Error : function call 'assertion_failed(boost::mpl::failed ************boost::mpl::equal, boost::mpl::v_item, boost::mpl::v_item, boost::mpl::vector0, 0>, 0>, boost::is_same, boost::mpl::arg<-1>>>::************)' does not match 'boost::mpl::assertion_failed<...>(boost::mpl::assert<{targ_expr}>::type)' (point of instantiation: 'test_unit_analysis()') (instantiating: 'operator+>, boost::mpl::vector_c>, dimension>, boost::mpl::vector_c>>(quantity>, boost::mpl::vector_c>>, quantity>, boost::mpl::vector_c>>)') quantity.hpp line 337 BOOST_MPL_ASSERT((mpl::equal<