Variable is undeclared but can be used

[wangfpp]

Bug report

https://codesandbox.io/s/adoring-lehmann-dvfqf?file=/src/main.js

What is the current behavior?

If the current behavior is a bug, please provide the steps to reproduce.

变量未声明可以使用

const useEffectFn = (_) => {
  return {
    visibleVar: null
  };
};
console.log(visibleVar); // 这里应该直接报错  should throw error
let visibleVar = useEffectFn();
console.log(visibleVar);

[vankop]

Thank you for creating this issue. Could you provide your webpack config?

[wangfpp]

I am using vue-cli-service": "~4.5.0",

[vankop]

I can not help with vue.. please reduce your issue to simple webpack config, thanks.