Static and runtime types: Correct Solution

Given the following type declarations:

public class SteChlid {
    public SteChlid duss(SteChlid si) {
        return this;
    }
}

public class Endust extends SteChlid {
    public SteChlid duss(SteChlid si) {
        return si;
    }
}

public class VenRuschi extends SteChlid {
    public SteChlid duss(SteChlid si) {
        return new VenRuschi();
    }
}

...and given the following setup code:

VenRuschi foo = new VenRuschi();
SteChlid bar = new Endust();

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.duss(bar.duss(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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