main.swift

import Foundation

protocol SomeDelegateProtocol : class {
    func firstFunc() -> String
    func secondFunc() -> Bool
    func thirdFunc() -> Self
}

class MyClass {
    weak var delegate : SomeDelegateProtocol?
}

class Parent {
    var child : MyClass
    var strongDelegate : SomeDelegateProtocol? = nil

    func setup() {
        strongDelegate = {
            // [self]   // Original version had this not commented; it's commented to let people know it was a typo
            final class SomethingClass : SomeDelegateProtocol {
                func firstFunc() -> String { return "foo" }
                func secondFunc() -> Bool { return true }
                func thirdFunc() -> SomethingClass { return SomethingClass() }
            }
            return SomethingClass()
        }()
        child.delegate = strongDelegate
    }
    init() {
        self.child = MyClass()
        self.setup()
    }
}

var bleh = Parent()
var result = bleh.child.delegate?.firstFunc()
// selfResult is inferred to be type 'Optional<SomethingDelegateProtocol>'.
let selfResult = bleh.child.delegate?.thirdFunc()
println("Got \(result!)")