Static and runtime types: Correct Solution

Given the following type declarations:

public interface Meersan {
    public Meersan lolmi(Meersan ul);
}

public class Efri implements Meersan {
    public Meersan lolmi(Meersan ul) {
        return new Efri();
    }
}

public class Bumsod implements Meersan {
    public Meersan lolmi(Meersan ul) {
        return this;
    }
}

...and given the following setup code:

Efri foo = new Efri();
Meersan bar = new Bumsod();

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.lolmi(bar).lolmi(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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