Escaping closure taking a `Self` value of a class type crashes the compiler

[fwcd]

Describe the bug The following program crashes the compiler:

class X {
    static func doStuff(continuation: @escaping (Self) -> Void) {}

    static func doStuff() async throws -> Self {
        try await withCheckedThrowingContinuation { continuation in
            doStuff { value in
                continuation.resume(returning: value)
            }
        }
    }
}

Compiling throws the following stack trace (click below to expand):

``` error: compile command failed due to signal 6 (use -v to see invocation) Assertion failed: (SelfValue && "no local self metadata"), function getDynamicSelfMetadata, file GenHeap.cpp, line 1778. Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the project and the crash backtrace. Stack dump: 0. Program arguments: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2022-08-29-a.xctoolchain/usr/bin/swift-frontend -frontend -c -primary-file self-class-crash.swift -target arm64-apple-macosx12.0 -Xllvm -aarch64-use-tbi -enable-objc-interop -color-diagnostics -new-driver-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2022-08-29-a.xctoolchain/usr/bin/swift-driver -empty-abi-descriptor -resource-dir /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2022-08-29-a.xctoolchain/usr/lib/swift -module-name main -o /var/folders/k2/hxsy4q4x32x_m8_3qj04sdv80000gn/T/TemporaryDirectory.6IAxjn/self-class-crash-1.o 1. Apple Swift version 5.8-dev (LLVM 03bd949eeee4761, Swift 2c40a850df6f409) 2. Compiling with the current language version 3. While evaluating request IRGenRequest(IR Generation for file "self-class-crash.swift") 4. While emitting IR SIL function "@$s4main1XC7doStuffACXDyYaKFZyScCyACXDs5Error_pGXEfU_". for expression at [self-class-crash.swift:5:51 - line:9:9] RangeText="{ continuation in doStuff { value in continuation.resume(returning: value) } " 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 0x00000001093ef78c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56 1 swift-frontend 0x00000001093eea10 llvm::sys::RunSignalHandlers() + 128 2 swift-frontend 0x00000001093efdcc SignalHandler(int) + 304 3 libsystem_platform.dylib 0x000000018156f4a4 _sigtramp + 56 4 libsystem_pthread.dylib 0x0000000181557ee0 pthread_kill + 288 5 libsystem_c.dylib 0x0000000181492340 abort + 168 6 libsystem_c.dylib 0x0000000181491754 err + 0 7 swift-frontend 0x00000001094aa790 swift::irgen::IRGenFunction::getDynamicSelfMetadata() (.cold.2) + 0 8 swift-frontend 0x0000000104ee5bd0 swift::irgen::IRGenFunction::getDynamicSelfMetadata() + 392 9 swift-frontend 0x0000000104fec2a0 swift::CanTypeVisitor<(anonymous namespace)::EmitTypeMetadataRef, swift::irgen::MetadataResponse, swift::irgen::DynamicMetadataRequest>::visit(swift::CanType, swift::irgen::DynamicMetadataRequest) + 1788 10 swift-frontend 0x0000000104fe9760 swift::irgen::IRGenFunction::emitTypeMetadataRef(swift::CanType, swift::irgen::DynamicMetadataRequest) + 536 11 swift-frontend 0x0000000104feead8 swift::irgen::GenericArguments::collect(swift::irgen::IRGenFunction&, swift::SubstitutionMap)::'lambda'(unsigned int, swift::CanType, swift::ProtocolConformanceRef)::operator()(unsigned int, swift::CanType, swift::ProtocolConformanceRef) const + 124 12 swift-frontend 0x0000000104f260b0 swift::irgen::GenericTypeRequirements::enumerateFulfillments(swift::irgen::IRGenModule&, swift::SubstitutionMap, llvm::function_ref) + 244 13 swift-frontend 0x0000000104fee9f0 swift::irgen::GenericArguments::collect(swift::irgen::IRGenFunction&, swift::SubstitutionMap) + 112 14 swift-frontend 0x0000000104fee444 emitNominalMetadataRef(swift::irgen::IRGenFunction&, swift::NominalTypeDecl*, swift::CanType, swift::irgen::DynamicMetadataRequest) + 320 15 swift-frontend 0x0000000104feebf8 (anonymous namespace)::EmitTypeMetadataRef::visitBoundGenericType(swift::CanTypeWrapper, swift::irgen::DynamicMetadataRequest) + 148 16 swift-frontend 0x0000000104fec18c swift::CanTypeVisitor<(anonymous namespace)::EmitTypeMetadataRef, swift::irgen::MetadataResponse, swift::irgen::DynamicMetadataRequest>::visit(swift::CanType, swift::irgen::DynamicMetadataRequest) + 1512 17 swift-frontend 0x0000000104fe9760 swift::irgen::IRGenFunction::emitTypeMetadataRef(swift::CanType, swift::irgen::DynamicMetadataRequest) + 536 18 swift-frontend 0x0000000104fe9dd4 swift::irgen::IRGenFunction::emitTypeMetadataRefForLayout(swift::SILType, swift::irgen::DynamicMetadataRequest) + 284 19 swift-frontend 0x0000000104f01c8c swift::irgen::IRGenFunction::emitValueWitnessTableRef(swift::SILType, swift::irgen::DynamicMetadataRequest, llvm::Value**) + 196 20 swift-frontend 0x0000000104f01bbc swift::irgen::IRGenFunction::emitValueWitnessTableRef(swift::SILType, llvm::Value**) + 32 21 swift-frontend 0x0000000104f18680 swift::irgen::emitLoadOfAlignmentMask(swift::irgen::IRGenFunction&, swift::SILType) + 60 22 swift-frontend 0x0000000104ee06c8 swift::irgen::HeapNonFixedOffsets::HeapNonFixedOffsets(swift::irgen::IRGenFunction&, swift::irgen::HeapLayout const&) + 828 23 swift-frontend 0x0000000104ee0c78 swift::irgen::HeapLayout::getPrivateMetadata(swift::irgen::IRGenModule&, llvm::Constant*) const + 464 24 swift-frontend 0x0000000104ee11cc swift::irgen::IRGenFunction::emitUnmanagedAlloc(swift::irgen::HeapLayout const&, llvm::Twine const&, llvm::Constant*, swift::irgen::HeapNonFixedOffsets const*) + 68 25 swift-frontend 0x0000000104ed4ef4 swift::irgen::emitFunctionPartialApplication(swift::irgen::IRGenFunction&, swift::SILFunction&, swift::irgen::FunctionPointer const&, llvm::Value*, swift::irgen::Explosion&, llvm::ArrayRef, swift::SubstitutionMap, swift::CanTypeWrapper, swift::CanTypeWrapper, swift::CanTypeWrapper, swift::irgen::Explosion&, bool) + 2676 26 swift-frontend 0x0000000104fbce4c swift::SILInstructionVisitor<(anonymous namespace)::IRGenSILFunction, void>::visit(swift::SILInstruction*) + 64324 27 swift-frontend 0x0000000104fa8b44 (anonymous namespace)::IRGenSILFunction::emitSILFunction() + 7260 28 swift-frontend 0x0000000104fa6954 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 896 29 swift-frontend 0x0000000104e8773c swift::irgen::IRGenerator::emitLazyDefinitions() + 1400 30 swift-frontend 0x0000000104f69868 swift::IRGenRequest::evaluate(swift::Evaluator&, swift::IRGenDescriptor) const + 2020 31 swift-frontend 0x0000000104fa60c8 swift::GeneratedModule swift::SimpleRequest::callDerived<0ul>(swift::Evaluator&, std::__1::integer_sequence) const + 196 32 swift-frontend 0x0000000104f79430 llvm::Expected swift::Evaluator::getResultUncached(swift::IRGenRequest const&) + 372 33 swift-frontend 0x0000000104f6ba2c swift::performIRGeneration(swift::FileUnit*, swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::StringRef, llvm::GlobalVariable**) + 212 34 swift-frontend 0x0000000104bcbd2c performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr >, llvm::PointerUnion, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 1664 35 swift-frontend 0x0000000104bcb108 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 576 36 swift-frontend 0x0000000104bd9cf4 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref, bool) + 160 37 swift-frontend 0x0000000104bcce2c swift::performFrontend(llvm::ArrayRef, char const*, void*, swift::FrontendObserver*) + 3256 38 swift-frontend 0x0000000104a3b9f0 swift::mainEntry(int, char const**) + 3136 39 dyld 0x00000001120bd08c start + 520 ```

Steps To Reproduce Steps to reproduce the behavior:

1. Compile the program with Swift 5.6 or the most recent snapshot toolchain

Expected behavior Not crashing.

Environment (please fill out the following information)

• OS: macOS 12.5.1
• Xcode Version/Tag/Branch: Apple Swift version 5.8-dev (LLVM 03bd949eeee4761, Swift 2c40a850df6f409)

Additional context Note that the crash neither seems to occur if the closure is not @escaping nor if we use X instead of Self.

[theblixguy]

Duplicate of https://github.com/apple/swift/issues/56757

[fwcd]

Good catch, so I think we can close this?