Inconsistency in polymorphic 'this' typing

[zhuravlikjb]

class A {
    p: A;
    c = this.p;
}

class B extends A {
    p: B;    
}

var s: B;
var k = s.c; // 'k' is 'A'

class A {
    c = this;
}

class B extends A {        
}

var s: B;
var k = s.c; // 'k' is 'B'

[zhuravlikjb]

After some experiments, a simple question: is 'this' polymorphic only for simple expression "this", and not when it's used as a qualifier in some reference expression, e.g. "this.foo"?

[mhegazy]

One thing to note, there are two uses of the keyword this. your example above uses an initializer. this will be evaluated once, in the context of the base class A; the type of the expression this.p here is A, and there is no polymorphism here. if you however, gave c the type this, this will be instantiated in the context of the derived class, and you would get the desired polymorphism.

[zhuravlikjb]

Thanks, now it's more clear how it behaves.