Assertion 'Pack expansion without unexpanded packs?' failed #28461
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c++14
clang:frontend
Language frontend issues, e.g. anything involving "Sema"
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crash
Prefer [crash-on-valid] or [crash-on-invalid]
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reduced: template <typename F>
auto apply(F f) {
f();
}
template <class...>
struct S {
template <int>
auto f(decltype(apply([](auto...) {})));
};
S<> s; |
|
It might be worth mentioning that something has been fixed here (which could be turned into a test case): One reduction of the code I attached is <<SNIP This leads to segfaults with: Apple LLVM version 7.3.0 (clang-703.0.31) but not with Apple LLVM version 8.0.0 (clang-800.0.31) and also not with clang version 3.8.0 (tags/RELEASE_380/final) or clang version 3.8.1 (tags/RELEASE_381/final) The reduction by David Majnemer, meanwhile, continues to make all of them segfault. |
EugeneZelenko
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clang:frontend
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@llvm/issue-subscribers-clang-frontend |
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Still crashes on trunk: https://godbolt.org/z/Mb5xWq6os Assertion: clang++: /root/llvm-project/clang/lib/Sema/SemaTemplateDeduction.cpp:769:
unsigned int {anonymous}::PackDeductionScope::addPacks(clang::TemplateArgument):
Assertion `!Packs.empty() && "Pack expansion without unexpanded packs?"' failed.Backtrace: PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1. <source>:10:6: current parser token ';'
2. <source>:6:8: instantiating class definition 'S<>'
3. <source>:2:6: instantiating function definition 'apply<S<>::(lambda at <source>:8:25)>'
#0 0x0000557590660def llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3c62def)
#1 0x000055759065eb5c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3c60b5c)
#2 0x00005575905a8b18 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x00007f742bdb6420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
#4 0x00007f742b88300b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
#5 0x00007f742b862859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
#6 0x00007f742b862729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
#7 0x00007f742b873fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
#8 0x00005575938ff4e9 clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, bool, llvm::function_ref<bool (llvm::ArrayRef<clang::QualType>)>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f014e9)
#9 0x0000557593706ebc clang::Sema::AddMethodTemplateCandidate(clang::FunctionTemplateDecl*, clang::DeclAccessPair, clang::CXXRecordDecl*, clang::TemplateArgumentListInfo*, clang::QualType, clang::Expr::Classification, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool, clang::OverloadCandidateParamOrder) (.constprop.0) SemaOverload.cpp:0:0
#10 0x0000557593707317 clang::Sema::AddMethodCandidate(clang::DeclAccessPair, clang::QualType, clang::Expr::Classification, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6d09317)
#11 0x0000557593722dfe clang::Sema::BuildCallToObjectOfClassType(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6d24dfe)
#12 0x00005575933ab565 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69ad565)
#13 0x00005575933b032b clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69b232b)
#14 0x000055759393d720 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#15 0x00005575939337aa clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#16 0x000055759396d2af clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
#17 0x000055759396e519 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#18 0x000055759397166e clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f7366e)
#19 0x00005575939c21f8 clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fc41f8)
#20 0x0000557592f46465 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6548465)
#21 0x00005575938a6d5a clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ea8d5a)
#22 0x0000557593338252 clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef<clang::SourceLocation>, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x693a252)
#23 0x0000557593718b6f FinishOverloadedCallExpr(clang::Sema&, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
#24 0x00005575937196f2 clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6d1b6f2)
#25 0x00005575933ab420 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69ad420)
#26 0x00005575933b032b clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69b232b)
#27 0x000055759393d720 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#28 0x00005575939337aa clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#29 0x00005575939439a8 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeLocBuilder&, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
#30 0x000055759394976f clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeSourceInfo*) SemaTemplateInstantiate.cpp:0:0
#31 0x000055759395212e clang::Sema::SubstType(clang::TypeSourceInfo*, clang::MultiLevelTemplateArgumentList const&, clang::SourceLocation, clang::DeclarationName, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f5412e)
#32 0x000055759395bb5d clang::Sema::SubstParmVarDecl(clang::ParmVarDecl*, clang::MultiLevelTemplateArgumentList const&, int, std::optional<unsigned int>, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f5db5d)
#33 0x000055759395cad0 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformFunctionTypeParams(clang::SourceLocation, llvm::ArrayRef<clang::ParmVarDecl*>, clang::QualType const*, clang::FunctionType::ExtParameterInfo const*, llvm::SmallVectorImpl<clang::QualType>&, llvm::SmallVectorImpl<clang::ParmVarDecl*>*, clang::Sema::ExtParameterInfoBuilder&, unsigned int*) SemaTemplateInstantiate.cpp:0:0
#34 0x0000557593961198 clang::Sema::SubstFunctionDeclType(clang::TypeSourceInfo*, clang::MultiLevelTemplateArgumentList const&, clang::SourceLocation, clang::DeclarationName, clang::CXXRecordDecl*, clang::Qualifiers, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f63198)
#35 0x000055759397c0d9 clang::TemplateDeclInstantiator::SubstFunctionType(clang::FunctionDecl*, llvm::SmallVectorImpl<clang::ParmVarDecl*>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f7e0d9)
#36 0x00005575939cb1fa clang::TemplateDeclInstantiator::VisitCXXMethodDecl(clang::CXXMethodDecl*, clang::TemplateParameterList*, std::optional<clang::ASTTemplateArgumentListInfo const*>, clang::TemplateDeclInstantiator::RewriteKind) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fcd1fa)
#37 0x00005575939cf61c clang::TemplateDeclInstantiator::VisitFunctionTemplateDecl(clang::FunctionTemplateDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6fd161c)
#38 0x0000557593953343 clang::Sema::InstantiateClass(clang::SourceLocation, clang::CXXRecordDecl*, clang::CXXRecordDecl*, clang::MultiLevelTemplateArgumentList const&, clang::TemplateSpecializationKind, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f55343)
#39 0x0000557593971fa3 clang::Sema::InstantiateClassTemplateSpecialization(clang::SourceLocation, clang::ClassTemplateSpecializationDecl*, clang::TemplateSpecializationKind, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f73fa3)
#40 0x00005575939fe873 void llvm::function_ref<void ()>::callback_fn<clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*)::'lambda'()>(long) SemaType.cpp:0:0
#41 0x0000557592f46465 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6548465)
#42 0x0000557593a07dc7 clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7009dc7)
#43 0x0000557593a08119 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x700a119)
#44 0x0000557593a082a9 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, unsigned int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x700a2a9)
#45 0x0000557593145f46 clang::Sema::ActOnUninitializedDecl(clang::Decl*) (.part.0) SemaDecl.cpp:0:0
#46 0x0000557592e16824 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6418824)
#47 0x0000557592e23e18 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6425e18)
#48 0x0000557592df0d01 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63f2d01)
#49 0x0000557592df15bf clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) Parser.cpp:0:0
#50 0x0000557592df7f61 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63f9f61)
#51 0x0000557592df88d6 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63fa8d6)
#52 0x0000557592dec69a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63ee69a)
#53 0x00005575918f05b8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ef25b8)
#54 0x0000557591140a99 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4742a99)
#55 0x00005575910c59a6 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x46c79a6)
#56 0x0000557591222d46 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4824d46)
#57 0x000055758db0f36d cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x111136d)
#58 0x000055758db0b06a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#59 0x0000557590f2715d void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#60 0x00005575905a9020 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bab020)
#61 0x0000557590f2777f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#62 0x0000557590eeebbc clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44f0bbc)
#63 0x0000557590eef64d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44f164d)
#64 0x0000557590ef76ed clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44f96ed)
#65 0x000055758db0d5ca clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x110f5ca)
#66 0x000055758da136a5 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x10156a5)
#67 0x00007f742b864083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#68 0x000055758db05e4e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x1107e4e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134 |
zyn0217
added a commit
that referenced
this issue
Apr 5, 2024
…eclaration (#82310) This patch attempts to fix the lambda call expression inside of a type alias declaration from two aspects: 1. Defer the lambda call expression building until after we have sufficient template arguments. This avoids the overeager (and often wrong) semantic checking before the type alias instantiation. 2. Properly obtain template arguments involving a template type alias for constraint checking. It is unfortunate that a `TypeAliasTemplateDecl` (or a `TypeAliasDecl`) is never a `DeclContext`, nor does it have an associated specialization Decl from which we could collect these template arguments. Thus, I added a new CodeSynthesisContext to record template arguments for alias declarations. Fixes #70601 Fixes #76674 Fixes #79555 Fixes #81145 Fixes #82104 Note that this doesn't involve the fix for #28461. That seems different, and I'd like to leave it as a follow-up.
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