[swift-evolution] PITCH: New :== operator for generic constraints

[David Sweeris]

> On Aug 16, 2016, at 6:59 PM, Karl via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I think the point is that existentials not conforming to their protocols is the underlying reason this doesn’t work already.
> 
> From the previous thread:
>> There are a couple of reasons this is the case.  IIRC in some cases it actually isn't possible for the existential to conform to the protocol in a sound way.  And even when it is possible, I believe it has been said that it is more difficult to implement than you might think.  Hopefully the situation will improve in the future but I'm not aware of any specific plans at the moment.
> 
> It seems like a reasonably straightforward axiom. I would be interested to learn more about those edge-cases.

Now that you mention it, I very vaguely recall that thread. What it called again? I want to go back and read that whole section.

- Dave Sweeris
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