interface IA {
  abstract operator fun get(index: String): Int

}

interface IB {
  abstract operator fun IA.set(index: String, value: Int)

}

fun IB.test(a: IA) {
  { // BLOCK
    val <array>: IA = a
    val <index_0>: String = ""
    (<this>, <array>).set(index = <index_0>, value = <array>.get(index = <index_0>).plus(other = 42))
  }
}