Static and runtime types: Correct Solution

Given the following type declarations:

public interface Phae {
    public Phae reoEvun(Phae ei);
}

public class Pequght implements Phae {
    public Phae reoEvun(Phae ei) {
        return ei;
    }
}

public class Nadprie implements Phae {
    public Phae reoEvun(Phae ei) {
        return new Nadprie();
    }
}

...and given the following setup code:

Phae foo = new Nadprie();
Phae bar = new Pequght();

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.reoEvun(foo.reoEvun(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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