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LWG 2975 ensure construct(pair<T,U>*, ...) used to construct pairs

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* include/std/scoped_allocator (__not_pair): Define SFINAE helper.
	(construct(_Tp*, _Args&&...)): Remove from overload set when _Tp is
	a specialization of std::pair.
	* testsuite/20_util/scoped_allocator/construct_pair.cc: Ensure
	pair elements are constructed correctly.

From-SVN: r261716
This commit is contained in:
Jonathan Wakely 2018-06-18 21:17:44 +01:00 • committed by Jonathan Wakely
parent df0b55f090
commit 05891e9f45
3 changed files with 51 additions and 7 deletions
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7
libstdc++-v3/ChangeLog
View file

@ -1,5 +1,12 @@
2018-06-18 Jonathan Wakely <jwakely@redhat.com>
LWG 2975 ensure construct(pair<T,U>*, ...) used to construct pairs
* include/std/scoped_allocator (__not_pair): Define SFINAE helper.
(construct(_Tp*, _Args&&...)): Remove from overload set when _Tp is
a specialization of std::pair.
* testsuite/20_util/scoped_allocator/construct_pair.cc: Ensure
pair elements are constructed correctly.
LWG 2989 hide path iostream operators from normal lookup
* include/bits/fs_path.h (operator<<, operator>>): Define inline as
friends.

23
libstdc++-v3/include/std/scoped_allocator
View file

@ -241,6 +241,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_constructible<_OuterAlloc, _Alloc>::value
>::type;
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2975. Missing case for pair construction in scoped [...] allocators
template<typename _Tp>
struct __not_pair { using type = void; };
template<typename _Tp, typename _Up>
struct __not_pair<pair<_Tp, _Up>> { };
public:
typedef _OuterAlloc outer_allocator_type;
typedef typename __inner_type::__type inner_allocator_type;
@ -348,13 +356,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return __traits::max_size(outer_allocator()); }
template<typename _Tp, typename... _Args>
void construct(_Tp* __p, _Args&&... __args)
{
auto& __inner = inner_allocator();
auto __use_tag
= __use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
_M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
}
typename __not_pair<_Tp>::type
construct(_Tp* __p, _Args&&... __args)
{
auto& __inner = inner_allocator();
auto __use_tag
= __use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
_M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
}
template<typename _T1, typename _T2, typename... _Args1,
typename... _Args2>

28
libstdc++-v3/testsuite/20_util/scoped_allocator/construct_pair.cc
View file

@ -73,9 +73,37 @@ test03()
a.deallocate(ptr, 1);
}
void
test04()
{
struct X
{
using allocator_type = std::allocator<int>;
X() = default;
X(const X&) { throw 1; }
X(const X&, const allocator_type&) { }
};
struct Y
{
using allocator_type = std::allocator<int>;
Y() = default;
Y(const Y&) = delete;
Y(std::allocator_arg_t, const allocator_type&, const Y&) { }
};
using pair_type = std::pair<X, Y>;
std::scoped_allocator_adaptor<std::allocator<pair_type>> a;
auto ptr = a.allocate(1);
/* not const */ pair_type p;
a.construct(ptr, p); // LWG 2975
a.deallocate(ptr, 1);
}
int main()
{
test01();
test02();
test03();
test04();
}