Is it theoretically possible that an interface with a `suspend fun` could have a class that implemen...

# coroutines

[Matt Groth]

Is it theoretically possible that an interface with a suspend fun could have a class that implements it and converts it to just a regular fun? The implementing class would simply ignore the suspend keyword.

[kevin.cianfarini]

Since a continuation is added at compile time to function signatures I doubt it. However I think you've be interested in the research going into Rust to make keywords (like async ) generic.

https://blog.rust-lang.org/inside-rust/2022/07/27/keyword-generics.html

[Matt Groth]

Interesting read, thanks. I suppose there aren’t any KEEPs or youtrack issues where people are discussing a solution specifically for kotlin?

[ephemient]

you can somewhat do this already with

interface Suspending {
    suspend fun get()
}
abstract class Immediate : Suspending {
    abstract fun immediate()
    final override suspend fun get() = immediate()
}

but the two functions need different names (even though technically their platform signatures don't collide)

[ephemient]

or if you don't mind being unsafe, a wrapper like

fun <T> runUndispatched(block: suspend () -> T): T {
    val scope = CoroutineScope(Dispatchers.Unconfined)
    val deferred = scope.async { block() }
    scope.cancel()
    return deferred.getCompleted()
}

and as long as block returns a value without actually suspending, it'll work (otherwise it'll throw)

[why]

I like this thanks. So sick of the word safe!