static Runnable _topLevelErrorHandling(Runnable r) {
  if (r == null) null;
  
  // maybe we don't want this anymore. just dm_current_generic()
  O info = _threadInfo();
  O mod = dm_current_generic();
  if (info == null && mod == null) ret r;
  
  ret r {
    temp (AutoCloseable) rcall enter(mod);
    _threadInheritInfo(info);
    r.run();
  };
}