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