Compiler crash on KeyPath assignment of async throwing function

Describe the bug

Compiler is crashing on assignment of async throwing function to a property through a method using a KeyPath.

Steps To Reproduce

Here is smallest code sample I could get:

struct Example {

  var crashing: () async throws -> Void

  mutating func assign<V>(
    _ keyPath: WritableKeyPath<Self, V>,
    _ value: V
  ) {
    self[keyPath: keyPath] = value
  }
}

Code calling assign causes crash:

var example: Example = .init {}
example.assign(
  \.crashing, {
    print("compiler crash")
  }
)

However, there is a workaround - explicitly marking closure as async throwing makes it compile without a crash.

example.assign(
  \.crashing, { () async throws in
    print("compiler crash")
  }
)

There is no issue if the function is only async or only throwing.

Expected behavior

Compiler should not crash.

Environment (please fill out the following information)

OS: macOS 12.6
Xcode Version/Tag/Branch: Xcode 14.0

Additional context

Previous Xcode (13.4) with swift 5.6 was not crashing on this.

Here is stack trace from Xcode 14.0:

1.  Apple Swift version 5.7 (swiftlang-5.7.0.127.4 clang-1400.0.29.50)
2.  Compiling with the current language version
3.  While evaluating request IRGenRequest(IR Generation for file "Example.swift")
4.  While emitting IR SIL function "@$sytIegHr_yts5Error_pIegHrzo_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           0x000000010524fe70 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x000000010524ee74 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x00000001052504f4 SignalHandler(int) + 344
3  libsystem_platform.dylib 0x00000001aad234a4 _sigtramp + 56
4  libsystem_pthread.dylib  0x00000001aad0bee0 pthread_kill + 288
5  libsystem_c.dylib        0x00000001aac46340 abort + 168
6  swift-frontend           0x00000001008aa524 PrettyStackTraceFrontend::~PrettyStackTraceFrontend() + 0
7  swift-frontend           0x00000001051aed88 llvm::report_fatal_error(llvm::Twine const&, bool) + 280
8  swift-frontend           0x00000001051fb080 report_at_maximum_capacity(unsigned long) + 0
9  swift-frontend           0x00000001051faed4 llvm::SmallVectorBase<unsigned int>::grow_pod(void*, unsigned long, unsigned long) + 228
10 swift-frontend           0x0000000100b240c0 (anonymous namespace)::AsyncCallEmission::setArgs(swift::irgen::Explosion&, bool, swift::irgen::WitnessMetadata*) + 468
11 swift-frontend           0x0000000100cc62b0 (anonymous namespace)::IRGenSILFunction::visitFullApplySite(swift::FullApplySite) + 4032
12 swift-frontend           0x0000000100ca58e8 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 7860
13 swift-frontend           0x0000000100b73364 swift::irgen::IRGenerator::emitLazyDefinitions() + 1156
14 swift-frontend           0x0000000100c73924 swift::IRGenRequest::evaluate(swift::Evaluator&, swift::IRGenDescriptor) const + 3024
15 swift-frontend           0x0000000100ca3768 swift::SimpleRequest<swift::IRGenRequest, swift::GeneratedModule (swift::IRGenDescriptor), (swift::RequestFlags)9>::evaluateRequest(swift::IRGenRequest const&, swift::Evaluator&) + 188
16 swift-frontend           0x0000000100c7fc44 llvm::Expected<swift::IRGenRequest::OutputType> swift::Evaluator::getResultUncached<swift::IRGenRequest>(swift::IRGenRequest const&) + 744
17 swift-frontend           0x0000000100c76b38 swift::performIRGeneration(swift::FileUnit*, swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::StringRef, llvm::GlobalVariable**) + 236
18 swift-frontend           0x00000001008a13cc 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*) + 2160
19 swift-frontend           0x00000001008a3158 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 5932
20 swift-frontend           0x0000000100843c44 swift::mainEntry(int, char const**) + 3940
21 dyld                     0x0000000107cbd08c start + 520

swiftlang / swift

Compiler crash on KeyPath assignment of async throwing function #61355