Ok, we found the issue, it is easy to reproduce with simple code snippet -

@JvmInline
value class ValueClassId(private val value: UUID)

class SomeService {

    suspend fun outerFails(id: UUID): ValueClassId {
        return inner(id)
    }

    suspend fun outerWorks(id: UUID) = try {
        somethingTrowing()
        justValueId(id)
    } catch (e: RuntimeException) {
        fallbackValueId(id)
    }

    private suspend fun inner(id: UUID) = try {
        somethingTrowing()
        justValueId(id)
    } catch (e: RuntimeException) {
        fallbackValueId(id)
    }

    private suspend fun justValueId(id: UUID): ValueClassId {
        delay(1)
        return ValueClassId(id)
    }

    private suspend fun fallbackValueId(id: UUID): ValueClassId {
        delay(1)
        return ValueClassId(id)
    }

    private suspend fun somethingTrowing(): Unit {
        delay(1)
        throw IllegalArgumentException()
    }
}

fun main(): Unit = runBlocking {
    val s = SomeService()
    val id = UUID.randomUUID()

    // works fine
    s.outerWorks(id)

    // Fails on: ContinuationImpl.kt:33
    // val outcome = invokeSuspend(param)
    // if (outcome === COROUTINE_SUSPENDED) return
    s.outerFails(id)
}

Always a good idea 🙂 At worst, it’ll get marked as duplicate and you’ll know which bug to track

As far as I know value classes are designed to be wrapper around primitive types. In your case you have UUID which is not primitive type.

you can change UUID in my example on String and you will face same issue -

class kotlin.coroutines.intrinsics.CoroutineSingletons cannot be cast to class java.lang.String

Thanks! I cannot reproduce on current master. It is likely, that the issue is fixed in the upcoming 1.5.10 release. Will check, whether it is fixed in 1.5.10, though.

@Ilmir Usmanov [JB] do you have any ETA when 1.5.10 will be released? or at least some RC version