> On Jun 29, 2016, at 6:55 AM, Brandon Knope via swift-evolution
> <swift-evolution@swift.org> wrote:
>
> What's the rationale for having associatedtype in protocols and typealias in
> the conforming types?
I didn't design it, but here's how I think about it: The associated type
requirement merely states that there must be a type with this name meeting
these criteria. `typealias` is one way to satisfy that requirement, but you can
also just define a nested type with that name:
struct MyCollection {
struct Index: Comparable { … }
}
Should you replace `struct` with `associatedtype`? No? Then why would you
replace `typealias` with `associatedtype`?
--
Brent Royal-Gordon
Architechies
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