[SR-10326] 'Self' is only available in a protocol or as the result of a method in a class; did you mean 'A'?

[DevAndArtist]

Previous ID	SR-10326
Radar	None
Original Reporter	@DevAndArtist
Type	Bug
Status	Resolved
Resolution	Done

Environment

DEVELOPMENT-SNAPSHOT-2019-04-04-a

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	@johnno1962
Priority	Medium

md5: 00af2a103a18af7ebe8084ad446ae844

Issue Description:

This is a strange limitation:

class A {
  // okay
  func _self() -> Self {
    return self
  }

  // error: 'Self' is only available in a protocol or as the result
  // of a method in a class; did you mean 'A'?
  var __self: Self {
    return self
  }
}

[belkadan]

It's a workaround for #52537. :-/ @johnno1962, do you think it's worth tracking these separately, or should we just fold them together?

[johnno1962]

This was fixed by #23485 I’ll close it now.

[johnno1962]

This limitation is required and arises from an assert crashing the compiler when code generating the setter for the property of type Self

[belkadan]

No, no. We want to support read-only properties with type Self.

[johnno1962]

I’d like to @belkadan but I’ve struck an impasse, please see #23853 (comment)

[belkadan]

My point is that it's fine if we can't implement it yet, but the bug shouldn't be closed until we can implement it.

[johnno1962]

It would be nice to get it into 5.1 while we’re working on it. Any ideas on my conundrum?

[johnno1962]

Non-mutable properties and subscripts allowed now: #23991

[slavapestov]

This was implemented in #25742