为什么在正确设置状态时不声明状态?

 async componentDidMount() {
    const claimNumber = 'T1339838' 
    const { runtime } = this.context
    const data = await runtime.select('comments-get', { claimNumber : claimNumber})

    // THIS commentsData ARE empty
    this.setState = ({ commentsData: data, })

    console.log("COMENTS DATA: ", this.state.commentsData)
  }