Evaluating the following forms after launching `emacs -Q' yields `(wrong-type-argument number-or-marker-p nil)': (require 'smie) (smie-backward-sexp-command) This is due to `smie-backward-sexp-command' not checking whether `n' is `nil' before passing `(- n)' to `smie-forward-sexp-command'. -- Clément. In GNU Emacs 24.4.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8) of 2015-01-25 on my-laptop Windowing system distributor `The X.Org Foundation', version 11.0.11501000 System Description: Linux Mint 17.1 Rebecca Important settings: value of $LC_TIME: en_DK.UTF-8 value of $LANG: en_US.UTF-8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils debug help-mode easymenu help-fns smie time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process dbusbind gfilenotify dynamic-setting system-font-setting font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs) Memory information: ((conses 16 73625 7003) (symbols 48 17900 0) (miscs 40 47 163) (strings 32 10002 4475) (string-bytes 1 278134) (vectors 16 9330) (vector-slots 8 389150 12295) (floats 8 65 248) (intervals 56 202 1) (buffers 960 13) (heap 1024 22193 868))