Issue Description:

I am attempting to re-create this in a project I can attach, but I have not been able to re-create in a new project.

We are using Sourcery for code generation within our project. It appears to happen once that file goes over a line count / size.

I have worked around this issue by breaking up our generated code into separate files for now.

Xcode Version 11.4.1 (11E503a)
Apple Swift version 5.2.2 (swiftlang-1103.0.32.6 clang-1103.0.32.51)

1. Apple Swift version 5.2.2 (swiftlang-1103.0.32.6 clang-1103.0.32.51) 2. Contents of /var/folders/h7/1wdv8g4n4sggzg5dbg5cy6y40000gn/T/inputs-27e459: 3. While deserializing SIL witness table for protocol conformance to 'InternalDecodable' (in module 'SmartThingsCore') for type 'SSE.Subscription.Filter' 4. While cross-referencing conformance for 'Coded' (in module 'SmartThingsCore') 5. While ... to 'Decodable' (in module 'Swift') 6. If you're seeing a crash here, check that your SDK and dependencies are at least as new as the versions used to build 'SmartThingsCore' 0 swift 0x0000000104ebf4ea PrintStackTraceSignalHandler(void*) + 42 1 swift 0x0000000104ebecc0 SignalHandler(int) + 352 2 libsystem_platform.dylib 0x00007fff716b75fd _sigtramp + 29 3 libsystem_platform.dylib 0x00007f958c03a000 _sigtramp + 446179872 4 libsystem_c.dylib 0x00007fff7158d808 abort + 120 5 swift 0x0000000101908ce1 swift::ModuleFile::readConformanceChecked(llvm::BitstreamCursor&, swift::GenericEnvironment*) + 3569 6 swift 0x000000010193e3a9 swift::SILDeserializer::readWitnessTableEntries(llvm::BitstreamEntry&, std::1::vector<swift::SILWitnessTable::Entry, std::1::allocator<swift::SILWitnessTable::Entry> >&, std::1::vector<swift::SILWitnessTable::ConditionalConformance, std::_1::allocator<swift::SILWitnessTable::ConditionalConformance> >&) + 857 7 swift 0x000000010193ee53 swift::SILDeserializer::readWitnessTableChecked(llvm::PointerEmbeddedInt<unsigned int, 31>, swift::SILWitnessTable*) + 1507 8 swift 0x000000010193f0d8 swift::SILDeserializer::getAllWitnessTables() + 120 9 swift 0x00000001019cd03b swift::SerializedSILLoader::getAllForModule(swift::Identifier, swift::FileUnit*) + 603 10 swift 0x0000000100f1da4e swift::CompilerInstance::performSILProcessing(swift::SILModule*, swift::UnifiedStatsReporter*) + 142 11 swift 0x0000000100c1b450 performCompileStepsPostSILGen(swift::CompilerInstance&, swift::CompilerInvocation&, std::1::unique_ptr<swift::SILModule, std::_1::default_delete<swift::SILModule> >, bool, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, bool, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 1712 12 swift 0x0000000100c12f75 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 55813 13 swift 0x0000000100b88f53 main + 1283 14 libdyld.dylib 0x00007fff714becc9 start + 1 15 libdyld.dylib 0x000000000000005a start + 2394166162 error: Abort trap: 6 (in target 'InternalSmartThingsCore-iOS' from project 'SmartKit')