The compiler crashes when actor has borrowing func that contains nested @Sendable func involving self.

[YOCKOW]

Description

The code below induces a compiler crash with the message:

• swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a: "Assertion failed: (!ActorIso), function emitUsingCoroutineAccessor, file SILGenLValue.cpp"
• Swift 6.0.3: "Unhandled SIL Instruction: hop_to_executor %5 : $MyValue // id: %11"

(Needless to say, the code is just a reproducer which is non-sense and probably invalid.)

Reproduction

actor MyValue<T> where T: Sendable & ~Copyable {
  var value: T

  init(_ value: consuming T) {
    self.value = value
  }

  private func _setValue(_ newValue: consuming T) {
    self.value = newValue
  }

  borrowing func withValue() async {
    @Sendable func __nestedSendableFunction() async {
      await self._setValue(self.value)
    }
    await __nestedSendableFunction()
  }
}

Stack dump

swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a

Assertion failed: (!ActorIso), function emitUsingCoroutineAccessor, file SILGenLValue.cpp, line 4030.
Stack dump:
0.	Program arguments: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/bin/swift-frontend -frontend -interpret _borrowing-actor_.swift -Xllvm -aarch64-use-tbi -enable-objc-interop -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk -color-diagnostics -empty-abi-descriptor -resource-dir /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift -module-name main -in-process-plugin-server-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift/host/libSwiftInProcPluginServer.dylib -plugin-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/local/lib/swift/host/plugins -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
1.	Apple Swift version 6.2-dev (LLVM 81859ac55f8d09a, Swift 8ec8a1229a7ea14)
2.	Compiling with effective version 5.10
3.	While evaluating request ASTLoweringRequest(Lowering AST to SIL for module main)
4.	While silgen emitFunction SIL function "@$s4main7MyValueCAARi_zrlE04withC0yyYaF".
 for 'withValue()' (at _borrowing-actor_.swift:12:13)
5.	While silgen emitFunction SIL function "@$s4main7MyValueCAARi_zrlE04withC0yyYaF24__nestedSendableFunctionL_yyYaYbs0F0RzRi_zlF".
 for '__nestedSendableFunction()' (at _borrowing-actor_.swift:13:15)
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           0x000000010b0edf60 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x000000010b0ec644 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x000000010b0ee5bc SignalHandler(int) + 304
3  libsystem_platform.dylib 0x000000018fe22e04 _sigtramp + 56
4  libsystem_pthread.dylib  0x000000018fdebf70 pthread_kill + 288
5  libsystem_c.dylib        0x000000018fcf8908 abort + 128
6  libsystem_c.dylib        0x000000018fcf7c1c err + 0
7  swift-frontend           0x000000010b223bf0 (anonymous namespace)::LogicalKeyPathApplicationComponent::set(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::ArgumentSource&&, swift::Lowering::ManagedValue) && (.cold.1) + 0
8  swift-frontend           0x000000010595ddc0 (anonymous namespace)::AccessEmitter<swift::Lowering::LValue::addMemberVarComponent(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::VarDecl*, swift::SubstitutionMap, swift::Lowering::LValueOptions, bool, swift::Lowering::SGFAccessKind, swift::AccessStrategy, swift::CanType, bool, std::__1::optional<swift::ActorIsolation>)::MemberVarAccessEmitter, swift::VarDecl>::emitUsingAccessor(swift::AccessorKind, bool) + 1108
9  swift-frontend           0x000000010594905c swift::Lowering::LValue::addMemberVarComponent(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::VarDecl*, swift::SubstitutionMap, swift::Lowering::LValueOptions, bool, swift::Lowering::SGFAccessKind, swift::AccessStrategy, swift::CanType, bool, std::__1::optional<swift::ActorIsolation>) + 620
10 swift-frontend           0x000000010594e1f4 SILGenLValue::visitMemberRefExpr(swift::MemberRefExpr*, swift::Lowering::SGFAccessKind, swift::Lowering::LValueOptions) + 924
11 swift-frontend           0x000000010594a144 swift::Lowering::SILGenFunction::emitLValue(swift::Expr*, swift::Lowering::SGFAccessKind, swift::Lowering::LValueOptions) + 56
12 swift-frontend           0x00000001058b5358 (anonymous namespace)::ArgEmitter::emit(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, bool, std::__1::optional<swift::AnyFunctionType::Param>) + 2312
13 swift-frontend           0x00000001058a6644 (anonymous namespace)::ArgEmitter::emitSingleArg(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, bool, std::__1::optional<swift::AnyFunctionType::Param>) + 320
14 swift-frontend           0x00000001058b3eec (anonymous namespace)::ArgEmitter::emitPreparedArgs(swift::Lowering::PreparedArguments&&, swift::Lowering::AbstractionPattern) + 220
15 swift-frontend           0x00000001058bf308 (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&) && + 532
16 swift-frontend           0x00000001058beb68 (anonymous namespace)::CallEmission::emitArgumentsForNormalApply(swift::Lowering::AbstractionPattern, swift::CanTypeWrapper<swift::SILFunctionType>, swift::ForeignInfo const&, llvm::SmallVectorImpl<swift::Lowering::ManagedValue>&, std::__1::optional<swift::SILLocation>&) + 1052
17 swift-frontend           0x00000001058aa0c4 (anonymous namespace)::CallEmission::apply(swift::Lowering::SGFContext) + 1800
18 swift-frontend           0x00000001058a8744 swift::Lowering::SILGenFunction::emitApplyExpr(swift::ApplyExpr*, swift::Lowering::SGFContext) + 2028
19 swift-frontend           0x0000000105908060 swift::Lowering::SILGenFunction::emitIgnoredExpr(swift::Expr*) + 912
20 swift-frontend           0x000000010599e98c swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 4288
21 swift-frontend           0x000000010599d8c0 swift::Lowering::SILGenFunction::emitStmt(swift::Stmt*) + 24
22 swift-frontend           0x000000010592b550 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 436
23 swift-frontend           0x0000000105896040 swift::Lowering::SILGenModule::emitFunctionDefinition(swift::SILDeclRef, swift::SILFunction*) + 6124
24 swift-frontend           0x0000000105897254 swift::Lowering::SILGenModule::emitOrDelayFunction(swift::SILDeclRef) + 268
25 swift-frontend           0x000000010589481c swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 184
26 swift-frontend           0x000000010599e900 swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 4148
27 swift-frontend           0x000000010599d8c0 swift::Lowering::SILGenFunction::emitStmt(swift::Stmt*) + 24
28 swift-frontend           0x000000010592b550 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 436
29 swift-frontend           0x0000000105896040 swift::Lowering::SILGenModule::emitFunctionDefinition(swift::SILDeclRef, swift::SILFunction*) + 6124
30 swift-frontend           0x0000000105897254 swift::Lowering::SILGenModule::emitOrDelayFunction(swift::SILDeclRef) + 268
31 swift-frontend           0x000000010589481c swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 184
32 swift-frontend           0x00000001059b2940 (anonymous namespace)::SILGenType::visitFuncDecl(swift::FuncDecl*) + 28
33 swift-frontend           0x00000001059af8f8 (anonymous namespace)::SILGenType::emitType() + 276
34 swift-frontend           0x00000001059af7d8 swift::Lowering::SILGenModule::visitNominalTypeDecl(swift::NominalTypeDecl*) + 24
35 swift-frontend           0x00000001058999f8 swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*) + 176
36 swift-frontend           0x0000000105899f14 swift::ASTLoweringRequest::evaluate(swift::Evaluator&, swift::ASTLoweringDescriptor) const + 632
37 swift-frontend           0x000000010599d280 swift::SimpleRequest<swift::ASTLoweringRequest, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>> (swift::ASTLoweringDescriptor), (swift::RequestFlags)17>::evaluateRequest(swift::ASTLoweringRequest const&, swift::Evaluator&) + 148
38 swift-frontend           0x000000010589f424 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'()) + 340
39 swift-frontend           0x000000010589a294 swift::performASTLowering(swift::ModuleDecl*, swift::Lowering::TypeConverter&, swift::SILOptions const&, swift::IRGenOptions const*) + 144
40 swift-frontend           0x000000010523591c swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 1184
41 swift-frontend           0x00000001052416a4 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) + 160
42 swift-frontend           0x0000000105237418 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 716
43 swift-frontend           0x0000000105236c34 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2208
44 swift-frontend           0x0000000104fe91b8 swift::mainEntry(int, char const**) + 3100
45 dyld                     0x000000018fa6c274 start + 2840

Swift 6.0.3

Unhandled SIL Instruction:   hop_to_executor %5 : $MyValue<T>                // id: %11
Stack dump:
0.	Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-frontend -frontend -interpret _borrowing-actor_.swift -Xllvm -aarch64-use-tbi -enable-objc-interop -stack-check -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk -color-diagnostics -new-driver-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-driver -empty-abi-descriptor -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift -module-name main -disable-clang-spi -target-sdk-version 15.2 -target-sdk-name macosx15.2 -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/local/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -plugin-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/local/lib/swift/host/plugins
1.	Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
2.	Compiling with effective version 5.10
3.	While evaluating request ExecuteSILPipelineRequest(Run pipelines { Mandatory Diagnostic Passes + Enabling Optimization Passes } on SIL for main)
4.	While running pass #247 SILFunctionTransform "MoveOnlyTypeEliminator" on SILFunction "@$s4main7MyValueCAARi_zrlE04withC0yyYaF24__nestedSendableFunctionL_yyYaYbs0F0RzRi_zlF".
 for '__nestedSendableFunction()' (at _borrowing-actor_.swift:13:15)
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           0x000000010a37ea9c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x000000010a37ccf0 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x000000010a37f068 SignalHandler(int) + 292
3  libsystem_platform.dylib 0x000000018fe22e04 _sigtramp + 56
4  swift-frontend           0x0000000105b5d708 swift::SILInstructionVisitor<(anonymous namespace)::SILMoveOnlyWrappedTypeEliminatorVisitor, bool>::visitAllocPackInst(swift::AllocPackInst*) + 40
5  swift-frontend           0x0000000105b5d108 (anonymous namespace)::SILMoveOnlyWrappedTypeEliminatorPass::run() + 6056
6  swift-frontend           0x0000000105b69b74 swift::SILPassManager::runFunctionPasses(unsigned int, unsigned int) + 3448
7  swift-frontend           0x0000000105b66158 swift::SILPassManager::executePassPipelinePlan(swift::SILPassPipelinePlan const&) + 11968
8  swift-frontend           0x0000000105b9f6a4 swift::SimpleRequest<swift::ExecuteSILPipelineRequest, std::__1::tuple<> (swift::SILPipelineExecutionDescriptor), (swift::RequestFlags)1>::evaluateRequest(swift::ExecuteSILPipelineRequest const&, swift::Evaluator&) + 56
9  swift-frontend           0x0000000105b83008 swift::ExecuteSILPipelineRequest::OutputType swift::Evaluator::getResultUncached<swift::ExecuteSILPipelineRequest, swift::ExecuteSILPipelineRequest::OutputType swift::evaluateOrFatal<swift::ExecuteSILPipelineRequest>(swift::Evaluator&, swift::ExecuteSILPipelineRequest)::'lambda'()>(swift::ExecuteSILPipelineRequest const&, swift::ExecuteSILPipelineRequest::OutputType swift::evaluateOrFatal<swift::ExecuteSILPipelineRequest>(swift::Evaluator&, swift::ExecuteSILPipelineRequest)::'lambda'()) + 412
10 swift-frontend           0x0000000105b85784 swift::runSILDiagnosticPasses(swift::SILModule&) + 612
11 swift-frontend           0x00000001050fc0e4 swift::CompilerInstance::performSILProcessing(swift::SILModule*) + 84
12 swift-frontend           0x0000000104d269c4 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 1376
13 swift-frontend           0x0000000104d26340 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2888
14 swift-frontend           0x0000000104d29374 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2944
15 swift-frontend           0x0000000104d27bb4 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 3572
16 swift-frontend           0x0000000104caea5c swift::mainEntry(int, char const**) + 3680
17 dyld                     0x000000018fa6c274 start + 2840

Expected behavior

The compiler emits a warning or an error. (Or compiles successfully?)

Environment

Apple Swift version 6.2-dev (LLVM 81859ac55f8d09a, Swift 8ec8a1229a7ea14)
Target: arm64-apple-macosx15.0

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