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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/ext/std/pair.hpp>
- #include <boost/hana/first.hpp>
- #include <boost/hana/second.hpp>
- #include <utility>
- namespace hana = boost::hana;
- template <typename T>
- T const& cref(T& t) { return t; }
- // a non-movable, non-copyable type
- template <int i>
- struct RefOnly {
- RefOnly() = default;
- RefOnly(RefOnly const&) = delete;
- RefOnly(RefOnly&&) = delete;
- };
- int main() {
- // This test makes sure that we return the proper reference types from
- // `first` and `second`.
- std::pair<RefOnly<0>, RefOnly<1>> p;
- {
- RefOnly<0>&& r1 = hana::first(std::move(p));
- RefOnly<0>& r2 = hana::first(p);
- RefOnly<0> const& r3 = hana::first(cref(p));
- (void)r1; (void)r2; (void)r3;
- }
- {
- RefOnly<1>&& r1 = hana::second(std::move(p));
- RefOnly<1>& r2 = hana::second(p);
- RefOnly<1> const& r3 = hana::second(cref(p));
- (void)r1; (void)r2; (void)r3;
- }
- }
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