bug#22029: 25.1.50; etags/tag search seems to fail

[jpff]

I look at a C file, and use M-. to find the definition of a word
Instead of opening a file with the definition I get a crash about xref
and a backtrace.  This was working a few days ago; I looked at
Changelogs etc but found no clue as to the change.  It is possible
that I have an old configuration, but I am not aware of having any
such.
Message seems to be
cl-no-applicable-method: No applicable method for %S: xref-backend-definitions, 
nil, "PVSINI"



In GNU Emacs 25.1.50.9 (x86_64-suse-linux-gnu, GTK+ Version 2.24.28)
 of 2015-11-27
Repository revision: 36b927c3d9077ad25b0deec21ddeb9708ac7abf3
Windowing system distributor 'The X.Org Foundation', version 11.0.11601000
System Description:     openSUSE 13.2 (Harlequin) (x86_64)

Configured features:
XPM JPEG TIFF GIF PNG SOUND GSETTINGS NOTIFY LIBXML2 FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK2 X11

Important settings:
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix

Major mode: C/l

Minor modes in effect:
  diff-auto-refine-mode: t
  auto-image-file-mode: t
  show-paren-mode: t
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: (only . t)
  abbrev-mode: t

Recent messages:
Local Ispell dictionary set to british [2 times]
Making completion list... [2 times]
Local Ispell dictionary set to british
Mark saved where search started
C-x g is undefined
C-z is undefined
Back to top level
Mark set
Entering debugger...
Making completion list...

Load-path shadows:
None found.

Features:
(shadow flyspell mailalias mailcrypt mail-extr comint ansi-color
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 help-fns mail-prsvr mail-utils
character-fold misearch multi-isearch bug-reference ispell add-log
dired find-func map debug thingatpt xref cl-seq project ring eieio
eieio-core cl-macs vc vc-dispatcher vc-git diff-mode easy-mmode imenu
cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs cal-julian delsel cus-start cus-load
image-file crypt crypt++ crypt+pgp-pub paren view cal-china cal-bahai
cal-islam cal-hebrew lunar solar cal-dst seq byte-opt gv bytecomp
byte-compile cconv cl-extra help-mode cl-loaddefs pcase cl-lib appt
diary-lib diary-loaddefs holidays hol-loaddefs cal-menu easymenu
calendar cal-loaddefs time time-date mule-util tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel 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 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 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 157149 5492)
 (symbols 48 26500 0)
 (miscs 40 244 418)
 (strings 32 37034 16224)
 (string-bytes 1 1208465)
 (vectors 16 20899)
 (vector-slots 8 599453 4464)
 (floats 8 769 495)
 (intervals 56 1328 0)
 (buffers 976 21)
 (heap 1024 42490 2355))

==John ffitch