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[clang++] Frontend assertion failure in clang::Sema::tryCaptureVariable #112632

Open yype opened 1 month ago

yype commented 1 month ago

Hi there, clang++ crashes from an assertion failure on the following invalid test case:

a = ^ b ( c < ({d e ( int a,[(a]))>>

Tested version(s): only 19.1.0 and trunk (assertions build).

Example: https://godbolt.org/z/E4qvYMb5x

Stack dump ``` clang++: /root/llvm-project/llvm/include/llvm/ADT/SmallVector.h:291: T& llvm::SmallVectorTemplateCommon >::operator[](llvm::SmallVectorTemplateCommon >::size_type) [with T = clang::sema::FunctionScopeInfo*; = void; llvm::SmallVectorTemplateCommon >::reference = clang::sema::FunctionScopeInfo*&; llvm::SmallVectorTemplateCommon >::size_type = long unsigned int]: Assertion `idx < size()' 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 1. :1:32: current parser token ']' 2. :1:5: block literal parsing 3. :1:16: in compound statement ('{}') #0 0x0000000003bb1d58 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bb1d58) #1 0x0000000003bafa1c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bafa1c) #2 0x0000000003afcd68 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0 #3 0x00007be3d8842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520) #4 0x00007be3d88969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc) #5 0x00007be3d8842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476) #6 0x00007be3d88287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3) #7 0x00007be3d882871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b) #8 0x00007be3d8839e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96) #9 0x0000000006c17d5a clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c17d5a) #10 0x0000000006c18281 clang::Sema::getCapturedDeclRefType(clang::ValueDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c18281) #11 0x0000000006c57df2 clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c57df2) #12 0x0000000006c5818f clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::LookupResult&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c5818f) #13 0x00000000069ca169 clang::Sema::ActOnNameClassifiedAsNonType(clang::Scope*, clang::CXXScopeSpec const&, clang::NamedDecl*, clang::SourceLocation, clang::Token const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69ca169) #14 0x0000000006702b3e clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&, bool, clang::Token&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6702b3e) #15 0x00000000066e5626 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5626) #16 0x00000000066e7147 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e7147) #17 0x00000000066e71d9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e71d9) #18 0x00000000066ebbf9 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ebbf9) #19 0x00000000066eff2d clang::Parser::ParseParenExpression(clang::Parser::ParenParseOption&, bool, bool, clang::OpaquePtr&, clang::SourceLocation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66eff2d) #20 0x00000000066e5ea1 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5ea1) #21 0x00000000066f2c23 clang::Parser::ParseArrayBoundExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f2c23) #22 0x00000000066ad42f clang::Parser::ParseBracketDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ad42f) #23 0x00000000066bf14b clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bf14b) #24 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #25 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #26 0x00000000066b8f60 clang::Parser::ParseParameterDeclarationClause(clang::DeclaratorContext, clang::ParsedAttributes&, llvm::SmallVectorImpl&, clang::SourceLocation&, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b8f60) #27 0x00000000066ba248 clang::Parser::ParseFunctionDeclarator(clang::Declarator&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ba248) #28 0x00000000066bf35f clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bf35f) #29 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #30 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #31 0x00000000066af3e7 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+++0x66af3e7) #32 0x00000000066b8437 clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b8437) #33 0x00000000066b88f9 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b88f9) #34 0x0000000006764f72 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6764f72) #35 0x0000000006765ca0 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6765ca0) #36 0x0000000006766b75 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6766b75) #37 0x00000000067683da clang::Parser::ParseCompoundStatement(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67683da) #38 0x00000000066f03ca clang::Parser::ParseParenExpression(clang::Parser::ParenParseOption&, bool, bool, clang::OpaquePtr&, clang::SourceLocation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f03ca) #39 0x00000000066e5ea1 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5ea1) #40 0x00000000066f2d1e clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f2d1e) #41 0x00000000067795d4 clang::Parser::ParseTemplateArgument() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67795d4) #42 0x0000000006781527 clang::Parser::ParseTemplateArgumentList(llvm::SmallVector&, clang::OpaquePtr, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6781527) #43 0x00000000067818d7 clang::Parser::ParseTemplateIdAfterTemplateName(bool, clang::SourceLocation&, llvm::SmallVector&, clang::SourceLocation&, clang::OpaquePtr) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67818d7) #44 0x0000000006781ab1 clang::Parser::AnnotateTemplateIdToken(clang::OpaquePtr, clang::TemplateNameKind, clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6781ab1) #45 0x00000000066ffb87 clang::Parser::ParseOptionalCXXScopeSpecifier(clang::CXXScopeSpec&, clang::OpaquePtr, bool, bool, bool*, bool, clang::IdentifierInfo const**, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ffb87) #46 0x00000000066711e3 clang::Parser::TryAnnotateTypeOrScopeToken(clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66711e3) #47 0x000000000669be63 clang::Parser::isDeclarationSpecifier(clang::ImplicitTypenameContext, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x669be63) #48 0x00000000066bb0fe clang::Parser::ParseParenDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bb0fe) #49 0x00000000066bed88 clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bed88) #50 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #51 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #52 0x000000000669b9bf clang::Parser::ParseDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x669b9bf) #53 0x00000000066e12a0 clang::Parser::ParseBlockId(clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e12a0) #54 0x00000000066e17e3 clang::Parser::ParseBlockLiteralExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e17e3) #55 0x00000000066e5aea clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5aea) #56 0x00000000066e7147 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e7147) #57 0x00000000066e71d9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e71d9) #58 0x00000000066a0b08 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a0b08) #59 0x00000000066afb19 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+++0x66afb19) #60 0x000000000666fb8e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666fb8e) #61 0x000000000667034e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x667034e) #62 0x0000000006677ae3 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6677ae3) #63 0x00000000066789cd clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66789cd) #64 0x0000000006678e70 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6678e70) #65 0x000000000666aeb2 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666aeb2) #66 0x0000000004526408 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4526408) #67 0x00000000047e0629 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e0629) #68 0x000000000475f1ae clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x475f1ae) #69 0x00000000048c5dce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48c5dce) #70 0x0000000000cdce6f cc1_main(llvm::ArrayRef, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcdce6f) #71 0x0000000000cd4b7a ExecuteCC1Tool(llvm::SmallVectorImpl&, llvm::ToolContext const&) driver.cpp:0:0 #72 0x000000000456a119 void llvm::function_ref::callback_fn>, std::__cxx11::basic_string, std::allocator>*, bool*) const::'lambda'()>(long) Job.cpp:0:0 #73 0x0000000003afd214 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3afd214) #74 0x000000000456a70f clang::driver::CC1Command::Execute(llvm::ArrayRef>, std::__cxx11::basic_string, std::allocator>*, bool*) const (.part.0) Job.cpp:0:0 #75 0x000000000453000d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x453000d) #76 0x00000000045310fd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x45310fd) #77 0x0000000004538a25 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4538a25) #78 0x0000000000cd9d3f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd9d3f) #79 0x0000000000ba9264 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xba9264) #80 0x00007be3d8829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90) #81 0x00007be3d8829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40) #82 0x0000000000cd462e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd462e) clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation) Compiler returned: 134 ```

Although the assertion failure is similar to those in #107840 and #69470, the test case provided in this issue triggers the failure only in versions 19.1.0 and the trunk. In contrast, the test cases in #107840 and #69470 both trigger the failure from version 17.0.1 to the trunk. Therefore, I believe the underlying root causes are different, which is why I am opening a new issue.

The test case was generated by a fuzzer.

shafik commented 1 month ago

CC @zyn0217 since you fixed a bunch of these cases in https://github.com/llvm/llvm-project/pull/93206 maybe this arose out of that fix somehow?

llvmbot commented 1 month ago

@llvm/issue-subscribers-clang-frontend

Author: yype (yype)

Hi there, clang++ crashes from an assertion failure on the following invalid test case: ```cpp a = ^ b ( c < ({d e ( int a,[(a]))>> ``` Tested version(s): only 19.1.0 and trunk (assertions build). Example: https://godbolt.org/z/E4qvYMb5x <details> <summary>Stack dump</summary> ``` clang++: /root/llvm-project/llvm/include/llvm/ADT/SmallVector.h:291: T& llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::operator[](llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type) [with T = clang::sema::FunctionScopeInfo*; <template-parameter-1-2> = void; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::reference = clang::sema::FunctionScopeInfo*&; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type = long unsigned int]: Assertion `idx < size()' 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 <source> 1. <source>:1:32: current parser token ']' 2. <source>:1:5: block literal parsing 3. <source>:1:16: in compound statement ('{}') #0 0x0000000003bb1d58 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bb1d58) #1 0x0000000003bafa1c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bafa1c) #2 0x0000000003afcd68 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0 #3 0x00007be3d8842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520) #4 0x00007be3d88969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc) #5 0x00007be3d8842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476) #6 0x00007be3d88287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3) #7 0x00007be3d882871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b) #8 0x00007be3d8839e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96) #9 0x0000000006c17d5a clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c17d5a) #10 0x0000000006c18281 clang::Sema::getCapturedDeclRefType(clang::ValueDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c18281) #11 0x0000000006c57df2 clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c57df2) #12 0x0000000006c5818f clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::LookupResult&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c5818f) #13 0x00000000069ca169 clang::Sema::ActOnNameClassifiedAsNonType(clang::Scope*, clang::CXXScopeSpec const&, clang::NamedDecl*, clang::SourceLocation, clang::Token const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69ca169) #14 0x0000000006702b3e clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&, bool, clang::Token&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6702b3e) #15 0x00000000066e5626 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5626) #16 0x00000000066e7147 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e7147) #17 0x00000000066e71d9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e71d9) #18 0x00000000066ebbf9 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ebbf9) #19 0x00000000066eff2d clang::Parser::ParseParenExpression(clang::Parser::ParenParseOption&, bool, bool, clang::OpaquePtr<clang::QualType>&, clang::SourceLocation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66eff2d) #20 0x00000000066e5ea1 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5ea1) #21 0x00000000066f2c23 clang::Parser::ParseArrayBoundExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f2c23) #22 0x00000000066ad42f clang::Parser::ParseBracketDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ad42f) #23 0x00000000066bf14b clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bf14b) #24 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #25 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #26 0x00000000066b8f60 clang::Parser::ParseParameterDeclarationClause(clang::DeclaratorContext, clang::ParsedAttributes&, llvm::SmallVectorImpl<clang::DeclaratorChunk::ParamInfo>&, clang::SourceLocation&, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b8f60) #27 0x00000000066ba248 clang::Parser::ParseFunctionDeclarator(clang::Declarator&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ba248) #28 0x00000000066bf35f clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bf35f) #29 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #30 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #31 0x00000000066af3e7 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+++0x66af3e7) #32 0x00000000066b8437 clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b8437) #33 0x00000000066b88f9 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66b88f9) #34 0x0000000006764f72 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+++0x6764f72) #35 0x0000000006765ca0 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6765ca0) #36 0x0000000006766b75 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6766b75) #37 0x00000000067683da clang::Parser::ParseCompoundStatement(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67683da) #38 0x00000000066f03ca clang::Parser::ParseParenExpression(clang::Parser::ParenParseOption&, bool, bool, clang::OpaquePtr<clang::QualType>&, clang::SourceLocation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f03ca) #39 0x00000000066e5ea1 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5ea1) #40 0x00000000066f2d1e clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66f2d1e) #41 0x00000000067795d4 clang::Parser::ParseTemplateArgument() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67795d4) #42 0x0000000006781527 clang::Parser::ParseTemplateArgumentList(llvm::SmallVector<clang::ParsedTemplateArgument, 16u>&, clang::OpaquePtr<clang::TemplateName>, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6781527) #43 0x00000000067818d7 clang::Parser::ParseTemplateIdAfterTemplateName(bool, clang::SourceLocation&, llvm::SmallVector<clang::ParsedTemplateArgument, 16u>&, clang::SourceLocation&, clang::OpaquePtr<clang::TemplateName>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67818d7) #44 0x0000000006781ab1 clang::Parser::AnnotateTemplateIdToken(clang::OpaquePtr<clang::TemplateName>, clang::TemplateNameKind, clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6781ab1) #45 0x00000000066ffb87 clang::Parser::ParseOptionalCXXScopeSpecifier(clang::CXXScopeSpec&, clang::OpaquePtr<clang::QualType>, bool, bool, bool*, bool, clang::IdentifierInfo const**, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ffb87) #46 0x00000000066711e3 clang::Parser::TryAnnotateTypeOrScopeToken(clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66711e3) #47 0x000000000669be63 clang::Parser::isDeclarationSpecifier(clang::ImplicitTypenameContext, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x669be63) #48 0x00000000066bb0fe clang::Parser::ParseParenDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bb0fe) #49 0x00000000066bed88 clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66bed88) #50 0x00000000066ac396 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::*)(clang::Declarator&)) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66ac396) #51 0x00000000067e0f81 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67e0f81) #52 0x000000000669b9bf clang::Parser::ParseDeclarator(clang::Declarator&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x669b9bf) #53 0x00000000066e12a0 clang::Parser::ParseBlockId(clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e12a0) #54 0x00000000066e17e3 clang::Parser::ParseBlockLiteralExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e17e3) #55 0x00000000066e5aea clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e5aea) #56 0x00000000066e7147 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e7147) #57 0x00000000066e71d9 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66e71d9) #58 0x00000000066a0b08 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66a0b08) #59 0x00000000066afb19 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+++0x66afb19) #60 0x000000000666fb8e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666fb8e) #61 0x000000000667034e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x667034e) #62 0x0000000006677ae3 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6677ae3) #63 0x00000000066789cd clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66789cd) #64 0x0000000006678e70 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6678e70) #65 0x000000000666aeb2 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x666aeb2) #66 0x0000000004526408 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4526408) #67 0x00000000047e0629 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47e0629) #68 0x000000000475f1ae clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x475f1ae) #69 0x00000000048c5dce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48c5dce) #70 0x0000000000cdce6f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcdce6f) #71 0x0000000000cd4b7a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0 #72 0x000000000456a119 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 #73 0x0000000003afd214 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3afd214) #74 0x000000000456a70f 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 #75 0x000000000453000d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x453000d) #76 0x00000000045310fd 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+++0x45310fd) #77 0x0000000004538a25 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4538a25) #78 0x0000000000cd9d3f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd9d3f) #79 0x0000000000ba9264 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xba9264) #80 0x00007be3d8829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90) #81 0x00007be3d8829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40) #82 0x0000000000cd462e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd462e) clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation) Compiler returned: 134 ``` </details> Although the assertion failure is similar to those in #107840 and #69470, the test case provided in this issue triggers the failure only in versions 19.1.0 and the trunk. In contrast, the test cases in #107840 and #69470 *both* trigger the failure from version 17.0.1 to the trunk. Therefore, I believe the underlying root causes are different, which is why I am opening a new issue. The test case was generated by a fuzzer.