Anyone with knowledge of Lib/compiler is urged to examine www.python.org/sf/1042238. It's breaking on some genexprs, in particular in Lib/_strptime.py
The failing code, distilled down, is:
import compiler a="""def foo(*x): return x foo((a for b in [[1,2,3],[4,5,6]] for a in b),'Z')""" compiler.compile(a,'<string>', 'exec')
It's the combination of the genexps and the function call with another argument.
This bug is bad enough (IMHO) to block 2.4b1. Please, if you know about this, have a look at the failure.