The problem is that it depends on internal whitespace to
distinguish it from augmented assignment;
Ah, didn't spot that. I guess the ellipsis is the next best
thing then.
An alternative would be to require parens:
(x, y, *) = z
But that would have the same issue.
Is this problem really important enough that it requires dedicated syntax? Isn't the itertools-based solution good enough? (Or failing that, couldn't we add something to itertools to make it more readable rather than going straight to new syntax?)