Bug报告

在构造函数中使用空值合并来初始化一个没有类型注解的类成员将导致TS7022错误。

🔎 搜索词

nullish , coalescing , 7022 , ?? , 和 ts7022

🕗 版本与回归信息

• 我尝试了每个版本，发现这种行为都存在，我也查阅了关于空值合并和类型推断的FAQ条目。

⏯ Playground链接

带有相关代码的Playground链接

💻 代码

export class Node {
  #parent
  #children = new Children(this)
  constructor (parent?: Node | null | undefined) {
    // Remove `??` and the code after and the code compiled. Now #parent is undefined which is not desired.
    this.#parent = parent ?? null
  }
  get parent () { return this.#parent }
  get children () { return this.#children }
}
export class Children {
  #parent
  #head
  #tail
  constructor (parent: Node) {
    this.#parent = parent
    this.#head = new Node(parent)
    this.#tail = new Node(parent)
  }
}

🙁 实际行为

尝试编译示例代码会导致TS7022错误： '#parent' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.

🙂 预期行为

代码应该能够编译，并且 #parent 应该被类型化为 Node | null。