Static and runtime types: Correct Solution

Given the following type declarations:

public class Ound {
    public Ound cesm(Ound sor) {
        return this;
    }
}

public class Qantint extends Ound {
    public Ound cesm(Ound sor) {
        return new Aiss();
    }
}

public class Aiss extends Ound {
    public Ound cesm(Ound sor) {
        return sor;
    }
}

...and given the following setup code:

Ound foo = new Aiss();
Ound bar = new Qantint();

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.cesm(bar).cesm(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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