hana/test/optional/unpack.cpp
2017-01-07 14:14:18 -08:00

35 lines
875 B
C++

// 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/assert.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/optional.hpp>
#include <boost/hana/unpack.hpp>
#include <laws/base.hpp>
namespace hana = boost::hana;
int main() {
hana::test::ct_eq<2> x{};
hana::test::_injection<0> f{};
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::unpack(hana::nothing, f),
f()
));
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::unpack(hana::just(x), f),
f(x)
));
// Previously, there was a bug that would make this fail.
auto non_const_nothing = hana::nothing;
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::unpack(non_const_nothing, f),
f()
));
}