SystemError PyState_AddModule called on module with slots in testmultiphase

[YuanchengJiang]

Bug report

Bug description:

import _testmultiphase
_testmultiphase.call_state_registration_func(1)

    _testmultiphase.call_state_registration_func(1)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^
SystemError: PyState_AddModule called on module with slots

Not sure if this is interesting, as it is a test lib.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

[ZeroIntensity]

This is expected behavior:

cpython/Lib/test/test_importlib/extension/test_loader.py

Lines 287 to 289 in d3aa5f6

	with self.subTest('PyState_AddModule'):
	with self.assertRaises(SystemError):
	module.call_state_registration_func(1)