CC Mode: Compensate for backward-sexp ignoring trailing commas after {...}

This fixes bug #32808.

* lisp/progmodes/cc-engine.el (c-beginning-of-statement-1): New variable
comma-delimited, set when we're about to scan backward over a comma.  Do not
reckon a brace block as bounding a statement when it is followed or preceded
by a comma (except when argument comma-delim is non-nil).
(c-guess-basic-syntax, CASE 9C): Call c-beginning-of-statement-1 with argument
comma-delim changed to non-nil.

1 files changed, 11 insertions, 4 deletions

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 9cd2174b665..376d0bb3d3a 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -1080,12 +1080,15 @@ comment at the start of cc-engine.el for more info."
                 (let ((before-sws-pos (point))
                       ;; The end position of the area to search for statement
                       ;; barriers in this round.
-                      (maybe-after-boundary-pos pos))
+                      (maybe-after-boundary-pos pos)
+                      comma-delimited)
 
                   ;; Go back over exactly one logical sexp, taking proper
                   ;; account of macros and escaped EOLs.
                   (while
                       (progn
+                        (setq comma-delimited (and (not comma-delim)
+                                                   (eq (char-before) ?\,)))
                         (unless (c-safe (c-backward-sexp) t)
                           ;; Give up if we hit an unbalanced block.  Since the
                           ;; stack won't be empty the code below will report a
@@ -1121,6 +1124,7 @@ comment at the start of cc-engine.el for more info."
                          ;; Just gone back over a brace block?
                          ((and
                            (eq (char-after) ?{)
+                           (not comma-delimited)
                            (not (c-looking-at-inexpr-block lim nil t))
                            (save-excursion
                              (c-backward-token-2 1 t nil)
@@ -1132,8 +1136,11 @@ comment at the start of cc-engine.el for more info."
                               (if (and (looking-at c-symbol-start)
                                        (not (looking-at c-keywords-regexp)))
                                   (c-backward-token-2 1 t nil))
-                              (not (looking-at
-                                    c-opt-block-decls-with-vars-key)))))
+                              (and
+                               (not (looking-at
+                                     c-opt-block-decls-with-vars-key))
+                               (or comma-delim
+                                   (not (eq (char-after) ?\,)))))))
                           (save-excursion
                             (c-forward-sexp) (point)))
                          ;; Just gone back over some paren block?
@@ -12711,7 +12718,7 @@ comment at the start of cc-engine.el for more info."
                                (c-back-over-member-initializers)
                                (point)))
                             (c-most-enclosing-brace state-cache (point))))
-              (c-beginning-of-statement-1 lim)
+              (c-beginning-of-statement-1 lim nil nil t)
               (c-add-stmt-syntax 'brace-list-intro nil t lim paren-state)))
 
            ;; CASE 9D: this is just a later brace-list-entry or