"Return the system-defined identity hash value of the given 
 [[value|identifiable]]. This hash value is consistent with 
 [[identity equality|Identifiable.equals]]."​
​see (`function identical`)
​shared native Integer identityHash(Identifiable identifiable);
​
​shared native("jvm") 
​Integer identityHash(Identifiable identifiable) {
    import java.lang {
        System​
    }
​
    return System.identityHashCode(identifiable);
}
​
​native("js")
​variable Integer _BasicId = 0;
​
​shared native("js") 
​Integer identityHash(Identifiable identifiable) {
    dynamic {
        dynamic x = identifiable;
        if (exists hash = x._BasicId) {
            return hash;
        }
        else {
            Integer hash = _BasicId++;
            x._BasicId = hash;
            return hash;
        }
    }
}
​