Hello Apple engineers, could you help me understand whether this crash is a UIKit bug or something in our code that causes it. Based on the documentation it is an invalid fetch instruction, that's why I suspect UIKit.
I've found a similar crash here on the forums reported a year ago, it seemed to be a UIKit bug - https://forums.developer.apple.com/forums/thread/729448.
I've attached the full crash report (the app name was replaced with <Redacted>):
Thread 0 Crashed:
0 libobjc.A.dylib 0x000000019daf7c20 objc_msgSend + 32 (:-1)
1 UIKitCore 0x00000001a3020c50 -[UIView _wrappedProcessTraitChanges:withBehavior:] + 1288 (UIView.m:0)
2 UIKitCore 0x00000001a3020720 -[UIView _processChangesFromOldTraits:toCurrentTraits:withBehavior:] + 196 (UIView.m:7840)
3 UIKitCore 0x00000001a3020618 -[UIView _updateTraitCollectionAndProcessChangesWithBehavior:previousCollection:] + 112 (UIView.m:7831)
4 UIKitCore 0x00000001a2fa90c0 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 944 (UIView.m:19850)
5 QuartzCore 0x00000001a22dfc28 CA::Layer::layout_if_needed(CA::Transaction*) + 496 (CALayer.mm:10944)
6 QuartzCore 0x00000001a22df7b4 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 148 (CALayer.mm:2638)
7 QuartzCore 0x00000001a2336914 CA::Context::commit_transaction(CA::Transaction*, double, double*) + 472 (CAContextInternal.mm:2613)
8 QuartzCore 0x00000001a22b57c4 CA::Transaction::commit() + 648 (CATransactionInternal.mm:420)
9 QuartzCore 0x00000001a22f8a0c CA::Transaction::flush_as_runloop_observer(bool) + 88 (CATransactionInternal.mm:928)
10 UIKitCore 0x00000001a303f568 _UIApplicationFlushCATransaction + 52 (UIApplication.m:3326)
11 UIKitCore 0x00000001a303cb64 __setupUpdateSequence_block_invoke_2 + 332 (_UIUpdateScheduler.m:1652)
12 UIKitCore 0x00000001a303c9d8 _UIUpdateSequenceRun + 84 (_UIUpdateSequence.mm:136)
13 UIKitCore 0x00000001a303c628 schedulerStepScheduledMainSection + 172 (_UIUpdateScheduler.m:1171)
14 UIKitCore 0x00000001a303d59c runloopSourceCallback + 92 (_UIUpdateScheduler.m:1334)
15 CoreFoundation 0x00000001a080c328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:1970)
16 CoreFoundation 0x00000001a080c2bc __CFRunLoopDoSource0 + 176 (CFRunLoop.c:2014)
17 CoreFoundation 0x00000001a0809dc0 __CFRunLoopDoSources0 + 244 (CFRunLoop.c:2051)
18 CoreFoundation 0x00000001a0808fbc __CFRunLoopRun + 840 (CFRunLoop.c:2969)
19 CoreFoundation 0x00000001a0808830 CFRunLoopRunSpecific + 588 (CFRunLoop.c:3434)
20 GraphicsServices 0x00000001ec7e81c4 GSEventRunModal + 164 (GSEvent.c:2196)
21 UIKitCore 0x00000001a336eeb0 -[UIApplication _run] + 816 (UIApplication.m:3844)
22 UIKitCore 0x00000001a341d5b4 UIApplicationMain + 340 (UIApplication.m:5496)
23 UIKitCore 0x00000001a3757fa8 UIApplicationMain(_:_:_:_:) + 104 (UIKit.swift:565)
24 <Redacted> 0x00000001028bde64 specialized static UIApplicationDelegate.main() + 28 (/<compiler-generated>:16)
25 <Redacted> 0x00000001028bde64 static AppDelegate.$main() + 28 (AppDelegate.swift:0)
26 <Redacted> 0x00000001028bde64 main + 116
27 dyld 0x00000001c61f6ec8 start + 2724 (dyldMain.cpp:1334)