Firebase-bolt给出*** TYPE RECURSION ***“错误

Question

我的.bolt文件中有以下类型定义，名为tasks.bolt

//...

type Channel {
   name: ShortNonEmptyString,
   tasks: Map<TaskId, Task>,
   members: Map<UserId, User>
}

type User {
   displayName: ShortNonEmptyString,
   tasks: Map<UserId, Task>,
   channels: Map<ChannelId, Channel>
}

type ChannelId extends String {
    validate() { this.length <= 20 }
}

type TaskId extends String {
    validate() { this.length <= 20 }
}

type UserId extends String {
    //XXX: min. max. length of the user's ID?
    validate() { this.length >= 10 }
}

type Percent {
    validate() { this >= 0 && this <= 1 }
}

type State {
   //TODO: check in client
    validate() { this >= 0 && this <= 3 }
}

type ShortNonEmptyString extends String {
    validate() { this.length > 0 && this.length < 16}
}

//...

编译后（firebase-bolt＆lt; tasks.bolt），输出包含以下内容：

"channels": {
    "$key4": {
        ".validate": "$key4.length <= 20 && ***TYPE RECURSION***"
    },
    ".validate": "newData.hasChildren()"
}

我理解这是递归，因为类型频道有用户和用户有频道。这是bolt编译器的正常行为吗？我的类型定义是否正确？我的做法好吗？

感谢您的帮助！