Version

3.2.27

Reproduction link

codesandbox.io

Steps to reproduce

1. setup function console.log visiable
2. let { visiable } = useEffectFn()

What is expected?

Variable undeclared should throw error directly

What is actually happening?

Variable undeclared should throw error directly

变量未声明可以直接使用 应该抛出错误

setup() {
    let state = reactive({
      visible: false,
    });
    console.log(visibleVar); // 此处应该抛出错误  而不是undefined    should throw error but get undefined
    let { visibleVar } = useEffectFn();
    const toggle = () => {
      state.visible = !state.visible;
    };
    return {
      ...toRefs(state),
      toggle,
    };
  },

You can copy the same code into main.js and it behaves the same.

So this is not related to Vue but to the build system you are using, likely.

@LinusBorg Do you mean it is caused by webpack or vite compilation?

Yes.