1 // Copyright Louis Dionne 2013-2017
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)
5 #include <boost/hana/assert.hpp>
6 #include <boost/hana/first.hpp>
7 #include <boost/hana/pair.hpp>
8 #include <boost/hana/second.hpp>
10 #include <type_traits>
11 namespace hana = boost::hana;
14 template <typename Target>
16 constexpr operator Target() const { return Target{}; }
21 NoCopy(NoCopy const&) = delete;
24 // Note: It is also useful to check with a non-empty class, because that
25 // triggers different instantiations due to EBO.
26 struct NoCopy_nonempty {
27 NoCopy_nonempty() = default;
28 NoCopy_nonempty(NoCopy_nonempty const&) = delete;
34 typedef std::pair<int, short> P1;
35 hana::pair<int, short> p1(3, 4);
36 hana::pair<int, short> p2 = p1;
37 BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == 3);
38 BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
41 static_assert(std::is_trivially_copy_constructible<hana::pair<int, int>>{}, "");
43 // make sure it also works constexpr
45 constexpr hana::pair<int, short> p1(3, 4);
46 constexpr hana::pair<int, short> p2 = p1;
47 static_assert(hana::first(p2) == 3, "");
48 static_assert(hana::second(p2) == 4, "");
51 // Make sure it works across pair types (pair<T, U> -> pair<U, V>)
53 hana::pair<int, short> p1(3, 4);
54 hana::pair<double, long> p2 = p1;
55 BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == 3);
56 BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
61 using Target = hana::pair<target1, target2>;
63 auto p1_ = hana::make_pair(target1{}, target2{});
64 Target p1(p1_); (void)p1;
66 auto p2_ = hana::make_pair(implicit_to<target1>{}, target2{});
69 auto p3_ = hana::make_pair(target1{}, implicit_to<target2>{});
72 auto p4_ = hana::make_pair(implicit_to<target1>{}, implicit_to<target2>{});
76 // And also constexpr across pair types
78 constexpr hana::pair<int, short> p1(3, 4);
79 constexpr hana::pair<double, long> p2 = p1;
80 static_assert(hana::first(p2) == 3, "");
81 static_assert(hana::second(p2) == 4, "");
84 // Make sure we don't define the copy constructor when it shouldn't be defined.
86 using Pair1 = hana::pair<NoCopy, NoCopy>;
88 static_assert(!std::is_copy_constructible<Pair1>::value, "");
90 using Pair2 = hana::pair<NoCopy_nonempty, NoCopy_nonempty>;
92 static_assert(!std::is_copy_constructible<Pair2>::value, "");