bug#55885: 29.0.50; missed error message

[Andreas Röhler]

The code below evaluates to nil, but should send an error:

(defvar foo-bar-baz
  (cond
      (t ()
      (when foo-bar-baz nil))))

Emacs 28.1 tells as expected:

Debugger entered--Lisp error: (void-variable foo-bar-baz)
  (if foo-bar-baz (progn nil))
  (cond (t nil (if foo-bar-baz (progn nil))))
  (defvar foo-bar-baz (cond (t nil (if foo-bar-baz (progn nil)))))
  eval((defvar foo-bar-baz (cond (t nil (if foo-bar-baz (progn nil))))) nil)
  elisp--eval-last-sexp(nil)
  eval-last-sexp(nil)
  funcall-interactively(eval-last-sexp nil)
  call-interactively(eval-last-sexp nil nil)
  command-execute(eval-last-sexp)


------

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 2.24.32, cairo version 1.16.0)
 of 2022-06-04
Repository revision: fe6f1dfeb4ad4aaf517d1ac34435f3750f7f4569
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Ubuntu 20.04.4 LTS

Configured using:
 'configure --with-modules -with-mailutils'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM
XINPUT2 XPM GTK2 ZLIB

Important settings:
  value of $LANG: de_DE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: ELisp/d

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-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
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media rmc puny
dired dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg
rfc6068 epg-config gnus-util text-property-search time-date 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-fns radix-tree cl-print debug backtrace help-mode find-func
cl-loaddefs cl-lib seq gv subr-x byte-opt bytecomp byte-compile cconv
iso-transl tooltip eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode 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 lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer nadvice
simple cl-generic indonesian philippine 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 emoji-zwj charscript charprop case-table
epa-hook jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads dbusbind inotify
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
emacs)

Memory information:
((conses 16 141917 6454)
 (symbols 48 29644 0)
 (strings 32 64292 1986)
 (string-bytes 1 1009077)
 (vectors 16 12076)
 (vector-slots 8 173860 12616)
 (floats 8 23 35)
 (intervals 56 253 5)
 (buffers 992 13))