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=(pair<U1, U2>&& u);
15
16 // UNSUPPORTED: c++03
17
18 #include <tuple>
19 #include <utility>
20 #include <memory>
21 #include <cassert>
22
23 #include "test_macros.h"
24
25 struct B
26 {
27 int id_;
28
BB29 explicit B(int i = 0) : id_(i) {}
30
~BB31 virtual ~B() {}
32 };
33
34 struct D
35 : B
36 {
DD37 explicit D(int i) : B(i) {}
38 };
39
40 struct TrackMove
41 {
TrackMoveTrackMove42 TrackMove() : value(0), moved_from(false) { }
TrackMoveTrackMove43 explicit TrackMove(int v) : value(v), moved_from(false) { }
TrackMoveTrackMove44 TrackMove(TrackMove const& other) : value(other.value), moved_from(false) { }
TrackMoveTrackMove45 TrackMove(TrackMove&& other) : value(other.value), moved_from(false) {
46 other.moved_from = true;
47 }
operator =TrackMove48 TrackMove& operator=(TrackMove const& other) {
49 value = other.value;
50 moved_from = false;
51 return *this;
52 }
operator =TrackMove53 TrackMove& operator=(TrackMove&& other) {
54 value = other.value;
55 moved_from = false;
56 other.moved_from = true;
57 return *this;
58 }
59
60 int value;
61 bool moved_from;
62 };
63
64 struct NonAssignable
65 {
66 NonAssignable& operator=(NonAssignable const&) = delete;
67 NonAssignable& operator=(NonAssignable&&) = delete;
68 };
69
70 struct MoveAssignable
71 {
72 MoveAssignable& operator=(MoveAssignable const&) = delete;
73 MoveAssignable& operator=(MoveAssignable&&) = default;
74 };
75
76 struct CopyAssignable
77 {
78 CopyAssignable& operator=(CopyAssignable const&) = default;
79 CopyAssignable& operator=(CopyAssignable&&) = delete;
80 };
81
82 struct NothrowMoveAssignable
83 {
operator =NothrowMoveAssignable84 NothrowMoveAssignable& operator=(NothrowMoveAssignable&&) noexcept { return *this; }
85 };
86
87 struct PotentiallyThrowingMoveAssignable
88 {
operator =PotentiallyThrowingMoveAssignable89 PotentiallyThrowingMoveAssignable& operator=(PotentiallyThrowingMoveAssignable&&) { return *this; }
90 };
91
main(int,char **)92 int main(int, char**)
93 {
94 {
95 typedef std::pair<long, std::unique_ptr<D>> T0;
96 typedef std::tuple<long long, std::unique_ptr<B>> T1;
97 T0 t0(2, std::unique_ptr<D>(new D(3)));
98 T1 t1;
99 t1 = std::move(t0);
100 assert(std::get<0>(t1) == 2);
101 assert(std::get<1>(t1)->id_ == 3);
102 }
103 {
104 using T = std::tuple<int, NonAssignable>;
105 using P = std::pair<int, NonAssignable>;
106 static_assert(!std::is_assignable<T&, P&&>::value, "");
107 }
108 {
109 using T = std::tuple<int, int, int>;
110 using P = std::pair<int, int>;
111 static_assert(!std::is_assignable<T&, P&&>::value, "");
112 }
113 {
114 typedef std::tuple<NothrowMoveAssignable, long> Tuple;
115 typedef std::pair<NothrowMoveAssignable, int> Pair;
116 static_assert(std::is_nothrow_assignable<Tuple&, Pair&&>::value, "");
117 static_assert(!std::is_assignable<Tuple&, Pair const&&>::value, "");
118 }
119 {
120 typedef std::tuple<PotentiallyThrowingMoveAssignable, long> Tuple;
121 typedef std::pair<PotentiallyThrowingMoveAssignable, int> Pair;
122 static_assert(std::is_assignable<Tuple&, Pair&&>::value, "");
123 static_assert(!std::is_nothrow_assignable<Tuple&, Pair&&>::value, "");
124 static_assert(!std::is_assignable<Tuple&, Pair const&&>::value, "");
125 }
126 {
127 // We assign through the reference and don't move out of the incoming ref,
128 // so this doesn't work (but would if the type were CopyAssignable).
129 {
130 using T = std::tuple<MoveAssignable&, int>;
131 using P = std::pair<MoveAssignable&, int>;
132 static_assert(!std::is_assignable<T&, P&&>::value, "");
133 }
134
135 // ... works if it's CopyAssignable
136 {
137 using T = std::tuple<CopyAssignable&, int>;
138 using P = std::pair<CopyAssignable&, int>;
139 static_assert(std::is_assignable<T&, P&&>::value, "");
140 }
141
142 // For rvalue-references, we can move-assign if the type is MoveAssignable
143 // or CopyAssignable (since in the worst case the move will decay into a copy).
144 {
145 using T1 = std::tuple<MoveAssignable&&, int>;
146 using P1 = std::pair<MoveAssignable&&, int>;
147 static_assert(std::is_assignable<T1&, P1&&>::value, "");
148
149 using T2 = std::tuple<CopyAssignable&&, int>;
150 using P2 = std::pair<CopyAssignable&&, int>;
151 static_assert(std::is_assignable<T2&, P2&&>::value, "");
152 }
153
154 // In all cases, we can't move-assign if the types are not assignable,
155 // since we assign through the reference.
156 {
157 using T1 = std::tuple<NonAssignable&, int>;
158 using P1 = std::pair<NonAssignable&, int>;
159 static_assert(!std::is_assignable<T1&, P1&&>::value, "");
160
161 using T2 = std::tuple<NonAssignable&&, int>;
162 using P2 = std::pair<NonAssignable&&, int>;
163 static_assert(!std::is_assignable<T2&, P2&&>::value, "");
164 }
165 }
166 {
167 // Make sure that we don't incorrectly move out of the source's reference.
168 using Dest = std::tuple<TrackMove, int>;
169 using Source = std::pair<TrackMove&, int>;
170 TrackMove track{3};
171 Source src(track, 4);
172 assert(!track.moved_from);
173
174 Dest dst;
175 dst = std::move(src); // here we should make a copy
176 assert(!track.moved_from);
177 assert(std::get<0>(dst).value == 3);
178 }
179 {
180 // But we do move out of the source's reference if it's a rvalue ref
181 using Dest = std::tuple<TrackMove, int>;
182 using Source = std::pair<TrackMove&&, int>;
183 TrackMove track{3};
184 Source src(std::move(track), 4);
185 assert(!track.moved_from); // we just took a reference
186
187 Dest dst;
188 dst = std::move(src);
189 assert(track.moved_from);
190 assert(std::get<0>(dst).value == 3);
191 }
192 {
193 // If the pair holds a value, then we move out of it too
194 using Dest = std::tuple<TrackMove, int>;
195 using Source = std::pair<TrackMove, int>;
196 Source src(TrackMove{3}, 4);
197 Dest dst;
198 dst = std::move(src);
199 assert(src.first.moved_from);
200 assert(std::get<0>(dst).value == 3);
201 }
202
203 return 0;
204 }
205