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 // template <class... Types> class tuple;
12 
13 // template <class U1, class U2>
14 //   tuple& operator=(const pair<U1, U2>& u);
15 
16 // UNSUPPORTED: c++03
17 
18 #include <cassert>
19 #include <memory>
20 #include <tuple>
21 #include <type_traits>
22 #include <utility>
23 
24 struct NothrowCopyAssignable {
25     NothrowCopyAssignable(NothrowCopyAssignable const&) = delete;
26     NothrowCopyAssignable& operator=(NothrowCopyAssignable const&) noexcept { return *this; }
27 };
28 struct PotentiallyThrowingCopyAssignable {
29     PotentiallyThrowingCopyAssignable(PotentiallyThrowingCopyAssignable const&) = delete;
30     PotentiallyThrowingCopyAssignable& operator=(PotentiallyThrowingCopyAssignable const&) { return *this; }
31 };
32 
33 #include "test_macros.h"
34 
35 TEST_CONSTEXPR_CXX20
36 bool test()
37 {
38     {
39         typedef std::pair<long, char> T0;
40         typedef std::tuple<long long, short> T1;
41         T0 t0(2, 'a');
42         T1 t1;
43         t1 = t0;
44         assert(std::get<0>(t1) == 2);
45         assert(std::get<1>(t1) == short('a'));
46     }
47     return true;
48 }
49 
50 int main(int, char**)
51 {
52     test();
53 #if TEST_STD_VER >= 20
54     static_assert(test());
55 #endif
56 
57     {
58         // test that the implicitly generated copy assignment operator
59         // is properly deleted
60         using T = std::tuple<int, int>;
61         using P = std::tuple<std::unique_ptr<int>, std::unique_ptr<int>>;
62         static_assert(!std::is_assignable<T&, const P &>::value, "");
63     }
64     {
65         typedef std::tuple<NothrowCopyAssignable, long> Tuple;
66         typedef std::pair<NothrowCopyAssignable, int> Pair;
67         static_assert(std::is_nothrow_assignable<Tuple&, Pair const&>::value, "");
68         static_assert(std::is_nothrow_assignable<Tuple&, Pair&>::value, "");
69         static_assert(std::is_nothrow_assignable<Tuple&, Pair const&&>::value, "");
70     }
71     {
72         typedef std::tuple<PotentiallyThrowingCopyAssignable, long> Tuple;
73         typedef std::pair<PotentiallyThrowingCopyAssignable, int> Pair;
74         static_assert(std::is_assignable<Tuple&, Pair const&>::value, "");
75         static_assert(!std::is_nothrow_assignable<Tuple&, Pair const&>::value, "");
76 
77         static_assert(std::is_assignable<Tuple&, Pair&>::value, "");
78         static_assert(!std::is_nothrow_assignable<Tuple&, Pair&>::value, "");
79 
80         static_assert(std::is_assignable<Tuple&, Pair const&&>::value, "");
81         static_assert(!std::is_nothrow_assignable<Tuple&, Pair const&&>::value, "");
82     }
83 
84     return 0;
85 }
86