Static and runtime types: Correct Solution

Given the following type declarations:

public interface Slimle {
    public Slimle rerung(Slimle oss);
}

public class Intwour implements Slimle {
    public Slimle rerung(Slimle oss) {
        return oss;
    }
}

public class PriWishis implements Slimle {
    public Slimle rerung(Slimle oss) {
        return new Intwour();
    }
}

...and given the following setup code:

Slimle foo = new PriWishis();
Slimle bar = new Intwour();

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.rerung(bar.rerung(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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