anchor.diff:    TYPE: The :class slot of the field.
     INDEX: The index of the field (used for making tags).
     BUFFER: The buffer to write to."
  -  (let ((size 0))
  +  (let ((size 0)
  +        msg)
       (declare (fixnum size index))
       (declare (buffer buffer))
       (cond ((keywordp type)
  
positive.code:   PACKED-P: Whether or not the field in question is packed.
    INDEX: The index of the field (used for making tags).
    BUFFER: The buffer to write to."
    (let ((size 0))
      (declare (fixnum size index))
      (declare (buffer buffer))
      (cond ((and packed-p (packed-type-p type))
  
negative.code:     (let ((type   (slot-value field 'class))
            (slot   (slot-value field 'internal-field-name))
            (reader (slot-value field 'reader))
            (index (proto-index field)))
        (if (eq (proto-label field) :repeated)
            (or (emit-repeated-field
                 (if slot (read-slot object slot
  