[v3 PATCH] Implement LWG 2729 for pair.
Ville Voutilainen
ville.voutilainen@gmail.com
Wed Aug 17 04:41:00 GMT 2016
Tested on Linux-PPC64.
2016-08-16 Ville Voutilainen <ville.voutilainen@gmail.com>
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: Likewise.
-------------- next part --------------
diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h
index 5ff160a..ef52538 100644
--- a/libstdc++-v3/include/bits/stl_pair.h
+++ b/libstdc++-v3/include/bits/stl_pair.h
@@ -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()
- {
- 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 _T1, typename _T2, typename _U1, typename _U2>
- 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;
- }
-
- template <typename _T1, typename _T2, typename _U1, typename _U2>
- 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;
- }
-
- template <typename _T1, typename _T2, typename _U1, typename _U2>
- 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;
- }
+ template <bool, typename _T1, typename _T2>
+ struct _PCC
+ {
+ template <typename _U1, typename _U2>
+ static constexpr bool _ConstructiblePair()
+ {
+ return __and_<is_constructible<_T1, const _U1&>,
+ is_constructible<_T2, const _U2&>>::value;
+ }
+
+ template <typename _U1, typename _U2>
+ static constexpr bool _ImplicitlyConvertiblePair()
+ {
+ return __and_<is_convertible<const _U1&, _T1>,
+ is_convertible<const _U2&, _T2>>::value;
+ }
+
+ template <typename _U1, typename _U2>
+ static constexpr bool _MoveConstructiblePair()
+ {
+ return __and_<is_constructible<_T1, _U1&&>,
+ is_constructible<_T2, _U2&&>>::value;
+ }
+ template <typename _U1, typename _U2>
+ static constexpr bool _ImplicitlyMoveConvertiblePair()
+ {
+ 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>(),
- bool>::type=true>
+ 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);
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index baa4d1f..e12403b 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -2846,6 +2846,13 @@ _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
diff --git a/libstdc++-v3/testsuite/20_util/pair/traits.cc b/libstdc++-v3/testsuite/20_util/pair/traits.cc
new file mode 100644
index 0000000..0989cf1
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/pair/traits.cc
@@ -0,0 +1,77 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++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,
+ "");
+}
More information about the Libstdc++
mailing list