When a class defines __eq__, a signal on this class will crash immediately when connected.
Example code:

from PySide6 import QtCore
from PySide6 import QtWidgets

class Main:
    def setup(self):
        self.input_dialog = QtWidgets.QInputDialog()

        print('before', flush=True)
        self.input_dialog.accepted.connect(self.input_accepted)
        print('after', flush=True)

    def input_accepted(self):
        pass

    def __eq__(self, other): return super().__eq__(other)
    # def __hash__(self): return id(self)

def main():
    application = QtWidgets.QApplication([])
    main_object = Main()
    main_object.setup()
    QtCore.QTimer.singleShot(0, application.quit)
    application.exec_()

if __name__ == "__main__":
    main()

When we also define a __hash__ function, everything works, again.

What happens?

In the implementation, PyObject_Hash is called, both on the signal function and on the class instance.
The class instance by default is hashable by PyObject s default, but when __eq__ gets explicitly
defined, the default __hash__ is gone.

The second hash call then creates an undetected error, which in turn has the effect that new types
cannot be created, and we segfault.

Solution: We don't call __hash__ a second time, but use the object address directly.
That has no negative effect on the hash function since random plus some offset remains random.