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Skip, I think you have misunderstood the point I was making. It was
not whether the loop variable should leak out of a list comprehension.
Rather, it was whether a local variable should, so to speak, "leak into"
a list comprehension. And the answer is: it depends on whether the code
is executed normally, or via exec/eval. Example:

def Test():
x = 1
print(\[x+i for i in range(1,3)\]) # Prints \[2,3\]
exec('print(\[x+i for i in range(1,3)\])') # Raises NameError (x)
Test()

I (at least at first) found the difference in behaviour surprising.