| Issue |
125165
|
| Summary |
[Clang] Crash during instantiation of a fold _expression_ that uses an invalid structured-binding pack
|
| Labels |
clang:frontend,
crash-on-invalid
|
| Assignees |
|
| Reporter |
Sirraide
|
Consider (https://godbolt.org/z/9oWz76GMf):
```c++
template <typename = void>
auto f(auto t) {
const auto& [...pack] = t;
(pack, ...);
};
void g() {
f('x');
}
```
After correctly diagnosing that we can’t decompose `t`, trying to instantiate the fold _expression_ crashes:
```console
clang++: /root/llvm-project/clang/lib/AST/ExprCXX.cpp:1960: clang::CXXFoldExpr::CXXFoldExpr(
clang::QualType, clang::UnresolvedLookupExpr*, clang::SourceLocation, clang::Expr*, clang::BinaryOperatorKind,
clang::SourceLocation, clang::Expr*, clang::SourceLocation, std::optional<unsigned int>):
Assertion `((LHS && LHS->containsUnexpandedParameterPack()) != (RHS && RHS->containsUnexpandedParameterPack()))
&& "Exactly one of LHS or RHS should contain an unexpanded pack"' failed.
```
The stack trace is in tree transform, and the crash doesn’t happen if the `t` parameter is not dependent. Full stack trace:
```console
<source>:3:17: error: cannot decompose non-class, non-array type 'char const'
3 | const auto& [...pack] = t;
| ^
<source>:8:5: note: in instantiation of function template specialization 'f<void, char>' requested here
8 | f('x');
| ^
clang++: /root/llvm-project/clang/lib/AST/ExprCXX.cpp:1960: clang::CXXFoldExpr::CXXFoldExpr(clang::QualType, clang::UnresolvedLookupExpr*, clang::SourceLocation, clang::Expr*, clang::BinaryOperatorKind, clang::SourceLocation, clang::Expr*, clang::SourceLocation, std::optional<unsigned int>): Assertion `((LHS && LHS->containsUnexpandedParameterPack()) != (RHS && RHS->containsUnexpandedParameterPack())) && "Exactly one of LHS or RHS should contain an unexpanded pack"' failed.
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 -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++26 <source>
1. <source>:8:10: current parser token ')'
2. <source>:7:10: parsing function body 'g'
3. <source>:7:10: in compound statement ('{}')
4. <source>:2:6: instantiating function definition 'f<void, char>'
#0 0x0000000003e422a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3e422a8)
#1 0x0000000003e3ff64 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3e3ff64)
#2 0x0000000003d8c438 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x000070c331a42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x000070c331a969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
#5 0x000070c331a42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
#6 0x000070c331a287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
#7 0x000070c331a2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
#8 0x000070c331a39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#9 0x0000000007ad32b1 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7ad32b1)
#10 0x0000000007440d37 clang::Sema::BuildCXXFoldExpr(clang::UnresolvedLookupExpr*, clang::SourceLocation, clang::Expr*, clang::BinaryOperatorKind, clang::SourceLocation, clang::Expr*, clang::SourceLocation, std::optional<unsigned int>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7440d37)
#11 0x0000000007396916 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCXXFoldExpr(clang::CXXFoldExpr*) SemaTemplateInstantiate.cpp:0:0
#12 0x000000000738120d clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#13 0x00000000073af157 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
#14 0x00000000073afd4e clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#15 0x00000000073b7d44 clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x73b7d44)
#16 0x000000000742d474 clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x742d474)
#17 0x000000000806d171 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x806d171)
#18 0x00000000072910da clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x72910da)
#19 0x0000000006d08455 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+++0x6d08455)
#20 0x0000000007115674 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
#21 0x000000000711653c 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+++0x711653c)
#22 0x0000000006d50106 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+++0x6d50106)
#23 0x0000000006d50f7c 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+++0x6d50f7c)
#24 0x000000000689f14d clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x689f14d)
#25 0x00000000068979e1 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x68979e1)
#26 0x0000000006899b47 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6899b47)
#27 0x0000000006899bd9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6899bd9)
#28 0x000000000689e749 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x689e749)
#29 0x0000000006922bd9 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6922bd9)
#30 0x0000000006918f4e clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6918f4e)
#31 0x0000000006919ea0 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6919ea0)
#32 0x000000000691ad65 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x691ad65)
#33 0x000000000691c56a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x691c56a)
#34 0x000000000682de43 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x682de43)
#35 0x0000000006862b1d clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6862b1d)
#36 0x0000000006821b8e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6821b8e)
#37 0x0000000006822349 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6822349)
#38 0x0000000006829af3 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6829af3)
#39 0x000000000682a9ed clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x682a9ed)
#40 0x000000000681ce8a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x681ce8a)
#41 0x00000000047d6698 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47d6698)
#42 0x0000000004a9c095 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4a9c095)
#43 0x0000000004a1ec4e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4a1ec4e)
#44 0x0000000004b89e8e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b89e8e)
#45 0x0000000000d416cf cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd416cf)
#46 0x0000000000d3916a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#47 0x000000000481d029 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
#48 0x0000000003d8c8e4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3d8c8e4)
#49 0x000000000481d61f 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
#50 0x00000000047e03ed clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e03ed)
#51 0x00000000047e146e 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+++0x47e146e)
#52 0x00000000047e8fa5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e8fa5)
#53 0x0000000000d3e4e3 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd3e4e3)
#54 0x0000000000c06e04 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc06e04)
#55 0x000070c331a29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#56 0x000070c331a29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#57 0x0000000000d38c15 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd38c15)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
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