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libstdc++: Fix constructor constraints for std::any (PR 90415)

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This removes a non-standard extension to std::any which causes errors
for valid code, due to recursive instantiation of a trait that isn't
supposed to be in the constraints.

It also removes some incorrect constraints on the in_place_type<T>
constructors and emplace members, which were preventing creating a
std::any object with another std::any as the contained value.

2020-04-24  Kamlesh Kumar  <kamleshbhalui@gmail.com>
	    Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/90415
	PR libstdc++/92156
	* include/std/any (any): Rename template parameters for consistency
	with the standard.
	(any::_Decay): Rename to _Decay_if_not_any.
	(any::any(T&&):: Remove is_constructible from constraints. Remove
	non-standard overload.
	(any::any(in_place_type_t<T>, Args&&...))
	(any::any(in_place_type_t<T>, initializer_list<U>, Args&&...))
	(any::emplace(Args&&...))
	(any::emplace(initializer_list<U>, Args&&...)):
	Use decay_t instead of _Decay.
	* testsuite/20_util/any/cons/90415.cc: New test.
	* testsuite/20_util/any/cons/92156.cc: New Test.
	* testsuite/20_util/any/misc/any_cast_neg.cc: Make dg-error directives
	more robust.
	* testsuite/20_util/any/modifiers/92156.cc: New test.
This commit is contained in:
Jonathan Wakely 2020-04-24 00:54:20 +01:00
parent ae962e573e
commit d1462b0782
6 changed files with 255 additions and 71 deletions
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21
libstdc++-v3/ChangeLog
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@ -1,3 +1,24 @@
2020-04-24 Kamlesh Kumar <kamleshbhalui@gmail.com>
Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/90415
PR libstdc++/92156
* include/std/any (any): Rename template parameters for consistency
with the standard.
(any::_Decay): Rename to _Decay_if_not_any.
(any::any(T&&):: Remove is_constructible from constraints. Remove
non-standard overload.
(any::any(in_place_type_t<T>, Args&&...))
(any::any(in_place_type_t<T>, initializer_list<U>, Args&&...))
(any::emplace(Args&&...))
(any::emplace(initializer_list<U>, Args&&...)):
Use decay_t instead of _Decay.
* testsuite/20_util/any/cons/90415.cc: New test.
* testsuite/20_util/any/cons/92156.cc: New Test.
* testsuite/20_util/any/misc/any_cast_neg.cc: Make dg-error directives
more robust.
* testsuite/20_util/any/modifiers/92156.cc: New test.
2020-04-23 Jonathan Wakely <jwakely@redhat.com>
* doc/xml/manual/status_cxx2020.xml: Update C++20 status table.

115
libstdc++-v3/include/std/any
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@ -105,8 +105,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Manager_internal<_Tp>,
_Manager_external<_Tp>>;
template<typename _Tp, typename _Decayed = decay_t<_Tp>>
using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>;
template<typename _Tp, typename _VTp = decay_t<_Tp>>
using _Decay_if_not_any = enable_if_t<!is_same_v<_VTp, any>, _VTp>;
/// Emplace with an object created from @p __args as the contained object.
template <typename _Tp, typename... _Args,
@ -125,10 +125,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void __do_emplace(initializer_list<_Up> __il, _Args&&... __args)
{
reset();
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
_M_manager = &_Mgr::_S_manage;
}
template <typename _Res, typename _Tp, typename... _Args>
using __any_constructible
= enable_if<__and_<is_copy_constructible<_Tp>,
is_constructible<_Tp, _Args...>>::value,
_Res>;
template <typename _Tp, typename... _Args>
using __any_constructible_t
= typename __any_constructible<bool, _Tp, _Args...>::type;
template<typename _VTp, typename... _Args>
using __emplace_t
= typename __any_constructible<_VTp&, _VTp, _Args...>::type;
public:
// construct/destruct
@ -165,65 +179,39 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
template <typename _Res, typename _Tp, typename... _Args>
using __any_constructible =
enable_if<__and_<is_copy_constructible<_Tp>,
is_constructible<_Tp, _Args...>>::value,
_Res>;
template <typename _Tp, typename... _Args>
using __any_constructible_t =
typename __any_constructible<bool, _Tp, _Args...>::type;
/// Construct with a copy of @p __value as the contained object.
template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
__any_constructible_t<_Tp, _ValueType&&> = true,
enable_if_t<!__is_in_place_type<_Tp>::value, bool> = true>
any(_ValueType&& __value)
template <typename _Tp, typename _VTp = _Decay_if_not_any<_Tp>,
typename _Mgr = _Manager<_VTp>,
enable_if_t<is_copy_constructible<_VTp>::value
&& !__is_in_place_type<_VTp>::value, bool> = true>
any(_Tp&& __value)
: _M_manager(&_Mgr::_S_manage)
{
_Mgr::_S_create(_M_storage, std::forward<_ValueType>(__value));
}
/// Construct with a copy of @p __value as the contained object.
template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
enable_if_t<__and_v<is_copy_constructible<_Tp>,
__not_<is_constructible<_Tp, _ValueType&&>>,
__not_<__is_in_place_type<_Tp>>>,
bool> = false>
any(_ValueType&& __value)
: _M_manager(&_Mgr::_S_manage)
{
_Mgr::_S_create(_M_storage, __value);
_Mgr::_S_create(_M_storage, std::forward<_Tp>(__value));
}
/// Construct with an object created from @p __args as the contained object.
template <typename _ValueType, typename... _Args,
typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
__any_constructible_t<_Tp, _Args&&...> = false>
template <typename _Tp, typename... _Args, typename _VTp = decay_t<_Tp>,
typename _Mgr = _Manager<_VTp>,
__any_constructible_t<_VTp, _Args&&...> = false>
explicit
any(in_place_type_t<_ValueType>, _Args&&... __args)
any(in_place_type_t<_Tp>, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
}
/// Construct with an object created from @p __il and @p __args as
/// the contained object.
template <typename _ValueType, typename _Up, typename... _Args,
typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
__any_constructible_t<_Tp, initializer_list<_Up>,
template <typename _Tp, typename _Up, typename... _Args,
typename _VTp = decay_t<_Tp>, typename _Mgr = _Manager<_VTp>,
__any_constructible_t<_VTp, initializer_list<_Up>,
_Args&&...> = false>
explicit
any(in_place_type_t<_ValueType>,
initializer_list<_Up> __il, _Args&&... __args)
any(in_place_type_t<_Tp>, initializer_list<_Up> __il, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
}
/// Destructor, calls @c reset()
@ -232,7 +220,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// assignments
/// Copy the state of another object.
any& operator=(const any& __rhs)
any&
operator=(const any& __rhs)
{
*this = any(__rhs);
return *this;
@ -243,7 +232,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*
* @post @c !__rhs.has_value() (not guaranteed for other implementations)
*/
any& operator=(any&& __rhs) noexcept
any&
operator=(any&& __rhs) noexcept
{
if (!__rhs.has_value())
reset();
@ -258,40 +248,37 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
/// Store a copy of @p __rhs as the contained object.
template<typename _ValueType>
enable_if_t<is_copy_constructible<_Decay<_ValueType>>::value, any&>
operator=(_ValueType&& __rhs)
template<typename _Tp>
enable_if_t<is_copy_constructible<_Decay_if_not_any<_Tp>>::value, any&>
operator=(_Tp&& __rhs)
{
*this = any(std::forward<_ValueType>(__rhs));
*this = any(std::forward<_Tp>(__rhs));
return *this;
}
/// Emplace with an object created from @p __args as the contained object.
template <typename _ValueType, typename... _Args>
typename __any_constructible<_Decay<_ValueType>&,
_Decay<_ValueType>, _Args&&...>::type
template <typename _Tp, typename... _Args>
__emplace_t<decay_t<_Tp>, _Args...>
emplace(_Args&&... __args)
{
__do_emplace<_Decay<_ValueType>>(std::forward<_Args>(__args)...);
using _VTp = decay_t<_Tp>;
__do_emplace<_VTp>(std::forward<_Args>(__args)...);
any::_Arg __arg;
this->_M_manager(any::_Op_access, this, &__arg);
return *static_cast<_Decay<_ValueType>*>(__arg._M_obj);
return *static_cast<_VTp*>(__arg._M_obj);
}
/// Emplace with an object created from @p __il and @p __args as
/// the contained object.
template <typename _ValueType, typename _Up, typename... _Args>
typename __any_constructible<_Decay<_ValueType>&,
_Decay<_ValueType>,
initializer_list<_Up>,
_Args&&...>::type
template <typename _Tp, typename _Up, typename... _Args>
__emplace_t<decay_t<_Tp>, initializer_list<_Up>, _Args&&...>
emplace(initializer_list<_Up> __il, _Args&&... __args)
{
__do_emplace<_Decay<_ValueType>, _Up>(__il,
std::forward<_Args>(__args)...);
using _VTp = decay_t<_Tp>;
__do_emplace<_VTp, _Up>(__il, std::forward<_Args>(__args)...);
any::_Arg __arg;
this->_M_manager(any::_Op_access, this, &__arg);
return *static_cast<_Decay<_ValueType>*>(__arg._M_obj);
return *static_cast<_VTp*>(__arg._M_obj);
}
// modifiers

64
libstdc++-v3/testsuite/20_util/any/cons/90415.cc Normal file
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@ -0,0 +1,64 @@
// { dg-options "-std=gnu++17" }
// { dg-do run { target c++17 } }
// 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
// <http://www.gnu.org/licenses/>.
#include <any>
#include <utility>
#include <tuple>
#include <testsuite_hooks.h>
void
test01()
{
// PR libstdc++/90415
static_assert( std::is_copy_constructible<std::tuple<std::any>>::value );
}
struct wrapper
{
wrapper() = default;
wrapper(const std::any& t);
wrapper(const wrapper& w);
auto& operator=(const std::any& t);
auto& operator=(const wrapper& w)
{
value = w.value;
return *this;
}
std::any value;
};
void
test02()
{
// PR libstdc++/91630
wrapper a, b;
a = b;
}
int main()
{
test01();
test02();
}

53
libstdc++-v3/testsuite/20_util/any/cons/92156.cc Normal file
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@ -0,0 +1,53 @@
// { dg-options "-std=gnu++17" }
// { dg-do run { target c++17 } }
// 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
// <http://www.gnu.org/licenses/>.
#include <any>
#include <utility>
#include <tuple>
#include <testsuite_hooks.h>
void
test01()
{
auto a = std::any(std::in_place_type<std::any>, 5);
VERIFY( std::any_cast<int>(std::any_cast<std::any>(a)) == 5 );
auto b = std::any(std::in_place_type<std::any>, {1});
(void) std::any_cast<std::initializer_list<int>>(std::any_cast<std::any>(b));
}
void
test02()
{
std::any p = std::pair<std::any, std::any>(1, 1);
auto pt = std::any_cast<std::pair<std::any, std::any>>(p);
VERIFY( std::any_cast<int>(pt.first) == 1 );
VERIFY( std::any_cast<int>(pt.second) == 1 );
std::any t = std::tuple<std::any>(1);
auto tt = std::any_cast<std::tuple<std::any>>(t);
VERIFY( std::any_cast<int>(std::get<0>(tt)) == 1 );
}
int main()
{
test01();
test02();
}

16
libstdc++-v3/testsuite/20_util/any/misc/any_cast_neg.cc
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@ -1,5 +1,5 @@
// { dg-options "-std=gnu++17" }
// { dg-do compile }
// { dg-do compile { target c++17 } }
// Copyright (C) 2014-2020 Free Software Foundation, Inc.
//
@ -26,20 +26,22 @@ using std::any_cast;
void test01()
{
const any y(1);
any_cast<int&>(y); // { dg-error "invalid 'static_cast'" "" { target { *-*-* } } 461 }
// { dg-error "Template argument must be constructible from a const value" "" { target { *-*-* } } 457 }
any_cast<int&>(y); // { dg-error "here" }
// { dg-error "Template argument must be constructible from a const value" "" { target { *-*-* } } 0 }
}
void test02()
{
any y(1);
any_cast<int&&>(y);
// { dg-error "Template argument must be constructible from an lvalue" "" { target { *-*-* } } 483 }
any_cast<int&&>(y); // { dg-error "here" }
// { dg-error "Template argument must be constructible from an lvalue" "" { target { *-*-* } } 0 }
}
void test03()
{
any y(1);
any_cast<int&>(std::move(y)); // { dg-error "invalid 'static_cast'" "" { target { *-*-* } } 501 }
// { dg-error "Template argument must be constructible from an rvalue" "" { target { *-*-* } } 497 }
any_cast<int&>(std::move(y)); // { dg-error "here" }
// { dg-error "Template argument must be constructible from an rvalue" "" { target { *-*-* } } 0 }
}
// { dg-prune-output "invalid 'static_cast'" }

57
libstdc++-v3/testsuite/20_util/any/modifiers/92156.cc Normal file
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@ -0,0 +1,57 @@
// { dg-options "-std=gnu++17" }
// { dg-do run { target c++17 } }
// 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
// <http://www.gnu.org/licenses/>.
#include <any>
#include <utility>
#include <tuple>
#include <testsuite_hooks.h>
void
test01()
{
std::any a;
a.emplace<std::any>(5);
VERIFY( std::any_cast<int>(std::any_cast<std::any>(a)) == 5 );
std::any b;
b.emplace<std::any>({1});
(void) std::any_cast<std::initializer_list<int>>(std::any_cast<std::any>(b));
}
void
test02()
{
std::any p;
p.emplace<std::pair<std::any, std::any>>(1, 1);
auto pt = std::any_cast<std::pair<std::any, std::any>>(p);
VERIFY( std::any_cast<int>(pt.first) == 1 );
VERIFY( std::any_cast<int>(pt.second) == 1 );
std::any t;
t.emplace<std::tuple<std::any>>(1);
auto tt = std::any_cast<std::tuple<std::any>>(t);
VERIFY( std::any_cast<int>(std::get<0>(tt)) == 1 );
}
int main()
{
test01();
test02();
}