Cannot OptIn to an experimental annotation class

A minimal repro:

import kotlin.time.*

@ExperimentalTime
val res = runBlocking {
    val mark = TimeSource.Monotonic.markNow()
    delay(300)
    mark.elapsedNow()
}

println(res)

Image for clarification:

[ileasile]

Does this compiles for you?

@file:DependsOn("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.2")
import kotlin.time.*
import kotlinx.coroutines.*
            
@OptIn(ExperimentalTime::class)
val res = runBlocking {
    val mark = kotlin.time.TimeSource.Monotonic.markNow()
    delay(3)
    mark.elapsedNow()
}
res

It seems that actual problem for you here is this issue

[ileasile]

@frankgerhardt sorry for delay, I haven’t mentioned your message… For now it works like this.

1. Restart kernel and execute:

@file:CompilerArgs("-Xopt-in=kotlin.RequiresOptIn")

Note that it should be the first executed cell in the notebook session.

1. Then execute the code you have mentioned, but with a minor change:

@file:DependsOn("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.2")
import kotlin.time.*
import kotlinx.coroutines.*
            
@OptIn(ExperimentalTime::class)
val res = runBlocking {
    val mark = kotlin.time.TimeSource.Monotonic.markNow()
    delay(3)
    mark.elapsedNow()
}
@OptIn(ExperimentalTime::class)
res