Static and runtime types: Correct Solution

Given the following type declarations:

public interface Ircol {
    public Ircol kugSiarn(Ircol er);
}

public class Ommed implements Ircol {
    public Ircol kugSiarn(Ircol er) {
        return er;
    }
}

public class Roso implements Ircol {
    public Ircol kugSiarn(Ircol er) {
        return this;
    }
}

...and given the following setup code:

Ommed foo = new Ommed();
Ircol bar = new Roso();

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.kugSiarn(foo).kugSiarn(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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