Static and runtime types: Correct Solution

Given the following type declarations:

public class SteUnoc {
    public SteUnoc edoum(SteUnoc dile) {
        return this;
    }
}

public class Duph extends SteUnoc {
    public SteUnoc edoum(SteUnoc dile) {
        return new Duph();
    }
}

public class Oudi extends SteUnoc {
    public SteUnoc edoum(SteUnoc dile) {
        return dile;
    }
}

...and given the following setup code:

SteUnoc foo = new Duph();
SteUnoc bar = new Oudi();

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.edoum(bar.edoum(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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