# Which (breaking) changes would you be willing to accept in a major language release? \[+ Feature wishes\] **URL:** \ **Category:** Discussion\ **Created:** [August 3, 2022, 8:39am UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429 "2022-08-03T08:39:23Z")\ **Posts on this page:** 13\ **Page:** 4
**Author:** ![stevapple](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/stevapple/32/31979_2.png) [@stevapple](https://forums.swift.org/u/stevapple)\ **Post date:** [August 15, 2022, 11:31am UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/62 "2022-08-15T11:31:04Z")
I would feel better if we force the use of `fileprivate` over `private` when it’s actually available in the file’s scope. Cases like `private extension` reuses `private` keyword but provides `fileprivate` semantics instead, introducing unnecessary confusion and styling issues. I’m personally satisfied with `fileprivate` (or `private(file)` as someone proposed), and I believe making the semantics clear at first glance is more important than eliminating keywords. ---
**Author:** ![jjrscott](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/jjrscott/32/12494_2.png) [@jjrscott](https://forums.swift.org/u/jjrscott)\ **Post date:** [August 15, 2022, 12:12pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/63 "2022-08-15T12:12:21Z")
> [@0xTim](#): > > Removing inheritance from the language (I'm only half kidding) I agree, especially after re-reading [Default Protocol Implementation Inheritance Behaviour - The current situation and what/if anything should be done about it](https://forums.swift.org/t/default-protocol-implementation-inheritance-behaviour-the-current-situation-and-what-if-anything-should-be-done-about-it/28049) 😳 Is it there for anything other that Objective-C compatibly and references? I'd like to see both of those split off. ---
**Author:** ![davedelong](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/davedelong/32/38708_2.png) [@davedelong](https://forums.swift.org/u/davedelong)\ **Post date:** [August 15, 2022, 2:52pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/64 "2022-08-15T14:52:10Z")
Yes, this would be fantastic. Related, I would love to see exhaustivity checking possible for _structs_. I tend to prefer structs over enums for almost everything, but it would be nice if I could tell the compiler somehow that this is an "exhaustive" struct. Perhaps using `CaseIterable` or something? ---
**Author:** ![tera](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/tera/32/38201_2.png) [@tera](https://forums.swift.org/u/tera)\ **Post date:** [August 15, 2022, 5:15pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/65 "2022-08-15T17:15:53Z")
What do you mean by "exhaustive" struct? When using in a switch statement? Please show an example. ---
**Author:** ![davedelong](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/davedelong/32/38708_2.png) [@davedelong](https://forums.swift.org/u/davedelong)\ **Post date:** [August 15, 2022, 5:37pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/66 "2022-08-15T17:37:01Z")
```swift public struct ServerEnvironment: Equatable, CaseIterable { public static let allCases = [.production, .qa, .dev] public static let production = ServerEnvironment(host: "production.example.com", name: "Production", ...) public static let qa = ServerEnvironment(host: "qa.example.com", name: "QA", ...) public static let dev = ServerEnvironment(host: "dev.example.com", name: "Development", ...) private init( ... ) { } } // elsewhere: let environment: ServerEnvironment = ... switch environment { case .production: // do something only for Production case .qa: // do something only for QA case .dev: // do something only for Development } ``` The "exhaustive" bit is that I would not need a `default` case because I have handled every possible case as defined by the `CaseIterable` conformance. It is not possible for the user of `ServerEnvironment` to get anything except one of those three values. ---
**Author:** ![DevAndArtist](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/devandartist/32/287_2.png) [@DevAndArtist](https://forums.swift.org/u/DevAndArtist)\ **Post date:** [August 15, 2022, 5:39pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/67 "2022-08-15T17:39:23Z")
Maybe this will be possible if we get something like `@const` and then the compiler could infer that from a `@const allCases` or something along the lines. ---
**Author:** ![vegerot](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/vegerot/32/8978_2.png) [@vegerot](https://forums.swift.org/u/vegerot)\ **Post date:** [August 16, 2022, 11:52pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/68 "2022-08-16T23:52:50Z")
yeah the constexpr proposal(s) have been stuck for months now 😔 ---
**Author:** ![flowtoolz](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/flowtoolz/32/13358_2.png) [@flowtoolz](https://forums.swift.org/u/flowtoolz)\ **Post date:** [August 19, 2022, 2:10pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/69 "2022-08-19T14:10:20Z")
To answer your title: ALL OF THEM. I put Swift's ability to evolve above everything else. ---
**Author:** ![Dmitriy\_Ignatyev](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/dmitriy_ignatyev/32/11340_2.png) [@Dmitriy\_Ignatyev](https://forums.swift.org/u/Dmitriy_Ignatyev)\ **Post date:** [August 20, 2022, 7:50pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/70 "2022-08-20T19:50:53Z")
> [@abdel-17](#): > > How would you hash function types? functions have mangled names, which can be used for hash value for example. ---
**Author:** ![Dmitriy\_Ignatyev](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/dmitriy_ignatyev/32/11340_2.png) [@Dmitriy\_Ignatyev](https://forums.swift.org/u/Dmitriy_Ignatyev)\ **Post date:** [August 20, 2022, 8:00pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/71 "2022-08-20T20:00:38Z")
> [@davedelong](#): > > but I _intentionally_ do no support anyone else making a related type You can currently achieve this in a way like: ```swift public struct ConformanceLimiter { fileprivate init() {} } public protocol ClosedProtocol { var conformanceLimiter: ConformanceLimiter { get } // can not be constructed outside of the library } ``` It is a bit ugly, but do the deal. ---
**Author:** ![Rod\_Brown](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/rod_brown/32/425_2.png) [@Rod\_Brown](https://forums.swift.org/u/Rod_Brown)\ **Post date:** [August 21, 2022, 11:07am UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/72 "2022-08-21T11:07:29Z")
In this case you can implement the `conformanceLimiter` as a `fatalError`: ```swift var conformanceLimiter: ConformanceLimiter { fatalError("I'm outside the file so I can't make one, but I can do anything else and conform") } ``` ---
**Author:** ![jayton](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/jayton/32/5592_2.png) [@jayton](https://forums.swift.org/u/jayton)\ **Post date:** [August 21, 2022, 5:42pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/73 "2022-08-21T17:42:04Z")
Alternatively, you can harvest a ConformanceLimiter from one of the library’s own types and return that. ---
**Author:** ![davedelong](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/davedelong/32/38708_2.png) [@davedelong](https://forums.swift.org/u/davedelong)\ **Post date:** [August 21, 2022, 9:00pm UTC](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429/74 "2022-08-21T21:00:38Z")
Yeah, I've done this before with an associated type to prevent "copying" a conformance limiter from one conformer to another: ```swift public protocol MyClosedProtocol { static var closer: Closer { get } // regular requirements... } public struct Closer { // publicly visible, but only internally constructible // generic type prevents using a Closer on different conformers of "MyClosedProtocol" internal init() { } } ``` [Previous page](https://forums.swift.org/t/which-breaking-changes-would-you-be-willing-to-accept-in-a-major-language-release-feature-wishes/59429.md?page=3)