1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // <tuple>
10
11 // constexpr const tuple& operator=(tuple&&) const;
12 //
13 // Constraints: (is_assignable_v<const Types&, Types> && ...) is true.
14
15 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
16
17 // test constraints
18
19 #include <cassert>
20 #include <tuple>
21 #include <type_traits>
22
23 #include "test_macros.h"
24 #include "copy_move_types.h"
25
26 static_assert(!std::is_assignable_v<const std::tuple<int>&, std::tuple<int>&&>);
27 static_assert(std::is_assignable_v<const std::tuple<int&>&, std::tuple<int&>&&>);
28 static_assert(std::is_assignable_v<const std::tuple<int&, int&>&, std::tuple<int&, int&>&&>);
29 static_assert(!std::is_assignable_v<const std::tuple<int&, int>&, std::tuple<int&, int>&&>);
30
31 // this is fallback to tuple's const copy assignment
32 static_assert(std::is_assignable_v<const std::tuple<ConstCopyAssign>&, std::tuple<ConstCopyAssign>&&>);
33
34 static_assert(!std::is_assignable_v<const std::tuple<CopyAssign>&, std::tuple<CopyAssign>&&>);
35 static_assert(std::is_assignable_v<const std::tuple<ConstMoveAssign>&, std::tuple<ConstMoveAssign>&&>);
36 static_assert(!std::is_assignable_v<const std::tuple<MoveAssign>&, std::tuple<MoveAssign>&&>);
37
test()38 constexpr bool test() {
39 // reference types
40 {
41 int i1 = 1;
42 int i2 = 2;
43 double d1 = 3.0;
44 double d2 = 5.0;
45 std::tuple<int&, double&> t1{i1, d1};
46 const std::tuple<int&, double&> t2{i2, d2};
47 t2 = std::move(t1);
48 assert(std::get<0>(t2) == 1);
49 assert(std::get<1>(t2) == 3.0);
50 }
51
52 // user defined const move assignment
53 {
54 std::tuple<ConstMoveAssign> t1{1};
55 const std::tuple<ConstMoveAssign> t2{2};
56 t2 = std::move(t1);
57 assert(std::get<0>(t2).val == 1);
58 }
59
60 // make sure the right assignment operator of the type in the tuple is used
61 {
62 std::tuple<TracedAssignment, const TracedAssignment> t1{};
63 const std::tuple<TracedAssignment, const TracedAssignment> t2{};
64 t2 = std::move(t1);
65 assert(std::get<0>(t2).constMoveAssign == 1);
66 assert(std::get<1>(t2).constCopyAssign == 1);
67 }
68
69 return true;
70 }
71
main(int,char **)72 int main(int, char**) {
73 test();
74 // gcc cannot have mutable member in constant expression
75 #if !defined(TEST_COMPILER_GCC)
76 static_assert(test());
77 #endif
78 return 0;
79 }
80