PrePitch: Add `default initializer` protocol to the standard library

[masters3d]

And here I was thinking this was going to be a slam dunk.

[Pitch] Add the DefaultConstructible protocol to the standard library

Correct. Treating protocols as "bags of syntax" is tempting (I still find myself accidentally doing it from time to time), but that's not what a Swift protocol is. Perhaps adding syntax to express a "bag of syntax" could be discussed either as its own topic (probably phase 2, but that's not my call), or later on as part of the macro system (it does sound rather macroish, IMHO). - Dave Sweeris

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On Dec 28, 2016, at 14:24, Xiaodi Wu <xiaodi.wu@gmail.com> wrote: On Wed, Dec 28, 2016 at …

On the past thread there seems to be a notion that all types need to conform to the protocol. I don’t think so but there are already types in the that provide default initialization that would make sense for them to conform.

We didn’t have property wrapper back then so I am struggling to come up with a usecase that does not envolve property wrappers.

@Default var foo1:Optional<String> // 

It is true that any package can provide conformance for this trivial functionality. In my view this is very similar to wanting to include the identity protocol from SwiftUI in the standard library.