Static and runtime types: Correct Solution

Given the following type declarations:

public interface Siloos {
    public Siloos rerUpho(Siloos hu);
}

public class DusIsna implements Siloos {
    public Siloos rerUpho(Siloos hu) {
        return new Danu();
    }
}

public class Danu implements Siloos {
    public Siloos rerUpho(Siloos hu) {
        return this;
    }
}

...and given the following setup code:

Siloos foo = new Danu();
DusIsna bar = new DusIsna();

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.rerUpho(foo.rerUpho(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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