vue-default-export

1. Create a <script setup lang="ts"> Setup.vue component
2. Define the props via an interface

interface Props {
    msg: string;
}

defineProp<Props>();

3. Create a <script lang="ts"> Define component that uses Setup.vue
4. npm run type-check

npm i
npm run type-check

You'll see

src/components/Define.vue:20:1 - error TS4082: Default export of the module has or is using private name 'Props'.

 20 export default defineComponent({
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 21   components: {
    ~~~~~~~~~~~~~~~
... 
 23   },
    ~~~~
 24 });
    ~~~

Found 1 error.