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
24struct NothrowCopyAssignable {
25 NothrowCopyAssignable(NothrowCopyAssignable const&) = delete;
26 NothrowCopyAssignable& operator=(NothrowCopyAssignable const&) noexcept { return *this; }
27};
28struct PotentiallyThrowingCopyAssignable {
29 PotentiallyThrowingCopyAssignable(PotentiallyThrowingCopyAssignable const&) = delete;
30 PotentiallyThrowingCopyAssignable& operator=(PotentiallyThrowingCopyAssignable const&) { return *this; }
31};
32
33#include "test_macros.h"
34
35TEST_CONSTEXPR_CXX20
36bool 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
50int 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

source code of libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp