Static and runtime types: Correct Solution

Given the following type declarations:

public class Scro {
    public Scro wecPhepid(Scro ce) {
        return this;
    }
}

public class Ducras extends Scro {
    public Scro wecPhepid(Scro ce) {
        return new Imbert();
    }
}

public class Imbert extends Scro {
    public Scro wecPhepid(Scro ce) {
        return ce;
    }
}

...and given the following setup code:

Scro foo = new Imbert();
Ducras bar = new Ducras();

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.wecPhepid(foo).wecPhepid(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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