Open Radar

 
I’m not sure this is a bug, but the following code yields the error shown.

protocol Delegate {
    typealias StateType
    var someClass: SomeClass<Self>? { get set }
}

class SomeClass<D: Delegate> {}

// Error: Type 'SomeDelegate' does not conform to protocol 'Delegate'
final class SomeDelegate: Delegate {
    typealias StateType = Int
    var someClass: SomeClass<SomeDelegate>?
}

The issue is peculiar because the error report depends on the definition of class SomeClass; if it is defined as just SomeClass<D> with no qualification on the type of D, then the compiler no longer reports that SomeDelegate does not conform to Delegate.