anchor.diff:  
   (defmethod make-load-form ((m map-descriptor) &optional environment)
     (make-load-form-saving-slots m :environment environment))
  -
  -(defstruct oneof
  -  "The struct which stores dynamic oneof data."
  -  ;; This slot stores the data which is set in the oneof.
  -  ;; Typing this slot as an OR of the oneof's field types doesn't seem
  -  ;; to get us any additional space savings. Furthermore, trying to add
  -  ;; a type would require making a new oneof defstruct for each oneof
  -  ;; defined, which greatly adds to the code's complexity.
  -  (value nil)
  -  ;; This slot indicates which field is set in the oneof
  -  ;; If it is set to -1, then there is no field set. Ifif it is a number,
  -  ;; say N, then the N-th field (0 indexed) in the oneof is set.
  -  (set-field -1 :type (signed-byte 32)))
  -
  -(defstruct oneof-descriptor
  -  "The meta-object for a protobuf map"
  -  ;; While oneofs do not have indices, each of its fields has a 'field-offset'
  -  ;; which tracks the order that the fields are defined in the message. Since
  -  ;; these fields share a single slot, they share the same field-offset. This
  -  ;; slot holds this value.
  -  (index nil :type (or null (unsigned-byte 29)))
  -  ;; A vector which stores the oneof's field descriptor.
  -  (fields nil :type (array field-descriptor))
  -  ;; The external name, but with '%' prepended.
  -  (internal-name nil :type symbol)
  -  ;; A symbol whose name is the name of the oneof.
  -  (external-name nil :type symbol))
  -
  -(defmethod make-load-form ((o oneof-descriptor) &optional environment)
  -  (make-load-form-saving-slots o :environment environment))
   
   (defstruct enum-descriptor
     "Describes a protobuf enum."
  
positive.code:               (and (slot-boundp m 'otype) (proto-output-type m))))
      (format stream "~S" (proto-class m))))
  
  
  ;;; Lisp-only extensions
  
  
negative.code:               (and (slot-boundp msg-desc 'message-type)
                     (eq (proto-message-type msg-desc) :extends))))
      (format stream "~S" (and (slot-boundp msg-desc 'class) (proto-class msg-desc)))))
  
  ;; Extensions protocol
  (defgeneric get-extension (object slot)
  