Typescript 尽管对象的类型已声明，但未解析的变量<；变量

在17号角，我用了

@for (notification of notifications; track notification) {
   <i>{{notification.quotationId}}</i> 
}

但在WebStorm中，我得到了警告

未解析的变量quotationID

在TypeScrip中，属性notifications的类型被设置为PendingQuotations，其为:

export type PendingQuotations = {
  quotationId: number,
  sender: string,
  date: string
}[]

为什么我会收到这个警告？

下面是我设置该属性的方式:

export class HeaderComponent implements OnInit {
  public notifications?: PendingQuotations;

  constructor(private generalService: GeneralService) { }

  ngOnInit(): void {
    this.$getNotifications().subscribe((pendingQuotations: PendingQuotations) => {
      if (pendingQuotations.length > 0) {
        this.notifications = pendingQuotations;
      }
    });
  }

  $getNotifications(): Observable<PendingQuotations> {
    return this.generalService.get<Response>('/quotation/pending-quotations')
      .pipe(
        map((res: Response) => res.messages[0] as unknown as PendingQuotations)
      );
  }
}

这是res的值:

{
    "code": "PENDING_QUOTATIONS",
    "status": "OK",
    "timestamp": "13.01.2024, 14:33:24",
    "messages": [
        [
            {
                "id": 1,
                "quotationId": 2,
                "receiver": "receiver@example.com",
                "sender": "sender@example.com",
                "date": "2024-01-13T09:27:59.256+00:00"
            }
        ],
        "I am a string"
    ],
    "token": null
}