>>::value,
pair&&, __nonesuch&&>::type __p)
noexcept(__and_<is_nothrow_move_assignable<_T1>,
is_nothrow_move_assignable<_T2>>::value)
{
@ -322,7 +386,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _U1, typename _U2>
pair&
typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
is_assignable<_T2&, const _U2&>>::value,
pair&>::type
operator=(const pair<_U1, _U2>& __p)
{
first = __p.first;
@ -331,7 +397,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _U1, typename _U2>
pair&
typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
is_assignable<_T2&, _U2&&>>::value,
pair&>::type
operator=(pair<_U1, _U2>&& __p)
{
first = std::forward<_U1>(__p.first);

7
libstdc++-v3/include/std/type_traits
View File

@ -2850,6 +2850,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__call_is_nothrow<result_of<_Fn(_Args...)>, _Fn, _Args...>>::type
{ };
struct __nonesuch {
__nonesuch() = delete;
~__nonesuch() = delete;
__nonesuch(__nonesuch const&) = delete;
void operator=(__nonesuch const&) = delete;
};
#if __cplusplus > 201402L
# define __cpp_lib_is_callable 201603

76
libstdc++-v3/testsuite/20_util/pair/traits.cc Normal file
View File

@ -0,0 +1,76 @@
// { dg-do compile { target c++11 } }
// Copyright (C) 2016 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/>.
#include <utility>
#include <type_traits>
#include <memory>
using namespace std;
struct Poison
{
Poison(Poison&&) = delete;
};
struct ThrowingCopy
{
ThrowingCopy(const ThrowingCopy&) {}
ThrowingCopy& operator=(const ThrowingCopy&) {}
};
int main()
{
static_assert(!is_copy_constructible<Poison>::value, "");
static_assert(!is_move_constructible<Poison>::value, "");
static_assert(!is_copy_assignable<Poison>::value, "");
static_assert(!is_move_assignable<Poison>::value, "");
static_assert(!is_copy_constructible<std::pair<int, Poison>>::value,
"");
static_assert(!is_move_constructible<std::pair<int, Poison>>::value,
"");
static_assert(!is_copy_assignable<std::pair<int, Poison>>::value, "");
static_assert(!is_move_assignable<std::pair<int, Poison>>::value, "");
static_assert(!is_constructible<std::pair<int, Poison>&,
std::pair<char, Poison>&>::value, "");
static_assert(!is_assignable<std::pair<int, Poison>&,
std::pair<char, Poison>&>::value, "");
static_assert(!is_constructible<std::pair<int, Poison>&,
std::pair<char, Poison>>::value, "");
static_assert(!is_assignable<std::pair<int, Poison>&,
std::pair<char, Poison>>::value, "");
static_assert(!is_copy_constructible<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
static_assert(is_move_constructible<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
static_assert(!is_nothrow_move_constructible<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
static_assert(!is_copy_assignable<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
static_assert(is_move_assignable<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
static_assert(!is_nothrow_move_assignable<std::pair<ThrowingCopy,
std::unique_ptr<int>>>::value,
"");
}