mrb_class_real(struct RClass* cl)
{
  if (cl == 0)
    return NULL;
  while ((cl->tt == MRB_TT_SCLASS) || (cl->tt == MRB_TT_ICLASS)) {
    cl = cl->super;
  }
  return cl;
}
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.