Revert r276548 - Make pair/tuples assignment operators SFINAE properly.

This is a breaking change. The SFINAE required is instantiated the second
the class is instantiated, and this can cause hard SFINAE errors
when applied to references to incomplete types. Ex.

struct IncompleteType;
extern IncompleteType it;
std::tuple<IncompleteType&> t(it); // SFINAE will blow up.




git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@276598 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2016-07-25 01:45:07 +00:00
parent 775417d97c
commit c76d8f7ff4
7 changed files with 7 additions and 352 deletions

View File

@@ -647,9 +647,6 @@ public:
_LIBCPP_CONSTEXPR tuple()
_NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
tuple(tuple const&) = default;
tuple(tuple&&) = default;
template <class _AllocArgT, class _Alloc, bool _Dummy = true, class = typename enable_if<
__lazy_and<
is_same<allocator_arg_t, _AllocArgT>,
@@ -888,25 +885,6 @@ public:
tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
: base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
using _CanCopyAssign = __all<is_copy_assignable<_Tp>::value...>;
using _CanMoveAssign = __all<is_move_assignable<_Tp>::value...>;
_LIBCPP_INLINE_VISIBILITY
tuple& operator=(typename conditional<_CanCopyAssign::value, tuple, __nat>::type const& __t)
_NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
{
base_.operator=(__t.base_);
return *this;
}
_LIBCPP_INLINE_VISIBILITY
tuple& operator=(typename conditional<_CanMoveAssign::value, tuple, __nat>::type&& __t)
_NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
{
base_.operator=(static_cast<base&&>(__t.base_));
return *this;
}
template <class _Tuple,
class = typename enable_if
<