1.  Apple Swift version 5.5 (swiftlang-1300.0.24.13 clang-1300.0.25.10)
2.  
3.  While evaluating request IRGenRequest(IR Generation for file "/Users/soleilyu/Code/self/t/SwiftCompilationAndRuntimeCrash/SwiftCompilationAndRuntimeCrash/SubClass.swift")
4.  While emitting IR SIL function "@$s31SwiftCompilationAndRuntimeCrash8SubClassCACycfc".
 for 'init()' (at /Users/soleilyu/Code/self/t/SwiftCompilationAndRuntimeCrash/SwiftCompilationAndRuntimeCrash/SubClass.swift:13:14)
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  swift-frontend           0x000000010f76bfc7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1  swift-frontend           0x000000010f76af58 llvm::sys::RunSignalHandlers() + 248
2  swift-frontend           0x000000010f76c5d6 SignalHandler(int) + 278
3  libsystem_platform.dylib 0x00007fff20436d7d _sigtramp + 29
4  libsystem_platform.dylib 0x00007fb500000002 _sigtramp + 18446743755340681890
5  swift-frontend           0x000000010cf1df04 (anonymous namespace)::X86_64ABIInfo::computeInfo(clang::CodeGen::CGFunctionInfo&) const + 2692
6  swift-frontend           0x000000010cb2b634 clang::CodeGen::CodeGenTypes::arrangeLLVMFunctionInfo(clang::CanQual<clang::Type>, bool, bool, llvm::ArrayRef<clang::CanQual<clang::Type> >, clang::FunctionType::ExtInfo, llvm::ArrayRef<clang::FunctionType::ExtParameterInfo>, clang::CodeGen::RequiredArgs) + 2804
7  swift-frontend           0x000000010ac0ab72 swift::irgen::Signature::getUncached(swift::irgen::IRGenModule&, swift::CanTypeWrapper<swift::SILFunctionType>, bool) + 1458
8  swift-frontend           0x000000010ad270cc swift::irgen::getObjCMethodCallee(swift::irgen::IRGenFunction&, swift::irgen::ObjCMethod const&, llvm::Value*, swift::irgen::CalleeInfo&&) + 172
9  swift-frontend           0x000000010ade466a (anonymous namespace)::IRGenSILFunction::visitFullApplySite(swift::FullApplySite) + 2890
10 swift-frontend           0x000000010adc467f swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 10335
11 swift-frontend           0x000000010ac70f77 swift::irgen::IRGenerator::emitGlobalTopLevel(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&) + 1607
12 swift-frontend           0x000000010ad91afa swift::IRGenRequest::evaluate(swift::Evaluator&, swift::IRGenDescriptor) const + 8938
13 swift-frontend           0x000000010adc1aec swift::SimpleRequest<swift::IRGenRequest, swift::GeneratedModule (swift::IRGenDescriptor), (swift::RequestFlags)9>::evaluateRequest(swift::IRGenRequest const&, swift::Evaluator&) + 204
14 swift-frontend           0x000000010ad9c87c llvm::Expected<swift::IRGenRequest::OutputType> swift::Evaluator::getResultUncached<swift::IRGenRequest>(swift::IRGenRequest const&) + 876
15 swift-frontend           0x000000010ad9640c swift::performIRGeneration(swift::FileUnit*, swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::StringRef, llvm::GlobalVariable**) + 348
16 swift-frontend           0x000000010a8b4e99 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 2841
17 swift-frontend           0x000000010a8a6826 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 13494
18 swift-frontend           0x000000010a7e8588 main + 1032
19 libdyld.dylib            0x00007fff2040cf5d start + 1
error: Segmentation fault: 11 (in target 'SwiftCompilationAndRuntimeCrash' from project 'SwiftCompilationAndRuntimeCrash')

Property 'handlers' with type '[String : (BaseClass?, Any?, BlockFromThirdParty?) -> Void]?' (aka 'Optional<Dictionary<String, (Optional<BaseClass>, Optional<Any>, Optional<(Any) -> ()>) -> ()>>') cannot override a property with type '[String : @convention(block) (BaseClass?, Any?, BlockFromThirdParty?) -> Void]?' (aka 'Optional<Dictionary<String, @convention(block) (Optional<BaseClass>, Optional<Any>, Optional<(Any) -> ()>) -> ()>>')