Static and runtime types: Correct Solution

Given the following type declarations:

public class Druntce {
    public Druntce soim(Druntce har) {
        return har;
    }
}

public class Sqerdfud extends Druntce {
    public Druntce soim(Druntce har) {
        return this;
    }
}

public class Mism extends Druntce {
    public Druntce soim(Druntce har) {
        return new Mism();
    }
}

...and given the following setup code:

Druntce foo = new Mism();
Sqerdfud bar = new Sqerdfud();

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.soim(bar).soim(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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