bug#40088: 27.0.90; Symbol’s value as variable is void: debugger-outer-match-data

[Joost Kremers <joostkremers@fastmail.fm>]

Running with `debug-on-error' set to `t', I get the following 
error when triggering an(other) error:

Starting from `emacs -Q`, run `M-x ielm RET` to get an Elisp 
prompt. Then:

```
*** Welcome to IELM ***  Type (describe-mode) for help.
ELISP> (mapconcat #'identity '(("config") ("value")) " ")
*** Eval error ***  Wrong type argument: characterp, "config"
```

So far, so good. Now do `M-x toggle-debug-on-error` and repeat the 
input:

``` 
ELISP> (mapconcat #'identity '(("config") ("value")) " ")
*** Eval error ***  Symbol’s value as variable is void: 
    debugger-outer-match-data
ELISP> 
```

The debug window doesn't pop up.

The output from `report-emacs-bug':

In GNU Emacs 27.0.90 (build 2, x86_64-pc-linux-gnu, GTK+ Version 
3.22.30)
 of 2020-03-11 built on IdeaPad
Repository revision: 1bc3fa0bd02cb167ae82b65fc56f95651d2bea16
Repository branch: emacs-27
Windowing system distributor 'The X.Org Foundation', version 
11.0.11906000
System Description: elementary OS 5.1.2 Hera

Recent messages:
Contacting host: elpa.gnu.org:443 [2 times]
Contacting host: melpa.org:443 [2 times]
Contacting host: orgmode.org:443
Package refresh done
scroll-up-command: End of buffer
Mark set
Debug on Error enabled globally
Entering debugger...
End of buffer [3 times]
Mark set
next-line: End of buffer
Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND DBUS GSETTINGS GLIB NOTIFY 
INOTIFY
GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS PDUMPER 
LCMS2 GMP

Important settings:
  value of $LC_MONETARY: en_IE.UTF-8
  value of $LC_NUMERIC: en_IE.UTF-8
  value of $LC_TIME: en_IE.UTF-8
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: IELM

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail debug backtrace help-mode
find-func cus-start cus-load ielm pp comint ansi-color ring 
finder-inf
mm-archive message dired dired-loaddefs format-spec rfc822 mml 
mml-sec
epa derived gnus-util rmail rmail-loaddefs text-property-search
time-date mailabbrev gmm-utils mailheader mm-decode mm-bodies 
mm-encode
mail-utils gnutls network-stream url-http mail-parse rfc2231 
rfc2047
rfc2045 mm-util ietf-drums mail-prsvr url-gw nsm rmc puny 
url-cache
url-auth url url-proxy url-privacy url-expand url-methods 
url-history
url-cookie url-domsuf url-util mailcap epg epg-config package 
easymenu
browse-url url-handlers url-parse auth-source cl-seq eieio 
eieio-core
cl-macs eieio-loaddefs password-cache json subr-x map url-vars seq
byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib 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 tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu 
font-core
term/tty-colors frame minibuffer 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 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 threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit 
x
multi-tty make-network-process emacs)

Memory information:
((conses 16 206582 84875)
 (symbols 48 14217 2)
 (strings 32 71046 30324)
 (string-bytes 1 1763859)
 (vectors 16 18700)
 (vector-slots 8 262878 17906)
 (floats 8 25 354)
 (intervals 56 280 0)
 (buffers 1000 13))



-- 
Joost Kremers
Life has its moments