… func run() -> Disposable { let subscription1 = SingleAssignmentDisposable() let subscription2 = SingleAssignmentDisposable() let subscription3 = SingleAssignmentDisposable() let observer1 = CombineLatestObserver(lock: self._lock, parent: self, index: 0, setLatestValue: { (e: E1) -> Void in self._latestElement1 = e }, this: subscription1) let observer2 = CombineLatestObserver(lock: self._lock, parent: self, index: 1, setLatestValue: { (e: E2) -> Void in self._latestElement2 = e }, this: subscription2) let observer3 = CombineLatestObserver(lock: self._lock, parent: self, index: 2, setLatestValue: { (e: E3) -> Void in self._latestElement3 = e }, this: subscription3) subscription1.setDisposable(self._parent._source1.subscribe(observer1)) subscription2.setDisposable(self._parent._source2.subscribe(observer2)) subscription3.setDisposable(self._parent._source3.subscribe(observer3)) return Disposables.create([ subscription1, subscription2, subscription3 ]) } … } CompositeDisposableでひとまとめにするので 下流では1つをdisposeすれば3つのDisposableに伝播する 上流のSubscriptionのラップ https://github.com/ReactiveX/RxSwift/blob/master/RxSwift/Observables/CombineLatest% Barity.swift#L -L