I've bumped into this code accidentally while trying to do something
unrelated. It looks wrong to me although there is a good chance I'm
misreading it. I'm attaching a patch that either fixes two bugs,
introduces two new bugs, or does something in between. I'll appreciate
if someone more experienced can take a look at it.

All test pass with this patch and my zsh seems to work fine. I haven't
verified that this code actually runs either during testing or when
I'm using zsh normally.

Roman.