With Allegro, compiling a function (with C-c C-c) with a reader error such as this: (defun fooo (p) (mp:process-state p)) currently falls off the end of ETYPECASE in COLLECT-NOTES because FASLFILE is T. I suspect it's not the right fix, but it works. --- swank-allegro.lisp.~1.142.~ 2011-02-18 12:06:00.000000000 +0100 +++ swank-allegro.lisp 2011-04-03 17:43:27.000000000 +0200 @@ -462,7 +462,7 @@ (merge-pathnames (pathname filename)) *default-pathname-defaults*))) (compile-from-temp-file string buffer position filename))) - (reader-error () (values nil nil t)))) + (reader-error () nil))) ;;;; Definition Finding