//// [subtypingWithOptionalProperties.ts]
// subtyping is not transitive due to optional properties but the subtyping algorithm assumes it is for the 99% case
// returns { s?: number; }
function f(a) {
    var b = a;
    return b;
}
var r = f({
    s: new Object()
}); // ok
r.s && r.s.toFixed(); // would blow up at runtime
