1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 // <functional>
11 //
12 // template <class T>
13 // struct unwrap_ref_decay;
14 //
15 // template <class T>
16 // using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type;
17
18 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
19
20 #include <functional>
21 #include <type_traits>
22
23
24 template <typename T, typename Result>
check()25 void check() {
26 static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, Result>);
27 static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, std::unwrap_ref_decay_t<T>>);
28 }
29
30 struct T { };
31
main()32 int main() {
33 check<T, T>();
34 check<T&, T>();
35 check<T const, T>();
36 check<T const&, T>();
37 check<T*, T*>();
38 check<T const*, T const*>();
39 check<T[3], T*>();
40 check<T const [3], T const*>();
41 check<T (), T (*)()>();
42 check<T (int) const, T (int) const>();
43 check<T (int) &, T (int) &>();
44 check<T (int) &&, T (int) &&>();
45
46 check<std::reference_wrapper<T>, T&>();
47 check<std::reference_wrapper<T>&, T&>();
48 check<std::reference_wrapper<T const>, T const&>();
49 check<std::reference_wrapper<T const>&, T const&>();
50 check<std::reference_wrapper<T*>, T*&>();
51 check<std::reference_wrapper<T*>&, T*&>();
52 check<std::reference_wrapper<T const*>, T const*&>();
53 check<std::reference_wrapper<T const*>&, T const*&>();
54 check<std::reference_wrapper<T[3]>, T (&)[3]>();
55 check<std::reference_wrapper<T[3]>&, T (&)[3]>();
56 check<std::reference_wrapper<T ()>, T (&)()>();
57 check<std::reference_wrapper<T ()>&, T (&)()>();
58 }
59