[SR-3170] Enum cases should satisfy static var {get} protocol requirements

[lilyball]

Previous ID	SR-3170
Radar	None
Original Reporter	@lilyball
Type	Improvement
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	5
Component/s	Compiler
Labels	Improvement
Assignee	@theblixguy
Priority	Medium

md5: d9521650445f1899139f2653dbcaffff

is duplicated by:

• SR-3510 Allow Enum case to conform to a protocol static function and static variable
• SR-9099 Enum case does not satisfy protocol static var

Issue Description:

Outside of pattern-matching, enum cases are used the same way static let properties are. To that end, they should be able to satisfy protocol requirements for static var { get } properties.

For example:

protocol Foo {
    static var bar: Self { get }
}

enum Baz: Foo {
    case bar
}

Right now this gives the following error:

unnamed.swift:5:6: error: type 'Baz' does not conform to protocol 'Foo'
enum Baz: Foo {
     ^
unnamed.swift:2:16: note: protocol requires property 'bar' with type 'Baz'; do you want to add a stub?
    static var bar: Self { get }
               ^
unnamed.swift:6:10: note: candidate is not a variable
    case bar
         ^

[belkadan]

The dup mentions cases with payloads matching static function requirements.

[DevAndArtist]

@slavapestov sorry, I was trying to type a comment, but Jira triggered some weird key-combo and assigned me to the ticket.

---

The improvement in that area should not only be limited to static properties right?

protocol Foo {
  static func baz(_ something: Int) -> Self
  static func abc(label: String) -> Self
}

enum Baz: Foo {
  case baz(Int)
  case abc(label: String)
}

[theblixguy]

Implemented on master: #28916

Please verify using the next available snapshot.