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 // test forward
11 
12 #include <utility>
13 #include <cassert>
14 
15 struct A
16 {
17 };
18 
19 A source() {return A();}
20 const A csource() {return A();}
21 
22 typedef char one;
23 struct two {one _[2];};
24 struct four {one _[4];};
25 struct eight {one _[8];};
26 
27 one test(A&);
28 two test(const A&);
29 
30 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
31 
32 four test(A&&);
33 eight test(const A&&);
34 
35 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
36 
37 int main()
38 {
39     A a;
40     const A ca = A();
41 
42     ((void)a); // Prevent unused warning
43     ((void)ca); // Prevent unused warning
44 
45 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
46     static_assert(sizeof(test(std::forward<A&>(a))) == 1, "");
47     static_assert(sizeof(test(std::forward<A>(a))) == 4, "");
48     static_assert(sizeof(test(std::forward<A>(source()))) == 4, "");
49 
50     static_assert(sizeof(test(std::forward<const A&>(a))) == 2, "");
51 //    static_assert(sizeof(test(std::forward<const A&>(source()))) == 2, "");
52     static_assert(sizeof(test(std::forward<const A>(a))) == 8, "");
53     static_assert(sizeof(test(std::forward<const A>(source()))) == 8, "");
54 
55     static_assert(sizeof(test(std::forward<const A&>(ca))) == 2, "");
56 //    static_assert(sizeof(test(std::forward<const A&>(csource()))) == 2, "");
57     static_assert(sizeof(test(std::forward<const A>(ca))) == 8, "");
58     static_assert(sizeof(test(std::forward<const A>(csource()))) == 8, "");
59 
60 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
61 
62     static_assert(sizeof(test(std::forward<A&>(a))) == 1, "");
63     static_assert(sizeof(test(std::forward<A>(a))) == 1, "");
64 //    static_assert(sizeof(test(std::forward<A>(source()))) == 2, "");
65 
66     static_assert(sizeof(test(std::forward<const A&>(a))) == 2, "");
67     static_assert(sizeof(test(std::forward<const A&>(source()))) == 2, "");
68     static_assert(sizeof(test(std::forward<const A>(a))) == 2, "");
69     static_assert(sizeof(test(std::forward<const A>(source()))) == 2, "");
70 
71     static_assert(sizeof(test(std::forward<const A&>(ca))) == 2, "");
72     static_assert(sizeof(test(std::forward<const A&>(csource()))) == 2, "");
73     static_assert(sizeof(test(std::forward<const A>(ca))) == 2, "");
74     static_assert(sizeof(test(std::forward<const A>(csource()))) == 2, "");
75 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
76 
77 #if _LIBCPP_STD_VER > 11
78     constexpr int i1 = std::move(23);
79     static_assert(i1 == 23, "" );
80     constexpr int i2 = std::forward<int>(42);
81     static_assert(i2 == 42, "" );
82 #endif
83 }
84