From c037fb42f191ee9e90b45c9d922fcc09cc3d6b2e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gerd=20M=C3=B6llmann?= <gerd@gnu.org>
Date: Tue, 2 Jul 2024 10:25:13 +0200
Subject: [PATCH] Fix null error in igc--diff

---
 lisp/emacs-lisp/igc.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/igc.el b/lisp/emacs-lisp/igc.el
index e909fc441ff..c46b0d6e8f2 100644
--- a/lisp/emacs-lisp/igc.el
+++ b/lisp/emacs-lisp/igc.el
@@ -33,7 +33,7 @@
 (defun igc--diff (i1 i2)
   (cl-loop for (t1 n1 s1) in i1
 	   for (_t2 n2 s2) in i2
-	   unless (= n1 n2)
+	   when (and n1 n2 (/= n1 n2))
 	   collect (list t1 (- n1 n2) (and s1 (- s1 s2)))))
 
 (defvar igc--a nil)