Properties forwarding (aliasing)

[anandabits (Matthew Johnson)]

@idrougge

The Kotlin language already has an idiom for specifying protocol or class conformance by forwarding its interface to a property: https://kotlinlang.org/docs/reference/delegation.html

Note that this idiom encourages "composition over inheritance" and fits well with protocol-oriented programming.

I pitched protocol-based forwarding in the early days of Swift evolution. There are some nuances around Self and associated types in Swift that I don’t believe are relevant to Kotlin. There was good discussion and I started working on a second draft of the proposal. I dropped it when it became clear it was not going to make it into Swift 3. I would like to revisit that topic someday.