[
  {
    "bases": [
      "AliasParent"
    ],
    "fields": [
      "old",
      "extra"
    ]
  },
  {
    "payload": {},
    "source": {
      "old": 1,
      "extra": 3
    },
    "generated": {
      "old": 1,
      "extra": 3
    }
  },
  {
    "payload": {
      "old": 8
    },
    "source": {
      "old": 8,
      "extra": 3
    },
    "generated": {
      "old": 8,
      "extra": 3
    }
  }
]