Open Radar

 
Preconditions:

- Build with Xcode 13.2 or higher (Both 13.2.1 and 13.3 beta tested and still crashing)
- Build using -O or -Osize 
- Run on iOS 14 (tested up to 14.8.1)

Summary:

If you have a ViewBuilder which performs an availability check (“if #available”) and within that limited availability you use an API only available in that version—such as using an iOS 15 API from within a 15 runtime check) the application will crash when attempting to demangle the symbols.

Code:

extension View {
    @ViewBuilder func crash() -> some View {
        if #available(iOS 15.0, *) {
            self.searchable(text: .constant("Test"))
        } else {
            self
        }
    }
}

@main
struct CrashSampleApp: App {
    var body: some Scene {
        WindowGroup {
            Text("Test")
              .crash()
        }
    }
}

Crash log:

```
#0  0x000000018e2e6f98 in swift::ResolveAsSymbolicReference::operator()(swift::Demangle::__runtime::SymbolicReferenceKind, swift::Demangle::__runtime::Directness, int, void const*) ()
#1  0x000000018e30461c in swift::Demangle::__runtime::Demangler::demangleSymbolicReference(unsigned char) ()
#2  0x000000018e301880 in swift::Demangle::__runtime::Demangler::demangleType(__swift::__runtime::llvm::StringRef, std::__1::function<swift::Demangle::__runtime::Node* (swift::Demangle::__runtime::SymbolicReferenceKind, swift::Demangle::__runtime::Directness, int, void const*)>) ()
#3  0x000000018e2ec510 in swift_getTypeByMangledNameImpl(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<swift::TargetMetadata<swift::InProcess> const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) ()
#4  0x000000018e2e9f0c in swift::swift_getTypeByMangledName(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<swift::TargetMetadata<swift::InProcess> const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) ()
#5  0x000000018e2ea120 in swift_getTypeByMangledNameInContext ()
#6  0x00000001022170f4 in __swift_instantiateConcreteTypeFromMangledName ()
#7  0x0000000102216b5c in specialized static ViewBuilder.buildLimitedAvailability<Ï„_0_0>(_:) [inlined] ()
#8  0x0000000102216b50 in specialized View.crash() at ../CrashSample/CrashSample/CrashSampleApp.swift:14
#9  0x0000000102216eac in closure #1 in CrashSampleApp.body.getter at ../CrashSample/CrashSample/CrashSampleApp.swift:25
#10 0x00000001b328d83c in WindowGroup.init(content:) ()
#11 0x0000000102216f90 in CrashSampleApp.body.getter [inlined] at ../CrashSample/CrashSample/CrashSampleApp.swift:23
#12 0x0000000102216f10 in protocol witness for App.body.getter in conformance CrashSampleApp at ../CrashSample/<compiler-generated>:22
#13 0x00000001b2ee4454 in partial apply for closure #1 in AppBodyAccessor.updateBody(of:changed:) ()
#14 0x00000001b3286188 in closure #1 in BodyAccessor.setBody(_:) ()
#15 0x00000001b2ee3e08 in AppBodyAccessor.updateBody(of:changed:) ()
#16 0x00000001b32862b0 in StaticBody.updateValue() ()
#17 0x00000001b2fa29a4 in partial apply for implicit closure #2 in implicit closure #1 in closure #1 in closure #1 in Attribute.init<Ï„_0_0>(_:) ()
#18 0x00000001a953b1c0 in AG::Graph::UpdateStack::update() ()
#19 0x00000001a953b5c8 in AG::Graph::update_attribute(AG::data::ptr<AG::Node>, bool) ()
#20 0x00000001a95404f0 in AG::Graph::input_value_ref_slow(AG::data::ptr<AG::Node>, AG::AttributeID, unsigned int, AGSwiftMetadata const*, bool*, long) ()
#21 0x00000001a95511cc in AGGraphGetValue ()
#22 0x00000001b3285c68 in StaticBody.container.getter ()
#23 0x00000001b3286294 in StaticBody.updateValue() ()
#24 0x00000001b2fa29a4 in partial apply for implicit closure #2 in implicit closure #1 in closure #1 in closure #1 in Attribute.init<Ï„_0_0>(_:) ()
#25 0x00000001a953b1c0 in AG::Graph::UpdateStack::update() ()
#26 0x00000001a953b5c8 in AG::Graph::update_attribute(AG::data::ptr<AG::Node>, bool) ()
#27 0x00000001a95404f0 in AG::Graph::input_value_ref_slow(AG::data::ptr<AG::Node>, AG::AttributeID, unsigned int, AGSwiftMetadata const*, bool*, long) ()
#28 0x00000001a95511cc in AGGraphGetValue ()
#29 0x00000001b328ed7c in WindowGroupSceneList.MakeList.id.getter ()
#30 0x00000001b328ee18 in WindowGroupSceneList.MakeList.updateValue() ()
#31 0x00000001b2e6a4f4 in partial apply for specialized implicit closure #2 in implicit closure #1 in closure #1 in closure #1 in Attribute.init<Ï„_0_0>(_:) ()
#32 0x00000001a953b1c0 in AG::Graph::UpdateStack::update() ()
#33 0x00000001a953b5c8 in AG::Graph::update_attribute(AG::data::ptr<AG::Node>, bool) ()
#34 0x00000001a953ff54 in AG::Graph::value_ref(AG::AttributeID, AGSwiftMetadata const*, bool*) ()
#35 0x00000001a9551214 in AGGraphGetValue ()
#36 0x00000001b2ee32fc in AppGraph.sceneList() ()
#37 0x00000001b35cb328 in AppSceneDelegate.makeSceneHost(restorationSceneItemID:userActivity:urlContexts:) ()
#38 0x00000001b35c990c in AppSceneDelegate.scene(_:willConnectTo:options:) ()
#39 0x00000001b35ca234 in @objc AppSceneDelegate.scene(_:willConnectTo:options:) ()
#40 0x0000000183916dac in +[UIScene _sceneForFBSScene:create:withSession:connectionOptions:] ()
#41 0x00000001843f1cd4 in -[UIApplication _connectUISceneFromFBSScene:transitionContext:] ()
#42 0x00000001843f200c in -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] ()
#43 0x0000000183f32d70 in -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] ()
#44 0x000000018566b090 in -[FBSScene _callOutQueue_agent_didCreateWithTransitionContext:completion:] ()
#45 0x00000001856925bc in __94-[FBSWorkspaceScenesClient createWithSceneID:groupID:parameters:transitionContext:completion:]_block_invoke.176 ()
#46 0x00000001856787b0 in -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] ()
#47 0x00000001856922d4 in __94-[FBSWorkspaceScenesClient createWithSceneID:groupID:parameters:transitionContext:completion:]_block_invoke ()
#48 0x00000001026ad884 in _dispatch_client_callout ()
#49 0x00000001026b0b8c in _dispatch_block_invoke_direct ()
#50 0x00000001856b692c in __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ ()
#51 0x00000001856b65f4 in -[FBSSerialQueue _targetQueue_performNextIfPossible] ()
#52 0x00000001856b6ac8 in -[FBSSerialQueue _performNextFromRunLoopSource] ()
#53 0x000000018036631c in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ ()
#54 0x000000018036621c in __CFRunLoopDoSource0 ()
#55 0x00000001803655e4 in __CFRunLoopDoSources0 ()
#56 0x000000018035fbb4 in __CFRunLoopRun ()
#57 0x000000018035f3bc in CFRunLoopRunSpecific ()
#58 0x000000018afdd70c in GSEventRunModal ()
#59 0x00000001843f03d0 in -[UIApplication _run] ()
#60 0x00000001843f51ac in UIApplicationMain ()
#61 0x00000001b34c6f6c in closure #1 in KitRendererCommon(_:) ()
#62 0x00000001b34c6efc in runApp<Ï„_0_0>(_:) ()
#63 0x00000001b309ca74 in static App.main() ()
#64 0x0000000102217050 in static CrashSampleApp.$main() [inlined] at ../CrashSample/CrashSample/CrashSampleApp.swift:20
#65 0x0000000102217038 in main ()
#66 0x00000001023410f4 in start ()
```