is_swappable_with.pass.cpp (2146B)
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_with 15 16 #include <type_traits> 17 #include <vector> 18 #include "test_macros.h" 19 20 namespace MyNS { 21 22 struct A { 23 A(A const&) = delete; 24 A& operator=(A const&) = delete; 25 }; 26 27 struct B { 28 B(B const&) = delete; 29 B& operator=(B const&) = delete; 30 }; 31 32 struct C {}; 33 struct D {}; 34 35 void swap(A&, A&) {} 36 37 void swap(A&, B&) {} 38 void swap(B&, A&) {} 39 40 void swap(A&, C&) {} // missing swap(C, A) 41 void swap(D&, C&) {} 42 43 struct M {}; 44 45 void swap(M&&, M&&) {} 46 47 } // namespace MyNS 48 49 int main() 50 { 51 using namespace MyNS; 52 { 53 // Test that is_swappable_with doesn't apply an lvalue reference 54 // to the type. Instead it is up to the user. 55 static_assert(!std::is_swappable_with<int, int>::value, ""); 56 static_assert(std::is_swappable_with<int&, int&>::value, ""); 57 static_assert(std::is_swappable_with<M, M>::value, ""); 58 static_assert(std::is_swappable_with<A&, A&>::value, ""); 59 } 60 { 61 // test that heterogeneous swap is allowed only if both 'swap(A, B)' and 62 // 'swap(B, A)' are valid. 63 static_assert(std::is_swappable_with<A&, B&>::value, ""); 64 static_assert(!std::is_swappable_with<A&, C&>::value, ""); 65 static_assert(!std::is_swappable_with<D&, C&>::value, ""); 66 } 67 { 68 // test that cv void is guarded against as required. 69 static_assert(!std::is_swappable_with_v<void, int>, ""); 70 static_assert(!std::is_swappable_with_v<int, void>, ""); 71 static_assert(!std::is_swappable_with_v<const void, const volatile void>, ""); 72 } 73 { 74 // test for presence of is_swappable_with_v 75 static_assert(std::is_swappable_with_v<int&, int&>, ""); 76 static_assert(!std::is_swappable_with_v<D&, C&>, ""); 77 } 78 }