Trunk Revision: 58651

Example of potential issue:

>>> a = [1,2,3,4,5]
>>>
>>> for x in a:
...   a.remove(x)
...
>>>
>>> a
[2, 4]


If this is the expected behavior of iteration in this case, my
apologies.  If this is not, I believe the issue lies in that
listiter_next does not act correctly after a listremove has occurred.

My knowledge of Python development is practically 0, so please take the
patch with a grain of salt.