Static and runtime types: Correct Solution

Given the following type declarations:

public class Tossru {
    public Tossru resa(Tossru e) {
        return new Ciolthi();
    }
}

public class Datel extends Tossru {
    public Tossru resa(Tossru e) {
        return e;
    }
}

public class Ciolthi extends Tossru {
    public Tossru resa(Tossru e) {
        return this;
    }
}

...and given the following setup code:

Tossru foo = new Ciolthi();
Tossru bar = new Datel();

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.resa(bar.resa(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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