1 // Copyright Louis Dionne 2013-2017
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/core/make.hpp>
7 #include <boost/hana/equal.hpp>
8 #include <boost/hana/optional.hpp>
9 namespace hana = boost::hana;
10 
11 
main()12 int main() {
13     constexpr auto x = hana::make<hana::optional_tag>();
14     BOOST_HANA_CONSTANT_CHECK(x == hana::make_optional());
15     BOOST_HANA_CONSTANT_CHECK(hana::is_nothing(x));
16 
17     constexpr auto just_x = hana::make<hana::optional_tag>('x');
18     static_assert(just_x == hana::make_optional('x'), "");
19     BOOST_HANA_CONSTANT_CHECK(hana::is_just(just_x));
20 }
21