Ahh, this *will* break some doctests: any with blank PS2 lines in the 'source' portion without the explicit trailing space:

1] >>> def foo():
2] ...    print("bar")
3] ...
4] ...    print("baz")
5] >>> foo()
6] bar
7] baz

If line 3 contains exactly "..." instead of starting with "... ", it will not be recognized as a PS2 line and the example will be parsed as:

'source'
>>> def foo():
...    print("bar")

'want'
...
...    print("baz")

IMO this isn't a *terribly* unreasonable tradeoff, though -- it would enable the specific ellipsis use-case as in the OP, at the cost of breaking some doctests, which shouldn't(?) be in any critical paths?