ceph/src/boost/libs/hana/test/pair/issue_90.cpp

   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/first.hpp>
   6 #include <boost/hana/pair.hpp>
   7 #include <boost/hana/second.hpp>
   8
   9 #include <utility>
  10 namespace hana = boost::hana;
  11
  12
  13 template <typename T>
  14 T const& cref(T& t) { return t; }
  15
  16 // a non-movable, non-copyable type
  17 struct RefOnly {
  18     RefOnly() = default;
  19     RefOnly(RefOnly const&) = delete;
  20     RefOnly(RefOnly&&) = delete;
  21 };
  22
  23 int main() {
  24     // This test makes sure that we return the proper reference types from
  25     // `first` and `second`.
  26     hana::pair<RefOnly, RefOnly> p;
  27
  28     {
  29         RefOnly&& r1 = hana::first(std::move(p));
  30         RefOnly& r2 = hana::first(p);
  31         RefOnly const& r3 = hana::first(cref(p));
  32
  33         (void)r1; (void)r2; (void)r3;
  34     }
  35
  36     {
  37         RefOnly&& r1 = hana::second(std::move(p));
  38         RefOnly& r2 = hana::second(p);
  39         RefOnly const& r3 = hana::second(cref(p));
  40
  41         (void)r1; (void)r2; (void)r3;
  42     }
  43 }