Static and runtime types: Correct Solution

Given the following type declarations:

public interface Slan {
    public Slan pseou(Slan un);
}

public class Picbec implements Slan {
    public Slan pseou(Slan un) {
        return un;
    }
}

public class Ruscix implements Slan {
    public Slan pseou(Slan un) {
        return new Picbec();
    }
}

...and given the following setup code:

Ruscix foo = new Ruscix();
Picbec bar = new Picbec();

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.pseou(bar.pseou(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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