Question about generics, I've function like this:

expect fun <T : HttpClientEngineConfig> getEngineFactory(): HttpClientEngineFactory<T>

where

HttpClientEngineFactory

is defined as:

public interface HttpClientEngineFactory<out T : HttpClientEngineConfig>

and on Jvm actual implementation is:

actual fun <T : HttpClientEngineConfig> getEngineFactory(): HttpClientEngineFactory<T> {
    return OkHttp
}

where

OkHttp

is defined as:

public object OkHttp : HttpClientEngineFactory<OkHttpConfig>

and for

OkHttpConfig

:

public class OkHttpConfig : HttpClientEngineConfig

the problem is that the actual implementation doesn't compile because of type mismatch, required:

HttpClientEngineFactory<T>

found:

OkHttp

OkHttp

isn't a

HttpClientEngineFactory<T>

, it's a

HttpClientEngineFactory<OkHttpConfig>

, and it's possible the caller may use

!(T : OkHttpConfig)

I've control over where it can be called (actually it is called only in one place in a function's implementation), does that make it safe to cast it to

HttpClientEngineFactory<T>

?

IMO it's more accurate to write

fun getEngineFactory(): HttpClientEngineFactory<*>

since the caller doesn't get to choose the type

Yeah, this works. this what I wanted actually since I don't care about the type in my dependent function's implementation. Thanks.