| //===----------------------------------------------------------------------===// |
| // |
| // 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_CORE_CONVERTIBLE_H |
| #define _LIBCPP___TYPE_TRAITS_IS_CORE_CONVERTIBLE_H |
| |
| #include <__config> |
| #include <__type_traits/integral_constant.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| // [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed. |
| // We can't test for that, but we can test implicit convertibility by passing it |
| // to a function. Notice that __is_core_convertible<void,void> is false, |
| // and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later. |
| |
| template <class _Tp, class _Up, class = void> |
| struct __is_core_convertible : public false_type {}; |
| |
| template <class _Tp, class _Up> |
| struct __is_core_convertible<_Tp, _Up, decltype( |
| static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() ) |
| )> : public true_type {}; |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___TYPE_TRAITS_IS_CORE_CONVERTIBLE_H |
