1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___TYPE_TRAITS_IS_SAME_H
10#define _LIBCPP___TYPE_TRAITS_IS_SAME_H
11
12#include <__config>
13#include <__type_traits/integral_constant.h>
14
15#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16# pragma GCC system_header
17#endif
18
19_LIBCPP_BEGIN_NAMESPACE_STD
20
21template <class _Tp, class _Up>
22struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
23
24#if _LIBCPP_STD_VER > 14
25template <class _Tp, class _Up>
26inline constexpr bool is_same_v = __is_same(_Tp, _Up);
27#endif
28
29// _IsSame<T,U> has the same effect as is_same<T,U> but instantiates fewer types:
30// is_same<A,B> and is_same<C,D> are guaranteed to be different types, but
31// _IsSame<A,B> and _IsSame<C,D> are the same type (namely, false_type).
32// Neither GCC nor Clang can mangle the __is_same builtin, so _IsSame
33// mustn't be directly used anywhere that contributes to name-mangling
34// (such as in a dependent return type).
35
36template <class _Tp, class _Up>
37using _IsSame = _BoolConstant<__is_same(_Tp, _Up)>;
38
39template <class _Tp, class _Up>
40using _IsNotSame = _BoolConstant<!__is_same(_Tp, _Up)>;
41
42_LIBCPP_END_NAMESPACE_STD
43
44#endif // _LIBCPP___TYPE_TRAITS_IS_SAME_H
45

source code of flutter_engine/third_party/libcxx/include/__type_traits/is_same.h