clang crashes with c++2b when variable is captured by a block nested inside a lambda (original) (raw)

$ cat test.cpp

struct S {
  constexpr ~S();
};

void func(S const &a) {
  [a](auto b) {
    ^{
      (void)a;
    };
  }(12);
}

$ clang++ -std=c++2b -fblocks -c -o /dev/null test.cpp

Assertion

clang++: /root/llvm-project/llvm/include/llvm/Support/Casting.h:109: static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = clang::Expr; From = clang::Stmt]: Assertion `Val && "isa<> used on a null pointer"' 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-18.1.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-13.2.0 -fcolor-diagnostics -fno-crash-diagnostics -fblocks -std=c++2b 1. :10:7: current parser token ')' 2. :5:23: parsing function body 'func' 3. :5:23: in compound statement ('{}') 4. :6:3: instantiating function definition 'func(const S &)::(anonymous class)::operator()' #0 0x00000000038d53d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x38d53d8) #1 0x00000000038d30bc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x38d30bc) #2 0x000000000381baa8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0 #3 0x00007cb4d3a42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520) #4 0x00007cb4d3a969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc) #5 0x00007cb4d3a42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476) #6 0x00007cb4d3a287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3) #7 0x00007cb4d3a2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b) #8 0x00007cb4d3a39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96) #9 0x00000000071d26aa clang::VarDecl::getInit() (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x71d26aa) #10 0x00000000071e2813 clang::VarDecl::isUsableInConstantExpressions(clang::ASTContext const&) const (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x71e2813) #11 0x000000000660582c clang::Sema::getNonOdrUseReasonInCurrentContext(clang::ValueDecl*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x660582c) #12 0x0000000006686d11 clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::DeclarationNameInfo const&, clang::NestedNameSpecifierLoc, clang::NamedDecl*, clang::SourceLocation, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6686d11) #13 0x000000000668754c clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::DeclarationNameInfo const&, clang::CXXScopeSpec const*, clang::NamedDecl*, clang::SourceLocation, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x668754c) #14 0x000000000668c721 clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x668c721) #15 0x00000000066b9c82 clang::Sema::ActOnBlockStmtExpr(clang::SourceLocation, clang::Stmt*, clang::Scope*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x66b9c82) #16 0x0000000006c6641f clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformBlockExpr(clang::BlockExpr*) SemaTemplateInstantiate.cpp:0:0 #17 0x0000000006c29100 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0 #18 0x0000000006c5eedf clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0 #19 0x0000000006c5fac4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0 #20 0x0000000006c65f4a clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6c65f4a) #21 0x0000000006cb6486 clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6cb6486) #22 0x0000000006251ba1 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6251ba1) #23 0x0000000006b9ac42 clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6b9ac42) #24 0x0000000006641d3a clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRefclang::SourceLocation, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6641d3a) #25 0x00000000069e1a07 CreateFunctionRefExpr(clang::Sema&, clang::FunctionDecl*, clang::NamedDecl*, clang::Expr const*, bool, clang::SourceLocation, clang::DeclarationNameLoc const&) SemaOverload.cpp:0:0 #26 0x0000000006a1e696 clang::Sema::BuildCallToObjectOfClassType(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRefclang::Expr*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6a1e696) #27 0x00000000066b515e clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRefclang::Expr*, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x66b515e) #28 0x00000000066b6f3c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRefclang::Expr*, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x66b6f3c) #29 0x000000000616d065 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x616d065) #30 0x0000000006164731 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6164731) #31 0x000000000616795a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x616795a) #32 0x0000000006167af9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6167af9) #33 0x000000000616c619 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x616c619) #34 0x00000000061e7e89 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x61e7e89) #35 0x00000000061de757 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x61de757) #36 0x00000000061df5f7 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x61df5f7) #37 0x00000000061e0519 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x61e0519) #38 0x00000000061e1e3a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x61e1e3a) #39 0x0000000006100951 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6100951) #40 0x0000000006135b11 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x6135b11) #41 0x00000000060f4adb clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x60f4adb) #42 0x00000000060f5261 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x60f5261) #43 0x00000000060fc516 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x60fc516) #44 0x00000000060fd3bd clang::Parser::ParseTopLevelDecl(clang::OpaquePtrclang::DeclGroupRef&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x60fd3bd) #45 0x00000000060f02ea clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x60f02ea) #46 0x000000000415d928 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x415d928) #47 0x00000000043cbfe9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x43cbfe9) #48 0x000000000434ba9e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x434ba9e) #49 0x00000000044ab01e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x44ab01e) #50 0x0000000000c10cd6 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0xc10cd6) #51 0x0000000000c084fa ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0 #52 0x000000000419ee49 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optionalllvm::StringRef>, std::__cxx11::basic_string<char, std::char_traits, std::allocator>, bool) const::'lambda'()>(long) Job.cpp:0:0 #53 0x000000000381bf54 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x381bf54) #54 0x000000000419f43f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optionalllvm::StringRef>, std::__cxx11::basic_string<char, std::char_traits, std::allocator>, bool) const (.part.0) Job.cpp:0:0 #55 0x00000000041671c5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x41671c5) #56 0x0000000004167c2d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x4167c2d) #57 0x000000000416fb65 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0x416fb65) #58 0x0000000000c0e06c clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0xc0e06c) #59 0x0000000000b05134 main (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0xb05134) #60 0x00007cb4d3a29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90) #61 0x00007cb4d3a29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40) #62 0x0000000000c07fde _start (/opt/compiler-explorer/clang-assertions-18.1.0/bin/clang+++0xc07fde) clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation) Compiler returned: 134