Anyone know why kotlin isn’t picking up my User in...

# announcements

[Ryan]

Anyone know why kotlin isn’t picking up my User interface on LoginUserV1?

[marstran]

Does LoginUserV1 implement the User interface?

[Ryan]

of course marius

[Ryan]

Screen Shot 2020-06-15 at 8.44.28 AM.png

[marstran]

👍
Could you try changing the return type of the function to Single<out User> ?

[Ryan]

seems like its good

[Ryan]

thanks

[Arkadii Ivanov]

Single<out X> also has some limitations. E.g. you won't be able to use operators where X is used as input, e.g. the following will not be possible:

fun foo(user: Single<out User>) {
    user.concatWith(/*SingleSource<out Nothing> is expected*/)
}

I wrote an article about it a while ago: https://badootech.badoo.com/reaktive-a-multiplatform-library-for-reactive-kotlin-android-ios-77b6ff25adb1

[Ryan]

I may do the cast still, it’s only in 2 places.

[Arkadii Ivanov]

Yeah but I believe it will be an unsafe cast and you will have warnings.