> In such case, current behavior works.  And your patch will raise OverflowError.

Try

[x for x in range(2**1000)] 

in a REPL. It doesn’t raise anything, it tries to create a list that will eventually exceed PY_SIZE_MAX, but it only crashes once it reaches that iteration.

This raises an OverflowError instead, the same way:
len(range(2**1000))
raises an OverflowError