=== tests/cases/compiler/numericIndexerConstraint4.ts ===
class A {
>A : A

    foo: number;
>foo : number
}

class B extends A {
>B : B
>A : A

    bar: string;
>bar : string
}

var x: {
>x : { [idx: number]: A; }

    [idx: number]: A;
>idx : number
>A : A

} = { data: new B() }
>{ data: new B() } : { [x: number]: undefined; data: B; }
>data : B
>new B() : B
>B : typeof B