Lambda not working as expeccted

package moreorless.ian

fun unaryOperation(x:Int, op:(Int) -> Int){

fun outsideFunction() {
    for (number in 1..30){
        unaryOperation(20, { x-> println(number)

            x * number



fun main(args: Array<String>) {



does not print 1

only if i add println(x) after the for loop outside lambda ? why?

You pass the lambda as op parameter to unaryFunction, but you do not invoke that op function. So the code in the lambda is not executed.

Following on what @ilya.gorbunov said, if you change your unaryFunction to this:

fun unaryOperation(x:Int, op:(Int) -> Int) = op(x)

then it should work as you expected.

This changed in kotlin 1.2 as in 1.1 no issues happened. Am i incorrect in this understanding @ilya.gorbunov?

thanks again!!

Nothing has been changed in this regard. This code works the same way in any Kotlin version from 1.0 to the current one.