12345678910111213141516171819202122232425262728293031323334 |
- // 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/pair.hpp>
- #include <type_traits>
- namespace hana = boost::hana;
- struct empty1 { };
- struct empty2 { };
- struct empty3 { };
- struct empty4 { };
- // Make sure the storage of a pair is compressed
- static_assert(sizeof(hana::pair<empty1, int>) == sizeof(int), "");
- static_assert(sizeof(hana::pair<int, empty1>) == sizeof(int), "");
- // Also make sure that a pair with only empty members is empty too. This is
- // important to ensure, for example, that a tuple of pairs of empty objects
- // will get the EBO.
- static_assert(std::is_empty<hana::pair<empty1, empty2>>{}, "");
- // Make sure that a pair of empty pairs is still empty.
- static_assert(std::is_empty<
- hana::pair<hana::pair<empty1, empty2>, empty3>
- >{}, "");
- static_assert(std::is_empty<
- hana::pair<hana::pair<empty1, empty2>, hana::pair<empty3, empty4>>
- >{}, "");
- int main() { }
|