# Fix Memory Leaks in AI-Generated SwiftUI Code > By Lawrence Arya, Founder & CEO of VP0. Published 2026-06-04. 6 min read. > Source: https://vp0.com/blogs/swiftui-memory-leak-ai-generated-code-fix Most AI SwiftUI leaks are retain cycles. A [weak self] capture list fixes the majority of them. **TL;DR.** AI-generated SwiftUI tends to leak memory in three predictable ways: closures that capture self strongly and create a retain cycle, Combine subscriptions that are never stored or cancelled, and timers or observers that are never invalidated. The fixes are equally predictable: add a [weak self] capture list to escaping closures, store cancellables in a Set and let them deinit, and invalidate timers in onDisappear. Confirm with the Leaks and Allocations instruments. Start from clean, structured code, like a free VP0 design at $0, so there is less to untangle. AI-generated SwiftUI leaks memory in a small number of predictable ways, which is good news: once you know the three patterns, you can find and fix almost any leak fast. The root cause is almost always a retain cycle that Automatic Reference Counting cannot break, not anything specific to SwiftUI. Here are the three patterns, the one-line fixes, and how to confirm with Instruments. To reduce how much you have to untangle, start from clean, structured code, like a free [VP0](https://vp0.com) design (the free iOS and React Native design library AI builders read from) at $0. ## The three leaks the AI keeps writing | Leak | What the AI wrote | The fix | |---|---|---| | Closure retain cycle | Escaping closure captures `self` strongly | `[weak self]` capture list | | Combine subscription | `sink` not stored, or strong `self` inside | Store in `Set`, `[weak self]` | | Live timer or observer | `Timer`/observer never invalidated | Invalidate in `onDisappear` | All three are reference cycles. [Automatic Reference Counting](https://docs.swift.org/swift-book/documentation/the-swift-programming-language/automaticreferencecounting/) frees an object when its reference count hits zero, but if a closure holds `self` strongly while `self` holds the closure, the count never reaches zero and the object lives forever. ## Fix one: capture lists The most common leak is an escaping closure (a network completion, a Combine `sink`, a timer handler) that captures `self` strongly. Break the cycle with a capture list: `{ [weak self] in guard let self else { return } ... }`. That makes the closure's reference to `self` weak, so it does not keep the object alive. The Swift book's section on [closure capture lists and reference cycles](https://docs.swift.org/swift-book/documentation/the-swift-programming-language/automaticreferencecounting/#Resolving-Strong-Reference-Cycles-for-Closures) covers exactly this. Use `weak` for anything that may legitimately go away, like `self` and delegates; reserve `unowned` for references you can prove outlive the closure. This is the same cycle that shows up cross-platform in [the Tinder swipe memory leak React Native fix](/blogs/tinder-swipe-memory-leak-react-native-fix/) and [fixing memory leaks in AI-generated swipe UI](/blogs/fixing-memory-leaks-ai-generated-swipe-ui/). ## Fix two: store your cancellables [Combine](https://developer.apple.com/documentation/combine) is a frequent offender. If you call `.sink` and ignore the returned `AnyCancellable`, the subscription can be torn down or leak depending on context; if you store it but the closure captures `self` strongly, you get a cycle. The fix is two habits: keep a `private var cancellables = Set()` on the object and `.store(in: &cancellables)` each subscription, and use `[weak self]` inside the `sink`. When the object deinits, the set releases the subscriptions. ## Fix three: invalidate timers and observers A repeating `Timer` retains its target, so a timer that runs for the life of a view that should have gone away keeps everything alive. Invalidate it in `onDisappear` (or use the SwiftUI `TimelineView` for purely visual cadence). The same goes for manual `NotificationCenter` observers and KVO: tear them down when the view leaves. ## Confirm it, do not guess Verify with [Instruments](https://developer.apple.com/documentation/xcode/gathering-information-about-memory-use): the Leaks tool flags cycles directly, and Allocations shows an object count that climbs and never drops as you push and pop a screen. The fastest manual check is a `deinit { print("gone") }` on your view model: push the view, pop it, and if "gone" never prints, you have a cycle. While you are auditing AI output, the same care applies to data-heavy screens like [the SwiftUI HealthKit sleep chart](/blogs/swiftui-healthkit-sleep-chart-template/) and to layout bugs like [React Native text cut off on iPhone SE](/blogs/react-native-text-cut-off-on-iphone-se-fix/). When the fix is beyond a quick patch, it can be worth [hiring a SwiftUI developer to fix AI code](/blogs/hire-swiftui-developer-to-fix-ai-code/). ## Key takeaways - AI SwiftUI leaks are retain cycles, not SwiftUI bugs; ARC cannot break them for you. - Add `[weak self]` to escaping closures; `weak` for maybe-gone, `unowned` for guaranteed-alive. - Store Combine cancellables in a `Set` and use `[weak self]` in the sink. - Invalidate timers and observers in `onDisappear`. - Confirm with the Leaks and Allocations instruments, and start from clean VP0 code at $0. ## Frequently asked questions ### Why does AI-generated SwiftUI code leak memory? Usually a retain cycle. The model writes an escaping closure (a network callback, a Combine sink, a timer handler) that captures self strongly, while self also holds the closure, so neither is freed. AI also tends to forget to store Combine cancellables or to invalidate timers. None of these are SwiftUI-specific bugs; they are ARC reference cycles the generator did not break. ### How do I fix a retain cycle in a SwiftUI closure? Add a capture list: write { [weak self] in ... } on escaping closures, then guard let self = self at the top. That makes the closure hold a weak reference, so it does not keep the object alive. Use weak for things that may go away (self, delegates) and reserve unowned for references guaranteed to outlive the closure. ### How do I find a memory leak in an iOS app? Run the app under Instruments with the Leaks and Allocations tools. Leaks flags retain cycles directly, and Allocations shows objects whose count climbs and never drops as you push and pop a screen. Push a view, pop it, and watch whether its view model deinits; if deinit never prints, you have a cycle to break. ### Do Combine subscriptions cause memory leaks in SwiftUI? They can. If you create a subscription with sink and do not store the returned cancellable, or you store it but the sink closure captures self strongly, you get a leak. Store cancellables in a Set on the object so they are released when it deinits, and use [weak self] inside the sink. ### What is the best way to avoid memory leaks in AI-generated SwiftUI? Start from clean, structured code and review every escaping closure for a capture list. A free VP0 design, the free iOS and React Native design library for AI builders, gives you well-structured screens to generate from in Cursor or Claude Code at $0, so there is less tangled code to leak in the first place. ## Frequently asked questions ### Why does AI-generated SwiftUI code leak memory? Usually a retain cycle. The model writes an escaping closure (a network callback, a Combine sink, a timer handler) that captures self strongly, while self also holds the closure, so neither is freed. AI also tends to forget to store Combine cancellables or to invalidate timers. None of these are SwiftUI-specific bugs; they are ARC reference cycles the generator did not break. ### How do I fix a retain cycle in a SwiftUI closure? Add a capture list: write { [weak self] in ... } on escaping closures, then guard let self = self at the top. That makes the closure hold a weak reference, so it does not keep the object alive. Use weak for things that may go away (self, delegates) and reserve unowned for references guaranteed to outlive the closure. ### How do I find a memory leak in an iOS app? Run the app under Instruments with the Leaks and Allocations tools. Leaks flags retain cycles directly, and Allocations shows objects whose count climbs and never drops as you push and pop a screen. Push a view, pop it, and watch whether its view model deinits; if deinit never prints, you have a cycle to break. ### Do Combine subscriptions cause memory leaks in SwiftUI? They can. If you create a subscription with sink and do not store the returned cancellable, or you store it but the sink closure captures self strongly, you get a leak. Store cancellables in a Set on the object so they are released when it deinits, and use [weak self] inside the sink. ### What is the best way to avoid memory leaks in AI-generated SwiftUI? Start from clean, structured code and review every escaping closure for a capture list. A free VP0 design, the free iOS and React Native design library for AI builders, gives you well-structured screens to generate from in Cursor or Claude Code at $0, so there is less tangled code to leak in the first place. --- *Published on the [VP0 Journal](https://vp0.com/blogs). Free to read, index and cite with attribution.*