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// Copyright Louis Dionne 2013-2017
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
#include <boost/hana/assert.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/first.hpp>
#include <boost/hana/pair.hpp>
#include <boost/hana/second.hpp>
#include <utility>
namespace hana = boost::hana;
struct MoveOnly {
int data_;
MoveOnly(MoveOnly const&) = delete;
MoveOnly& operator=(MoveOnly const&) = delete;
MoveOnly(int data = 1) : data_(data) { }
MoveOnly(MoveOnly&& x) : data_(x.data_) { x.data_ = 0; }
MoveOnly& operator=(MoveOnly&& x)
{ data_ = x.data_; x.data_ = 0; return *this; }
bool operator==(const MoveOnly& x) const { return data_ == x.data_; }
};
struct MoveOnlyDerived : MoveOnly {
MoveOnlyDerived(MoveOnlyDerived&&) = default;
MoveOnlyDerived(int data = 1) : MoveOnly(data) { }
};
constexpr auto in_constexpr_context(int a, short b) {
hana::pair<int, short> p1(a, b);
hana::pair<int, short> p2;
hana::pair<double, long> p3;
p2 = std::move(p1);
p3 = std::move(p2);
return p3;
}
int main() {
// from pair<T, U> to pair<T, U>
{
hana::pair<MoveOnly, short> p1(MoveOnly{3}, 4);
hana::pair<MoveOnly, short> p2;
p2 = std::move(p1);
BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
}
// from pair<T, U> to pair<V, W>
{
hana::pair<MoveOnlyDerived, short> p1(MoveOnlyDerived{3}, 4);
hana::pair<MoveOnly, long> p2;
p2 = std::move(p1);
BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
}
// make sure that also works in a constexpr context
// (test fails under GCC <= 6 due to buggy constexpr)
#if BOOST_HANA_CONFIG_GCC >= BOOST_HANA_CONFIG_VERSION(7, 0, 0)
{
constexpr auto p = in_constexpr_context(3, 4);
static_assert(hana::first(p) == 3, "");
static_assert(hana::second(p) == 4, "");
}
#endif
}
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