1 // Copyright Louis Dionne 2013-2016
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/at.hpp>
6 #include <boost/hana/first.hpp>
7 #include <boost/hana/pair.hpp>
8 #include <boost/hana/second.hpp>
9 #include <boost/hana/tuple.hpp>
10 namespace hana = boost::hana;
11
12
13 // This test makes sure that tuples containing pairs behave properly. It is
14 // useful to test this specific case because tuple and pair (may) share a lot
15 // of implementation details (for EBO), and that can easily lead to subtle bugs.
16 // For example, if both pair and tuple inherit from similar base classes for
17 // EBO, accessing a tuple of pairs or a pair of tuples (which requires some
18 // base class casting magic) can lead to ambiguous overloads.
19
main()20 int main() {
21 struct empty1 { };
22 struct empty2 { };
23
24 {
25 hana::tuple<hana::pair<empty1, empty2>> t{};
26 hana::first(hana::at_c<0>(t));
27 hana::second(hana::at_c<0>(t));
28 }
29 {
30 hana::tuple<hana::pair<int, empty2>> t{};
31 hana::first(hana::at_c<0>(t));
32 hana::second(hana::at_c<0>(t));
33 }
34 {
35 hana::tuple<hana::pair<int, int>> t{};
36 hana::first(hana::at_c<0>(t));
37 hana::second(hana::at_c<0>(t));
38 }
39 {
40 hana::tuple<hana::pair<empty1, int>> t{};
41 hana::first(hana::at_c<0>(t));
42 hana::second(hana::at_c<0>(t));
43 }
44
45 {
46 hana::pair<hana::tuple<>, hana::tuple<>> p{};
47 hana::first(p);
48 hana::second(p);
49 }
50 {
51 hana::pair<hana::tuple<int>, hana::tuple<int>> p{};
52 hana::first(p);
53 hana::second(p);
54 }
55 {
56 hana::pair<hana::tuple<>, hana::tuple<int>> p{};
57 hana::first(p);
58 hana::second(p);
59 }
60 {
61 hana::pair<hana::tuple<empty1>, hana::tuple<empty2>> p{};
62 hana::first(p);
63 hana::second(p);
64 }
65 {
66 hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty2>> p{};
67 hana::first(p);
68 hana::second(p);
69 }
70 {
71 hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty1, empty2>> p{};
72 hana::first(p);
73 hana::second(p);
74 }
75 }
76