Immutable covariant list

Immutable.kt

import java.util.*

abstract class Stream<out T>() {
    abstract fun <R> with(value: R): Stream<Pair<T, R>>;
}

сlass ImmutableList<out T>: Stream<T> {

    private val data: ArrayList<T>;

    constructor(data: ArrayList<T>): super() {
        this.data = data;
    }

    constructor(vararg data: T): this(data.toArrayList())

    override fun <R> with(value: R): ImmutableList<Pair<T, R>> {
        val result = ArrayList<Pair<T, R>>();
        for (d in this.data) {
            result.add(Pair(d, value))
        }
        return ImmutableList(result);
    }
}

fun main(args : Array<String>) {
    val list = ImmutableList<Int>(1, 2, 3, 4, 5);
    val whatever: ImmutableList<Pair<Int, String>> = list.with("alal");
}