The environment created by vue-cli cannot determine the type of async function

[maclaren0920]

Version

3.5.0

Reproduction link

#3653

Environment info

 System:
    OS: macOS 10.14.3
    CPU: (8) x64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
  Binaries:
    Node: 10.15.3 - ~/.nvm/versions/node/v10.15.3/bin/node
    Yarn: 1.13.0 - ~/.nvm/versions/node/v10.15.3/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v10.15.3/bin/npm
  Browsers:
    Chrome: 73.0.3683.75
    Firefox: 65.0.1
    Safari: 12.0.3
  npmGlobalPackages:
    @vue/cli: 3.5.0

Steps to reproduce

mounted() {
let str = Object.getPrototypeOf(this.test1).constructor;
console.log(str); // ƒ Function() { [native code] }
},
methods: {
async test1() {

}

}

What is expected?

Solve this problem

What is actually happening?

Unable to determine type

[LinusBorg]

Still no reproduction.

I realize there may be a language barrier. Sharing runnable code is all the more important.

[haoqunjiang]

babel/babel#4691
babel/babel#7767
babel/babel#8642

Unless you turn off babel transpiling, there's no way to distinguish an async function from normal functions.