On Mon, Jun 11, 2018 at 3:10 PM Rob Cliffe via Python-Dev <python-dev@python.org> wrote:
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)

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

​Change 'def' to 'class' and run it again.  You'll be even more surprised.​