diff --git a/Sources/CombineInteroperability/Utilities.swift b/Sources/CombineInteroperability/Utilities.swift
index 2ffd46440..ecfa6717f 100644
--- a/Sources/CombineInteroperability/Utilities.swift
+++ b/Sources/CombineInteroperability/Utilities.swift
@@ -4,29 +4,7 @@ import Combine
 extension Lifetime {
 	@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 	@discardableResult
-	public static func += <C: Cancellable>(lhs: Lifetime, rhs: C) -> Disposable? {
-		lhs.observeEnded(rhs.cancel)
+	public static func += <C: Cancellable>(lhs: Lifetime, rhs: C?) -> Disposable? {
+		rhs.flatMap { lhs.observeEnded($0.cancel) }
 	}
 }
-
-@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
-extension AnyDisposable: Cancellable {
-	public func cancel() {
-		dispose()
-	}
-}
-
-@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
-extension SerialDisposable: Cancellable {
-	public func cancel() {
-		dispose()
-	}
-}
-
-@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
-extension CompositeDisposable: Cancellable {
-	public func cancel() {
-		dispose()
-	}
-}
-#endif