#include <boost/fusion/include/define_struct.hpp>
#include <boost/utility/identity_type.hpp>


template<int a, int b>
struct AB {};

struct Silly{
    AB<2,3> ab;
};

BOOST_FUSION_ADAPT_STRUCT(
    Silly,
    (BOOST_IDENTITY_TYPE((AB<2,3>)), ab))

::Silly s;