taking the spread operator example mentioned above from stackoverflow:

fun sumNumbers(vararg numbers: Int): Int {
    return numbers[1]
}

val numbers = intArrayOf(2, 3, 4)
val sum = sumNumbers(*numbers)

i decompiled the kotlin byte code and found, that the spread operator generates a copy of the numbers array:

sum = sumNumbers(Arrays.copyOf(numbers, numbers.length));

Is that on purpose? Does it make sense?

That's an interesting implementation of

sumNumbers

. I can see in my mind you unit tests for that:

sumNumbers(0, 1) == 1
sumNumbers(0, 6, 0, 0, 0, 0) == 6
sumNumbers(-2, 3, 2) == 3

sorry, i did not mention, that i replaced the original line

return numbers.sum()

from the example with

return numers[1]

because i did not want to implement numbers.sum() just for seeing the java code of the call site. Best would be the unit test for

sumNumbers(0)

😇