#define SS_ASSERT_TYPE(_obj_,_type_) do {                                                                                       \
     if (!(_obj_) || SS_MAGIC_OF(_obj_)!=SS_MAGIC(_type_))                                                                       \
         SS_ERROR_FMT(TYPE, ("%s should be type %s", #_obj_, #_type_))                                                           \
 } while (false)