Initializing non-existent property with type with parameter pack causes ICE

[keith]

With this code:

struct Thing<each T> {
    init() {
        self.abc = 1
    }
}

The compiler crashes:

error: compile command failed due to signal 6 (use -v to see invocation)
Assertion failed: (isa<To>(Val) && "cast<Ty>() argument of incompatible type!"), function cast, file Casting.h, line 578.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0.      Program arguments: /Users/ksmiley/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-06-05-a.xctoolchain/usr/bin/swift-frontend -frontend -c -primary-file /tmp/foo.swift -target arm64-apple-macosx13.0 -Xllvm -aarch64-use-tbi -enable-objc-interop -sdk /Applications/Xcode-15.0.0-beta1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk -color-diagnostics -new-driver-path /Users/ksmiley/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-06-05-a.xctoolchain/usr/bin/swift-driver -disable-availability-checking -empty-abi-descriptor -plugin-path /Users/ksmiley/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-06-05-a.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Users/ksmiley/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-06-05-a.xctoolchain/usr/local/lib/swift/host/plugins -resource-dir /Users/ksmiley/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-06-05-a.xctoolchain/usr/lib/swift -module-name foo -target-sdk-version 14.0 -target-sdk-name macosx14.0 -o /var/folders/gj/wf3swl0x215b2sq1qy84kzkm0000gn/T/TemporaryDirectory.tJyZTc/foo-1.o
1.      Apple Swift version 5.9-dev (LLVM 4a3b38183d7bb09, Swift 44a40979e52be8e)
2.      Compiling with the current language version
3.      While evaluating request TypeCheckSourceFileRequest(source_file "/tmp/foo.swift")
4.      While evaluating request TypeCheckFunctionBodyRequest(foo.(file).Thing.init()@/tmp/foo.swift:3:5)
5.      While type-checking statement at [/tmp/foo.swift:3:12 - line:5:4] RangeText="{
        self.abc = 1
   "
6.      While type-checking expression at [/tmp/foo.swift:4:9 - line:4:20] RangeText="self.abc = "
7.      While type-checking-target starting at /tmp/foo.swift:4:9
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           0x0000000104f41f30 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x0000000104f412d4 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x0000000104f42570 SignalHandler(int) + 304
3  libsystem_platform.dylib 0x00000001a84eaa24 _sigtramp + 56
4  libsystem_pthread.dylib  0x00000001a84bbc28 pthread_kill + 288
5  libsystem_c.dylib        0x00000001a83c9ae8 abort + 180
6  libsystem_c.dylib        0x00000001a83c8e44 err + 0
7  swift-frontend           0x0000000105425b54 swift::PackType::getExpandedGenericArgs(swift::ArrayRefView<swift::Type, swift::GenericTypeParamType*, swift::GenericTypeParamType* swift::staticCastHelper<swift::GenericTypeParamType>(swift::Type const&), true>, llvm::ArrayRef<swift::Type>) (.cold.5) + 0
8  swift-frontend           0x00000001017faf34 swift::PackType::getExpandedGenericArgs(swift::ArrayRefView<swift::Type, swift::GenericTypeParamType*, swift::GenericTypeParamType* swift::staticCastHelper<swift::GenericTypeParamType>(swift::Type const&), true>, llvm::ArrayRef<swift::Type>) + 376
9  swift-frontend           0x00000001017fad54 swift::BoundGenericType::getExpandedGenericArgs() + 248
10 swift-frontend           0x00000001015a7e98 (anonymous namespace)::TypePrinter::visitBoundGenericType(swift::BoundGenericType*) + 1848
11 swift-frontend           0x000000010158b278 swift::Type::print(swift::ASTPrinter&, swift::PrintOptions const&) const + 76
12 swift-frontend           0x000000010158c5a0 swift::TypeBase::getString(swift::PrintOptions const&) const + 188
13 swift-frontend           0x000000010171615c formatDiagnosticArgument(llvm::StringRef, llvm::StringRef, llvm::ArrayRef<swift::DiagnosticArgument>, unsigned int, swift::DiagnosticFormatOptions, llvm::raw_ostream&) + 5704
14 swift-frontend           0x00000001017149c4 swift::DiagnosticEngine::formatDiagnosticText(llvm::raw_ostream&, llvm::StringRef, llvm::ArrayRef<swift::DiagnosticArgument>, swift::DiagnosticFormatOptions) + 844
15 swift-frontend           0x0000000100443254 swift::PrintingDiagnosticConsumer::printDiagnostic(swift::SourceManager&, swift::DiagnosticInfo const&) + 756
16 swift-frontend           0x0000000100442078 swift::PrintingDiagnosticConsumer::handleDiagnostic(swift::SourceManager&, swift::DiagnosticInfo const&) + 1212
17 swift-frontend           0x0000000101716de8 swift::DiagnosticEngine::emitDiagnostic(swift::Diagnostic const&) + 884
18 swift-frontend           0x0000000101716a20 swift::DiagnosticEngine::handleDiagnostic(swift::Diagnostic&&) + 176
19 swift-frontend           0x000000010171441c swift::InFlightDiagnostic::flush() + 56
20 swift-frontend           0x000000010114361c swift::constraints::MissingMemberFailure::diagnoseAsError()::$_21::operator()(swift::Type) const + 604
21 swift-frontend           0x00000001011427e4 swift::constraints::MissingMemberFailure::diagnoseAsError() + 4136
22 swift-frontend           0x0000000101121ca8 swift::constraints::DefineMemberBasedOnUse::diagnose(swift::constraints::Solution const&, bool) const + 108
23 swift-frontend           0x000000010105e730 swift::constraints::ConstraintSystem::applySolutionFixes(swift::constraints::Solution const&) + 1576
24 swift-frontend           0x000000010105ee6c swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget) + 92
25 swift-frontend           0x000000010126a650 swift::TypeChecker::typeCheckTarget(swift::constraints::SyntacticElementTarget&, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 396
26 swift-frontend           0x000000010126a46c swift::TypeChecker::typeCheckExpression(swift::constraints::SyntacticElementTarget&, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 184
27 swift-frontend           0x000000010126a32c swift::TypeChecker::typeCheckExpression(swift::Expr*&, swift::DeclContext*, swift::constraints::ContextualTypeInfo, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 84
28 swift-frontend           0x0000000101342a18 (anonymous namespace)::StmtChecker::typeCheckASTNode(swift::ASTNode&) + 236
29 swift-frontend           0x0000000101345854 swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 328
30 swift-frontend           0x0000000101343f10 bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::BraceStmt>(swift::BraceStmt*&) + 136
31 swift-frontend           0x000000010134359c swift::TypeCheckFunctionBodyRequest::evaluate(swift::Evaluator&, swift::AbstractFunctionDecl*) const + 1028
32 swift-frontend           0x00000001016e62c0 llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckFunctionBodyRequest>(swift::TypeCheckFunctionBodyRequest const&) + 392
33 swift-frontend           0x00000001016e605c llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckFunctionBodyRequest, (void*)0>(swift::TypeCheckFunctionBodyRequest const&) + 120
34 swift-frontend           0x00000001016347d0 swift::TypeCheckFunctionBodyRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckFunctionBodyRequest>(swift::Evaluator&, swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType) + 52
35 swift-frontend           0x000000010137b678 swift::TypeCheckSourceFileRequest::evaluate(swift::Evaluator&, swift::SourceFile*) const + 312
36 swift-frontend           0x000000010137d958 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckSourceFileRequest>(swift::TypeCheckSourceFileRequest const&) + 388
37 swift-frontend           0x000000010137d6e8 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckSourceFileRequest, (void*)0>(swift::TypeCheckSourceFileRequest const&) + 84
38 swift-frontend           0x000000010137b458 swift::TypeCheckSourceFileRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckSourceFileRequest>(swift::Evaluator&, swift::TypeCheckSourceFileRequest, swift::TypeCheckSourceFileRequest::OutputType) + 44
39 swift-frontend           0x00000001004273a4 bool llvm::function_ref<bool (swift::SourceFile&)>::callback_fn<swift::CompilerInstance::performSema()::$_9>(long, swift::SourceFile&) + 16
40 swift-frontend           0x00000001004218d0 swift::CompilerInstance::forEachFileToTypeCheck(llvm::function_ref<bool (swift::SourceFile&)>) + 76
41 swift-frontend           0x0000000100421864 swift::CompilerInstance::performSema() + 76
42 swift-frontend           0x0000000100294508 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) + 60
43 swift-frontend           0x0000000100287e5c performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 724
44 swift-frontend           0x0000000100286df0 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2456
45 swift-frontend           0x00000001000d1524 swift::mainEntry(int, char const**) + 2144
46 dyld                     0x00000001a8163f28 start + 2236

Steps to reproduce

xcrun --toolchain org.swift.59202306051a swiftc /tmp/foo.swift -Xfrontend -disable-availability-checking

Environment

• 6/5/23 main snapshot

[vanvoorden]

@hborla I saw a similar error in #71258.