diff --git a/RxSwift/Traits/PrimitiveSequence/Completable.swift b/RxSwift/Traits/PrimitiveSequence/Completable.swift
index ff8fae21a..1bca0ffa4 100644
--- a/RxSwift/Traits/PrimitiveSequence/Completable.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Completable.swift
@@ -123,12 +123,7 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
                 let callStack = [String]()
         #endif
 
-        let disposable: Disposable
-        if let onDisposed = onDisposed {
-            disposable = Disposables.create(with: onDisposed)
-        } else {
-            disposable = Disposables.create()
-        }
+        let disposable: Disposable = onDisposed.map(Disposables.create(with:)) ?? Disposables.create()
 
         let observer: CompletableObserver = { event in
             switch event {
diff --git a/RxSwift/Traits/PrimitiveSequence/Maybe.swift b/RxSwift/Traits/PrimitiveSequence/Maybe.swift
index 13f472ab9..d73048fb3 100644
--- a/RxSwift/Traits/PrimitiveSequence/Maybe.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Maybe.swift
@@ -138,12 +138,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
         #else
             let callStack = [String]()
         #endif
-        let disposable: Disposable
-        if let onDisposed = onDisposed {
-            disposable = Disposables.create(with: onDisposed)
-        } else {
-            disposable = Disposables.create()
-        }
+        let disposable: Disposable = onDisposed.map(Disposables.create(with:)) ?? Disposables.create()
 
         let observer: MaybeObserver = { event in
             switch event {
diff --git a/RxSwift/Traits/PrimitiveSequence/Single.swift b/RxSwift/Traits/PrimitiveSequence/Single.swift
index ffb8aa917..79595d175 100644
--- a/RxSwift/Traits/PrimitiveSequence/Single.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Single.swift
@@ -135,12 +135,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
             let callStack = [String]()
         #endif
 
-        let disposable: Disposable
-        if let onDisposed = onDisposed {
-            disposable = Disposables.create(with: onDisposed)
-        } else {
-            disposable = Disposables.create()
-        }
+        let disposable: Disposable = onDisposed.map(Disposables.create(with:)) ?? Disposables.create()
 
         let observer: SingleObserver = { event in
             switch event {