Unknown Swift compiler crash on https://github.com/jspahrsummers/RxSwift/tree/da89d91ab9d7a48adf5ffacc2e877081be0ecf42

gistfile1.txt

0  swift                    0x000000010c789608 llvm::sys::PrintStackTrace(__sFILE*) + 40
1  swift                    0x000000010c789af4 SignalHandler(int) + 452
2  libsystem_platform.dylib 0x00007fff8d7185aa _sigtramp + 26
3  libsystem_platform.dylib 0x00007fb542170838 _sigtramp + 3030745768
4  swift                    0x000000010ca1990b swift::BoundGenericType::get(swift::NominalTypeDecl*, swift::Type, llvm::ArrayRef<swift::Type>) + 331
5  swift                    0x000000010caa4091 swift::Type::transform(std::__1::function<swift::Type (swift::Type)> const&) const + 4001
6  swift                    0x000000010caa3298 swift::Type::transform(std::__1::function<swift::Type (swift::Type)> const&) const + 424
7  swift                    0x000000010ca0f9dd substDependentTypes(swift::ArchetypeBuilder&, swift::Type) + 205
8  swift                    0x000000010caa3120 swift::Type::transform(std::__1::function<swift::Type (swift::Type)> const&) const + 48
9  swift                    0x000000010caa32ff swift::Type::transform(std::__1::function<swift::Type (swift::Type)> const&) const + 527
10 swift                    0x000000010ca0f692 swift::ArchetypeBuilder::substDependentType(swift::Type) + 50
11 swift                    0x000000010bc3c81e swift::Lowering::TypeConverter::getTypeLoweringForUncachedLoweredType(swift::Lowering::TypeConverter::TypeKey) + 46
12 swift                    0x000000010bc3c176 swift::Lowering::TypeConverter::getTypeLowering(swift::Lowering::AbstractionPattern, swift::Type, unsigned int) + 2198
13 swift                    0x000000010bc0d9a9 getSILFunctionType(swift::SILModule&, swift::CanType, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::AnyFunctionType::ExtInfo, (anonymous namespace)::Conventions const&) + 265
14 swift                    0x000000010bc0aff1 swift::getNativeSILFunctionType(swift::SILModule&, swift::CanType, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::CanTypeWrapper<swift::AnyFunctionType>) + 113
15 swift                    0x000000010bc62fa8 swift::Lowering::SILGenModule::emitProtocolWitness(swift::ProtocolConformance*, swift::SILLinkage, swift::SILDeclRef, swift::SILDeclRef, swift::Lowering::IsFreeFunctionWitness_t, llvm::ArrayRef<swift::Substitution>) + 1784
16 swift                    0x000000010bc63ea2 (anonymous namespace)::SILGenConformance::emitFuncEntry(swift::FuncDecl*, swift::ValueDecl*, llvm::ArrayRef<swift::Substitution>) + 194
17 swift                    0x000000010bc6014b swift::Lowering::SILGenModule::getWitnessTable(swift::ProtocolConformance*) + 1659
18 swift                    0x000000010bc64d0b SILGenType::emitType() + 315
19 swift                    0x000000010bc663a1 SILGenType::visitNominalTypeDecl(swift::NominalTypeDecl*) + 33
20 swift                    0x000000010bc64c9b SILGenType::emitType() + 203
21 swift                    0x000000010bc5f7fe swift::Lowering::SILGenModule::visitNominalTypeDecl(swift::NominalTypeDecl*) + 30
22 swift                    0x000000010bc4e6ab swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*, unsigned int) + 395
23 swift                    0x000000010bc4e95b swift::SILModule::constructSIL(swift::Module*, swift::SourceFile*, unsigned int) + 331
24 swift                    0x000000010bc4ea60 swift::performSILGeneration(swift::SourceFile&, unsigned int) + 32
25 swift                    0x000000010bb4e001 frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 3217
26 swift                    0x000000010bb4d35d main + 1533
27 libdyld.dylib            0x00007fff8d2395fd start + 1
Stack dump:
0.	Program arguments: /Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -c /Users/justin/GitHub/RxSwift/RxSwift/ArrayExtensions.swift /Users/justin/GitHub/RxSwift/RxSwift/SpinLock.swift /Users/justin/GitHub/RxSwift/RxSwift/Scheduler.swift /Users/justin/GitHub/RxSwift/RxSwift/AsyncBuffer.swift /Users/justin/GitHub/RxSwift/RxSwift/NSLockingExtensions.swift /Users/justin/GitHub/RxSwift/RxSwift/Box.swift /Users/justin/GitHub/RxSwift/RxSwift/Disposable.swift /Users/justin/GitHub/RxSwift/RxSwift/Event.swift -primary-file /Users/justin/GitHub/RxSwift/RxSwift/AsyncSequence.swift /Users/justin/GitHub/RxSwift/RxSwift/Observable.swift /Users/justin/GitHub/RxSwift/RxSwift/Promise.swift /Users/justin/GitHub/RxSwift/RxSwift/Stream.swift /Users/justin/GitHub/RxSwift/RxSwift/Atomic.swift -enable-objc-attr-requires-objc-module -target x86_64-apple-macosx10.9 -module-name RxSwift -sdk /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk -I /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Products/Debug -F /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Products/Debug -g -import-underlying-module -module-cache-path /Users/justin/Library/Developer/Xcode/DerivedData/ModuleCache -Xcc -iquote -Xcc /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/RxSwift-generated-files.hmap -Xcc -I/Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/RxSwift-own-target-headers.hmap -Xcc -ivfsoverlay -Xcc /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/all-product-headers.yaml -Xcc -iquote -Xcc /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/RxSwift-project-headers.hmap -Xcc -I/Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Products/Debug/include -Xcc -I/Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -Xcc -I/Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/DerivedSources/x86_64 -Xcc -I/Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/DerivedSources -Xcc -DDEBUG=1 -Xcc -ivfsoverlay -Xcc /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/unextended-module-overlay.yaml -emit-module-doc-path /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/Objects-normal/x86_64/AsyncSequence~partial.swiftdoc -O0 -emit-module-path /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/Objects-normal/x86_64/AsyncSequence~partial.swiftmodule -serialize-diagnostics-path /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/Objects-normal/x86_64/AsyncSequence.dia -emit-dependencies-path /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/Objects-normal/x86_64/AsyncSequence.d -o /Users/justin/Library/Developer/Xcode/DerivedData/RxSwift-aelnxtexwokxwygxikkrkbmhgxaz/Build/Intermediates/RxSwift.build/Debug/RxSwift.build/Objects-normal/x86_64/AsyncSequence.o 
<unknown>:0: error: unable to execute command: Segmentation fault: 11
<unknown>:0: error: swift frontend command failed due to signal (use -v to see invocation)