[TypedThrow] Generic Failure Protocol Crashes

[pbk20191]

Description

I was trying to merge TaskGroup API with generic Protocol. However code is not compiled.

Reproduction

Declare Generic Failure Protocol like below CompatDiscardingTaskGroup

@usableFromInline
package protocol CompatDiscardingTaskGroup<Failure> {
    
    
    associatedtype Failure:Error = any Error
    typealias Block = @Sendable @isolated(any) () async throws(Failure) -> Void
    
    @inlinable
    var isCancelled:Bool { get }
    
    @inlinable
    var isEmpty:Bool { get }
    
    @inlinable
    func cancelAll()
    
    @inlinable
    mutating func addTaskUnlessCancelled(
        priority: TaskPriority?,
        operation: @escaping Block
    ) -> Bool
    
    @inlinable
    mutating func addTask(
        priority: TaskPriority?,
        operation: @escaping Block
    )
    
    @inlinable
    @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
    mutating func addTask(executorPreference taskExecutor: (any TaskExecutor)?, priority: TaskPriority?, operation: @escaping Block)
    
    @inlinable
    @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
    mutating func addTaskUnlessCancelled(executorPreference taskExecutor: (any TaskExecutor)?, priority: TaskPriority?, operation: @escaping Block) -> Bool
    
}

Below code block is compiled which is expected

@available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, macCatalyst 17.0, visionOS 1.0, *)
extension ThrowingDiscardingTaskGroup: CompatDiscardingTaskGroup {

}


extension ThrowingTaskGroup: CompatDiscardingTaskGroup where ChildTaskResult == Void {

}

However this code block is not compiled, and rather crash

@available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, macCatalyst 17.0, visionOS 1.0, *)
extension DiscardingTaskGroup: CompatDiscardingTaskGroup {
    @usableFromInline
    package typealias Failure = Never
}

extension TaskGroup: CompatDiscardingTaskGroup where ChildTaskResult == Void {
    @usableFromInline
    package typealias Failure = Never

    
}

Stack dump

Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0.	Program arguments: /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-frontend -frontend -emit-module -experimental-skip-non-inlinable-function-bodies-without-types /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/CompatDiscardingTaskGroup.swift /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/SafetyRegion.swift /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/Suppress.swift /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/TaskGroup.swift /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/ThrowingTaskGroup.swift /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/imp.swift -target arm64-apple-macos10.15 -Xllvm -aarch64-use-tbi -enable-objc-interop -stack-check -sdk /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk -I /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Products/Debug -I /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -F /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Products/Debug -F /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -no-color-diagnostics -enable-testing -g -debug-info-format=dwarf -dwarf-version=4 -module-cache-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -swift-version 6 -enforce-exclusivity=checked -Onone -D SWIFT_PACKAGE -D DEBUG -D Xcode -serialize-debugging-options -enable-experimental-opaque-type-erasure -const-gather-protocols-file /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup_const_extract_protocols.json -enable-experimental-feature IsolatedAny -enable-experimental-feature DebugDescriptionMacro -enable-upcoming-feature FullTypedThrows -empty-abi-descriptor -plugin-path /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/host/plugins/testing -validate-clang-modules-once -clang-build-session-file /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -Xcc -working-directory -Xcc /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/.swiftpm/xcode -resource-dir /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift -enable-anonymous-context-mangled-names -file-compilation-dir /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/.swiftpm/xcode -Xcc -ivfsstatcache -Xcc /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/SDKStatCaches.noindex/macosx15.0-24A5264i-495167fbbdaa9fb73ea1f786c83da506.sdkstatcache -Xcc -I/Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/swift-overrides.hmap -Xcc -I/Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Products/Debug/include -Xcc -I/Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/DerivedSources-normal/arm64 -Xcc -I/Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/DerivedSources/arm64 -Xcc -I/Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/DerivedSources -Xcc -DSWIFT_PACKAGE -Xcc -DDEBUG=1 -module-name BackportDiscardingTaskGroup -package-name tetra -disable-clang-spi -target-sdk-version 15.0 -target-sdk-name macosx15.0 -external-plugin-path /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib/swift/host/plugins#/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/local/lib/swift/host/plugins#/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -plugin-path /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/local/lib/swift/host/plugins -emit-module-doc-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup.swiftdoc -emit-module-source-info-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup.swiftsourceinfo -emit-objc-header-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup-Swift.h -serialize-diagnostics-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup-master-emit-module.dia -emit-dependencies-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup-master-emit-module.d -o /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup.swiftmodule -emit-abi-descriptor-path /Users/bagbyeong-gwan/Library/Developer/Xcode/DerivedData/Tetra-eoeesywducengtdmcmtvnsxowdrs/Build/Intermediates.noindex/Tetra.build/Debug/BackportDiscardingTaskGroup.build/Objects-normal/arm64/BackportDiscardingTaskGroup.abi.json
1.	Apple Swift version 6.0 (swiftlang-6.0.0.3.300 clang-1600.0.20.10)
2.	Compiling with the current language version
3.	While evaluating request ASTLoweringRequest(Lowering AST to SIL for module BackportDiscardingTaskGroup)
4.	While generating SIL witness table protocol conformance TaskGroup<ChildTaskResult>: CompatDiscardingTaskGroup at extension of TaskGroup (at /Users/bagbyeong-gwan/IDE/XcodeWorkSpace/Tetra/Sources/BackportDiscardingTaskGroup/imp.swift:13:1)
5.	While generating protocol witness thunk SIL function "@$sScGyxG27BackportDiscardingTaskGroup06CompatbcD0ABytRszrlAbCP03addC15UnlessCancelled8priority9operationSbScPSg_yyYaYb7FailureQzYKYActFTW".
 for 'addTaskUnlessCancelled(priority:operation:)' (in module '_Concurrency')
6.	While emitting reabstraction thunk in SIL function "@$ss5NeverOIeAghHzr_ytIeAghHr_TR".
 for <<debugloc at "<compiler-generated>":0:0>>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           0x00000001084b2cd0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x00000001084b0f44 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x00000001084b32d8 SignalHandler(int) + 352
3  libsystem_platform.dylib 0x00000001a01d0184 _sigtramp + 56
4  swift-frontend           0x00000001038a30f0 swift::Lowering::SILGenFunction::emitApplyWithRethrow(swift::SILLocation, swift::SILValue, swift::SILType, swift::SubstitutionMap, llvm::ArrayRef<swift::SILValue>) + 2268
5  swift-frontend           0x0000000103991334 buildThunkBody(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::CanTypeWrapper<swift::SILFunctionType>, swift::CanType, llvm::function_ref<void (swift::Lowering::SILGenFunction&)>) + 1988
6  swift-frontend           0x00000001039930dc createThunk(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::ManagedValue, swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::Lowering::TypeLowering const&) + 3672
7  swift-frontend           0x00000001039886b8 (anonymous namespace)::Transform::transform(swift::Lowering::ManagedValue, swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType, swift::SILType, swift::Lowering::SGFContext) + 1712
8  swift-frontend           0x00000001039960f0 (anonymous namespace)::TranslateArguments::processSingle(swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::ManagedValue, (anonymous namespace)::ParamInfo) + 276
9  swift-frontend           0x0000000103993aa8 (anonymous namespace)::ExpanderBase<(anonymous namespace)::TranslateArguments, (anonymous namespace)::ParamInfo>::expand(swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType) + 600
10 swift-frontend           0x000000010399c9a8 (anonymous namespace)::TranslateArguments::expandParam(swift::Lowering::AbstractionPattern, swift::AnyFunctionType::CanParam, swift::Lowering::AbstractionPattern, swift::AnyFunctionType::CanParam) + 352
11 swift-frontend           0x000000010398c808 (anonymous namespace)::TranslateArguments::process(swift::Lowering::AbstractionPattern, swift::ArrayRefView<swift::AnyFunctionType::Param, swift::AnyFunctionType::CanParam, swift::AnyFunctionType::CanParam::getFromParam(swift::AnyFunctionType::Param const&), true>, swift::Lowering::AbstractionPattern, swift::ArrayRefView<swift::AnyFunctionType::Param, swift::AnyFunctionType::CanParam, swift::AnyFunctionType::CanParam::getFromParam(swift::AnyFunctionType::Param const&), true>, bool) + 4724
12 swift-frontend           0x000000010398f5c0 swift::Lowering::SILGenFunction::emitProtocolWitness(swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::AnyFunctionType>, swift::SILDeclRef, swift::SubstitutionMap, swift::SILDeclRef, swift::SubstitutionMap, swift::Lowering::IsFreeFunctionWitness_t, bool, bool, std::__1::optional<swift::ActorIsolation>) + 3512
13 swift-frontend           0x00000001039c3e8c swift::Lowering::SILGenModule::emitProtocolWitness(swift::ProtocolConformanceRef, swift::SILLinkage, swift::IsSerialized_t, swift::SILDeclRef, swift::SILDeclRef, swift::Lowering::IsFreeFunctionWitness_t, swift::Witness) + 4272
14 swift-frontend           0x00000001039c6da4 (anonymous namespace)::SILGenWitnessTable<(anonymous namespace)::SILGenConformance>::addMethodImplementation(swift::SILDeclRef, swift::SILDeclRef, swift::Witness) + 376
15 swift-frontend           0x00000001039c67a8 (anonymous namespace)::SILGenWitnessTable<(anonymous namespace)::SILGenConformance>::addMethod(swift::SILDeclRef) + 780
16 swift-frontend           0x00000001039c62ac swift::SILWitnessVisitor<(anonymous namespace)::SILGenConformance>::visitProtocolDecl(swift::ProtocolDecl*) + 1920
17 swift-frontend           0x00000001039c29e4 swift::Lowering::SILGenModule::getWitnessTable(swift::NormalProtocolConformance*) + 548
18 swift-frontend           0x00000001039c5a40 SILGenExtension::emitExtension(swift::ExtensionDecl*) + 880
19 swift-frontend           0x0000000103891118 swift::ASTVisitor<swift::Lowering::SILGenModule, void, void, void, void, void, void>::visit(swift::Decl*) + 264
20 swift-frontend           0x0000000103897200 swift::ASTLoweringRequest::evaluate(swift::Evaluator&, swift::ASTLoweringDescriptor) const + 1804
21 swift-frontend           0x00000001039aee68 swift::SimpleRequest<swift::ASTLoweringRequest, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>> (swift::ASTLoweringDescriptor), (swift::RequestFlags)9>::evaluateRequest(swift::ASTLoweringRequest const&, swift::Evaluator&) + 196
22 swift-frontend           0x000000010389c0f4 swift::ASTLoweringRequest::OutputType swift::Evaluator::getResultUncached<swift::ASTLoweringRequest, swift::ASTLoweringRequest::OutputType swift::evaluateOrFatal<swift::ASTLoweringRequest>(swift::Evaluator&, swift::ASTLoweringRequest)::'lambda'()>(swift::ASTLoweringRequest const&, swift::ASTLoweringRequest::OutputType swift::evaluateOrFatal<swift::ASTLoweringRequest>(swift::Evaluator&, swift::ASTLoweringRequest)::'lambda'()) + 524
23 swift-frontend           0x0000000102e7d6a8 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2484
24 swift-frontend           0x0000000102e81468 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 1672
25 swift-frontend           0x0000000102e7f438 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 4752
26 swift-frontend           0x0000000102e052d8 swift::mainEntry(int, char const**) + 2812
27 dyld                     0x000000019fe19298 start + 2876
Command SwiftEmitModule failed with a nonzero exit code

Expected behavior

Code should compile. Since Failure type is very obvious in this case( Never and any Error)

Environment

• xcode beta swift 6
• swift 6 2024-06-18

Additional information

No response