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92 lines
3.1 KiB
C++
92 lines
3.1 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++98, c++03
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// test forward
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#include <utility>
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#include <type_traits>
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#include <cassert>
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#include "test_macros.h"
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struct A
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{
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};
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A source() noexcept {return A();}
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const A csource() noexcept {return A();}
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constexpr bool test_constexpr_forward() {
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#if TEST_STD_VER > 11
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int x = 42;
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const int cx = 101;
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return std::forward<int&>(x) == 42
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&& std::forward<int>(x) == 42
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&& std::forward<const int&>(x) == 42
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&& std::forward<const int>(x) == 42
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&& std::forward<int&&>(x) == 42
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&& std::forward<const int&&>(x) == 42
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&& std::forward<const int&>(cx) == 101
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&& std::forward<const int>(cx) == 101;
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#else
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return true;
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#endif
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}
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int main()
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{
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A a;
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const A ca = A();
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((void)a); // Prevent unused warning
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((void)ca); // Prevent unused warning
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static_assert(std::is_same<decltype(std::forward<A&>(a)), A&>::value, "");
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static_assert(std::is_same<decltype(std::forward<A>(a)), A&&>::value, "");
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static_assert(std::is_same<decltype(std::forward<A>(source())), A&&>::value, "");
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static_assert(noexcept(std::forward<A&>(a)), "");
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static_assert(noexcept(std::forward<A>(a)), "");
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static_assert(noexcept(std::forward<A>(source())), "");
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static_assert(std::is_same<decltype(std::forward<const A&>(a)), const A&>::value, "");
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static_assert(std::is_same<decltype(std::forward<const A>(a)), const A&&>::value, "");
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static_assert(std::is_same<decltype(std::forward<const A>(source())), const A&&>::value, "");
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static_assert(noexcept(std::forward<const A&>(a)), "");
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static_assert(noexcept(std::forward<const A>(a)), "");
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static_assert(noexcept(std::forward<const A>(source())), "");
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static_assert(std::is_same<decltype(std::forward<const A&>(ca)), const A&>::value, "");
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static_assert(std::is_same<decltype(std::forward<const A>(ca)), const A&&>::value, "");
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static_assert(std::is_same<decltype(std::forward<const A>(csource())), const A&&>::value, "");
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static_assert(noexcept(std::forward<const A&>(ca)), "");
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static_assert(noexcept(std::forward<const A>(ca)), "");
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static_assert(noexcept(std::forward<const A>(csource())), "");
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#if TEST_STD_VER > 11
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{
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constexpr int i2 = std::forward<int>(42);
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static_assert(std::forward<int>(42) == 42, "");
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static_assert(std::forward<const int&>(i2) == 42, "");
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static_assert(test_constexpr_forward(), "");
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}
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#endif
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#if TEST_STD_VER == 11 && defined(_LIBCPP_VERSION)
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// Test that std::forward is constexpr in C++11. This is an extension
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// provided by both libc++ and libstdc++.
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{
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constexpr int i2 = std::forward<int>(42);
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static_assert(std::forward<int>(42) == 42, "" );
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static_assert(std::forward<const int&>(i2) == 42, "");
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}
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#endif
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}
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