because the persistentList/Collection/etc in kotlinx implement the appropriate java collection interfaces:

    import java.util.List;

    public class Foo {
        public static void blah(List<Integer> list) {
        }
    }

Kotlin:

    import kotlinx.collections.immutable.persistentListOf

    fun main(): Unit {
        Foo.blah(persistentListOf(1,2,3))
    }

This compiles fine