1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // UNSUPPORTED: c++98, c++03, c++11, c++14 11 12 // type_traits 13 14 // is_swappable 15 16 #include <type_traits> 17 #include <utility> 18 #include <vector> 19 #include "test_macros.h" 20 21 namespace MyNS { 22 23 // Make the test types non-copyable so that generic std::swap is not valid. 24 struct A { 25 A(A const&) = delete; 26 A& operator=(A const&) = delete; 27 }; 28 29 struct B { 30 B(B const&) = delete; 31 B& operator=(B const&) = delete; 32 }; 33 34 struct C {}; 35 struct D {}; 36 37 void swap(A&, A&) {} 38 39 void swap(A&, B&) {} 40 void swap(B&, A&) {} 41 42 void swap(A&, C&) {} // missing swap(C, A) 43 void swap(D&, C&) {} 44 45 struct M { 46 M(M const&) = delete; 47 M& operator=(M const&) = delete; 48 }; 49 50 void swap(M&&, M&&) {} 51 52 struct DeletedSwap { 53 friend void swap(DeletedSwap&, DeletedSwap&) = delete; 54 }; 55 56 } // namespace MyNS 57 58 namespace MyNS2 { 59 60 struct AmbiguousSwap {}; 61 62 template <class T> 63 void swap(T&, T&) {} 64 65 } // end namespace MyNS2 66 67 int main() 68 { 69 using namespace MyNS; 70 { 71 // Test that is_swappable applies an lvalue reference to the type. 72 static_assert(std::is_swappable<A>::value, ""); 73 static_assert(std::is_swappable<A&>::value, ""); 74 static_assert(!std::is_swappable<M>::value, ""); 75 static_assert(!std::is_swappable<M&&>::value, ""); 76 } 77 static_assert(!std::is_swappable<B>::value, ""); 78 static_assert(std::is_swappable<C>::value, ""); 79 { 80 // test non-referencable types 81 static_assert(!std::is_swappable<void>::value, ""); 82 static_assert(!std::is_swappable<int() const>::value, ""); 83 static_assert(!std::is_swappable<int() &>::value, ""); 84 } 85 { 86 // test that a deleted swap is correctly handled. 87 static_assert(!std::is_swappable<DeletedSwap>::value, ""); 88 } 89 { 90 // test that a swap with ambiguous overloads is handled correctly. 91 static_assert(!std::is_swappable<MyNS2::AmbiguousSwap>::value, ""); 92 } 93 { 94 // test for presence of is_swappable_v 95 static_assert(std::is_swappable_v<int>, ""); 96 static_assert(!std::is_swappable_v<M>, ""); 97 } 98 } 99
