| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___TYPE_TRAITS_IS_IMPLICITLY_DEFAULT_CONSTRUCTIBLE_H |
| #define _LIBCPP___TYPE_TRAITS_IS_IMPLICITLY_DEFAULT_CONSTRUCTIBLE_H |
| |
| #include <__config> |
| #include <__type_traits/integral_constant.h> |
| #include <__type_traits/is_default_constructible.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #ifndef _LIBCPP_CXX03_LANG |
| // First of all, we can't implement this check in C++03 mode because the {} |
| // default initialization syntax isn't valid. |
| // Second, we implement the trait in a funny manner with two defaulted template |
| // arguments to workaround Clang's PR43454. |
| template <class _Tp> |
| void __test_implicit_default_constructible(_Tp); |
| |
| template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type> |
| struct __is_implicitly_default_constructible |
| : false_type |
| { }; |
| |
| template <class _Tp> |
| struct __is_implicitly_default_constructible<_Tp, decltype(std::__test_implicit_default_constructible<_Tp const&>({})), true_type> |
| : true_type |
| { }; |
| |
| template <class _Tp> |
| struct __is_implicitly_default_constructible<_Tp, decltype(std::__test_implicit_default_constructible<_Tp const&>({})), false_type> |
| : false_type |
| { }; |
| #endif // !C++03 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___TYPE_TRAITS_IS_IMPLICITLY_DEFAULT_CONSTRUCTIBLE_H |