$> swift Handler.swift
Found return instr that returns non-void in Function of void return type!
  ret { i64, i64 } %147, !dbg !216
 void<unknown>:0: error: fatal error encountered during compilation; please file a bug report with your project and the crash log
<unknown>:0: note: Broken function found, compilation aborted!
0  swift                    0x000000010898fa9a PrintStackTraceSignalHandler(void*) + 42
1  swift                    0x000000010898eea6 SignalHandler(int) + 966
2  libsystem_platform.dylib 0x00007fff69718f5a _sigtramp + 26
3  libsystem_platform.dylib 0x00007ffeeb009b10 _sigtramp + 2173635536
4  libsystem_c.dylib        0x00007fff694b61ae abort + 127
5  swift                    0x0000000104c778e9 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*)::$_1::__invoke(void*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool) + 521
6  swift                    0x0000000108942d48 llvm::report_fatal_error(llvm::Twine const&, bool) + 280
7  swift                    0x0000000108942c2b llvm::report_fatal_error(char const*, bool) + 43
8  swift                    0x000000010890ab56 (anonymous namespace)::VerifierLegacyPass::runOnFunction(llvm::Function&) + 54
9  swift                    0x00000001088b231e llvm::FPPassManager::runOnFunction(llvm::Function&) + 446
10 swift                    0x00000001088ba653 llvm::legacy::FunctionPassManagerImpl::run(llvm::Function&) + 115
11 swift                    0x00000001088ba54c llvm::legacy::FunctionPassManager::run(llvm::Function&) + 396
12 swift                    0x0000000104e32e18 swift::performLLVM(swift::IRGenOptions&, swift::DiagnosticEngine*, llvm::sys::SmartMutex<false>*, llvm::GlobalVariable*, llvm::Module*, llvm::TargetMachine*, swift::version::Version const&, llvm::StringRef, swift::UnifiedStatsReporter*) + 5208
13 swift                    0x0000000104e37fe4 performIRGeneration(swift::IRGenOptions&, swift::ModuleDecl*, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::LLVMContext&, swift::SourceFile*, llvm::GlobalVariable**, unsigned int) + 2516
14 swift                    0x0000000104e349a7 swift::performIRGeneration(swift::IRGenOptions&, swift::ModuleDecl*, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::LLVMContext&, llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, llvm::GlobalVariable**) + 727
15 swift                    0x0000000104c83baf performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 47871
16 swift                    0x0000000104c74bbf swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 7839
17 swift                    0x0000000104c1e768 main + 13144
18 libdyld.dylib            0x00007fff6940a015 start + 1
19 libdyld.dylib            0x000000000000000a start + 2529124342
Stack dump:
0.  Program arguments: /Applications/Xcode10.0-beta2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -interpret Handler.swift -enable-objc-interop -sdk /Applications/Xcode10.0-beta2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -color-diagnostics -module-name Handler 
1.  Running pass 'Module Verifier' on function '@"$S7Handler05QueryA0PAAE11forceHandle5query8ReturnedQyd___SbAA6ChangeVcSgtqd___tKAA0B0Rd__lF"'
zsh: abort      swift Handler.swift