Flow JS“多态类型而不是交集类型”错误是什么意思？

Flow JS错误是什么意思？

Expected polymorphic type instead of any member of intersection type.

细节：

错误Document在下面的导出行中引发。我不明白为什么会这样，或者我可以做些什么来解决它。（我尝试在Flow文档中查找此内容，但仍然无法弄清楚。）

// @flow
import Document, {Head, Main, NextScript} from 'next/document'

export default class IntlDocument extends Document {
  static async getInitialProps (context) {
    const props = await super.getInitialProps(context)
    const {req: {localeDataScript}} = context
    return {
      ...props,
      localeDataScript
    }
  }

  render () {
    return (
      <html>
        <Head />
        <body>
          <Main />
          <script
            dangerouslySetInnerHTML={{
              __html: this.props.localeDataScript
            }}
          />
          <NextScript />
        </body>
      </html>
    )
  }
}

和next/document类型声明是这样的：

declare module "next/document" {
  import type {Component} from 'react';

  declare type Context = {
    pathname: string,
    query: any,
    req?: any,
    res?: any,
    xhr?: any,
    err?: any,
  };
  declare export var Head: Class<Component<void, *, *>>;
  declare export var Main: Class<Component<void, *, *>>;
  declare export var NextScript: Class<Component<void, *, *>>;
  declare export default Class<Component<void, *, *>> & {
    getInitialProps: (ctx: Context) => Promise<*>;
    renderPage(cb: Function): void;
  };
}