[SR-11989] Better diagnostic for invalid 'enclosing self' property wrapper subscript

[slavapestov]

Previous ID	SR-11989
Radar	rdar://problem/58438128
Original Reporter	@slavapestov
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s
Labels	Bug, StarterBug
Assignee	janebond (JIRA)
Priority	Medium

md5: 20d8a77f9190fc316ad55bfd7bb733b2

Issue Description:

This used to emit bad diagnostics and then crash the compiler. I've fixed the crash but we need to fix the bad diagnostic:

public class Store {
    @Published public var state: Any
    init() {
      self.state = 0
    }
}

@propertyWrapper public struct Published<Value> {
  public init(wrappedValue: Value) {}
  public var wrappedValue: Value {
    get { fatalError() }
    set {}
  }
  public static subscript(_enclosingInstance object: Any,
                          wrapped wrappedKeyPath: Any,
                          storage storageKeyPath: Any)
      -> Value {
    get { fatalError() }
    set {}
  }
  public struct Publisher {}
  public var projectedValue: Publisher {
    mutating get { fatalError() }
  }
}

[slavapestov]

@swift-ci create

[slavapestov]

@swift-ci create

[slavapestov]

I also added this FIXME to buildStorageReference(); probably it should be addressed at the same time:

    // FIXME: Since we're not resolving overloads or anything, we should be
    // building fully type-checked AST above; we already have all the
    // information that we need.

[swift-ci]

Comment by Hassan ElDesouky (JIRA)

@slavapestov Can you provide more details?