Compiler crashes when calling assumeIsolated on an actor instance that is a parameterized protocol type where the parameter is generic

[TheHarcker]

Description

The swift compiler crashes when compiling the snippet below.

Reproduction

protocol A<B>: Actor {
    associatedtype B
}

func someGenericContext<C>(a: any A<C>) {
    a.assumeIsolated { _ in true }
}

Stack dump

0.	Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-frontend -frontend -c -primary-file Sources/POC-Swift-crash/POC_Swift_crash.swift -target arm64-apple-macosx15.0 -Xllvm -aarch64-use-tbi -enable-objc-interop -stack-check -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk -color-diagnostics -new-driver-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-driver -empty-abi-descriptor -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift -module-name POC_Swift_crash -disable-clang-spi -target-sdk-version 15.2 -target-sdk-name macosx15.2 -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/local/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -plugin-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/local/lib/swift/host/plugins -o /var/folders/br/_96cjb497ngb81vl5_zn5rz80000gn/T/TemporaryDirectory.5lCu06/POC_Swift_crash-1.o
1.	Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
2.	Compiling with effective version 5.10
3.	While evaluating request ASTLoweringRequest(Lowering AST to SIL for file "Sources/POC-Swift-crash/POC_Swift_crash.swift")
4.	While silgen emitFunction SIL function "@$s15POC_Swift_crash18someGenericContext1ayAA1A_px1BRts_XP_tlF".
 for 'someGenericContext(a:)' (at Sources/POC-Swift-crash/POC_Swift_crash.swift:5:1)
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           0x0000000109f16a9c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x0000000109f14cf0 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x0000000109f17068 SignalHandler(int) + 292
3  libsystem_platform.dylib 0x0000000188bf2e04 _sigtramp + 56
4  swift-frontend           0x0000000105f9e33c swift::Mangle::ASTMangler::appendRequirement(swift::Requirement const&, swift::GenericSignature, bool) + 136
5  swift-frontend           0x0000000105f9e33c swift::Mangle::ASTMangler::appendRequirement(swift::Requirement const&, swift::GenericSignature, bool) + 136
6  swift-frontend           0x0000000105f9c800 swift::Mangle::ASTMangler::appendGenericSignatureParts(swift::GenericSignature, swift::Mangle::ASTMangler::GenericSignatureParts const&) + 196
7  swift-frontend           0x0000000105f8f400 swift::Mangle::ASTMangler::appendGenericSignature(swift::GenericSignature) + 168
8  swift-frontend           0x0000000105f9100c swift::Mangle::ASTMangler::mangleReabstractionThunkHelper(swift::CanTypeWrapper<swift::SILFunctionType>, swift::Type, swift::Type, swift::Type, swift::Type, swift::ModuleDecl*) + 200
9  swift-frontend           0x000000010542297c swift::Lowering::SILGenModule::getOrCreateReabstractionThunk(swift::CanTypeWrapper<swift::SILFunctionType>, swift::CanTypeWrapper<swift::SILFunctionType>, swift::CanTypeWrapper<swift::SILFunctionType>, swift::CanType, swift::CanType) + 1216
10 swift-frontend           0x00000001053f9054 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&) + 3472
11 swift-frontend           0x00000001053ee8fc (anonymous namespace)::Transform::transform(swift::Lowering::ManagedValue, swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType, swift::SILType, swift::Lowering::SGFContext) + 1700
12 swift-frontend           0x000000010533f7a4 swift::Lowering::Conversion::emit(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::ManagedValue, swift::Lowering::SGFContext) const + 472
13 swift-frontend           0x000000010533f278 swift::Lowering::SILGenFunction::emitConvertedRValue(swift::SILLocation, swift::Lowering::Conversion const&, swift::Lowering::SGFContext, llvm::function_ref<swift::Lowering::ManagedValue (swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::SGFContext)>) + 384
14 swift-frontend           0x000000010533f43c swift::Lowering::ConvertingInitialization::tryPeephole(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::Conversion, llvm::function_ref<swift::Lowering::ManagedValue (swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::SGFContext)>) + 360
15 swift-frontend           0x000000010533f198 swift::Lowering::SILGenFunction::emitConvertedRValue(swift::SILLocation, swift::Lowering::Conversion const&, swift::Lowering::SGFContext, llvm::function_ref<swift::Lowering::ManagedValue (swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::SGFContext)>) + 160
16 swift-frontend           0x0000000105376bc8 (anonymous namespace)::RValueEmitter::visitFunctionConversionExpr(swift::FunctionConversionExpr*, swift::Lowering::SGFContext) + 2000
17 swift-frontend           0x000000010535f58c swift::Lowering::SILGenFunction::emitRValueAsSingleValue(swift::Expr*, swift::Lowering::SGFContext) + 40
18 swift-frontend           0x000000010533f234 swift::Lowering::SILGenFunction::emitConvertedRValue(swift::SILLocation, swift::Lowering::Conversion const&, swift::Lowering::SGFContext, llvm::function_ref<swift::Lowering::ManagedValue (swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::SGFContext)>) + 316
19 swift-frontend           0x00000001052bee74 swift::Lowering::ArgumentSource::getConverted(swift::Lowering::SILGenFunction&, swift::Lowering::Conversion const&, swift::Lowering::SGFContext) && + 136
20 swift-frontend           0x00000001052fe25c (anonymous namespace)::ArgEmitter::emit(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, std::__1::optional<swift::AnyFunctionType::Param>) + 5528
21 swift-frontend           0x00000001052ec0f0 (anonymous namespace)::ArgEmitter::emitSingleArg(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, std::__1::optional<swift::AnyFunctionType::Param>) + 216
22 swift-frontend           0x00000001052fc9ac (anonymous namespace)::ArgEmitter::emitPreparedArgs(swift::Lowering::PreparedArguments&&, swift::Lowering::AbstractionPattern) + 256
23 swift-frontend           0x0000000105308878 (anonymous namespace)::CallSite::emit(swift::Lowering::SILGenFunction&, swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::SILFunctionType>, (anonymous namespace)::ParamLowering&, llvm::SmallVectorImpl<swift::Lowering::ManagedValue>&, llvm::SmallVectorImpl<(anonymous namespace)::DelayedArgument>&, swift::ForeignInfo const&) && + 664
24 swift-frontend           0x0000000105308298 (anonymous namespace)::CallEmission::emitArgumentsForNormalApply(swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::SILFunctionType>, swift::ForeignInfo const&, llvm::SmallVectorImpl<swift::Lowering::ManagedValue>&, std::__1::optional<swift::SILLocation>&) + 1000
25 swift-frontend           0x00000001052f0e7c (anonymous namespace)::CallEmission::apply(swift::Lowering::SGFContext) + 2028
26 swift-frontend           0x00000001052ef408 swift::Lowering::SILGenFunction::emitApplyExpr(swift::ApplyExpr*, swift::Lowering::SGFContext) + 3116
27 swift-frontend           0x0000000105385390 void llvm::function_ref<void (swift::Expr*)>::callback_fn<swift::Lowering::RValue swift::Lowering::SILGenFunction::emitOpenExistentialExpr<swift::Lowering::RValue, (anonymous namespace)::RValueEmitter::visitOpenExistentialExpr(swift::OpenExistentialExpr*, swift::Lowering::SGFContext)::$_0>(swift::OpenExistentialExpr*, (anonymous namespace)::RValueEmitter::visitOpenExistentialExpr(swift::OpenExistentialExpr*, swift::Lowering::SGFContext)::$_0)::'lambda'(swift::Expr*)>(long, swift::Expr*) + 36
28 swift-frontend           0x00000001053693e4 swift::Lowering::SILGenFunction::emitOpenExistentialExprImpl(swift::OpenExistentialExpr*, llvm::function_ref<void (swift::Expr*)>) + 812
29 swift-frontend           0x0000000105375894 (anonymous namespace)::RValueEmitter::visitOpenExistentialExpr(swift::OpenExistentialExpr*, swift::Lowering::SGFContext) + 272
30 swift-frontend           0x000000010535fc74 swift::Lowering::SILGenFunction::emitIgnoredExpr(swift::Expr*) + 888
31 swift-frontend           0x0000000105417274 swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 5512
32 swift-frontend           0x000000010538efc8 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 492
33 swift-frontend           0x00000001052dab1c swift::Lowering::SILGenModule::emitFunctionDefinition(swift::SILDeclRef, swift::SILFunction*) + 8420
34 swift-frontend           0x00000001052db3bc swift::Lowering::SILGenModule::emitOrDelayFunction(swift::SILDeclRef) + 216
35 swift-frontend           0x00000001052d89ec swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 364
36 swift-frontend           0x00000001052df038 swift::ASTLoweringRequest::evaluate(swift::Evaluator&, swift::ASTLoweringDescriptor) const + 1804
37 swift-frontend           0x000000010541592c 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
38 swift-frontend           0x00000001052e3f14 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'()) + 528
39 swift-frontend           0x00000001048bdb90 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 920
40 swift-frontend           0x00000001048c0e88 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 1684
41 swift-frontend           0x00000001048bfbb4 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 3572
42 swift-frontend           0x0000000104846a5c swift::mainEntry(int, char const**) + 3680
43 dyld                     0x000000018883c274 start + 2840

Expected behavior

I expected the code to compile successfully.

Environment

swift-driver version: 1.115.1 Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
Target: arm64-apple-macosx15.0

Additional information

No response

[bc-lee]

Not reproducible on swift-6.1-DEVELOPMENT-SNAPSHOT-2025-01-03-a or swift-DEVELOPMENT-SNAPSHOT-2025-01-03-a. It seems to have been fixed.

[TheHarcker]

When using the latest toolchains (swift-6.1-DEVELOPMENT-SNAPSHOT-2025-01-17-a and swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a) , I'm also unable to reproduce the crash.