[swift-evolution] [Pitch/plea] Recursive protocol constraints

[David Sweeris]

> On Nov 13, 2016, at 14:13, Douglas Gregor via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I also have a nagging feeling that we will need some form of restrictions on this feature for implementation reasons, e.g., because some recursive constraints will form unsolvable systems.

I'm having a bit of trouble understanding what you mean by "unsolvable system". Do you happen to have a handy example?

- Dave Sweeris