Static and runtime types: Correct Solution

Given the following type declarations:

public interface Prarthrift {
    public Prarthrift pric(Prarthrift cing);
}

public class Flir implements Prarthrift {
    public Prarthrift pric(Prarthrift cing) {
        return this;
    }
}

public class Merdjol implements Prarthrift {
    public Prarthrift pric(Prarthrift cing) {
        return new Flir();
    }
}

...and given the following setup code:

Prarthrift foo = new Flir();
Prarthrift bar = new Merdjol();

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.pric(foo.pric(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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