From 462ca0654d2aa2a2b6506f2e9a1a9ceb8e683cad Mon Sep 17 00:00:00 2001
From: Gregory Heytings <gregory@heytings.org>
Date: Sun, 25 Apr 2021 10:33:48 +0000
Subject: [PATCH] Fix infloop in Modula-2 mode

* lisp/progmodes/modula2.el (m2-smie-refine-colon): Stop looping when
point does not move with forward-sexp (Bug#48011)
---
 lisp/progmodes/modula2.el | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lisp/progmodes/modula2.el b/lisp/progmodes/modula2.el
index 2a0374aa81..5756d91831 100644
--- a/lisp/progmodes/modula2.el
+++ b/lisp/progmodes/modula2.el
@@ -201,7 +201,10 @@ m2-smie-refine-colon
          ((zerop (length tok))
           (let ((forward-sexp-function nil))
             (condition-case nil
-                (forward-sexp -1)
+                (let ((p (point)))
+                  (forward-sexp -1)
+                  (if (= p (point))
+                      (setq res ":")))
               (scan-error (setq res ":")))))
          ((member tok '("|" "OF" "..")) (setq res ":-case"))
          ((member tok '(":" "END" ";" "BEGIN" "VAR" "RECORD" "PROCEDURE"))
-- 
2.30.2