[Python-3000] Change to class construction?

[Collin Winter]

While experimenting with porting setuptools to py3k (as of r56155), I
ran into this situation:

class C:
  a = (4, 5)
  b = [c for c in range(2) if a]

results in a "NameError: global name 'a' is not defined" error, while

class C:
  a = (4, 5)
  b = [c for c in a]

works fine. This gives the same error as above:

class C:
  a = (4, 5)
  b = [a for c in range(2)]

Both now-erroneous snippets work in 2.5.1. Was this change intentional?

Collin Winter