[Python-Dev] listcomps vs. for loops

[Guido van Rossum]

> > It's only list comprehensions where I plan to remove x from the scope
> > after the comprehension is finished.
> > 
> > Do you need a warning for that change too?  Code that relies on it is
> > pretty sick IMO.
> 
> Yes, it's sick, but since you made clear previously that listcomps
> semantics equivalent to the corresponding for loop, I wouldn't be
> surprised to discover that someone converted a for loop to a listcomp
> without fixing that sickness.  So yes, it needs a warning.

OK, fair enough.  Someone update the doc bug report for this.
Initially, we're just going to document it as deprecated behavior (or
maybe "despised" behavior :-).

--Guido van Rossum (home page: http://www.python.org/~guido/)