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:   (declare (ignore test))
    (%expansion-equal (first expected) (first actual)))
  
  (defclass boolean-result (failure-result)
    ()
    (:documentation
  
negative.code:   (:documentation
     "Return the result of the assertion."))
  
  (defgeneric record-failure (type form actual expected extras test)
    (:documentation
     "Record the details of the failure."))
  
  (defclass failure-result ()
    ((form
      :initarg :form
  