bug#11504: 24.0.95; next-error fails walk ruby stack trace

[Eric Hanchrow <eric.hanchrow@gmail.com>]

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgement at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

I put this into a file named /tmp/hmm.rb:
-->8---->8---->8---->8---->8---->8---->8---->8---->8---->8---->8--
def crap(level=0)
  if level == 10
    raise StandardError, "oh crap!!", caller
  else
    crap(level + 1)
  end
end

crap
--8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<--

Then I typed M-x compile RET ruby /tmp/hmm.rb RET

As expected, I saw a *compilation* buffer that contained

-->8---->8---->8---->8---->8---->8---->8---->8---->8---->8---->8--
ruby hmm.rb
hmm.rb:5:in `crap': oh crap!! (StandardError)
	from hmm.rb:9
--8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<--

Also as expected, when I typed C-x `, a little triangular pointer
appeared in the *compilation* buffer, just to the left of the second
line above, and line 5 in my hmm.rb buffer briefly glowed.

However, after I typed a second C-x `, I expected the triangular pointer
in *compilation* to move down one line, and line 9 in hmm.rb to glow.
Instead, Emacs rang the bell and displayed ``Moved past last error'' in
the echo area.

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/Applications/Emacs.app/Contents/Resources/etc/DEBUG.


In GNU Emacs 24.0.95.1 (x86_64-apple-darwin, NS apple-appkit-1038.36)
 of 2012-04-02 on bob.porkrind.org
Windowing system distributor `Apple', version 10.3.1138
Configured using:
 `configure '--host=x86_64-apple-darwin' '--build=i686-apple-darwin'
 '--with-ns' 'build_alias=i686-apple-darwin'
 'host_alias=x86_64-apple-darwin' 'CC=gcc -mmacosx-version-min=10.5''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default enable-multibyte-characters: t

Major mode: Ruby

Minor modes in effect:
  shell-dirtrack-mode: t
  tooltip-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 input:
C-x C-f / t m p / h m m <tab> C-g C-x C-f / t m p /
h m <tab> <return> M-x c o m p i l e <return> C-a C-k
r u b y SPC h <tab> <return> C-x ` C-x ` C-p C-p C-a
C-k C-x C-o C-n C-M-n C-p M-m M-d <tab> C-M-f C-M-f
C-k C-x C-s M-x m a k e <return> C-g M-x r e c o m
p <tab> <return> C-x ` C-x ` C-g C-a M-> C-p C-k C-p
C-p C-k C-x C-o M-> C-x C-o C-x C-s M-x M-p <return>
C-x ` C-x ` M-x r e p o r t - e m <tab> <return>

Recent messages:
Quit
(No files need saving)
Compilation exited abnormally with code 1
compilation-next-error: Moved past last error
Quit
Mark set [2 times]
Saving file /tmp/hmm.rb...
Wrote /tmp/hmm.rb
(No files need saving)
Compilation exited abnormally with code 1
compilation-next-error: Moved past last error

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 help-mode easymenu view shell pcomplete compile
comint ansi-color ring ruby-mode regexp-opt time-date tooltip ediff-hook
vc-hooks lisp-float-type mwheel ns-win tool-bar dnd fontset image fringe
lisp-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 loaddefs button faces cus-face files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process ns multi-tty
emacs)