I was going to demo the ispell completion the other day, and it
blonked at me... the error happens when there's more than a certain
number of completions, and in that code, it uses a
char-to-int/int-to-char conversion... it increments a char var to
form the keys you push to select which completion you want to use.
To repeat: In a `message' buffer, (I think the ispell complete is on
by default... or maybe I have it switched on someplace?), type `hel'
and push `M-Tab'. It signals an error. But `hell' `M-Tab' displays
a choice list in a window at the top of the frame.