We're seeing a _very_ similar crash. Though it doesn't reproduce 100% of the time, it happens quite regularly.Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Application Specific Information: abort() called CoreSimulator 704.12.2 - Device: iPhone 11 (2CFE4E5E-4E50-4F44-A315-7E722C65F4AC) - Runtime: iOS 13.5 (17F61) - DeviceType: iPhone 11 AttributeGraph precondition failure: invalid input index: 2. Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 libsystem_kernel.dylib 0x00007fff51b617fa __pthread_kill + 10 1 libsystem_pthread.dylib 0x00007fff51c0cbc1 pthread_kill + 432 2 libsystem_c.dylib 0x00007fff51af0b7c abort + 120 3 com.apple.AttributeGraph 0x00007fff2fc8ce40 AG::precondition_failure(char const*, ...) + 273 4 com.apple.AttributeGraph 0x00007fff2fc64846 AG::Graph::input_value_ref_slow(unsigned int, unsigned int, AGTypeID, bool*) + 490 5 com.apple.SwiftUI 0x00007fff2c538ab1 RootGeometry.update(context:) + 97 6 com.apple.SwiftUI 0x00007fff2c53c4d8 partial apply for protocol witness for static UntypedAttribute._update(_:graph:attribute:) in conformance RootGeometry + 24 7 com.apple.AttributeGraph 0x00007fff2fc60d3d AG::Graph::UpdateStack::update() + 455 8 com.apple.AttributeGraph 0x00007fff2fc6124b AG::Graph::update_attribute(unsigned int, bool) + 373 9 com.apple.AttributeGraph 0x00007fff2fc64723 AG::Graph::input_value_ref_slow(unsigned int, unsigned int, AGTypeID, bool*) + 199 10 com.apple.SwiftUI 0x00007fff2c5ceb92 _PositionAwareLayoutContext.dimensions.getter + 50 11 com.apple.SwiftUI 0x00007fff2c65c164 partial apply for thunk for @callee_guaranteed () -> (@unowned CGSize) + 20 12 com.apple.SwiftUI 0x00007fff2c65c582 specialized closure #1 in GeometryProxy.sync<A>(_:) + 66 13 com.apple.SwiftUI 0x00007fff2c65ca7e specialized closure #1 in GeometryProxy.sync<A>(_:) + 14 14 com.apple.SwiftUI 0x00007fff2c65caa1 partial apply for specialized + 17 15 com.apple.SwiftUI 0x00007fff2c80ee27 ViewRendererHost.updateViewGraph<A>(body:) + 71 16 com.apple.SwiftUI 0x00007fff2c80eb23 protocol witness for ViewGraphDelegate.updateViewGraph<A>(body:) in conformance _UIHostingView<A1> + 19 17 com.apple.SwiftUI 0x00007fff2c65b5ca GeometryProxy.size.getter + 186 18 com.apple.SwiftUI 0x00007fff2c65c3e5 GeometryProxy.frame(in:) + 21 19 com.myco.UI 0x0000000103bfe695 closure #1 in FramePreferenceViewModifier.body(content:) + 149 (FramePreference.swift:54) 20 com.myco.UI 0x0000000103bffb3c partial apply for closure #1 in FramePreferenceViewModifier.body(content:) + 12 21 com.apple.SwiftUI 0x00007fff2c65be76 GeometryReader.Child.update(context:) + 390 22 com.apple.SwiftUI 0x00007fff2c65c0b0 protocol witness for static UntypedAttribute._update(_:graph:attribute:) in conformance GeometryReader<A>.Child + 32 23 com.apple.AttributeGraph 0x00007fff2fc78309 partial apply + 25 24 com.apple.AttributeGraph 0x00007fff2fc60d3d AG::Graph::UpdateStack::update() + 455 25 com.apple.AttributeGraph 0x00007fff2fc6124b AG::Graph::update_attribute(unsigned int, bool) + 373 26 com.apple.AttributeGraph 0x00007fff2fc65d53 AG::Subgraph::update(unsigned int) + 729 27 com.apple.SwiftUI 0x00007fff2c5359e0 ViewGraph.runTransaction(in:) + 224 28 com.apple.SwiftUI 0x00007fff2c535796 closure #1 in ViewGraph.flushTransactions() + 262 29 com.apple.SwiftUI 0x00007fff2c535475 ViewGraph.flushTransactions() + 213 30 com.apple.SwiftUI 0x00007fff2c819ac3 closure #1 in ViewRendererHost.render(interval:updateDisplayList:) + 179 31 com.apple.SwiftUI 0x00007fff2c80f785 ViewRendererHost.render(interval:updateDisplayList:) + 373 32 com.apple.SwiftUI 0x00007fff2c96f9e2 _UIHostingView.layoutSubviews() + 226 33 com.apple.SwiftUI 0x00007fff2c96fa05 @objc _UIHostingView.layoutSubviews() + 21 34 com.apple.UIKitCore 0x00007fff49193678 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2478 35 com.apple.QuartzCore 0x00007fff2b4c6398 -[CALayer layoutSublayers] + 255 36 com.apple.QuartzCore 0x00007fff2b4cc523 CA::Layer::layout_if_needed(CA::Transaction*) + 523 37 com.apple.QuartzCore 0x00007fff2b4d7bba CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 80 38 com.apple.QuartzCore 0x00007fff2b420c04 CA::Context::commit_transaction(CA::Transaction*, double) + 324 39 com.apple.QuartzCore 0x00007fff2b4545ef CA::Transaction::commit() + 649 40 com.apple.SwiftUI 0x00007fff2c96fb14 _UIHostingView.displayLinkTimer(timestamp:) + 244 41 com.apple.SwiftUI 0x00007fff2c45343d DisplayLink.displayLinkTimer(_:) + 77 42 com.apple.SwiftUI 0x00007fff2c453496 @objc DisplayLink.displayLinkTimer(_:) + 38 43 com.apple.QuartzCore 0x00007fff2b3814c6 CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 538 44 com.apple.QuartzCore 0x00007fff2b4588f0 display_timer_callback(__CFMachPort*, void*, long, void*) + 299 45 com.apple.CoreFoundation 0x00007fff23d6187d __CFMachPortPerform + 157 46 com.apple.CoreFoundation 0x00007fff23da14e9 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41 47 com.apple.CoreFoundation 0x00007fff23da0ae8 __CFRunLoopDoSource1 + 472 48 com.apple.CoreFoundation 0x00007fff23d9b514 __CFRunLoopRun + 2228 49 com.apple.CoreFoundation 0x00007fff23d9a944 CFRunLoopRunSpecific + 404 50 com.apple.GraphicsServices 0x00007fff38ba6c1a GSEventRunModal + 139 51 com.apple.UIKitCore 0x00007fff48c8b9ec UIApplicationMain + 1605 52 com.myco.myapp 0x0000000100821e28 main + 56 (AppDelegate.swift:14) 53 libdyld.dylib 0x00007fff51a231fd start + 1

I was able to create a reliable reproducer of the precondition failure. The magic combination seems to be a SwiftUI List in a Tab, where each element in the List utilizes a GeometryReader to read the GeometryProxy's frame. Also, the List rows are populated in "onAppear". Simply switching to a tab containing a List configured as described causes the precondition failure.I've submitted FB7733658.

I’m seeing the same “FailedToInstallAppError: Failed to install ”XCPreviewAgent.app” Could not install the preview host ”XCPreviewAgent.app” on iPhone 14 Pro” issue (with the same beta build of Xcode 15). In my case, I have a PreviewProvider declared in a file in a framework that is embedded in an app target. The current scheme is configured to launch the app.

This is still an issue in Xcode Version 15.0.1 (15A507). I created Feedback FB13283487. The Feedback includes a sample application that replicates the issue.