Issue 22920: Crash with itertools.chain.from_iterable

import itertools

l = []
it = itertools.chain.from_iterable(l)
l.append(it)
next(it)

Ian Kelly (python-list, version unspecified) got "Segmentation fault (core dumped)".  With 2.7, 3.4.2, 3.5, I get same in interactive interpreter, the Windows "python has stopped working" box from console, or subprocess hang with Idle.