Message 254576 - Python tracker

Another bug:

    class MainError(Exception):
        pass

    class SubError(Exception):
        pass

    def main():
        try:
            raise MainError()
        except MainError:
            yield

    coro = main()
    coro.send(None)
    coro.throw(SubError())


SubError will propagate, but won't have MainError in its __context__