From ba1508ed17f57642421f510fd9e1ac35e17bf208 Mon Sep 17 00:00:00 2001
From: Alan Mackenzie <acm@muc.de>
Date: Sat, 18 Jun 2022 11:23:06 +0000
Subject: [PATCH] CC Mode: Fix infinite loop in noise macro near end of buffer

This fixes bug #55771.  Also fix an inaccuracy in c-defun-name-1 with the same
cause.

* lisp/progmodes/cc-cmds.el (c-defun-name-1)
* lisp/progmodes/cc-engine.el (c-forward-noise-clause): Check the return
value of c-forward-token-2 and act upon it when not zero.
---
 lisp/progmodes/cc-cmds.el   | 11 +++++------
 lisp/progmodes/cc-engine.el |  9 +++++----
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lisp/progmodes/cc-cmds.el b/lisp/progmodes/cc-cmds.el
index e9cc63709e6..82268f49433 100644
--- a/lisp/progmodes/cc-cmds.el
+++ b/lisp/progmodes/cc-cmds.el
@@ -2115,13 +2115,12 @@ with a brace block."
 	  (c-forward-syntactic-ws)
 	  (when (eq (char-after) ?\")
 	    (forward-sexp 1)
+	    (c-forward-syntactic-ws)
 	    (c-forward-token-2))	; over the comma and following WS.
-	  (buffer-substring-no-properties
-	   (point)
-	   (progn
-	     (c-forward-token-2)
-	     (c-backward-syntactic-ws)
-	     (point))))
+	  (setq pos (point))
+	  (and (zerop (c-forward-token-2))
+	       (progn (c-backward-syntactic-ws) t)
+	       (buffer-substring-no-properties pos (point))))
 
 	 ((and (c-major-mode-is 'objc-mode) (looking-at "[-+]\\s-*("))     ; Objective-C method
 	  ;; Move to the beginning of the method name.
diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 8794a527f88..f9c33f51495 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -1239,7 +1239,7 @@ comment at the start of cc-engine.el for more info."
 			   (not comma-delimited)
 			   (not (c-looking-at-inexpr-block lim nil t))
 			   (save-excursion
-			     (c-backward-token-2 1 t nil)
+			     (c-backward-token-2 1 t nil) ; Don't test the value
 			     (not (looking-at "=\\([^=]\\|$\\)")))
 			   (or
 			    (not c-opt-block-decls-with-vars-key)
@@ -8289,9 +8289,10 @@ multi-line strings (but not C++, for example)."
 (defun c-forward-noise-clause ()
   ;; Point is at a c-noise-macro-with-parens-names macro identifier.  Go
   ;; forward over this name, any parenthesis expression which follows it, and
-  ;; any syntactic WS, ending up at the next token.  If there is an unbalanced
-  ;; paren expression, leave point at it.  Always Return t.
-  (c-forward-token-2)
+  ;; any syntactic WS, ending up at the next token or EOB.  If there is an
+  ;; unbalanced paren expression, leave point at it.  Always Return t.
+  (or (zerop (c-forward-token-2))
+      (goto-char (point-max)))
   (if (and (eq (char-after) ?\()
 	   (c-go-list-forward))
       (c-forward-syntactic-ws))
-- 
2.39.2