vue2项目，只要用上async就会报错

问题遇到的现象和发生背景

vue2项目，只要用上async就会报错，不使用就没问题，可能是没吧es7转换成es5
尝试过重新下载babel的plugin-transform-runtime，但是也无效
浏览器的sources显示

报错

代码

package.json

    {
  "name": "icps",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "test": "vue-cli-service build --mode test"
  },
  "dependencies": {
    "axios": "^0.19.2",
    "babel-plugin-import": "^1.13.3",
    "babel-polyfill": "^6.26.0",
    "core-js": "^3.6.4",
    "dot-prop": "^6.0.1",
    "echarts": "^4.8.0",
    "element-ui": "^2.13.0",
    "nprogress": "^0.2.0",
    "qiankun": "^2.6.3",
    "register-service-worker": "^1.7.1",
    "sass-resources-loader": "^2.0.3",
    "sortablejs": "^1.10.2",
    "vue": "^2.6.12",
    "vue-drag-resize": "^1.4.2",
    "vue-input-limit": "^0.1.3",
    "vue-qr": "^2.2.1",
    "vue-router": "^3.1.3",
    "vue2-svg-icon": "^1.3.2",
    "vuex": "^3.1.2"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "~4.4.0",
    "@vue/cli-plugin-eslint": "~4.4.0",
    "@vue/cli-plugin-router": "~4.4.0",
    "@vue/cli-plugin-vuex": "~4.4.0",
    "@vue/cli-service": "~4.4.0",
    "babel-eslint": "^10.1.0",
    "compression-webpack-plugin": "^6.0.4",
    "eslint": "^6.7.2",
    "eslint-plugin-vue": "^6.2.2",
    "happypack": "^5.0.1",
    "image-webpack-loader": "^7.0.1",
    "less": "^4.1.2",
    "less-loader": "^7.3.0",
    "sass": "^1.27.0",
    "sass-loader": "^8.0.0",
    "uglifyjs-webpack-plugin": "^1.0.0-rc.0",
    "vue-template-compiler": "^2.6.10",
    "vue2-svg-icon": "^1.3.2",
    "webpack": "^4.42.1",
    "webpack-bundle-analyzer": "^3.9.0",
    "webpack-cli": "^3.3.11"
  },
  "description": "## Project setup ``` yarn install ```",
  "main": ".eslintrc.js",
  "author": "fxg1997",
  "license": "ICSC"
}

babel.config.js

module.exports = {
  presets: [
    '@vue/cli-plugin-babel/preset'
  ],
  plugins: [
    ["@babel/plugin-transform-modules-commonjs", { "strictMode": false }],
    ["import", { libraryName: "ant-design-vue", libraryDirectory: "es", style: "css" }]
  ],
}

原始代码
router.afterEach(async () => {
console.log(123)
const hasWaterMask = window.sessionStorage.getItem('watermark') === 'Y';
const UserInfo = await getUserInfo();
if (UserInfo && hasWaterMask) {
Watermark.set(UserInfo.userRealName)
}
NProgress.done();
});
注！删除了async 和await可以正常运行
再次尝试添加
async function aa(){
console.log("aa");
}
aa()
报相同错误

你能提供一下vue版本 和部分代码我这里好复现

实在找不到问题所在，可以试试promise