I wrote two extension functions that take differen...

# getting-started

[Colton Idle]

I wrote two extension functions that take different Types in the List type generic, but I get an error saying that I can't do that

private fun List<NetworkFoo>.mapToDomain(): List<DomainFoo> {
  return this.map { //stuff }
}

and

private fun List<NetworkBar>.mapToDomain(): List<DomainBar> {
  return this.map { //stuff }
}

Error

Platform declaration clash: The following declarations have the same JVM signature

I suppose the error message is helpful in giving me a hint that these two methods are identical in JVM land?

If I use the auto-correct option I get

@JvmName("mapToDomaincom.network.model.NetworkBar")

but the annotation gives me an error of:

Illegal JVM name

[ephemient]

both functions have the exact same types after erasure so they conflict. JVM name must not contain .;[/<> (and if targeting Android, additional restrictions apply on some versions, mainly excluding whitespace from names before Android 11)

[Stephan Schroeder]

Since the return-type is different, you're probably best of using two different method names, e.g. mapToDomainFoo and mapToDomainBar.
Like ephemient mentiond currently both extensions have the same jvm-bytecode representation
private static List mapToDomain(List this) (since the JVM doesn't retain generic type info) and therefore clash.

[Ruckus]

You don't need to include the package in @JvmName, just the function name, so @JvmName("mapToDomainkBar") should be what you want. I have also had issues with auto correct spewing out garbage from time to time, especially with anything related to `typealias`es.

[ephemient]

if you don't have Java callers, the JVM name doesn't have to be a valid Java identifier, you could @JvmName("map-NetworkFoo-to-DomainFoo") and @JvmName("map-NetworkBar-to-DomainBar").

[Colton Idle]

Thanks for the info everyone. Learned something new.

I want to just use the JvmName annotation, but if I use

@JvmName("asdf-mapToDomain")

it still fails with the error,

Illegal JVM name

[Colton Idle]

I think the kotlin compiler just got stuck in some loop. Restarted the IDE and the errors went away.