third_party/llvm-project/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// test forward

#include <utility>
#include <cassert>

#include "test_macros.h"

struct A
{
};

A source() {return A();}
const A csource() {return A();}

typedef char one;
struct two {one _[2];};
struct four {one _[4];};
struct eight {one _[8];};

one test(A&);
two test(const A&);

int main()
{
    A a;
    const A ca = A();

    ((void)a); // Prevent unused warning
    ((void)ca); // Prevent unused warning

#if TEST_STD_VER < 11
    static_assert(sizeof(test(std::forward<A&>(a))) == 1, "");
    static_assert(sizeof(test(std::forward<A>(a))) == 1, "");

    // Libc++'s C++03 implementation of 'forward' cannot accept true non-const
    // rvalues.
    // static_assert(sizeof(test(std::forward<A>(source()))) == 2, "");

    static_assert(sizeof(test(std::forward<const A&>(a))) == 2, "");
    static_assert(sizeof(test(std::forward<const A&>(source()))) == 2, "");
    static_assert(sizeof(test(std::forward<const A>(a))) == 2, "");
    static_assert(sizeof(test(std::forward<const A>(source()))) == 2, "");

    static_assert(sizeof(test(std::forward<const A&>(ca))) == 2, "");
    static_assert(sizeof(test(std::forward<const A&>(csource()))) == 2, "");
    static_assert(sizeof(test(std::forward<const A>(ca))) == 2, "");
    static_assert(sizeof(test(std::forward<const A>(csource()))) == 2, "");
#endif
}