Exercise: Usage of generic types
The code below will not compile due to a type mismatch. Which lines will show compilation errors?
fun takeIntList(list: List<Int>) {}
takeIntList(listOf<Any>())
takeIntList(listOf<Nothing>())
fun takeIntMutableList(list: MutableList<Int>) {}
takeIntMutableList(mutableListOf<Any>())
takeIntMutableList(mutableListOf<Nothing>())
fun takeAnyList(list: List<Any>) {}
takeAnyList(listOf<Int>())
takeAnyList(listOf<Nothing>())
class BoxOut<out T>
fun takeBoxOutInt(box: BoxOut<Int>) {}
takeBoxOutInt(BoxOut<Int>())
takeBoxOutInt(BoxOut<Number>())
takeBoxOutInt(BoxOut<Nothing>())
fun takeBoxOutNumber(box: BoxOut<Number>) {}
takeBoxOutNumber(BoxOut<Int>())
takeBoxOutNumber(BoxOut<Number>())
takeBoxOutNumber(BoxOut<Nothing>())
fun takeBoxOutNothing(box: BoxOut<Nothing>) {}
takeBoxOutNothing(BoxOut<Int>())
takeBoxOutNothing(BoxOut<Number>())
takeBoxOutNothing(BoxOut<Nothing>())
fun takeBoxOutStar(box: BoxOut<*>) {}
takeBoxOutStar(BoxOut<Int>())
takeBoxOutStar(BoxOut<Number>())
takeBoxOutStar(BoxOut<Nothing>())
class BoxIn<in T>
fun takeBoxInInt(box: BoxIn<Int>) {}
takeBoxInInt(BoxIn<Int>())
takeBoxInInt(BoxIn<Number>())
takeBoxInInt(BoxIn<Nothing>())
takeBoxInInt(BoxIn<Any>())
Once you are done with the exercise, you can check your solution here.
