diff --git a/lisp/calendar/todo-mode.el b/lisp/calendar/todo-mode.el
index 8155a4241a..7b27e7049d 100644
--- a/lisp/calendar/todo-mode.el
+++ b/lisp/calendar/todo-mode.el
@@ -6583,17 +6583,19 @@ todo-modes-set-1
     (visual-line-mode)
     (setq wrap-prefix (make-string todo-indent-to-here 32))))
 
+(defun todo-hl-line-range ()
+  "Make `todo-toggle-item-highlighting' highlight entire item."
+  (save-excursion
+    (when (todo-item-end)
+      (cons (todo-item-start)
+            (todo-item-end)))))
+
 (defun todo-modes-set-2 ()
   "Make some settings that apply to multiple Todo modes."
   (add-to-invisibility-spec 'todo)
   (setq buffer-read-only t)
   (setq-local desktop-save-buffer 'todo-desktop-save-buffer)
-  (when (boundp 'hl-line-range-function)
-    (setq-local hl-line-range-function
-		(lambda() (save-excursion
-			    (when (todo-item-end)
-			      (cons (todo-item-start)
-				    (todo-item-end))))))))
+  (setq-local hl-line-range-function 'todo-hl-line-range))
 
 (defun todo-modes-set-3 ()
   "Make some settings that apply to multiple Todo modes."