Static and runtime types: Correct Solution

Given the following type declarations:

public class Chram {
    public Chram doess(Chram darm) {
        return this;
    }
}

public class Spla extends Chram {
    public Chram doess(Chram darm) {
        return new Spla();
    }
}

public class Smen extends Chram {
    public Chram doess(Chram darm) {
        return darm;
    }
}

...and given the following setup code:

Chram foo = new Smen();
Spla bar = new Spla();

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.doess(foo.doess(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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