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)
5 #include <boost/hana/assert.hpp>
6 #include <boost/hana/config.hpp>
7 #include <boost/hana/equal.hpp>
8 #include <boost/hana/optional.hpp>
9 namespace hana
= boost::hana
;
13 BOOST_HANA_CONSTEXPR_LAMBDA
auto incr
= [](auto x
) -> decltype(x
+ 1) {
17 BOOST_HANA_CONSTEXPR_CHECK(hana::sfinae(incr
)(1) == hana::just(2));
20 BOOST_HANA_CONSTANT_CHECK(hana::sfinae(incr
)(invalid
{}) == hana::nothing
);