| 1 | //===----------------------------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | // UNSUPPORTED: c++03, c++11, c++14, c++17 |
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| 10 | |
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| 11 | // struct identity; |
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| 12 | |
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| 13 | #include <functional> |
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| 14 | |
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| 15 | #include <cassert> |
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| 16 | #include <concepts> |
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| 17 | #include <utility> |
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| 18 | |
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| 19 | #include "MoveOnly.h" |
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| 20 | |
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| 21 | static_assert(std::semiregular<std::identity>); |
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| 22 | static_assert(requires { typename std::identity::is_transparent; }); |
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| 23 | |
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| 24 | constexpr bool test() { |
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| 25 | std::identity id; |
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| 26 | int i = 42; |
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| 27 | assert(id(i) == 42); |
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| 28 | assert(id(std::move(i)) == 42); |
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| 29 | |
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| 30 | MoveOnly m1 = 2; |
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| 31 | MoveOnly m2 = id(std::move(m1)); |
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| 32 | assert(m2.get() == 2); |
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| 33 | |
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| 34 | assert(&id(i) == &i); |
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| 35 | static_assert(&id(id) == &id); |
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| 36 | |
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| 37 | const std::identity idc; |
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| 38 | assert(idc(1) == 1); |
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| 39 | assert(std::move(id)(1) == 1); |
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| 40 | assert(std::move(idc)(1) == 1); |
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| 41 | |
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| 42 | id = idc; // run-time checks assignment |
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| 43 | static_assert(std::is_same_v<decltype(id(i)), int&>); |
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| 44 | static_assert(std::is_same_v<decltype(id(std::declval<int&&>())), int&&>); |
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| 45 | static_assert( |
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| 46 | std::is_same_v<decltype(id(std::declval<int const&>())), int const&>); |
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| 47 | static_assert( |
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| 48 | std::is_same_v<decltype(id(std::declval<int const&&>())), int const&&>); |
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| 49 | static_assert(std::is_same_v<decltype(id(std::declval<int volatile&>())), |
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| 50 | int volatile&>); |
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| 51 | static_assert(std::is_same_v<decltype(id(std::declval<int volatile&&>())), |
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| 52 | int volatile&&>); |
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| 53 | static_assert( |
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| 54 | std::is_same_v<decltype(id(std::declval<int const volatile&>())), |
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| 55 | int const volatile&>); |
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| 56 | static_assert( |
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| 57 | std::is_same_v<decltype(id(std::declval<int const volatile&&>())), |
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| 58 | int const volatile&&>); |
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| 59 | |
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| 60 | struct S { |
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| 61 | constexpr S() = default; |
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| 62 | constexpr S(S&&) noexcept(false) {} |
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| 63 | constexpr S(S const&) noexcept(false) {} |
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| 64 | }; |
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| 65 | S x; |
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| 66 | static_assert(noexcept(id(x))); |
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| 67 | static_assert(noexcept(id(S()))); |
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| 68 | |
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| 69 | return true; |
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| 70 | } |
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| 71 | |
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| 72 | int main(int, char**) { |
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| 73 | test(); |
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| 74 | static_assert(test()); |
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| 75 | |
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| 76 | return 0; |
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| 77 | } |
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| 78 | |
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