anchor.diff:  #+nil
   (eval-when ()
   
  -(defclass singleton-1 (singleton)
  -  ((sl-a)
  -   (sl-b))
  -  (:metaclass singleton))
  +(defsingleton singleton-1 ()
  +  ((sl-1)
  +   (sl-b)))
  +
  +(let ((c (find-class 'singleton-1)))
  +  (finalize-inheritance c)
  +  (multiple-value-bind (st-1 st-2)
  +      (subtypep c 'singleton)
  +    (multiple-value-bind (mt-1 mt-2)
  +        (subtypep (class-of c) 'singleton)
  +      (values st-1 st-2
  +              mt-1 mt-2))))
  +
  +;; => T, T, T, T
  +
   
   (finalize-inheritance (find-class 'singleton-1))
   
  
positive.code: 
  (validate-class singleton)
  
  
  ;; FIXME: Automatically finalize SINGLETON after initialization.
  ;;
  
negative.code:   (:nicknames #:ltp.common.mop.singleton)
    (:use #:ltp/common/mop
          #:ltp/common
          #:cl)
    (:export
     #:singleton
     #:defsingleton
     ))
  
  (in-package #:ltp/common/mop/singleton)
  
  