Is there a proposal to allow `fun interface`s to be suspended?

It works? (Playground):

suspend fun main() {
    val kotlin = SuspendRunnable { "kotlin" }
    println(kotlin.run())
}
fun interface SuspendRunnable<R> {
    suspend fun run(): R
}

What version of kotlin are you using?

yea you are right - looks like this was added in a recent version

https://youtrack.jetbrains.com/issue/KT-44787 it was only broken in the old JVM backend, which was a while ago