Typescript possible undefined loses type when using withDefaults and setting explicitly to undefined

[VividLemon]

If you do

interface Props { id?: number }

const props = withDefaults(defineProps<Props>(), { id: undefined })

if you observer props.id, even though the default is undefined, it will lose it's type and it will always claim to be number.

[johnsoncodehk]

This is withDefaults types behavior, please forward to https://github.com/vuejs/core.