| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++98, c++03, c++11, c++14 |
| |
| // template <class T> constexpr add_const<T>& as_const(T& t) noexcept; // C++17 |
| // template <class T> add_const<T>& as_const(const T&&) = delete; // C++17 |
| |
| #include <utility> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| |
| struct S {int i;}; |
| bool operator==(const S& x, const S& y) { return x.i == y.i; } |
| bool operator==(const volatile S& x, const volatile S& y) { return x.i == y.i; } |
| |
| template<typename T> |
| void test(T& t) |
| { |
| static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const (t))>::type>::value, ""); |
| static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const< T>(t))>::type>::value, ""); |
| static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<const T>(t))>::type>::value, ""); |
| static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<volatile T>(t))>::type>::value, ""); |
| static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<const volatile T>(t))>::type>::value, ""); |
| |
| assert(std::as_const(t) == t); |
| assert(std::as_const< T>(t) == t); |
| assert(std::as_const<const T>(t) == t); |
| assert(std::as_const<volatile T>(t) == t); |
| assert(std::as_const<const volatile T>(t) == t); |
| } |
| |
| int main(int, char**) |
| { |
| int i = 3; |
| double d = 4.0; |
| S s{2}; |
| test(i); |
| test(d); |
| test(s); |
| |
| return 0; |
| } |