[clang] crash on valid in isPackExpansion #116036
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clang:frontend
Language frontend issues, e.g. anything involving "Sema"
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C++20 concepts
crash-on-valid
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C++11 lambda expressions
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godbolt has On the other hand, I have clang 19.1.0-rc4 built and also one around 19.1.1, both crash. |
EugeneZelenko
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@llvm/issue-subscribers-clang-frontend Author: vient (vient)
Minified from real code (minification may not be the best since half of cvise passes crash or fail)
```cpp
template <bool> using __bool_constant = int;
int invoke;
template <typename>
concept invocable = requires { invoke; };
template <template <typename> typename> struct Walk {
static void traverse(auto)
requires invocable<decltype([](auto...) {})>;
};
template <typename> using DoNotPrune = __bool_constant<false>;
template <template <typename> typename Prune = DoNotPrune>
auto for_each_leaf(auto value) {
Walk<Prune>::traverse(value);
}
auto collect(int value) {
for_each_leaf(value);
}
```
compiled with `clang++-19 -std=c++23 -o test.o -c test.cpp` produces this
```
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: clang++-19 -std=c++23 -o test.o -c test.cpp
1. test.cpp:15:22: current parser token ')'
2. test.cpp:14:25: parsing function body 'collect'
3. test.cpp:14:25: in compound statement ('{}')
4. test.cpp:11:6: instantiating function definition 'for_each_leaf<DoNotPrune, int>'
#0 0x00007f1c43e1cb06 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm-19/bin/../lib/libLLVM.so.19.1+0xea3b06)
#1 0x00007f1c43e1a7b0 llvm::sys::RunSignalHandlers() (/usr/lib/llvm-19/bin/../lib/libLLVM.so.19.1+0xea17b0)
#2 0x00007f1c43e1bf64 llvm::sys::CleanupOnSignal(unsigned long) (/usr/lib/llvm-19/bin/../lib/libLLVM.so.19.1+0xea2f64)
#3 0x00007f1c43d6a6d0 (/usr/lib/llvm-19/bin/../lib/libLLVM.so.19.1+0xdf16d0)
#4 0x00007f1c4ee28420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
#5 0x00007f1c4bd46ffe clang::TemplateArgument::isPackExpansion() const (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1279ffe)
#6 0x00007f1c4c86f2ac (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1da22ac)
#7 0x00007f1c4c8287c6 clang::Sema::SubstType(clang::TypeLoc, clang::MultiLevelTemplateArgumentList const&, clang::SourceLocation, clang::DeclarationName) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d5b7c6)
#8 0x00007f1c4c82a81f clang::Sema::SubstParmVarDecl(clang::ParmVarDecl*, clang::MultiLevelTemplateArgumentList const&, int, std::optional<unsigned int>, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d5d81f)
#9 0x00007f1c4c862f1a (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d95f1a)
#10 0x00007f1c4c8662da (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d992da)
#11 0x00007f1c4c864e1c (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d97e1c)
#12 0x00007f1c4c857f9e (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d8af9e)
#13 0x00007f1c4c86a2d7 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d9d2d7)
#14 0x00007f1c4c82865b (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d5b65b)
#15 0x00007f1c4c82f565 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d62565)
#16 0x00007f1c4c82fed0 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d62ed0)
#17 0x00007f1c4c859a24 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d8ca24)
#18 0x00007f1c4c8307c2 clang::Sema::SubstConstraintExpr(clang::Expr*, clang::MultiLevelTemplateArgumentList const&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d637c2)
#19 0x00007f1c4c1811b4 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x16b41b4)
#20 0x00007f1c4c179ec4 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x16acec4)
#21 0x00007f1c4c179c5c clang::Sema::CheckConstraintSatisfaction(clang::NamedDecl const*, llvm::ArrayRef<clang::Expr const*>, llvm::SmallVectorImpl<clang::Expr*>&, clang::MultiLevelTemplateArgumentList const&, clang::SourceRange, clang::ConstraintSatisfaction&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x16acc5c)
#22 0x00007f1c4c17ce2d clang::Sema::CheckInstantiatedFunctionTemplateConstraints(clang::SourceLocation, clang::FunctionDecl*, llvm::ArrayRef<clang::TemplateArgument>, clang::ConstraintSatisfaction&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x16afe2d)
#23 0x00007f1c4c77a4a9 clang::Sema::FinishTemplateArgumentDeduction(clang::FunctionTemplateDecl*, llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&, unsigned int, clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, llvm::SmallVectorImpl<clang::Sema::OriginalCallArg> const*, bool, llvm::function_ref<bool ()>) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1cad4a9)
#24 0x00007f1c4c7d5bd7 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d08bd7)
#25 0x00007f1c4c0386ed clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x156b6ed)
#26 0x00007f1c4c77bf8b clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, bool, bool, clang::QualType, clang::Expr::Classification, llvm::function_ref<bool (llvm::ArrayRef<clang::QualType>)>) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1caef8b)
#27 0x00007f1c4c663c44 clang::Sema::AddTemplateOverloadCandidate(clang::FunctionTemplateDecl*, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool, bool, clang::CallExpr::ADLCallKind, clang::OverloadCandidateParamOrder, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1b96c44)
#28 0x00007f1c4c6742fc (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba72fc)
#29 0x00007f1c4c6741d0 clang::Sema::AddOverloadedCallCandidates(clang::UnresolvedLookupExpr*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba71d0)
#30 0x00007f1c4c674510 clang::Sema::buildOverloadedCallSet(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::OverloadCandidateSet*, clang::ActionResult<clang::Expr*, true>*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba7510)
#31 0x00007f1c4c674810 clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba7810)
#32 0x00007f1c4c32725a clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x185a25a)
#33 0x00007f1c4c33aa3e clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x186da3e)
#34 0x00007f1c4c85a15a (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d8d15a)
#35 0x00007f1c4c82ed21 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d61d21)
#36 0x00007f1c4c85f89d (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d9289d)
#37 0x00007f1c4c82ecb4 clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1d61cb4)
#38 0x00007f1c4c894b2b clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1dc7b2b)
#39 0x00007f1c4c0386ed clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x156b6ed)
#40 0x00007f1c4c77f8ff clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1cb28ff)
#41 0x00007f1c4c3223e1 clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef<clang::SourceLocation>, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x18553e1)
#42 0x00007f1c4c674b30 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba7b30)
#43 0x00007f1c4c67491f clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x1ba791f)
#44 0x00007f1c4c32725a clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x185a25a)
#45 0x00007f1c4c33aa3e clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x186da3e)
#46 0x00007f1c4b750e9c clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc83e9c)
#47 0x00007f1c4b754619 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc87619)
#48 0x00007f1c4b74de59 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc80e59)
#49 0x00007f1c4b74dd29 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc80d29)
#50 0x00007f1c4b7b5c15 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xce8c15)
#51 0x00007f1c4b7b3f30 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xce6f30)
#52 0x00007f1c4b7b3906 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xce6906)
#53 0x00007f1c4b7bc460 clang::Parser::ParseCompoundStatementBody(bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xcef460)
#54 0x00007f1c4b7bd582 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xcf0582)
#55 0x00007f1c4b7d737f clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xd0a37f)
#56 0x00007f1c4b719b44 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc4cb44)
#57 0x00007f1c4b7d63a3 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xd093a3)
#58 0x00007f1c4b7d5d5b clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xd08d5b)
#59 0x00007f1c4b7d4f77 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xd07f77)
#60 0x00007f1c4b7d3437 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xd06437)
#61 0x00007f1c4b701efe clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0xc34efe)
#62 0x00007f1c4d7a8bb5 clang::FrontendAction::Execute() (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x2cdbbb5)
#63 0x00007f1c4d71e2a4 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x2c512a4)
#64 0x00007f1c4d824c9e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x2d57c9e)
#65 0x0000560ce11456e0 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm-19/bin/clang+0x116e0)
#66 0x0000560ce11429e5 (/usr/lib/llvm-19/bin/clang+0xe9e5)
#67 0x00007f1c4d3bd9a9 (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x28f09a9)
#68 0x00007f1c43d6a468 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm-19/bin/../lib/libLLVM.so.19.1+0xdf1468)
#69 0x00007f1c4d3bd34d clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x28f034d)
#70 0x00007f1c4d3839a9 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x28b69a9)
#71 0x00007f1c4d383c1e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x28b6c1e)
#72 0x00007f1c4d3a06fb clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/usr/lib/llvm-19/bin/../lib/libclang-cpp.so.19.1+0x28d36fb)
#73 0x0000560ce114245f clang_main(int, char**, llvm::ToolContext const&) (/usr/lib/llvm-19/bin/clang+0xe45f)
#74 0x0000560ce114f706 main (/usr/lib/llvm-19/bin/clang+0x1b706)
#75 0x00007f1c429b7083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#76 0x0000560ce114072e _start (/usr/lib/llvm-19/bin/clang+0xc72e)
clang++-19: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Ubuntu clang version 19.1.4 (++20241111014147+a3f0f1d004a6-1~exp1~20241111134204.61)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-19/bin
```
# Crash reproducer for Ubuntu clang version 19.1.4 (++20241111014147+a3f0f1d004a6-1~exp1~20241111134204.61)
# Driver args: "--driver-mode=g++" "-std=c++23" "-o" "test.o" "-c" "test.cpp"
# Original command: "/usr/lib/llvm-19/bin/clang" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-emit-obj" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "test.cpp" "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-debugger-tuning=gdb" "-fdebug-compilation-dir=/tmp" "-fcoverage-compilation-dir=/tmp" "-resource-dir" "/usr/lib/llvm-19/lib/clang/19" "-internal-isystem" "/usr/lib/gcc/x86_64-linux-gnu/14.2.0/../../../../include/c++/14.2.0" "-internal-isystem" "/usr/lib/gcc/x86_64-linux-gnu/14.2.0/../../../../include/c++/14.2.0/x86_64-linux-gnu" "-internal-isystem" "/usr/lib/gcc/x86_64-linux-gnu/14.2.0/../../../../include/c++/14.2.0/backward" "-internal-isystem" "/usr/lib/llvm-19/lib/clang/19/include" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/usr/lib/gcc/x86_64-linux-gnu/14.2.0/../../../../x86_64-linux-gnu/include" "-internal-externc-isystem" "/usr/include/x86_64-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-std=c++23" "-fdeprecated-macro" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fskip-odr-check-in-gmf" "-fcxx-exceptions" "-fexceptions" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-o" "test.o" "-x" "c++" "test.cpp"
"/usr/lib/llvm-19/bin/clang" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-emit-obj" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "test.cpp" "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-debugger-tuning=gdb" "-fdebug-compilation-dir=/tmp" "-fcoverage-compilation-dir=/tmp" "-std=c++23" "-fdeprecated-macro" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fskip-odr-check-in-gmf" "-fcxx-exceptions" "-fexceptions" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-x" "c++" "test-5fa5ce.cpp"Somehow can't reproduce in godbolt but got another (?) crash with assertion trunk: https://godbolt.org/z/abvenc4Md |
|
So the original code only crashes on clang-19 but the example you provides crashed back to clang-16: https://godbolt.org/z/MK3q56T3K w/o the reproducer that only crashes on clang-19 we can't dig into the recent regression. Do you have a non minimized version? |
|
I did not say that original code crashes only with clang-19, I only tried clang-19. I'm pretty sure that crash stack trace with minified version is the same as with the original. regression:19 tag was not placed by me. Thing that bugs me is that clang from llvm apt repo crashes but clang in godbolt (without assertions) does not. |
|
Tested locally with clang 18 and 19 from llvm repos (for Ubuntu 20.04) as well as my own builds. Results:
Also found my build with debug info, here is the stack trace guess |
|
Reduced to template <typename>
concept invocable = true;
template <int Depth = 0>
struct Walk {
static int traverse(auto /*Depth=1*/)
requires invocable<decltype([](auto /*depth of invented
TemplateTypeParmDecl=1, depth of the
ParmVarDecl=2*/
...) {})>;
};
int res = Walk<>::traverse(42);https://gcc.godbolt.org/z/dMK3s5P9c The template depth of the lambda is incorrect: the invented TemplateTypeParmDecl is of depth 1, while the depth of the ParmVarDecl is 2. Logically the depth of that for We don't have any template arguments for the unevaluated lambda to be turned into a non-dependent expression, so we shouldn't really be evaluating the constraint satisfaction. However, we don't have any mechanism for it to skip dependent constraint evaluation IIRC (whereas we do have such for compound requirements), so even if we managed to correct the depth of the invented template parameter of the inner lambda, it would still run into a crash because the substituted expression is still dependent. You're probably seeing intermittent crashes because, without an assertion build, it would be UB for clang to proceed with a wrong template argument type where it's expecting a pack. |
zyn0217
added
concepts
|
CC @erichkeane |
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Minified from real code (minification may not be the best since half of cvise passes crash or fail)
compiled with
clang++-19 -std=c++23 -o test.o -c test.cppproduces thisSomehow can't reproduce in godbolt but got another (?) crash with assertion trunk: https://godbolt.org/z/abvenc4Md
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