| 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_swappable |
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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 | // Make the test types non-copyable so that generic std::swap is not valid. |
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| 22 | struct A { |
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| 23 | A(A const&) = delete; |
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| 24 | A& operator=(A const&) = delete; |
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| 25 | }; |
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| 26 | |
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| 27 | struct B { |
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| 28 | B(B const&) = delete; |
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| 29 | B& operator=(B const&) = delete; |
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| 30 | }; |
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| 31 | |
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| 32 | void swap(A&, A&) noexcept {} |
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| 33 | void swap(B&, B&) {} |
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| 34 | |
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| 35 | struct M { |
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| 36 | M(M const&) = delete; |
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| 37 | M& operator=(M const&) = delete; |
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| 38 | }; |
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| 39 | |
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| 40 | void swap(M&&, M&&) noexcept {} |
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| 41 | |
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| 42 | struct ThrowingMove { |
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| 43 | ThrowingMove(ThrowingMove&&) {} |
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| 44 | ThrowingMove& operator=(ThrowingMove&&) { return *this; } |
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| 45 | }; |
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| 46 | |
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| 47 | } // namespace MyNS |
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| 48 | |
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| 49 | int main(int, char**) |
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| 50 | { |
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| 51 | using namespace MyNS; |
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| 52 | { |
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| 53 | // Test that is_swappable applies an lvalue reference to the type. |
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| 54 | static_assert(std::is_nothrow_swappable<int>::value, "" ); |
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| 55 | static_assert(std::is_nothrow_swappable<int&>::value, "" ); |
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| 56 | static_assert(!std::is_nothrow_swappable<M>::value, "" ); |
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| 57 | static_assert(!std::is_nothrow_swappable<M&&>::value, "" ); |
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| 58 | } |
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| 59 | { |
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| 60 | // Test that it correctly deduces the noexcept of swap. |
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| 61 | static_assert(std::is_nothrow_swappable<A>::value, "" ); |
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| 62 | static_assert(!std::is_nothrow_swappable<B>::value |
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| 63 | && std::is_swappable<B>::value, "" ); |
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| 64 | static_assert(!std::is_nothrow_swappable<ThrowingMove>::value |
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| 65 | && std::is_swappable<ThrowingMove>::value, "" ); |
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| 66 | } |
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| 67 | { |
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| 68 | // Test that it doesn't drop the qualifiers |
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| 69 | static_assert(!std::is_nothrow_swappable<const A>::value, "" ); |
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| 70 | } |
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| 71 | { |
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| 72 | // test non-referenceable types |
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| 73 | static_assert(!std::is_nothrow_swappable<void>::value, "" ); |
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| 74 | static_assert(!std::is_nothrow_swappable<int() const>::value, "" ); |
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| 75 | static_assert(!std::is_nothrow_swappable<int(int, ...) const &>::value, "" ); |
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| 76 | } |
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| 77 | { |
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| 78 | // test for presence of is_nothrow_swappable_v |
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| 79 | static_assert(std::is_nothrow_swappable_v<int>, "" ); |
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| 80 | static_assert(!std::is_nothrow_swappable_v<void>, "" ); |
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| 81 | } |
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| 82 | |
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| 83 | return 0; |
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| 84 | } |
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| 85 | |
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