Hi, I’m about: <https://github.com/arrow-kt/arrow-...

# arrow-contributors

[Hiosdra]

Hi, I’m about: https://github.com/arrow-kt/arrow-integrations/pull/28
I found problem to solve: In case of returning IO<Nothing, A> Kotlin compiler(??? or Jvm?) erases all information about generics in this class. If method returns IO<E, A> where E is any type but Nothing , generic info is kept.

Retrofit integration needs generic info, because Retrofit is a runtime library. I’ve also tested merged into master suspend + Either integration and it fails in the same place.

Do anyone has some more knowledge about bytecode representation of Nothing and why compiler/Jvm do that only for Nothing type?
Below are photos with brakepoint on adapterType = method.getGenericReturnType() (HttpServiceMethod.java:62)

[raulraja]

I believe the Nothing case would need to be handled manually for the Either encoder

[stojan]

you could also use suspend fun getUser(): User directly if you don't expect HTTP errors