Static and runtime types: Correct Solution

Given the following type declarations:

public class Splowid {
    public Splowid uscher(Splowid lus) {
        return new Piam();
    }
}

public class Prontjics extends Splowid {
    public Splowid uscher(Splowid lus) {
        return this;
    }
}

public class Piam extends Splowid {
    public Splowid uscher(Splowid lus) {
        return lus;
    }
}

...and given the following setup code:

Splowid foo = new Piam();
Splowid bar = new Prontjics();

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.uscher(foo.uscher(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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