diff options
Diffstat (limited to 'src/boost/libs/hana/test/optional/nested_type.cpp')
-rw-r--r-- | src/boost/libs/hana/test/optional/nested_type.cpp | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/optional/nested_type.cpp b/src/boost/libs/hana/test/optional/nested_type.cpp new file mode 100644 index 000000000..6e85c2045 --- /dev/null +++ b/src/boost/libs/hana/test/optional/nested_type.cpp @@ -0,0 +1,33 @@ +// 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/optional.hpp> +#include <boost/hana/type.hpp> + +#include <type_traits> +namespace hana = boost::hana; + + +// This test makes sure that an optional holding a hana::type has a +// nested ::type alias. + + +template <typename ...> +using void_t = void; + +template <typename T, typename = void> +struct has_type : std::false_type { }; + +template <typename T> +struct has_type<T, void_t<typename T::type>> + : std::true_type +{ }; + + +struct T; + +static_assert(std::is_same<decltype(hana::just(hana::type_c<T>))::type, T>{}, ""); +static_assert(!has_type<decltype(hana::nothing)>{}, ""); + +int main() { } |