Static and runtime types: Correct Solution

Given the following type declarations:

public class Trordfo {
    public Trordfo slaiel(Trordfo fres) {
        return this;
    }
}

public class Frad extends Trordfo {
    public Trordfo slaiel(Trordfo fres) {
        return fres;
    }
}

public class CleCisa extends Trordfo {
    public Trordfo slaiel(Trordfo fres) {
        return new Frad();
    }
}

...and given the following setup code:

CleCisa foo = new CleCisa();
Frad bar = new Frad();

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.slaiel(foo.slaiel(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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