+ ;; MULTIPLE-VALUE-SETQ is required to always return just the primary
+ ;; value of the value-from, even if there are no vars. (SETF VALUES)
+ ;; in turn is required to return as many values as there are
+ ;; value-places, hence this:
+ (if vars
+ `(values (setf (values ,@vars) ,value-form))
+ `(values ,value-form)))