Static and runtime types: Correct Solution

Given the following type declarations:

public interface Sasm {
    public Sasm ornpan(Sasm oc);
}

public class Niiar implements Sasm {
    public Sasm ornpan(Sasm oc) {
        return this;
    }
}

public class Intas implements Sasm {
    public Sasm ornpan(Sasm oc) {
        return oc;
    }
}

...and given the following setup code:

Sasm foo = new Niiar();
Sasm bar = new Intas();

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.ornpan(bar).ornpan(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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