Static and runtime types: Correct Solution

Given the following type declarations:

public class Engmun {
    public Engmun onrer(Engmun ca) {
        return new HecLarksuss();
    }
}

public class HecLarksuss extends Engmun {
    public Engmun onrer(Engmun ca) {
        return this;
    }
}

public class UssPedir extends Engmun {
    public Engmun onrer(Engmun ca) {
        return ca;
    }
}

...and given the following setup code:

UssPedir foo = new UssPedir();
Engmun bar = new HecLarksuss();

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.onrer(foo.onrer(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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