bug#28407: 26.0.50; xref should use imenu

[Tom Tromey <tom@tromey.com>]

It would be nice if imenu were a back end for xref.
Then M-. could also use symbols found by imenu.

A further wrinkle on this would be if xref, project, and imenu worked
together, so that M-. would automatically know to look at imenu results
for other buffers in the same project.

Tom



In GNU Emacs 26.0.50 (build 18, x86_64-pc-linux-gnu, GTK+ Version 3.22.17)
 of 2017-09-09 built on bapiya
Repository revision: 4131f9785e30f2a31745125c714e922892113c62
Windowing system distributor 'Fedora Project', version 11.0.11903000
System Description:	Fedora release 25 (Twenty Five)

Recent messages:
Hunk already applied [3 times]
Mark saved where search started
user-error: No definitions found for: funlike_invocation_p
Quit
M-. runs the command xref-find-definitions
Type "q" in help window to restore its previous buffer.
uncompressing xref.el.gz...done
Mark saved where search started
uncompressing imenu.el.gz...done
Mark saved where search started [2 times]

Configured using:
 'configure --prefix=/home/tromey/Emacs/install'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  flyspell-mode: t
  which-function-mode: t
  erc-services-mode: t
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
  erc-ring-mode: t
  erc-networks-mode: t
  erc-pcomplete-mode: t
  erc-track-mode: t
  erc-match-mode: t
  erc-netsplit-mode: t
  erc-hl-nicks-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  savehist-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-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
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: do-auto-fill
  transient-mark-mode: t

Load-path shadows:
/home/tromey/.emacs.d/elpa/bubbles-0.5/bubbles hides /home/tromey/Emacs/install/share/emacs/26.0.50/lisp/play/bubbles

Features:
(shadow emacsbug make-mode cc-awk texinfo log-edit cl-print debug nndoc
gnus-dup debbugs-gnu debbugs soap-client url-http url-auth url-gw
rng-xsd rng-dt rng-util xsd-regexp smerge-mode whitespace gnus-html
url-queue help-fns radix-tree url-cache mm-url url url-proxy url-privacy
url-expand url-methods url-history url-cookie url-domsuf goto-addr
log-view pcvs-util term/xterm xterm shell find-file copyright pulse
etags xref project vc-mtn vc-hg vc-bzr vc-src vc-sccs vc-svn vc-cvs
vc-rcs jka-compr shr-color url-util shr svg xml dom browse-url
find-dired add-log misearch multi-isearch bug-reference vc-git diff-mode
map cc-mode cc-fonts cc-guess cc-menus cc-cmds dabbrev supercite
easy-mmode regi mail-hist nnir flow-fill mm-archive mailalias sort
smiley gnus-cite gnus-async gnus-bcklg mail-extr gnus-ml disp-table
gnus-topic nndraft nnmh nnfolder utf-7 network-stream nsm starttls
gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg nntp
gnus-cache gnus-registry registry ebdb-gnus gnus-art mm-uu mml2015
mm-view mml-smime smime dig mailcap gnus-sum gnus-group gnus-undo
smtpmail gnus-start gnus-cloud nnimap nnmail mail-source tls gnutls utf7
netrc nnoo parse-time gnus-spec gnus-int gnus-range gnus-win gnus
nnheader elec-pair flyspell ispell diminish edmacro kmacro projectile
grep compile ibuf-ext ibuffer ibuffer-loaddefs dash appt diary-lib
diary-loaddefs which-func imenu minimap autorevert filenotify cus-start
cus-load status erc-services erc-list erc-menu erc-join erc-ring
erc-networks erc-pcomplete pcomplete erc-track erc-match erc-netsplit
erc-hl-nicks color erc-button erc-fill erc-stamp wid-edit erc-goodies
erc erc-backend erc-compat thingatpt pp warnings advice vc-dir ewoc vc
vc-dispatcher cc-styles cc-align cc-engine cc-vars cc-defs ebdb-complete
ebdb-message sendmail message puny dired dired-loaddefs format-spec
rfc822 mml mml-sec epa derived epg gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 mm-util
ietf-drums mail-prsvr mail-utils gmm-utils mailheader ebdb-mua ebdb-com
crm mailabbrev ebdb-format qp ebdb cl-extra help-mode eieio-opt speedbar
sb-image ezimage dframe find-func eieio-base pcase subr-x cal-menu
calendar cal-loaddefs timezone ange-ftp comint ansi-color ring server
savehist finder-inf dwarf-mode-autoloads gdb-shell-autoloads
lisppaste-autoloads pydoc-info-autoloads info-look cl
weblogger-autoloads info package easymenu epg-config url-handlers
url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache url-vars seq byte-opt gv bytecomp byte-compile cconv
cl-loaddefs cl-lib 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 replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch 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 composite charscript charprop 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 2205844 699201)
 (symbols 48 58822 76)
 (miscs 40 16108 11738)
 (strings 32 597642 63371)
 (string-bytes 1 15642233)
 (vectors 16 252143)
 (vector-slots 8 3921716 191337)
 (floats 8 4806 1815)
 (intervals 56 142400 1766)
 (buffers 992 191))