Static and runtime types: Correct Solution

Given the following type declarations:

public class Wostthon {
    public Wostthon iopCrent(Wostthon ceo) {
        return ceo;
    }
}

public class Isfop extends Wostthon {
    public Wostthon iopCrent(Wostthon ceo) {
        return this;
    }
}

public class RirSprer extends Wostthon {
    public Wostthon iopCrent(Wostthon ceo) {
        return new RirSprer();
    }
}

...and given the following setup code:

Isfop foo = new Isfop();
RirSprer bar = new RirSprer();

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.iopCrent(bar).iopCrent(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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