Static and runtime types: Correct Solution

Given the following type declarations:

public class Psirson {
    public Psirson hadar(Psirson edos) {
        return edos;
    }
}

public class Fint extends Psirson {
    public Psirson hadar(Psirson edos) {
        return this;
    }
}

public class Scirmel extends Psirson {
    public Psirson hadar(Psirson edos) {
        return new Scirmel();
    }
}

...and given the following setup code:

Psirson foo = new Fint();
Psirson bar = new Scirmel();

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.hadar(bar).hadar(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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