anchor.diff:    "Return the result of a result assertion."
     (declare (ignore test))
     (logically-equal (car actual) (car expected)))
  +
  +(defmethod record-failure ((type (eql :result))
  +                           form actual expected extras test)
  +  "Return an instance of a boolean failure result."
  +  (call-next-method 'boolean-result form actual expected extras test))
   
   (defclass output-result (failure-result)
     ()
  
positive.code:   (:documentation
     "Failure details of the assertion."))
  
  (defclass equal-result (failure-result)
    ()
    (:documentation
  
negative.code:   (or
     (eql (car actual) (car expected))
     (typep (car actual) (car expected))))
  
  (defmethod record-failure ((type (eql :error))
                             form actual expected extras test)
    "Return an instance of an error failure result."
    (call-next-method 'error-result form actual expected extras test))
  
  (defclass macro-result (failure-result)
    ()
  