Thread 0 name:
Thread 0 Crashed:
0 libsystem_platform.dylib 0x000000020eb8eb44 _platform_strlen + 4
1 libc++.1.dylib 0x000000019797c7f4 std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>::append(char const*) + 32 (string:2845)
2 libswiftCore.dylib 0x00000001859283c0 _gatherGenericParameters(swift::TargetContextDescriptor<swift::InProcess> const*, __swift::__runtime::llvm::ArrayRef<swift::MetadataOrPack>, swift::TargetMetadata<swift::InProcess> const*, __swift:... + 144 (MetadataLookup.cpp:1218)
3 libswiftCore.dylib 0x0000000185927f5c swift::TypeLookupError::TypeLookupError<_gatherGenericParameters(swift::TargetContextDescriptor<swift::InProcess> const*, __swift::__runtime::llvm::ArrayRef<swift::MetadataOrPack>, swift::TargetMet... + 76 (TypeLookupError.h:134)
4 libswiftCore.dylib 0x00000001858f9ba0 swift_getAssociatedTypeWitnessSlowImpl(swift::MetadataRequest, swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::... + 772 (Metadata.cpp:6636)
5 libswiftCore.dylib 0x00000001858f7ab4 swift_getAssociatedTypeWitness + 92 (Metadata.cpp:6702)
6 SwiftUI 0x000000018c5090d0 static ControlWidgetConfigurationAdaptor._makeWidgetConfiguration(widget:inputs:) + 152 (<stdin>:0)
7 SwiftUI 0x000000018bd69170 TupleWidgetConfiguration.MakeList.visit<A>(type:) + 1124 (TupleWidget.swift:88)
8 SwiftUI 0x000000018c42e948 TypeConformance<>.visitType<A>(visitor:) + 120 (WidgetConfiguration.swift:132)
9 SwiftUI 0x000000018bd68768 static TupleWidgetConfiguration._makeWidgetConfiguration(widget:inputs:) + 1668 (TupleWidget.swift:59)
10 SwiftUI 0x000000018c628548 closure #1 in WidgetGraph.init<A>(rootBundle:) + 1168 (WidgetGraph.swift:53)
iOS Control Widget Crash
It looks like the crash is happening on launch. Have you tried running your extension target itself and debugging to see if you can pinpoint the calling line your code? That aside, the crash is related to an invalid memory address.