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// UNSUPPORTED: c++03, c++11, c++14
10
11// <utility>
12
13// struct in_place_t {
14// explicit in_place_t() = default;
15// };
16// inline constexpr in_place_t in_place{};
17
18// template <class T>
19// struct in_place_type_t {
20// explicit in_place_type_t() = default;
21// };
22// template <class T>
23// inline constexpr in_place_type_t<T> in_place_type{};
24
25// template <size_t I>
26// struct in_place_index_t {
27// explicit in_place_index_t() = default;
28// };
29// template <size_t I>
30// inline constexpr in_place_index_t<I> in_place_index{};
31
32#include <cassert>
33#include <memory>
34#include <type_traits>
35#include <utility>
36
37template <class Tp, class Up>
38constexpr bool check_tag(Up) {
39 return std::is_same<Tp, std::decay_t<Tp>>::value
40 && std::is_same<Tp, Up>::value;
41}
42
43int main(int, char**) {
44 // test in_place_t
45 {
46 using T = std::in_place_t;
47 static_assert(check_tag<T>(std::in_place));
48 }
49 // test in_place_type_t
50 {
51 using T1 = std::in_place_type_t<void>;
52 using T2 = std::in_place_type_t<int>;
53 using T3 = std::in_place_type_t<const int>;
54 static_assert(!std::is_same<T1, T2>::value && !std::is_same<T1, T3>::value);
55 static_assert(!std::is_same<T2, T3>::value);
56 static_assert(check_tag<T1>(std::in_place_type<void>));
57 static_assert(check_tag<T2>(std::in_place_type<int>));
58 static_assert(check_tag<T3>(std::in_place_type<const int>));
59 }
60 // test in_place_index_t
61 {
62 using T1 = std::in_place_index_t<0>;
63 using T2 = std::in_place_index_t<1>;
64 using T3 = std::in_place_index_t<static_cast<std::size_t>(-1)>;
65 static_assert(!std::is_same<T1, T2>::value && !std::is_same<T1, T3>::value);
66 static_assert(!std::is_same<T2, T3>::value);
67 static_assert(check_tag<T1>(std::in_place_index<0>));
68 static_assert(check_tag<T2>(std::in_place_index<1>));
69 static_assert(check_tag<T3>(std::in_place_index<static_cast<std::size_t>(-1)>));
70 }
71
72 return 0;
73}
74

source code of libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp