Static and runtime types: Correct Solution

Given the following type declarations:

public interface Diund {
    public Diund iuir(Diund al);
}

public class Assga implements Diund {
    public Diund iuir(Diund al) {
        return this;
    }
}

public class OpoHisswa implements Diund {
    public Diund iuir(Diund al) {
        return al;
    }
}

...and given the following setup code:

Diund foo = new OpoHisswa();
Diund bar = new Assga();

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.iuir(foo.iuir(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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