interface Conditional{
   fun isEligible(): Boolean
}

class Super()

class A(): Super(), Conditional
class B(): Super()

I would like to create a list that only contains Super subclasses that have implemented Conditional interface. (Just to help me with some compile-time static type checking)

Compiler would allow me to create this:

val conditionals: List<Super : Conditional> = listOf(A())

But it would not allow me to create this:

val conditionals: List<Super : Conditional> = listOf(A(), B())

I understand you can use generics with classes and function declarations, but how about value declarations?

EDIT I tried the following but type inference doesn't work well, it seems I'd need to do casting to a specific interface

CodePudding user response：

Unfortunately, intersection types are not denotable yet in Kotlin code (see