withoutActuallyEscaping with sending @escaping causes crash

[ph1ps]

Description

This is pretty much a non-sensical use case. On accident, I tried to use an already @escaping closure in withoutActuallyEscaping. The crash does not happen with non-sending @escaping closures.

Reproduction

func send(
    operation: sending @escaping () async -> Void
) async {
  _ = await withoutActuallyEscaping(operation) { escapingClosure in
    await Task {
      await escapingClosure()
    }.value
  }
}

Stack dump

Stack dump:
0.	Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-frontend -frontend -interpret main.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 -swift-version 6 -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 the current language version
3.	While evaluating request ASTLoweringRequest(Lowering AST to SIL for module main)
4.	While silgen emitFunction SIL function "@$s4main4send9operationyyyYacn_tYaF".
 for 'send(operation:)' (at main.swift:1:1)
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           0x000000010a696a9c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x000000010a694cf0 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x000000010a697068 SignalHandler(int) + 292
3  libsystem_platform.dylib 0x0000000195daee04 _sigtramp + 56
4  swift-frontend           0x0000000105941770 (anonymous namespace)::TypeClassifierBase<(anonymous namespace)::LowerType, swift::Lowering::TypeLowering*>::visit(swift::CanType, swift::Lowering::AbstractionPattern, swift::Lowering::IsTypeExpansionSensitive_t) + 56
5  swift-frontend           0x00000001059415b4 swift::Lowering::TypeConverter::getTypeLowering(swift::Lowering::AbstractionPattern, swift::Type, swift::TypeExpansionContext) + 668
6  swift-frontend           0x0000000105b3ae3c swift::Lowering::SILGenFunction::emitRValueForNonMemberVarDecl(swift::SILLocation, swift::ConcreteDeclRef, swift::CanType, swift::AccessSemantics, swift::Lowering::SGFContext) + 1844
7  swift-frontend           0x0000000105af597c (anonymous namespace)::RValueEmitter::visitMakeTemporarilyEscapableExpr(swift::MakeTemporarilyEscapableExpr*, swift::Lowering::SGFContext) + 64
8  swift-frontend           0x0000000105adfc74 swift::Lowering::SILGenFunction::emitIgnoredExpr(swift::Expr*) + 888
9  swift-frontend           0x0000000105aff53c (anonymous namespace)::RValueEmitter::visitAssignExpr(swift::AssignExpr*, swift::Lowering::SGFContext) + 568
10 swift-frontend           0x0000000105adfc74 swift::Lowering::SILGenFunction::emitIgnoredExpr(swift::Expr*) + 888
11 swift-frontend           0x0000000105b97274 swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 5512
12 swift-frontend           0x0000000105b0efc8 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 492
13 swift-frontend           0x0000000105a5ab1c swift::Lowering::SILGenModule::emitFunctionDefinition(swift::SILDeclRef, swift::SILFunction*) + 8420
14 swift-frontend           0x0000000105a5b3bc swift::Lowering::SILGenModule::emitOrDelayFunction(swift::SILDeclRef) + 216
15 swift-frontend           0x0000000105a589ec swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 364
16 swift-frontend           0x0000000105a5f038 swift::ASTLoweringRequest::evaluate(swift::Evaluator&, swift::ASTLoweringDescriptor) const + 1804
17 swift-frontend           0x0000000105b9592c 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
18 swift-frontend           0x0000000105a63f14 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
19 swift-frontend           0x000000010503e304 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2828
20 swift-frontend           0x0000000105041374 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2944
21 swift-frontend           0x000000010503fbb4 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 3572
22 swift-frontend           0x0000000104fc6a5c swift::mainEntry(int, char const**) + 3680
23 dyld                     0x00000001959f8274 start + 2840
zsh: trace trap  swift -swift-version 6 main.swift

Expected behavior

Firstly, I'd expect this to not crash. But secondly, I don't know what else to expect. Maybe a compiler warning or error that you are passing an @escaping closure to withoutActuallyEscaping, which does not make sense.

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