=== tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembersOptionality4.ts ===
// Base has required property, derived adds an optional property, no errors

interface Base { foo: string; }
>Base : Base
>foo : string

interface Derived extends Base { bar: string; }
>Derived : Derived
>Base : Base
>bar : string

interface T {
>T : T

    Foo: Base;
>Foo : Base
>Base : Base
}

interface S extends T {
>S : S
>T : T

    Foo2?: Derived // ok
>Foo2 : Derived
>Derived : Derived
}

interface T2 {
>T2 : T2

    1: Base; 
>Base : Base
}

interface S2 extends T2 {
>S2 : S2
>T2 : T2

    2?: Derived; // ok
>Derived : Derived
}

interface T3 {
>T3 : T3

    '1': Base;
>Base : Base
}

interface S3 extends T3 {
>S3 : S3
>T3 : T3

    '1.0'?: Derived; // ok
>Derived : Derived
}

// object literal case
var a: { Foo: Base; }
>a : { Foo: Base; }
>Foo : Base
>Base : Base

var b: { Foo2?: Derived; }
>b : { Foo2?: Derived; }
>Foo2 : Derived
>Derived : Derived

var r = true ? a : b; // ok
>r : { Foo: Base; } | { Foo2?: Derived; }
>true ? a : b : { Foo: Base; } | { Foo2?: Derived; }
>true : boolean
>a : { Foo: Base; }
>b : { Foo2?: Derived; }