Hi, I am new to Kolin (my second day using it) an...

# coroutines

[Krzysztof]

Hi,

I am new to Kolin (my second day using it) and trying to understand compilation error I have with coroutines.

I have a class that looks more or less like that:

class org.test.reactive.kitchen.SuspendedKitchen {
  suspend fun getPotatoes(): Potatoes = ...
  fun chop(potatoes: Potatoes): ChoppedPotatoes = ...
  fun fry(fish: Fish): FriedFish = ...
  suspend fun fry(choppedPotatoes: ChoppedPotatoes): Chips = ...
}

Now if I have code like that:

launch {
  val kitchen = SuspendedKitchen()
   val chips = kitchen.getPotatoes()
        .let(kitchen::chop)
        .let(kitchen::fry) // <-- does not work
}

The .let(kitchen:fry) fails with:

Callable reference resolution ambiguity: 
public final suspend fun fry(choppedPotatoes: ChoppedPotatoes): Chips defined in org.test.reactive.kitchen.SuspendedKitchen public final fun fry(fish: Fish): FriedFish defined in org.test.reactive.kitchen.SuspendedKitchen

It complains about totally different types so I don't know how is that ambiguous. Does suspend mess up type resolution?
But in such case why this one works fine:

launch {
  val kitchen = SuspendedKitchen()
   val chips = kitchen.getPotatoes()
     .let(kitchen::chop)
     .let { kitchen.fry(it) } // <-- works
}

Is that expected behavior? I don't see why they would behave differently?

[octylFractal]

https://youtrack.jetbrains.com/issue/KT-15917 + https://youtrack.jetbrains.com/issue/KT-16907

[Krzysztof]

Ah, ok thanks

[octylFractal]

I know that those don't directly deal with inline methods like let, but I presume that the issue is at least related

[octylFractal]

like, perhaps an inline in a suspend context always acts as if it it was declared suspend inline, and the lambda was declared as a suspend lambda as well. which would mean that when it tries to compile kitchen::fry, it can either generate a normal lambda with the right parameters (but we need a suspend lambda! so this doesn't work); or it can generate a suspend lambda with the wrong parameters

[octylFractal]

not 100% sure that's what the compiler does though