anchor.diff:                             (decode-uint32 ,vbuf ,vidx))
                            (if (= 1 (ilogand (iash map-tag -3) #x1FFFFFFF))
                                (multiple-value-setq (key-data ,vidx)
  -                               (deserialize-prim ,key-type ,vbuf ,vidx))
  -                             ,(cond ((keywordp val-type)
  +                               (deserialize-prim ,key-class ,vbuf ,vidx))
  +                             ,(cond ((keywordp val-class)
                                        `(multiple-value-setq (val-data ,vidx)
  -                                        (deserialize-prim ,val-type ,vbuf ,vidx)))
  +                                        (deserialize-prim ,val-class ,vbuf ,vidx)))
                                       ((typep val-msg 'message-descriptor)
                                        (if (eq (proto-message-type val-msg) :group)
                                            (let ((tag2 (make-tag $wire-type-end-group 2)))
  
positive.code:                                     (t
                                       (undefined-field-type
                                        "While generating 'deserialize-object' for ~S,"
                                        message val-type field))))))))))
                (t
                 (setf nslot temp)
                 ;; Non-repeating field.
  
negative.code:                      (t
                        (undefined-field-type "While generating 'deserialize-object' for ~S,"
                                              message class field))))
                ((typep msg 'map-descriptor)
                 (setf nslot temp)
                 (let* ((start vidx)
                        (key-class (map-descriptor-key-class msg))
                        (val-class (map-descriptor-val-class msg))
                        (val-msg  (and val-class (not (keywordp val-class))
                                       (or (find-message val-class)
                                           (find-enum val-class)
                                           (find-type-alias val-class)))))
                   (ret
                    (make-tag $wire-type-string index)
                    `(progn
  