anchor.diff:          (cond ((/= (length values) (length old-values))
                  (consistency-error
                   stream form-as-string
  -                "Source had ~S return values ~:@_while there are actually ~S."
  +                "Source had ~S return values ~:_while there are actually ~S."
                   (length old-values) (length values)))
                 (t
                  (loop for value in values
  
positive.code:   (:report (lambda (condition stream)
               (let ((on (transcription-error-on condition)))
                 (format stream
                         "~@<Transcription error in ~A~@[ ~:@_at position ~A~].~
                         ~:@_~?~:@_~
                         Form: ~:@_~S~:@>"
                         (if (typep on 'reference)
                             ;; Allow M-. to work in the slime debugger.
  
negative.code:                 (not (eq (car old-value) :readable)))
             (consistency-error
              stream form-as-string
              "Unreadable value ~:_~S ~:_in source became readable ~:_~S."
              old-value-value value))
            ((and (not value-readable-p)
                  (not (eq (car old-value) :unreadable)))
             (consistency-error
              stream form-as-string
              "Readable value ~:_~S~:_ in source became unreadable ~:_~S."
              old-value-value value))
            ;; At this point we know that both are readable or both are
            ;; unreadable.
  