template <typename Component, typename Context>
struct default_attribute_of<Component, Context,
typename enable_if_c<Component::is_pass_through_unary>::type>
: attribute_of<typename Component::subject_type, Context>{};
}
template <typename Component, typename Context>
struct default_attribute_of<Component, Context,
typename enable_if_c<Component::is_pass_through_unary>::type>
: attribute_of<typename Component::subject_type, Context>{};
}