'final' is deprecated inside 'interface' but my code is not compiled without 'final'

1

 

package interfaceinline


import java.util.ArrayList


interface ListHasShape<H: HasShape>:Iterable<H>{

  val list: ArrayList<H>


  inline final fun <reified T : Data> by() = emptyList<T>()

}


open class HasShape(var shape: Shape)


interface Data


abstract class Shape


If I preserve ‘final’ then

Modifier ‘final’ is deprecated inside ‘interface’


If I remove ‘final’ then

 ‘‘inline’’ modifier is not allowed on virtual members. Only private or final members can be inlined.


How to write properly?

PS. Full project code is here.

2

In your case the solution would be to move the function out of the interface and make it an extension: 

interface ListHasShape<H: HasShape>:Iterable<H>{
    val list: ArrayList<H>
}
inline fun <reified T : Data> ListHasShape<*>.by() = emptyList<T>()