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b32b8144 | 1 | // Copyright Louis Dionne 2013-2017 |
7c673cae FG |
2 | // Distributed under the Boost Software License, Version 1.0. |
3 | // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
4 | ||
5 | #include <boost/hana/assert.hpp> | |
b32b8144 | 6 | #include <boost/hana/config.hpp> |
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7 | #include <boost/hana/first.hpp> |
8 | #include <boost/hana/pair.hpp> | |
9 | #include <boost/hana/second.hpp> | |
10 | ||
11 | #include <utility> | |
12 | namespace hana = boost::hana; | |
13 | ||
14 | ||
15 | struct MoveOnly { | |
16 | int data_; | |
17 | MoveOnly(MoveOnly const&) = delete; | |
18 | MoveOnly& operator=(MoveOnly const&) = delete; | |
19 | MoveOnly(int data = 1) : data_(data) { } | |
20 | MoveOnly(MoveOnly&& x) : data_(x.data_) { x.data_ = 0; } | |
21 | ||
22 | MoveOnly& operator=(MoveOnly&& x) | |
23 | { data_ = x.data_; x.data_ = 0; return *this; } | |
24 | ||
25 | bool operator==(const MoveOnly& x) const { return data_ == x.data_; } | |
26 | }; | |
27 | ||
28 | struct MoveOnlyDerived : MoveOnly { | |
29 | MoveOnlyDerived(MoveOnlyDerived&&) = default; | |
30 | MoveOnlyDerived(int data = 1) : MoveOnly(data) { } | |
31 | }; | |
32 | ||
33 | constexpr auto in_constexpr_context(int a, short b) { | |
34 | hana::pair<int, short> p1(a, b); | |
35 | hana::pair<int, short> p2; | |
36 | hana::pair<double, long> p3; | |
37 | p2 = std::move(p1); | |
38 | p3 = std::move(p2); | |
39 | return p3; | |
40 | } | |
41 | ||
42 | int main() { | |
43 | // from pair<T, U> to pair<T, U> | |
44 | { | |
45 | hana::pair<MoveOnly, short> p1(MoveOnly{3}, 4); | |
46 | hana::pair<MoveOnly, short> p2; | |
47 | p2 = std::move(p1); | |
48 | BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3}); | |
49 | BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4); | |
50 | } | |
51 | ||
52 | // from pair<T, U> to pair<V, W> | |
53 | { | |
54 | hana::pair<MoveOnlyDerived, short> p1(MoveOnlyDerived{3}, 4); | |
55 | hana::pair<MoveOnly, long> p2; | |
56 | p2 = std::move(p1); | |
57 | BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3}); | |
58 | BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4); | |
59 | } | |
60 | ||
61 | // make sure that also works in a constexpr context | |
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62 | // (test fails under GCC <= 6 due to buggy constexpr) |
63 | #if BOOST_HANA_CONFIG_GCC >= BOOST_HANA_CONFIG_VERSION(7, 0, 0) | |
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64 | { |
65 | constexpr auto p = in_constexpr_context(3, 4); | |
66 | static_assert(hana::first(p) == 3, ""); | |
67 | static_assert(hana::second(p) == 4, ""); | |
68 | } | |
b32b8144 | 69 | #endif |
7c673cae | 70 | } |