CC Mode: Fontify foo in "const auto foo :" correctly

* lisp/progmodes/cc-engine.el (c-forward-decl-or-cast-1): While attempting to
find a declaration's identifier, recast the latest found id. as that
identifier when there is no other type identifier and the result of the most
recent c-forward-type call is 'maybe or 'found.  In the latter case, remove
the id. from the found types list, too.

1 files changed, 24 insertions, 4 deletions

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 0c338fa3868..447942e9a2a 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -9275,9 +9275,10 @@ This function might do hidden buffer changes."
   ;;
   ;;   The third element of the return value is non-nil when the declaration
   ;;   parsed might be an expression.  The fourth element is the position of
-  ;;   the start of the type identifier.  The fifth element is t if either
-  ;;   CONTEXT was 'top, or the declaration is detected to be treated as top
-  ;;   level (e.g. with the keyword "extern").
+  ;;   the start of the type identifier, or the same as the first element when
+  ;;   there is no type identifier.  The fifth element is t if either CONTEXT
+  ;;   was 'top, or the declaration is detected to be treated as top level
+  ;;   (e.g. with the keyword "extern").
   ;;
   ;; If a cast is parsed:
   ;;
@@ -9680,7 +9681,26 @@ This function might do hidden buffer changes."
                (setq got-identifier (c-forward-name))
                (setq name-start pos))
           (when (looking-at "[0-9]")
-            (setq got-number t))) ; We've probably got an arithmetic expression.
+            (setq got-number t)) ; We probably have an arithmetic expression.
+          (and maybe-typeless
+               (or (eq at-type 'maybe)
+                   (when (eq at-type 'found)
+                     ;; Remove the ostensible type from the found types list.
+                     (when type-start
+                       (c-unfind-type
+                        (buffer-substring-no-properties
+                         type-start
+                         (save-excursion
+                           (goto-char type-start)
+                           (c-end-of-token)
+                           (point)))))
+                     t))
+               ;; The token which we assumed to be a type is actually the
+               ;; identifier, and we have no explicit type.
+               (setq at-type nil
+                     name-start type-start
+                     id-start type-start
+                     got-identifier t)))
 
       ;; Skip over type decl suffix operators and trailing noise macros.
       (while