DoYouRetainSelf.swift

import Foundation

class Child {
    deinit {
        print("Child.deinit")
    }

    var parent: Parent?

    func removeFromParent() {
        defer {
            print("removed myself from parent")
        }

        print("going to remove myself from parent...")
        autoreleasepool {
            parent?.children.removeAll { $0 === self }
            parent = nil
        }
    }
}

class Parent {
    var children: [Child] = []

    func add(child: Child) {
        children.append(child)
        child.parent = self
    }
}

func setup() -> Parent {
    return autoreleasepool {
        let parent = Parent()
        let child = Child()
        parent.add(child: child)
        return parent
    }
}

let root = setup()
root.children[0].removeFromParent()