TypeScript Version: 2.0.9

Code

class Base {
    protected constructor() { }
    public instance1 = new Base(); // allowed
}

class Subclass extends Base {
    public instance1_1 = new Base(); // allowed
    public instance1_2 = new Subclass(); // allowed
}

class SubclassOfSubclass extends Subclass {
    public instance2_1 = new Base(); // error
    public instance2_2 = new Subclass(); // error
    public instance2_3 = new SubclassOfSubclass(); // error
}

Expected behavior:
Calling a protected constructor of a parent's parent is allowed.

Actual behavior:
test.ts(12,26): error TS2674: Constructor of class 'Base' is protected and only accessible within the class declaration.
test.ts(13,26): error TS2674: Constructor of class 'Base' is protected and only accessible within the class declaration.
test.ts(14,26): error TS2674: Constructor of class 'Base' is protected and only accessible within the class declaration.