class X {
    constructor(public z) { }
    a: number;
}

class Y {
    constructor(public z) {
    }
    a: number;
    b: string;
}

class Z {
    z: any;
    c: string;
}

var c1 = new X(3);
var c2 = new Y(5);
var c3 = new Z();
c1 = c2 = c3; // a bug made this not report the same error as below
c2 = c3; // Error TS111: Cannot convert Z to Y