libs/hana/test/pair/tag_of.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/core/tag_of.hpp>
   6 #include <boost/hana/ext/std/integral_constant.hpp>
   7 #include <boost/hana/integral_constant.hpp>
   8 #include <boost/hana/pair.hpp>
   9
  10 #include <type_traits>
  11 namespace hana = boost::hana;
  12
  13
  14 int main() {
  15     {
  16         struct T { }; struct U { };
  17         static_assert(std::is_same<
  18             hana::tag_of<hana::pair<T, U>>::type,
  19             hana::pair_tag
  20         >{}, "");
  21     }
  22
  23     // Bug #1
  24     {
  25         using Pair = hana::pair<hana::integral_constant<int, 3>, int>;
  26         using PairTag = hana::tag_of<Pair>::type;
  27         using Tag = hana::tag_of<std::integral_constant<unsigned long, 0>>::type;
  28     }
  29
  30     // Bug #2
  31     {
  32         using Pair = hana::pair<std::integral_constant<int, 3>, int>;
  33         using PairTag = hana::tag_of<Pair>::type;
  34         using Tag = hana::tag_of<std::integral_constant<unsigned long, 0>>::type;
  35     }
  36 }