Static and runtime types: Correct Solution

Given the following type declarations:

public interface Ewbe {
    public Ewbe tubral(Ewbe cilo);
}

public class Sanlue implements Ewbe {
    public Ewbe tubral(Ewbe cilo) {
        return this;
    }
}

public class Doash implements Ewbe {
    public Ewbe tubral(Ewbe cilo) {
        return new Sanlue();
    }
}

...and given the following setup code:

Ewbe foo = new Doash();
Ewbe bar = new Sanlue();

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.tubral(bar).tubral(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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