Problem with generator expression and class definition

[Maric Michaud]

I faced a strange behavior with generator expression, which seems like a bug, for both 
python 2.4 and 2.5 :

>>> class A :
...     a = 1, 2, 3
...     b = 1, 2, 3
...     C = list((e,f) for e in a for f in b)
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in A
  File "<stdin>", line 4, in <genexpr>
NameError: global name 'b' is not defined
>>> class A :
...     a = 1, 2, 3
...     b = 1, 2, 3
...     C = [ (e,f) for e in a for f in b ]
...
>>> A.C
[(1, 1), (1, 2), (1, 3), (2, 1), (2, 2), (2, 3), (3, 1), (3, 2), (3, 3)]

Any comment ? I'm ready to report it as a bug if there is no objection.