I've been seeing this problem the last few days when using M-. to follow a symbol's definition:
Debugger entered--Lisp error: (wrong-type-argument stringp nil) set-buffer(nil) (save-current-buffer (set-buffer standard-output) (prog1 (progn ... ... ... ... ...) (assert ...) (setq buffer-read-only t) (slime-init-popup-buffer vars%))) (with-current-buffer standard-output (prog1 (progn ... ... ... ... ...) (assert ...) (setq buffer-read-only t) (slime-init-popup-buffer vars%))) (let* ((vars% ...) (standard-output ...)) (with-current-buffer standard-output (prog1 ... ... ... ...))) (slime-with-popup-buffer (xref-buffer-name% package t emacs-snapshot) (slime-xref-mode) (slime-set-truncate-lines) (setq slime-popup-buffer-quit-function (quote slime-xref-quit)) (erase-buffer) (prog1 (progn ... ... ... ...) (assert ...) (shrink-window-if-larger-than-buffer))) (let ((xref-buffer-name% ...)) (slime-with-popup-buffer (xref-buffer-name% package t emacs-snapshot) (slime-xref-mode) (slime-set-truncate-lines) (setq slime-popup-buffer-quit-function ...) (erase-buffer) (prog1 ... ... ...))) (slime-with-xref-buffer (type symbol package emacs-snapshot) (slime-insert-xrefs xrefs) (goto-char (point-min)) (forward-line) (skip-chars-forward " ")) (if (null xrefs) (message "No references found for %s." symbol) (setq slime-next-location-function (quote slime-goto-next-xref)) (slime-with-xref-buffer (type symbol package emacs-snapshot) (slime-insert-xrefs xrefs) (goto-char ...) (forward-line) (skip-chars-forward " "))) slime-show-xrefs((("/home/ckonstanski/IandC/dev/svn/iclisp/araneida/web/graph/tracker-graph.lisp" ("(DEFGENERIC PLOT-GRAPHS (TRACKER-GRAPH ROOT-DIR))" ...) ("(DEFMETHOD PLOT-GRAPHS TRACKER-GRAPH T)" ...))) definition "plot-graphs" "#:iclisp") (cond ((null xrefs) (error "No known definition for: %s (in %s)" name ...)) (1loc (slime-push-definition-stack) (slime-pop-to-location ... where)) ((slime-length= xrefs 1) (error "%s" ...)) (t (slime-show-xrefs file-alist ... name ...))) (let* ((--cl-rest-- ...) (1loc ...) (file-alist ...)) (cond (... ...) (1loc ... ...) (... ...) (t ...))) (progn (let* (... ... ...) (cond ... ... ... ...))) (destructuring-bind (1loc file-alist) (slime-analyze-xrefs xrefs) (cond (... ...) (1loc ... ...) (... ...) (t ...))) slime-edit-definition-cont((("(DEFGENERIC PLOT-GRAPHS (TRACKER-GRAPH ROOT-DIR))" (:location ... ... ...)) ("(DEFMETHOD PLOT-GRAPHS TRACKER-GRAPH T)" (:location ... ... ...))) "plot-graphs" nil) (or (run-hook-with-args-until-success (quote slime-edit-definition-hooks) name where) (slime-edit-definition-cont (slime-find-definitions name) name where)) slime-edit-definition("plot-graphs") call-interactively(slime-edit-definition)
The only thing that has changed on my side is slime, which I have been updating from CVS. My emacs is 22.2-r2 (gentoo ebuild).
Carlos Konstanski