In Emacs 20.7 running under Debian GNU/linux `testing' (kernel version
2.4.6), I have an intermittent but annoying problem.
Under two kinds of circumstance, I get the generic and mysterious
Wrong type argument: number-or-marker-p, (+ -4)
This happens (i) when I try to do filename completion with
`visit-file' or `dired'
or (ii) when I call `switch-to-buffer-in-another-frame'
(C-x 5 b).
It happens only occasionally, though, and I can always fix it by
exiting the emacs session and restarting. I don't know how to
reproduce the behaviour reliably, but I can be sure that it will
happen ultimately if the emacs session is long enough.
Does anyone know how I might trace this problem to its origins? Or
solve it? Thanks very much in advance,