[swift-evolution] Enhanced Existentials

[Douglas Gregor]

Sent from my iPhone

> On Jan 6, 2017, at 11:04 PM, Russ Bishop <xenadu at gmail.com> wrote:
> 
> 
>> On Jan 4, 2017, at 8:48 PM, Douglas Gregor via swift-evolution <swift-evolution at swift.org> wrote:
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>> 
>>> 
>>> Would love to see this come forward into discussion.
>> 
>> Yeah. I'm less sure about the other enhancements to existentials fitting into Swift 4, e.g., the creation of existentials for protocols with associated types. Although important, it's a big feature that will take a bunch of design and implementation time, and I'm leery of accepting something that we might not actually be able to achieve. 
>> 
>>  - Doug
> 
> By this are you referring to generalized existentials?

Yes. I actually prefer the term "generalized existentials".

> If so I’ll say this is such a constant pain point and perverts so many API designs… not to mention vomiting AnyXYZ type-erased wrappers everywhere… In my completely non-authoritative personal opinion we shouldn’t ship Swift 4 without it :)

To be absolutely clear, I think this is an extremely important feature. It's also a significant undertaking in both design and implementation. 

  - Doug