(c-guess-basic-syntax CASE 5D.5): Fix an infinite loop on invalid syntax.

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index c29faecb8c0ea1ca0f1ec4c80592ce2bb231e594..817b161ff878b8a29db9d445680b4eb65e965c32 100644 (file)
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -8252,21 +8252,24 @@ comment at the start of cc-engine.el for more info."
              (c-add-syntax 'inher-cont (c-point 'boi)))
 
             ;; CASE 5D.5: Continuation of the "expression part" of a
-            ;; top level construct.
+            ;; top level construct.  Or, perhaps, an unrecognised construct.
             (t
-             (while (and (eq (car (c-beginning-of-decl-1 containing-sexp))
+             (while (and (setq placeholder (point))
+                         (eq (car (c-beginning-of-decl-1 containing-sexp))
                              'same)
                          (save-excursion
                            (c-backward-syntactic-ws)
-                           (eq (char-before) ?}))))
+                           (eq (char-before) ?}))
+                         (< (point) placeholder)))
              (c-add-stmt-syntax
-              (if (eq char-before-ip ?,)
+              (cond
+               ((eq (point) placeholder) 'statement) ; unrecognised construct
                   ;; A preceding comma at the top level means that a
                   ;; new variable declaration starts here.  Use
                   ;; topmost-intro-cont for it, for consistency with
                   ;; the first variable declaration.  C.f. case 5N.
-                  'topmost-intro-cont
-                'statement-cont)
+               ((eq char-before-ip ?,) 'topmost-intro-cont)
+               (t 'statement-cont))
               nil nil containing-sexp paren-state))
             ))