class Base {
    protected x: string;
    method() {
        var b: Base;
        var d1: Derived1;
        var d2: Derived2;
        var d3: Derived3;
        var d4: Derived4;

        b.x;            // OK, accessed within their declaring class
        d1.x;           // OK, accessed within their declaring class
        d2.x;           // OK, accessed within their declaring class
        d3.x;           // Error, redefined in a subclass, can only be accessed in the declaring class or one of its subclasses
        d4.x;           // OK, accessed within their declaring class
    }
}

class Derived1 extends Base {
    method1() {
        var b: Base;
        var d1: Derived1;
        var d2: Derived2;
        var d3: Derived3;
        var d4: Derived4;

        b.x;            // Error, isn't accessed through an instance of the enclosing class
        d1.x;           // OK, accessed within a class derived from their declaring class, and through an instance of the enclosing class
        d2.x;           // Error, isn't accessed through an instance of the enclosing class
        d3.x;           // Error, redefined in a subclass, can only be accessed in the declaring class or one of its subclasses
        d4.x;           // Error, isn't accessed through an instance of the enclosing class
    }
}

class Derived2 extends Base {
    method2() {
        var b: Base;
        var d1: Derived1;
        var d2: Derived2;
        var d3: Derived3;
        var d4: Derived4;

        b.x;            // Error, isn't accessed through an instance of the enclosing class
        d1.x;           // Error, isn't accessed through an instance of the enclosing class
        d2.x;           // OK, accessed within a class derived from their declaring class, and through an instance of the enclosing class
        d3.x;           // Error, redefined in a subclass, can only be accessed in the declaring class or one of its subclasses
        d4.x;           // OK, accessed within a class derived from their declaring class, and through an instance of the enclosing class or one of its subclasses
    }
}

class Derived3 extends Derived1 {
    protected x: string;
    method3() {
        var b: Base;
        var d1: Derived1;
        var d2: Derived2;
        var d3: Derived3;
        var d4: Derived4;

        b.x;            // Error, isn't accessed through an instance of the enclosing class
        d1.x;           // Error, isn't accessed through an instance of the enclosing class
        d2.x;           // Error, isn't accessed through an instance of the enclosing class
        d3.x;           // OK, accessed within their declaring class
        d4.x;           // Error, isn't accessed through an instance of the enclosing class
    }
}

class Derived4 extends Derived2 {
    method4() {
        var b: Base;
        var d1: Derived1;
        var d2: Derived2;
        var d3: Derived3;
        var d4: Derived4;

        b.x;            // Error, isn't accessed through an instance of the enclosing class
        d1.x;           // Error, isn't accessed through an instance of the enclosing class
        d2.x;           // Error, isn't accessed through an instance of the enclosing class
        d3.x;           // Error, redefined in a subclass, can only be accessed in the declaring class or one of its subclasses
        d4.x;           // OK, accessed within a class derived from their declaring class, and through an instance of the enclosing class
    }
}


var b: Base;
var d1: Derived1;
var d2: Derived2;
var d3: Derived3;
var d4: Derived4;

b.x;                    // Error, neither within their declaring class nor classes derived from their declaring class
d1.x;                   // Error, neither within their declaring class nor classes derived from their declaring class
d2.x;                   // Error, neither within their declaring class nor classes derived from their declaring class
d3.x;                   // Error, neither within their declaring class nor classes derived from their declaring class
d4.x;                   // Error, neither within their declaring class nor classes derived from their declaring class