See issue33712, issue33713 and issue33714 for three cases in the stdlib where an exception can be set in the tp_clear handler. This caused a crash in the garbage collector, or can be just silenced if failed at the shutdown stage. In the master branch it will cause writing a traceback to the stderr. It would be better to handle exceptions locally in the tp_clear handlers. But perhaps it may be worth to handle leaked exceptions in the garbage collector too. I'm just not sure about a solution. Writing a traceback to the stderr can cause a regression if it was just silenced before. But silencing it can hide bugs.