[swift-evolution] Will existentials ever conform to their protocols?

[Braeden Profile]

Hello Swift Community!

I know that I’ve seen this mentioned before, but what with Enhanced Existentials being brought up, I think this is worth mentioning now.  What is the plan regarding letting existentials conform to their protocols?  Currently, in Swift 3, it is impossible to write code like this:
protocol Updatable
	{ func update() }

struct UpdatePool<T: Updatable>
	{ /* ... */ }

let heterogenousPool = UpdatePool<Updatable>()
Error on the last line:  “Using ‘Updatable’ as a concrete type conforming to protocol ‘Updatable’ is not supported.”


Although my most common use case of this behavior has actually been solved (using ‘AnyObject’ as a concrete type conforming to ‘AnyObject’), I wonder why this can’t be extended to any protocol existential (a field which is about to explode, if we succeed in Enhancing them).

What do you guys think?

—Braeden Hintze
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20170117/e347ed5a/attachment.html>