ceph/src/boost/libs/hana/test/pair/cnstr.default.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/assert.hpp>
   6 #include <boost/hana/first.hpp>
   7 #include <boost/hana/pair.hpp>
   8 #include <boost/hana/second.hpp>
   9 namespace hana = boost::hana;
  10
  11
  12 struct NoDefault {
  13     NoDefault() = delete;
  14     explicit constexpr NoDefault(int) { }
  15 };
  16
  17 struct DefaultOnly {
  18     DefaultOnly() = default;
  19     DefaultOnly(DefaultOnly const&) = delete;
  20     DefaultOnly(DefaultOnly&&) = delete;
  21 };
  22
  23 struct NonConstexprDefault {
  24     NonConstexprDefault() { }
  25 };
  26
  27 int main() {
  28     {
  29         hana::pair<float, short*> p;
  30         BOOST_HANA_RUNTIME_CHECK(hana::first(p) == 0.0f);
  31         BOOST_HANA_RUNTIME_CHECK(hana::second(p) == nullptr);
  32     }
  33
  34     // make sure it also works constexpr
  35     {
  36         constexpr hana::pair<float, short*> p;
  37         static_assert(hana::first(p) == 0.0f, "");
  38         static_assert(hana::second(p) == nullptr, "");
  39     }
  40
  41     // make sure the default constructor is not instantiated when the
  42     // members of the pair are not default-constructible
  43     {
  44         hana::pair<NoDefault, NoDefault> p{NoDefault{1}, NoDefault{2}};
  45         (void)p;
  46     }
  47
  48     // make sure it works when only the default constructor is defined
  49     {
  50         hana::pair<DefaultOnly, DefaultOnly> p;
  51         (void)p;
  52     }
  53
  54     {
  55         hana::pair<NonConstexprDefault, NonConstexprDefault> p;
  56         (void)p;
  57     }
  58 }