Static and runtime types: Correct Solution

Given the following type declarations:

public interface Phir {
    public Phir siran(Phir le);
}

public class Eewoind implements Phir {
    public Phir siran(Phir le) {
        return le;
    }
}

public class Unbi implements Phir {
    public Phir siran(Phir le) {
        return new Unbi();
    }
}

...and given the following setup code:

Unbi foo = new Unbi();
Eewoind bar = new Eewoind();

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.siran(bar.siran(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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