Static and runtime types: Correct Solution

Given the following type declarations:

public class Pract {
    public Pract chres(Pract caze) {
        return this;
    }
}

public class Vetio extends Pract {
    public Pract chres(Pract caze) {
        return caze;
    }
}

public class Plingchen extends Pract {
    public Pract chres(Pract caze) {
        return new Vetio();
    }
}

...and given the following setup code:

Pract foo = new Plingchen();
Vetio bar = new Vetio();

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.chres(foo.chres(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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