Partial type passes for values that are strings and incorrect objects #16691

interface Foo {
    key: string
    value: string
}

const shouldFail0: Partial<Foo> = '' // does not fail
const shouldPass0: Partial<Foo> = {} // does not fail
const shouldFail1: Partial<Foo> = {
    ker: ''
} // fails

interface Bar {
    (): Partial<Foo>
}

const shouldFail2: Bar = () => ({
    car: ''
}) // does not fails
const shouldFail3: Bar = () => ('') // does not fails
const shouldFail4: Bar = () => {
    return undefined
} // fails