    "Determine if the arguments are [[identical]]. Equivalent to
     `x===y`. Only instances of [[Identifiable]] have
     well-defined identity."
    see (`function identityHash`)
    tagged("Comparisons")
    shared Boolean identical(
            "An object with well-defined identity."
            Identifiable x,
            "A second object with well-defined identity."
            Identifiable y)
                    => x===y;