Comment 3 for bug 1686327

Yeah, I think it would be pretty tricky. Right now pyflakes skips over conditional branches as if they aren't even there, so all it sees is:

    a = False
    print(b)
    a = True
    b = 1

Technically it could be fixed when `a` is assigned a literal, but between the effort required to implement the fix and the added complexity to the code I don't think it's worthwhile.