Static and runtime types: Correct Solution

Given the following type declarations:

public class Biling {
    public Biling sawdo(Biling o) {
        return this;
    }
}

public class Ciasang extends Biling {
    public Biling sawdo(Biling o) {
        return new Tosswi();
    }
}

public class Tosswi extends Biling {
    public Biling sawdo(Biling o) {
        return o;
    }
}

...and given the following setup code:

Biling foo = new Ciasang();
Tosswi bar = new Tosswi();

Part 1

Draw an AST for the following expression, labeling the static type (a.k.a. compile-time type) of each node in the tree:

foo.sawdo(foo).sawdo(bar)

(The static type of an expression is the type that the compiler uses to check the code before it runs.)

Solution

Part 2

Draw an AST for the same expression, this time labeling the runtime type of each node in the tree.

(The runtime type of an expression is the type of the actual value that appears when the code runs.)

Solution

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