1 //===----------------------------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // UNSUPPORTED: c++98, c++03
15 #include <type_traits>
18 #include "test_macros.h"
24 A source() noexcept {return A();}
25 const A csource() noexcept {return A();}
28 constexpr bool test_constexpr_forward() {
32 return std::forward<int&>(x) == 42
33 && std::forward<int>(x) == 42
34 && std::forward<const int&>(x) == 42
35 && std::forward<const int>(x) == 42
36 && std::forward<int&&>(x) == 42
37 && std::forward<const int&&>(x) == 42
38 && std::forward<const int&>(cx) == 101
39 && std::forward<const int>(cx) == 101;
50 ((void)a); // Prevent unused warning
51 ((void)ca); // Prevent unused warning
53 static_assert(std::is_same<decltype(std::forward<A&>(a)), A&>::value, "");
54 static_assert(std::is_same<decltype(std::forward<A>(a)), A&&>::value, "");
55 static_assert(std::is_same<decltype(std::forward<A>(source())), A&&>::value, "");
56 static_assert(noexcept(std::forward<A&>(a)), "");
57 static_assert(noexcept(std::forward<A>(a)), "");
58 static_assert(noexcept(std::forward<A>(source())), "");
60 static_assert(std::is_same<decltype(std::forward<const A&>(a)), const A&>::value, "");
61 static_assert(std::is_same<decltype(std::forward<const A>(a)), const A&&>::value, "");
62 static_assert(std::is_same<decltype(std::forward<const A>(source())), const A&&>::value, "");
63 static_assert(noexcept(std::forward<const A&>(a)), "");
64 static_assert(noexcept(std::forward<const A>(a)), "");
65 static_assert(noexcept(std::forward<const A>(source())), "");
67 static_assert(std::is_same<decltype(std::forward<const A&>(ca)), const A&>::value, "");
68 static_assert(std::is_same<decltype(std::forward<const A>(ca)), const A&&>::value, "");
69 static_assert(std::is_same<decltype(std::forward<const A>(csource())), const A&&>::value, "");
70 static_assert(noexcept(std::forward<const A&>(ca)), "");
71 static_assert(noexcept(std::forward<const A>(ca)), "");
72 static_assert(noexcept(std::forward<const A>(csource())), "");
76 constexpr int i2 = std::forward<int>(42);
77 static_assert(std::forward<int>(42) == 42, "");
78 static_assert(std::forward<const int&>(i2) == 42, "");
79 static_assert(test_constexpr_forward(), "");
82 #if TEST_STD_VER == 11 && defined(_LIBCPP_VERSION)
83 // Test that std::forward is constexpr in C++11. This is an extension
84 // provided by both libc++ and libstdc++.
86 constexpr int i2 = std::forward<int>(42);
87 static_assert(std::forward<int>(42) == 42, "" );
88 static_assert(std::forward<const int&>(i2) == 42, "");