CC Mode: Change the default value of objc-font-lock-extra-types to nil

This fixes bug #59234, in which random identifiers in a .m file were getting
fontified as types.

* lisp/progmodes/cc-vars.el (objc-font-lock-extra-types): Change the default
value to nil.

* etc/NEWS: Mention the change in default value of objc-font-lock-extra-types,
and how to get the old behavior back.

2 files changed, 7 insertions, 2 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 64c26f93c50..dd026016382 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1679,6 +1679,12 @@ command is installed.
 
 ---
 *** C++ Mode now supports most of the new features in the C++20 Standard.
+---
+*** In objective-C Mode, the default value of
+objc-font-lock-extra-types has been changed to nil, since too many
+identifiers were getting misfontified as types.  This may cause some
+actual types not to get fontified.  To get the old behavior back,
+customize the variable to the value suggested in its doc string.
 
 ** Cperl Mode
 
diff --git a/lisp/progmodes/cc-vars.el b/lisp/progmodes/cc-vars.el
index 2206e0fcab6..60ed3521b8a 100644
--- a/lisp/progmodes/cc-vars.el
+++ b/lisp/progmodes/cc-vars.el
@@ -1609,8 +1609,7 @@ as a type name.")
   :type 'c-extra-types-widget
   :group 'c)
 
-(defcustom objc-font-lock-extra-types
-  (list (concat "[" c-upper "]\\sw*[" c-lower "]\\sw*"))
+(defcustom objc-font-lock-extra-types nil
   (c-make-font-lock-extra-types-blurb "ObjC" "objc-mode" (concat
 "For example, a value of (\"[" c-upper "]\\\\sw*[" c-lower "]\\\\sw*\") means
 capitalized words are treated as type names (the requirement for a