Implicit optional promotion of variadic tuple assertion failure: !tupleTy.containsPackExpansionType()

[natecook1000]

Description

In one version of my code base, the compiler crashes when it should use implicit optional promotion of a tuple with variadic members. I can work around the issue by explicitly putting the variadic tuple in a .some(...) optional case.

Reproduction

I haven't been able to reproduce the crash in a reduced codebase, but I have a branch that exhibits the behavior with a single parameter uncommented:

https://github.com/apple/swift-argument-parser/blob/option-tuples/Sources/ArgumentParser/Parsable%20Properties/Option.swift#L957-L960

The problem is a call from within one initializer to another, where both have the same generic parameters and constraints, but the callee's first parameter is an optional.

The callee is defined here:

https://github.com/apple/swift-argument-parser/blob/option-tuples/Sources/ArgumentParser/Parsable%20Properties/Option.swift#L868-L878

If the variadic tuple value is passed as an explicit optional case value (.some(wrappedValue)), there's no compiler crash.

Stack dump

Assertion failed: (!tupleTy.containsPackExpansionType() && "can't extract elements from tuples containing pack expansions " "right now"), function extractElements, file RValue.cpp, line 715.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0.	Program arguments: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/bin/swift-frontend -frontend -c /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Completions/BashCompletionsGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Completions/CompletionsGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Completions/FishCompletionsGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Completions/ZshCompletionsGenerator.swift "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Argument.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/ArgumentDiscussion.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/ArgumentHelp.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/ArgumentVisibility.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/CompletionKind.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Errors.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Flag.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/NameSpecification.swift" -primary-file "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Option.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/OptionGroup.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/AsyncParsableCommand.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/CommandConfiguration.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/CommandGroup.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/EnumerableFlag.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/ExpressibleByArgument.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/ParsableArguments.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/ParsableArgumentsValidation.swift" "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Types/ParsableCommand.swift" /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/ArgumentDecoder.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/ArgumentDefinition.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/ArgumentSet.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/CommandParser.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/InputKey.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/InputOrigin.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/Name.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/Parsed.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/ParsedValues.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/ParserError.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsing/SplitArguments.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Usage/DumpHelpGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Usage/HelpCommand.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Usage/HelpGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Usage/MessageInfo.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Usage/UsageGenerator.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Utilities/CollectionExtensions.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Utilities/Platform.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Utilities/SequenceExtensions.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Utilities/StringExtensions.swift /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Utilities/Tree.swift -emit-dependencies-path /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/ArgumentParser-tool.build/Option.d -emit-reference-dependencies-path /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/ArgumentParser-tool.build/Option.swiftdeps -target arm64-apple-macosx10.13 -Xllvm -aarch64-use-tbi -enable-objc-interop -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk -I /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/Modules-tool -I /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift/macosx/testing -I /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks -color-diagnostics -enable-testing -g -debug-info-format=dwarf -dwarf-version=4 -module-cache-path /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/ModuleCache -swift-version 5 -Onone -D SWIFT_PACKAGE -D DEBUG -enable-experimental-feature StrictConcurrency -empty-abi-descriptor -plugin-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift/host/plugins/testing -resource-dir /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a.xctoolchain/usr/lib/swift -enable-anonymous-context-mangled-names -file-compilation-dir /Volumes/Data/Projects/swift-argument-parser -Xcc -isysroot -Xcc /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk -Xcc -F -Xcc /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -Xcc -F -Xcc /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks -Xcc -fPIC -Xcc -g -module-name ArgumentParser -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 15.0 -target-sdk-name macosx15.0 -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 -parse-as-library -o /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/ArgumentParser-tool.build/Option.swift.o -index-store-path /Volumes/Data/Projects/swift-argument-parser/.build/arm64-apple-macosx/debug/index/store -index-system-modules
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 file "/Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Option.swift")
4.	While silgen emitValueConstructor SIL function "@$s14ArgumentParser6OptionV12wrappedValue4name7parsing4help10completionACyqd___qd_0_qd_1_qd_1_QptGqd___qd_0_qd_1_qd_1_Qpt_AA17NameSpecificationVAA06SingleE15ParsingStrategyVAA0A4HelpVSgAA14CompletionKindVSgtcRvd_1_qd___qd_0_qd_1_qd_1_QptRszAA013ExpressibleByA0Rd__AaTRd_0_AaTRd_1_r1_lufC".
 for 'init(wrappedValue:name:parsing:help:completion:)' (at /Volumes/Data/Projects/swift-argument-parser/Sources/ArgumentParser/Parsable Properties/Option.swift:946:10)
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           0x0000000106ba5f60 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x0000000106ba4644 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x0000000106ba65bc SignalHandler(int) + 304
3  libsystem_platform.dylib 0x000000019afcd6a4 _sigtramp + 56
4  libsystem_pthread.dylib  0x000000019af938cc pthread_kill + 296
5  libsystem_c.dylib        0x000000019ae99b48 abort + 124
6  libsystem_c.dylib        0x000000019ae98e58 err + 0
7  swift-frontend           0x0000000106c9e788 swift::Lowering::RValue::extractElements(llvm::SmallVectorImpl<swift::Lowering::RValue>&) && (.cold.3) + 0
8  swift-frontend           0x0000000101343108 swift::Lowering::RValue::extractElements(llvm::SmallVectorImpl<swift::Lowering::RValue>&) && + 936
9  swift-frontend           0x00000001013369b0 swift::Lowering::ArgumentSourceExpansion::ArgumentSourceExpansion(swift::Lowering::SILGenFunction&, swift::Lowering::ArgumentSource&&, bool) + 296
10 swift-frontend           0x000000010136cd44 (anonymous namespace)::ArgEmitter::emit(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, bool, std::__1::optional<swift::AnyFunctionType::Param>) + 756
11 swift-frontend           0x000000010135e644 (anonymous namespace)::ArgEmitter::emitSingleArg(swift::Lowering::ArgumentSource&&, swift::Lowering::AbstractionPattern, bool, std::__1::optional<swift::AnyFunctionType::Param>) + 320
12 swift-frontend           0x000000010136beec (anonymous namespace)::ArgEmitter::emitPreparedArgs(swift::Lowering::PreparedArguments&&, swift::Lowering::AbstractionPattern) + 220
13 swift-frontend           0x0000000101377308 (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
14 swift-frontend           0x0000000101376b68 (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
15 swift-frontend           0x00000001013620c4 (anonymous namespace)::CallEmission::apply(swift::Lowering::SGFContext) + 1800
16 swift-frontend           0x0000000101360744 swift::Lowering::SILGenFunction::emitApplyExpr(swift::ApplyExpr*, swift::Lowering::SGFContext) + 2028
17 swift-frontend           0x00000001013bfa88 swift::Lowering::SILGenFunction::emitRValueAsSingleValue(swift::Expr*, swift::Lowering::SGFContext) + 56
18 swift-frontend           0x00000001013cf1cc (anonymous namespace)::RValueEmitter::visitRebindSelfInConstructorExpr(swift::RebindSelfInConstructorExpr*, swift::Lowering::SGFContext) + 348
19 swift-frontend           0x00000001013c0060 swift::Lowering::SILGenFunction::emitIgnoredExpr(swift::Expr*) + 912
20 swift-frontend           0x000000010145698c swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 4288
21 swift-frontend           0x00000001014558c0 swift::Lowering::SILGenFunction::emitStmt(swift::Stmt*) + 24
22 swift-frontend           0x0000000101398bd4 swift::Lowering::SILGenFunction::emitValueConstructor(swift::ConstructorDecl*) + 7152
23 swift-frontend           0x000000010134dd6c swift::Lowering::SILGenModule::emitFunctionDefinition(swift::SILDeclRef, swift::SILFunction*) + 5400
24 swift-frontend           0x000000010134f254 swift::Lowering::SILGenModule::emitOrDelayFunction(swift::SILDeclRef) + 268
25 swift-frontend           0x0000000101350110 swift::Lowering::SILGenModule::emitConstructor(swift::ConstructorDecl*) + 364
26 swift-frontend           0x000000010146ba10 swift::ASTVisitor<SILGenExtension, void, void, void, void, void, void>::visit(swift::Decl*) + 204
27 swift-frontend           0x0000000101468030 SILGenExtension::emitExtension(swift::ExtensionDecl*) + 180
28 swift-frontend           0x0000000101467f70 swift::Lowering::SILGenModule::visitExtensionDecl(swift::ExtensionDecl*) + 24
29 swift-frontend           0x00000001013519f8 swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*) + 176
30 swift-frontend           0x0000000101351f14 swift::ASTLoweringRequest::evaluate(swift::Evaluator&, swift::ASTLoweringDescriptor) const + 632
31 swift-frontend           0x0000000101455280 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
32 swift-frontend           0x0000000101357424 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
33 swift-frontend           0x000000010135254c swift::performASTLowering(swift::FileUnit&, swift::Lowering::TypeConverter&, swift::SILOptions const&, swift::IRGenOptions const*) + 96
34 swift-frontend           0x0000000100ced6e0 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 612
35 swift-frontend           0x0000000100cf96a4 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) + 160
36 swift-frontend           0x0000000100cef418 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 716
37 swift-frontend           0x0000000100ceec34 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2208
38 swift-frontend           0x0000000100aa11b8 swift::mainEntry(int, char const**) + 3100
39 dyld                     0x000000019abeee4c start + 6768

Expected behavior

Successful compilation of the initializer.

Environment

Apple Swift version 6.2-dev (LLVM 81859ac55f8d09a, Swift 8ec8a12)
Target: arm64-apple-macosx15.0

Additional information

No response