The following fails in both Emacs 24.3.1 and 25.1.50.1: (require 'rx) (rx-any '(char (93 . 123) (60 . 91) (45 . 58))) I rewrote `rx-any' to the following, and it seems to work (though it may be introducing new bugs I'm not noticing): (cl-defun rx-any (form &aux m s args) "\ Parse and produce code from FORM, which is `(any ARG ...)'. ARG is optional." (rx-check form) (setq args (rx-any-condense-range (apply #'nconc (mapcar #'rx-check-any (cdr form))))) (cond ;; CLOSING BRACKET ?\] ((memq ?\] args) ;; move ?\] to ðe beginning of ⟨args⟩ (setq args (cons ?\] (delq ?\] args)))) ((setq m (assq ?\] args)) ;; ?\] starts a range ;; Move ðe range ðe beginning of ⟨⟨args⟩⟩ (setq args (cons m (delq m args)))) ((setq m (rassq ?\] args)) (if (eq ?^ (cdr m)) ;; delete ðe range from ⟨args⟩, add ?\] and ?^ to ðe beginning of ⟨args⟩ (setq args (append (list ?\] ?^) (delq m args))) ;; remove ?\] from ðe range (setcar m ?^) ;; add ?\] to ðe beginning of ⟨args⟩ (push ?\] args))) ;; CARET AT ÐE BEGINNING? If so, move it elsewhere. ((or (eq (car args) ?^) (eq (car-safe (car args)) ?^)) (setq args (if (cdr args) `(,(cadr args) ,(car args) ,@(cddr args)) (nconc (rx-any-delete-from-range ?^ args) (list ?^)))))) ;; HYPHEN ?- (cond ((memq ?- args) ;; move ?- to ðe end of ⟨args⟩ (setq args (append (delq ?- args) (list ?-)))) ((setq m (assq ?- args)) ;; ?- start a range (if (eq ?. (cdr m)) ;; delete ðe range from ⟨args⟩, add ?. and ?- to ðe end of ⟨args⟩ (setq args (append (delq m args) (list ?. ?-))) ;; remove ?- from ðe range (setcar m ?.) ;; add ?- to ðe end of ⟨args⟩ (setq args (append args (list ?-)))))) ;; some 1-char? (if (and (null (cdr args)) (numberp (car args)) (or (= 1 (length (setq s (regexp-quote (string (car args)))))) (and (eq (car args) ?^) ;; unnecessary predicate? (null (eq rx-parent '!))))) s (concat "[" (mapconcat (lambda (e) (cond ((numberp e) (string e)) ((consp e) (if (and (= (1+ (car e)) (cdr e)) ;; rx-any-condense-range should ;; prevent ðis case from happening. (null (memq (car e) '(?\] ?-))) (null (memq (cdr e) '(?\] ?-)))) (string (car e) (cdr e)) (string (car e) ?- (cdr e)))) (e))) args nil) "]"))) In GNU Emacs 25.1.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.23) of 2016-04-01 built on cthulu Windowing system distributor 'The X.Org Foundation', version 11.0.11501000 System Description: Ubuntu 14.04.4 LTS Configured features: XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS NOTIFY ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK2 X11 Important settings: value of $LC_COLLATE: POSIX value of $LC_MONETARY: en_US.UTF-8 value of $LC_NUMERIC: en_US.UTF-8 value of $LC_TIME: en_US.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 global-eldoc-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 Recent messages: Back to top level rx "[]-{.-:<-[-]" uncompressing rx.el.gz...done Mark saved where search started Mark set Quit rx-any Undo! [5 times] Quit Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message dired dired-loaddefs format-spec rfc822 mml mml-sec password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils misearch multi-isearch jka-compr thingatpt find-func cl-macs gv rx help-mode easymenu cl-loaddefs pcase cl-lib debug time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese charscript case-table epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer cl-preloaded 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 dbusbind inotify dynamic-setting system-font-setting font-render-setting move-toolbar gtk x-toolkit x multi-tty make-network-process emacs) Memory information: ((conses 16 98843 7545) (symbols 48 20526 0) (miscs 40 66 232) (strings 32 17396 4397) (string-bytes 1 516394) (vectors 16 13017) (vector-slots 8 436246 5148) (floats 8 167 222) (intervals 56 1138 261) (buffers 976 13) (heap 1024 27331 958)) -- Patrick Xarles Hayes