anchor.diff:    ())
   
   
  -(defmethod direct-slot-definition-class ((class singleton-class)
  +(defmethod direct-slot-definition-class ((class singleton)
                                            &rest initargs)
     (find-class 'singleton-direct-slot-definition))
   
  
positive.code:   ())
  
  
  (defmethod effective-slot-definition-class ((class singleton-class)
                                              &rest initargs)
    (find-class 'singleton-effective-slot-definition))
  
  
negative.code: 
  
  
  (defclass singleton (standard-class)
    ())
  
  
  (validate-class singleton)
  
  
  (defclass singleton-slot-definition (standard-slot-definition)
  