bug#47080: 28.0.50; Spurious variable left uninitialized compiler warning

[Michael Heerdegen]

Hello,

here is the test case:

#+begin_src emacs-lisp
;; -*- lexical-binding: t -*-

(require 'pcase)
(require 'find-func) ;not involved AFAICT, just funs used in example

(defun my-find-function (function)
  (interactive (find-function-read))
  (pcase (find-function-library function)
    ((or 'nil
         (and `(,_ . ,file) (guard (or (not (stringp file)) (string-match-p 
"\\.c$" file))))
         (guard (not (find-definition-noselect function nil))))
     (describe-function function))))
#+end_src

Compiling gives me:

| compile-test.el:6:1: Warning: Variable `file' left uninitialized
| compile-test.el:6:1: Warning: Variable `file' left uninitialized

TIA,

Michael.


In GNU Emacs 28.0.50 (build 8, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo 
version 1.16.0)
 of 2021-03-12 built on drachen
Repository revision: 69b952bcac5366df4cd37a7681318b29bc23e3c8
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12010000
System Description: Debian GNU/Linux bullseye/sid

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG SOUND
THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM GTK3 ZLIB