http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58252
--- Comment #11 from Jan Hubicka <hubicka at gcc dot gnu.org> --- I am still hoping for help from C++ FE maintainers, but I think the bits we are missing is logic from tree lookup_base (tree t, tree base, base_access access, base_kind *kind_ptr, tsubst_flags_t complain) that seems to be the tool C++ FE looks up base and binfo of given subtype. I am trying to get through the (somewhat convoluted at first glance) logic of this function.