Cannot use functional option in defineComponent

[iceprosurface]

What problem does this feature solve?

It works in @vue/composition-api.

import { defineComponent } from '@vue/composition-api'

defineComponent({ functional: true })

Is there a correct way to create functional component in vue2.7.0+ using typescript?

What does the proposed API look like?

import { defineComponent } from 'vue'
defineComponent({ functional: true })