fetch_probe_arguments (NULL, &typeinfo_arg);
type_name = cplus_typename_from_type_info (typeinfo_arg);
canon = cp_canonicalize_string (type_name.c_str ());
fetch_probe_arguments (NULL, &typeinfo_arg);
type_name = cplus_typename_from_type_info (typeinfo_arg);
canon = cp_canonicalize_string (type_name.c_str ());