Debugging byte compiled files

["Phillip Lord" <Phillip.Lord@newcastle.ac.uk>]

I've recently found a bug in my own pabbrev.el package. It's taken
me so long because it only occurs when the file is byte compiled
and I don't routinely byte compile my own packages. 

I think that the problem is coming from this macro...

(defmacro pabbrev-save-buffer-modified-p (&rest body)
  "Eval BODY without affected buffer modification status"
  `(let ((buffer-modified (buffer-modified-p)))
     ,@body
     (set-buffer-modified-p buffer-modified)))

the backtrace looks something like this...


(macro . #[(&rest body) "\301\302\303\b\304\"BB\207" [body let
((buffer-modified (buffer-modified-p))) append ((set-buffer-modified-p
buffer-modified))] 5 ("/home/oub/emacs/site-lisp/versch/pabbrev.elc" .
17814)])

Backtrace is: 
  backtrace()
  pabbrev-command-hook-fail((invalid-function (macro . #[...
"\301\302\303\b\304\"BB\207" [body let ... append ...] 5 ...])) "pre")
  pabbrev-pre-command-hook()
  run-hooks(pre-command-hook)


I have no real clear idea how to debug this. The error happens
frequently
but not repeatedly, and it all happens in the pre-command-hook. It has 
never occurred to me without byte compilation. 

Has anyone got any idea how I go about finding out what the problem is? 

Cheers

Phil