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

1 files changed, 9 insertions, 6 deletions

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 0282b156bb0..c9a836ff198 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -8251,21 +8251,24 @@ 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))
              ))