Nested objects based on indexer not checked for freshness

[basarat]

TypeScript Version: Nightly today

Code

type CSSPropertyMap = {
    color?: string
}
type NestedCSSProperties = {
    nested?: {
        [selector:string]: CSSProperties
    }
}

type CSSProperties = CSSPropertyMap & NestedCSSProperties;

let style: CSSProperties;

// ok
style = {
    color: 'red'
}

// ok
style = {
    nested: {
        '&:hover': {
            color: 'red'
        }
    }
}

// does error
style = {
    colour: 'red'
}

// should error but doesn't
style = {
    nested: {
        '&:hover': {
            colour: 'red'
        }
    }
}

Expected behavior:
Error

Actual behavior:
Does not error

Thanks 🌹

[basarat]

Note: it can be rewritten to work:

type CSSProperties = {
    color?: string
}
type NestedCSSProperties = {
    nested: {
        [selector: string]: CSSProperties
    }
}


let style: CSSProperties;
let stylen: NestedCSSProperties;

// ok
style = {
    color: 'red'
}

// ok
stylen = {
    nested: {
        '&:hover': {
            color: 'red'
        }
    }
}


// does error
style = {
    colour: 'red'
}

// does error
stylen = {
    nested: {
        '&:hover': {
            colour: 'red'
        }
    }
}

Basically the & in the original code throws off the compiler (I think)

[basarat]

Unions and intersections are not checked for freshness. Its in the spec : https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#3115-excess-properties my bad 🌹