bug#18963: 25.0.50; byte compiler confuses compilation-mode

[Tom Tromey]

I ran the byte compiler via M-x compile.
I got some warnings like:

In toplevel form:
src/something.el:17:1:Warning: Unused lexical argument `obj'

compilation-mode things that the line "In toplevel form:" is some sort
of error.  The words "toplevel form" are red.  If I next-error it says:

    Find this error in (default toplevel form): 

This also happens for the text "In provide:", also emitted by the byte
compiler.

This makes compilation mode harder to use.





In GNU Emacs 25.0.50.7 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.9)
 of 2014-11-02 on bapiya
Repository revision: 118270 larsi@gnus.org-20141103010307-bxryy53hat500i4w
Windowing system distributor `Fedora Project', version 11.0.11404000
Configured using:
 `configure --prefix=/home/tromey/Emacs/install'

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

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  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
  global-auto-revert-mode: t
  desktop-save-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-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-netsplit-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

Recent input:
I O S-SPC m e t h o d SPC d e f i n i t i o n s . C-f 
C-f C-p M-v C-l C-n C-e SPC SPC P e r h a p s SPC <M-backspace> 
M-q C-h f e <backspace> d e c l a r e <return> C-h 
C-g <help-echo> <down-mouse-1> <mouse-1> C-x 1 C-v 
M-v M-v C-c b SPC SPC P e r h a p s SPC a SPC n e w 
SPC d e c l a r e <backspace> a t i o n SPC c o u l 
d SPC b e SPC p r o v i d e d SPC f o r SPC t h i s 
SPC a s SPC w e l l , SPC f <backspace> s i n c e SPC 
t h e r e SPC a r e SPC o t h e r SPC c a s e s SPC 
( e . g . , SPC c a l l b a k c s C-b C-b C-t C-e ) 
, SPC w h e r e SPC a SPC f i x e d SPC c a l l i n 
g SPC c o n v e n t i o n SPC i s SPC n e e d e d . 
M-v C-l C-z n C-u C-n C-n C-p C-e M-b M-b _ C-u C-g 
C-/ C-n C-n C-n M-b _ C-e M-b _ C-x C-s <switch-frame> 
ESC [ > 1 ; 2 8 0 2 ; 0 c C-x C-c C-r C-g C-g C-x C-c 
n C-z n C-x k <return> y e s <return> C-x b * c o m 
<tab> <return> C-u C-u C-p C-z n C-x 1 M-x M-p <re
turn>

Recent messages:
C-h C-g is undefined

scroll-down-command: Beginning of buffer
Auto-saving...done
Quit
Undo!
Saving file /home/tromey/Emacs/ET/q.el...
Wrote /home/tromey/Emacs/ET/q.el
When done with this frame, type C-z k
View mode: type C-h for help, h for commands, q to quit.
Quit [2 times]

Load-path shadows:
/home/tromey/.emacs.d/elpa/css-mode-1.0/css-mode hides 
/home/tromey/Emacs/install/share/emacs/25.0.50/lisp/textmodes/css-mode
/home/tromey/.emacs.d/elpa/bubbles-0.5/bubbles hides 
/home/tromey/Emacs/install/share/emacs/25.0.50/lisp/play/bubbles

Features:
(view xterm shadow emacsbug python json elcomp mail-hist find-dired
pcmpl-unix pcmpl-gnu shell make-mode flow-fill mule-util bbdb-gui
bbdb-hooks sort gnus-cite smiley shr-color color shr browse-url
mm-archive gnus-async gnus-bcklg qp gnus-ml disp-table gnus-topic
nndraft nnmh nnfolder utf-7 bbdb-gnus bbdb-snarf mail-extr bbdb-com
warnings cl gnutls network-stream starttls gnus-agent gnus-srvr
gnus-score score-mode nnvirtual gnus-msg nntp gnus-cache gnus-registry
registry eieio-base gnus-art mm-uu mml2015 mm-view mml-smime smime dig
mailcap gnus-sum gnus-group gnus-undo smtpmail sendmail gnus-start
gnus-cloud nnimap nnmail mail-source tls utf7 netrc nnoo parse-time
gnus-spec gnus-int gnus-range gnus-win gnus gnus-ems nnheader idutils
derived log-edit message rfc822 mml mml-sec mm-decode mm-bodies
mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev
mail-utils gmm-utils mailheader pcvs-util eieio-opt speedbar sb-image
ezimage dframe dabbrev help-mode debug copyright misearch multi-isearch
edebug texinfo sh-script smie executable sgml-mode org-element org-rmail
org-mhe org-irc org-info org-gnus org-docview doc-view image-mode
org-bibtex bibtex org-bbdb org-w3m org org-macro org-footnote
org-pcomplete org-list org-faces org-entities noutline outline
org-version ob-emacs-lisp ob ob-tangle ob-ref ob-lob ob-table ob-exp
org-src ob-keys ob-comint ob-core ob-eval org-compat org-macs
org-loaddefs smerge-mode diff-mode easy-mmode bug-reference goto-addr
add-log vc-arch vc-mtn vc-hg jka-compr dired vc-sccs vc-svn vc-cvs
vc-rcs vc-bzr cc-mode cc-fonts cc-guess cc-menus cc-cmds vc-git flyspell
ispell diminish projectile edmacro kmacro pkg-info find-func lisp-mnt
epl grep compile dash s appt diary-lib diary-loaddefs cal-menu calendar
cal-loaddefs which-func imenu minimap autorevert filenotify desktop
frameset 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-button wid-edit erc-fill erc-stamp erc-netsplit
erc-goodies erc erc-backend erc-compat format-spec auth-source cl-macs
gv eieio byte-opt bytecomp byte-compile cl-extra cconv eieio-core
cl-loaddefs cl-lib gnus-util mm-util mail-prsvr password-cache thingatpt
pp advice help-fns vc-dir ewoc vc vc-dispatcher cc-styles cc-align
cc-engine cc-vars cc-defs bbdb timezone ange-ftp comint ansi-color ring
server savehist dwarf-mode-autoloads gdb-shell-autoloads
jabber-autoloads lisppaste-autoloads pydoc-info-autoloads info-look info
easymenu weblogger-autoloads package epg-config bbdb-autoloads time-date
tooltip eldoc 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 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 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 1035551 167150)
 (symbols 48 101382 4)
 (miscs 40 41442 4406)
 (strings 32 312663 74620)
 (string-bytes 1 7385334)
 (vectors 16 97840)
 (vector-slots 8 2094764 78121)
 (floats 8 568 988)
 (intervals 56 55382 13335)
 (buffers 976 223)
 (heap 1024 260845 31440))

Tom