=== tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembersOptionality.ts ===
// Derived member is not optional but base member is, should be ok

interface Base { foo: string; }
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
>foo : Symbol(foo, Decl(subtypingWithObjectMembersOptionality.ts, 2, 16))

interface Derived extends Base { bar: string; }
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
>bar : Symbol(bar, Decl(subtypingWithObjectMembersOptionality.ts, 3, 32))

interface Derived2 extends Derived { baz: string; }
>Derived2 : Symbol(Derived2, Decl(subtypingWithObjectMembersOptionality.ts, 3, 47))
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))
>baz : Symbol(baz, Decl(subtypingWithObjectMembersOptionality.ts, 4, 36))

// S is a subtype of a type T, and T is a supertype of S, if one of the following is true, where S' denotes the apparent type (section 3.8.1) of S:
//   - S' and T are object types and, for each member M in T, one of the following is true:
//      - M is a property and S' contains a property N where
//          M and N have the same name,
//          the type of N is a subtype of that of M,
//          M and N are both public or both private, and
//          if M is a required property, N is also a required property.
//      - M is an optional property and S' contains no property of the same name as M.
interface T {
>T : Symbol(T, Decl(subtypingWithObjectMembersOptionality.ts, 4, 51))

    Foo?: Base;
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 14, 13))
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
}

interface S extends T {
>S : Symbol(S, Decl(subtypingWithObjectMembersOptionality.ts, 16, 1))
>T : Symbol(T, Decl(subtypingWithObjectMembersOptionality.ts, 4, 51))

    Foo: Derived
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 18, 23))
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))
}

interface T2 {
>T2 : Symbol(T2, Decl(subtypingWithObjectMembersOptionality.ts, 20, 1))

    1?: Base; 
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
}

interface S2 extends T2 {
>S2 : Symbol(S2, Decl(subtypingWithObjectMembersOptionality.ts, 24, 1))
>T2 : Symbol(T2, Decl(subtypingWithObjectMembersOptionality.ts, 20, 1))

    1: Derived;
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))
}

interface T3 {
>T3 : Symbol(T3, Decl(subtypingWithObjectMembersOptionality.ts, 28, 1))

    '1'?: Base;
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
}

interface S3 extends T3 {
>S3 : Symbol(S3, Decl(subtypingWithObjectMembersOptionality.ts, 32, 1))
>T3 : Symbol(T3, Decl(subtypingWithObjectMembersOptionality.ts, 28, 1))

    '1.': Derived;
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))
}

// object literal case
var a: { Foo?: Base; };
>a : Symbol(a, Decl(subtypingWithObjectMembersOptionality.ts, 39, 3))
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 39, 8))
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))

var b = { Foo: <Derived>null };
>b : Symbol(b, Decl(subtypingWithObjectMembersOptionality.ts, 40, 3))
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 40, 9))
>Derived : Symbol(Derived, Decl(subtypingWithObjectMembersOptionality.ts, 2, 31))

var r = true ? a : b;
>r : Symbol(r, Decl(subtypingWithObjectMembersOptionality.ts, 41, 3))
>a : Symbol(a, Decl(subtypingWithObjectMembersOptionality.ts, 39, 3))
>b : Symbol(b, Decl(subtypingWithObjectMembersOptionality.ts, 40, 3))

module TwoLevels {
>TwoLevels : Symbol(TwoLevels, Decl(subtypingWithObjectMembersOptionality.ts, 41, 21))

    interface T {
>T : Symbol(T, Decl(subtypingWithObjectMembersOptionality.ts, 43, 18))

        Foo?: Base;
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 44, 17))
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
    }

    interface S extends T {
>S : Symbol(S, Decl(subtypingWithObjectMembersOptionality.ts, 46, 5))
>T : Symbol(T, Decl(subtypingWithObjectMembersOptionality.ts, 43, 18))

        Foo: Derived2 
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 48, 27))
>Derived2 : Symbol(Derived2, Decl(subtypingWithObjectMembersOptionality.ts, 3, 47))
    }

    interface T2 {
>T2 : Symbol(T2, Decl(subtypingWithObjectMembersOptionality.ts, 50, 5))

        1?: Base;
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
    }

    interface S2 extends T2 {
>S2 : Symbol(S2, Decl(subtypingWithObjectMembersOptionality.ts, 54, 5))
>T2 : Symbol(T2, Decl(subtypingWithObjectMembersOptionality.ts, 50, 5))

        1: Derived2;
>Derived2 : Symbol(Derived2, Decl(subtypingWithObjectMembersOptionality.ts, 3, 47))
    }

    interface T3 {
>T3 : Symbol(T3, Decl(subtypingWithObjectMembersOptionality.ts, 58, 5))

        '1'?: Base;
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))
    }

    interface S3 extends T3 {
>S3 : Symbol(S3, Decl(subtypingWithObjectMembersOptionality.ts, 62, 5))
>T3 : Symbol(T3, Decl(subtypingWithObjectMembersOptionality.ts, 58, 5))

        '1.': Derived2;
>Derived2 : Symbol(Derived2, Decl(subtypingWithObjectMembersOptionality.ts, 3, 47))
    }

    // object literal case
    var a: { Foo?: Base; };
>a : Symbol(a, Decl(subtypingWithObjectMembersOptionality.ts, 69, 7))
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 69, 12))
>Base : Symbol(Base, Decl(subtypingWithObjectMembersOptionality.ts, 0, 0))

    var b = { Foo: <Derived2>null };
>b : Symbol(b, Decl(subtypingWithObjectMembersOptionality.ts, 70, 7))
>Foo : Symbol(Foo, Decl(subtypingWithObjectMembersOptionality.ts, 70, 13))
>Derived2 : Symbol(Derived2, Decl(subtypingWithObjectMembersOptionality.ts, 3, 47))

    var r = true ? a : b;
>r : Symbol(r, Decl(subtypingWithObjectMembersOptionality.ts, 71, 7))
>a : Symbol(a, Decl(subtypingWithObjectMembersOptionality.ts, 69, 7))
>b : Symbol(b, Decl(subtypingWithObjectMembersOptionality.ts, 70, 7))
}