| 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 |
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| 10 | |
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| 11 | // type_traits |
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| 12 | |
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| 13 | // is_nothrow_swappable_with |
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| 14 | |
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| 15 | #include <type_traits> |
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| 16 | #include <vector> |
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| 17 | #include "test_macros.h" |
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| 18 | |
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| 19 | namespace MyNS { |
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| 20 | |
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| 21 | struct A { |
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| 22 | A(A const&) = delete; |
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| 23 | A& operator=(A const&) = delete; |
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| 24 | }; |
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| 25 | |
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| 26 | struct B { |
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| 27 | B(B const&) = delete; |
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| 28 | B& operator=(B const&) = delete; |
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| 29 | }; |
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| 30 | |
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| 31 | struct C {}; |
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| 32 | struct D {}; |
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| 33 | |
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| 34 | void swap(A&, A&) {} |
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| 35 | |
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| 36 | void swap(A&, B&) noexcept {} |
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| 37 | void swap(B&, A&) noexcept {} |
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| 38 | |
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| 39 | void swap(A&, C&) noexcept {} |
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| 40 | void swap(C&, A&) {} |
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| 41 | |
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| 42 | struct M {}; |
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| 43 | |
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| 44 | void swap(M&&, M&&) noexcept {} |
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| 45 | |
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| 46 | } // namespace MyNS |
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| 47 | |
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| 48 | int main(int, char**) |
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| 49 | { |
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| 50 | using namespace MyNS; |
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| 51 | { |
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| 52 | // Test that is_swappable_with doesn't apply an lvalue reference |
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| 53 | // to the type. Instead it is up to the user. |
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| 54 | static_assert(!std::is_nothrow_swappable_with<int, int>::value, "" ); |
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| 55 | static_assert(std::is_nothrow_swappable_with<int&, int&>::value, "" ); |
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| 56 | static_assert(std::is_nothrow_swappable_with<M, M>::value, "" ); |
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| 57 | static_assert(std::is_swappable_with<A&, A&>::value && |
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| 58 | !std::is_nothrow_swappable_with<A&, A&>::value, "" ); |
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| 59 | } |
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| 60 | { |
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| 61 | // test that heterogeneous swap is allowed only if both 'swap(A, B)' and |
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| 62 | // 'swap(B, A)' are valid. |
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| 63 | static_assert(std::is_nothrow_swappable_with<A&, B&>::value, "" ); |
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| 64 | static_assert(!std::is_nothrow_swappable_with<A&, C&>::value && |
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| 65 | std::is_swappable_with<A&, C&>::value, "" ); |
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| 66 | static_assert(!std::is_nothrow_swappable_with<D&, C&>::value, "" ); |
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| 67 | } |
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| 68 | { |
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| 69 | // test we guard against cv void inputs as required. |
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| 70 | static_assert(!std::is_nothrow_swappable_with_v<void, int>, "" ); |
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| 71 | static_assert(!std::is_nothrow_swappable_with_v<int, void>, "" ); |
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| 72 | static_assert(!std::is_nothrow_swappable_with_v<const void, const volatile void>, "" ); |
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| 73 | |
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| 74 | } |
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| 75 | { |
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| 76 | // test for presence of is_nothrow_swappable_with_v |
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| 77 | static_assert(std::is_nothrow_swappable_with_v<int&, int&>, "" ); |
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| 78 | static_assert(!std::is_nothrow_swappable_with_v<int&&, int&&>, "" ); |
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| 79 | } |
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| 80 | |
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| 81 | return 0; |
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| 82 | } |
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| 83 | |
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