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// <functional>
10//
11// template <class T>
12// struct unwrap_ref_decay;
13//
14// template <class T>
15// using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type;
16
17// UNSUPPORTED: c++03, c++11, c++14, c++17
18
19#include <functional>
20#include <type_traits>
21
22#include "test_macros.h"
23
24
25template <typename T, typename Result>
26void check() {
27 static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, Result>);
28 static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, std::unwrap_ref_decay_t<T>>);
29}
30
31struct T { };
32
33int main(int, char**) {
34 check<T, T>();
35 check<T&, T>();
36 check<T const, T>();
37 check<T const&, T>();
38 check<T*, T*>();
39 check<T const*, T const*>();
40 check<T[3], T*>();
41 check<T const [3], T const*>();
42 check<T (), T (*)()>();
43 check<T (int) const, T (int) const>();
44 check<T (int) &, T (int) &>();
45 check<T (int) &&, T (int) &&>();
46
47 check<std::reference_wrapper<T>, T&>();
48 check<std::reference_wrapper<T>&, T&>();
49 check<std::reference_wrapper<T const>, T const&>();
50 check<std::reference_wrapper<T const>&, T const&>();
51 check<std::reference_wrapper<T*>, T*&>();
52 check<std::reference_wrapper<T*>&, T*&>();
53 check<std::reference_wrapper<T const*>, T const*&>();
54 check<std::reference_wrapper<T const*>&, T const*&>();
55 check<std::reference_wrapper<T[3]>, T (&)[3]>();
56 check<std::reference_wrapper<T[3]>&, T (&)[3]>();
57 check<std::reference_wrapper<T ()>, T (&)()>();
58 check<std::reference_wrapper<T ()>&, T (&)()>();
59
60 return 0;
61}
62

source code of libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp