duplicates:

• SR-8814 GenericSignatureBuilder should re-introduce conformance requirements when adding a superclass requirement

Issue Description:

The code works if we replace class ClassB with struct ClassB, or when we implement methodB() in ClassB. Any other way it crashes.

Can be reproduced in XCode10.2 or in REPL.

protocol ProtocolB {               
    associatedtype BType: Hashable               
    func methodB()
}
extension ProtocolB {
    func methodB() {}
}
class ClassB<T: Hashable>: ProtocolB {         
    typealias BType = T 
}

Hashable protocol is just an example, any other protocol also causes this, custom or otherwise.

Running this will crash with stacktrace :

0 lldb 0x000000010a32ef95 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37

1 lldb 0x000000010a32e347 llvm::sys::RunSignalHandlers() + 39

2 lldb 0x000000010a32f5f2 SignalHandler(int) + 258

3 libsystem_platform.dylib 0x00007fff78b96b3d _sigtramp + 29

4 libsystem_platform.dylib 0x00007fa36c8e42a8 _sigtramp + 4090812296

5 LLDB 0x0000000111c5963d swift::Lowering::TypeConverter::getProtocolDispatchStrategy(swift::ProtocolDecl*) + 13

6 LLDB 0x0000000111a6b0db swift::irgen::TypeConverter::getProtocolInfo(swift::ProtocolDecl*, swift::irgen::ProtocolInfoKind) + 219

7 LLDB 0x0000000111a6aff0 swift::irgen::IRGenModule::getProtocolInfo(swift::ProtocolDecl*, swift::irgen::ProtocolInfoKind) + 16

8 LLDB 0x00000001119b338d swift::irgen::FulfillmentMap::searchWitnessTable(swift::irgen::IRGenModule&, swift::CanType, swift::ProtocolDecl*, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&, llvm::SmallPtrSetImpl<swift::ProtocolDecl*>*) + 61

9 LLDB 0x00000001119b32f1 swift::irgen::FulfillmentMap::searchWitnessTable(swift::irgen::IRGenModule&, swift::CanType, swift::ProtocolDecl*, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&) + 465

10 LLDB 0x00000001119b40f1 void llvm::function_ref<void (unsigned int, swift::CanType, llvm::Optional<swift::ProtocolConformanceRef>)>::callback_fn<swift::irgen::FulfillmentMap::searchNominalTypeMetadata(swift::irgen::IRGenModule&, swift::CanType, swift::MetadataState, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&)::$_1>(long, unsigned int, swift::CanType, llvm::Optional<swift::ProtocolConformanceRef>) + 1553

11 LLDB 0x0000000111a6f0ef swift::irgen::GenericTypeRequirements::enumerateFulfillments(swift::irgen::IRGenModule&, swift::SubstitutionMap, llvm::function_ref<void (unsigned int, swift::CanType, llvm::Optional<swift::ProtocolConformanceRef>)>) + 255

12 LLDB 0x00000001119b2ddc swift::irgen::FulfillmentMap::searchNominalTypeMetadata(swift::irgen::IRGenModule&, swift::CanType, swift::MetadataState, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&) + 236

13 LLDB 0x00000001119b2cba swift::irgen::FulfillmentMap::searchTypeMetadata(swift::irgen::IRGenModule&, swift::CanType, swift::irgen::IsExact_t, swift::MetadataState, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&) + 746

14 LLDB 0x0000000111aeede5 swift::irgen::LocalTypeDataCache::addAbstractForTypeMetadata(swift::irgen::IRGenFunction&, swift::CanType, swift::irgen::IsExact_t, swift::irgen::MetadataResponse) + 85

15 LLDB 0x0000000111aeed70 swift::irgen::IRGenFunction::bindLocalTypeDataFromTypeMetadata(swift::CanType, swift::irgen::IsExact_t, llvm::Value*, swift::MetadataState) + 256

16 LLDB 0x0000000111a6dd96 swift::irgen::emitPolymorphicParameters(swift::irgen::IRGenFunction&, swift::SILFunction&, swift::irgen::Explosion&, swift::irgen::WitnessMetadata*, llvm::function_ref<llvm::Value* (unsigned int)> const&) + 678

17 LLDB 0x0000000111abf1b4 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 4596

18 LLDB 0x00000001119ee737 swift::irgen::IRGenerator::emitLazyDefinitions() + 567

19 LLDB 0x0000000111aa07bf 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**) + 1199

20 LLDB 0x0000000111a9f5f6 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**) + 1398

21 LLDB 0x00000001126ab22a lldb_private::SwiftExpressionParser::Parse(lldb_private::DiagnosticManager&, unsigned int, unsigned int, unsigned int) + 7506

22 LLDB 0x00000001126f52f7 lldb_private::SwiftUserExpression::Parse(lldb_private::DiagnosticManager&, lldb_private::ExecutionContext&, lldb_private::ExecutionPolicy, bool, bool, unsigned int) + 911

23 LLDB 0x000000011249066f lldb_private::UserExpression::Evaluate(lldb_private::ExecutionContext&, lldb_private::EvaluateExpressionOptions const&, llvm::StringRef, llvm::StringRef, lldb_private::SharingPtr<lldb_private::ValueObject>&, lldb_private::Status&, unsigned int, std::_*1::basic_string<char, std::1::char_traits<char>, std::1::allocator<char> >, std::*_1::shared_ptr<lldb_private::Module>) + 1361

24 LLDB 0x0000000112350bbd lldb_private::REPL::IOHandlerInputComplete(lldb_private::IOHandler&, std::_1::basic_string<char, std::1::char_traits<char>, std::_1::allocator<char> >&) + 1863

25 LLDB 0x00000001123e267e lldb_private::IOHandlerEditline::Run() + 338

26 LLDB 0x00000001122ad168 lldb_private::Debugger::ExecuteIOHandlers() + 68

27 LLDB 0x00000001122afde8 lldb_private::Debugger::IOHandlerThread(void*) + 14

28 LLDB 0x00000001124ee91b lldb_private::HostNativeThreadBase::ThreadCreateTrampoline(void*) + 105

29 libsystem_pthread.dylib 0x00007fff78b9f305 _pthread_body + 126

30 libsystem_pthread.dylib 0x00007fff78ba226f _pthread_start + 70

31 libsystem_pthread.dylib 0x00007fff78b9e415 thread_start + 13

[1] 13746 segmentation fault swift