anchor.diff:                            (iincf map-len (emit-non-repeated-field v val-class 2 buffer))
                             ;todo(benkuehnert): + or i+ here?
                             (+ ret-len (+ map-len (backpatch map-len)))))))
  -               (loop for k being the hash-keys of (read-slot object slot reader)
  +               (loop for k being the hash-keys of value
                          using (hash-value v)
                        sum (serialize-pair k v)))))
             ((typep msg 'protobuf-type-alias)
  
positive.code:           ((typep msg 'map-descriptor)
             (let* ((tag (make-tag $wire-type-string index))
                    (key-class (map-descriptor-key-class msg))
                    (val-class (map-descriptor-key-class msg))
                    (val-msg  (and val-class (not (keywordp val-class))
                                   (or (find-message val-class)
                                       (find-enum val-class)
  
negative.code:                        (let* ((end (+ start embedded-msg-len))
                                (deserializer (custom-deserializer type))
                                (obj
                                  (cond (lazy-p
                                         ;; For lazy fields, just store bytes in the %bytes
                                         ;; field.
                                         (deserialize-object-to-bytes
  