Check result from c-backward-token-2 to avoid infinite loop

This fixes bug #33784.

* lisp/progmodes/cc-fonts.el (c-get-fontification-context): While moving back
over enclosing parentheses, check that c-backward-token-2 actually moves.

diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index 39d167f0190645b7ee528c8c8f3fec285824ad1b..2e47bdab56701c1c6edbb0348a997d71106f789a 100644 (file)
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -1284,8 +1284,8 @@ casts and declarations are fontified.  Used on level 2 and higher."
                (save-excursion
                  (goto-char match-pos)
                  (while
-                     (progn (c-backward-token-2)
-                            (eq (char-after) ?\()))
+                     (and (zerop (c-backward-token-2))
+                          (eq (char-after) ?\()))
                  (looking-at c-arithmetic-op-regexp)))
           (cons nil nil))
          ;; In a C++ member initialization list.