[clang] crash when parsing function body

[5chmidti]

I found this minimal example that crashes in the Parser.
The example is the smallest example I could extract from the bigger project it's in, so the code might look weird.
C++20 is not required for the crash to happen.
The clang version I used was compiled from HEAD a few hours ago (git sha in log).

struct Vec {
  double x;
};

template <typename T>
struct Foo {
  int bar() {
    auto& [min_x] = min;
    return min_x;
  }

  Vec min;
};

# Crash reproducer for clang version 15.0.0 (https://github.com/llvm/llvm-project.git fc604825ec0a6ed164e9d047ca1489eb7f0fbf39)
# Driver args: "--driver-mode=g++" "-c" "/home/user/dev/tmp/source/main.cpp" "-std=c++20"
# Original command:  "/tmp/test-clang-ast-crash/build/bin/clang-13" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-obj" "-mrelax-all" "--mrelax-relocations" "-disable-free" "-clear-ast-before-backend" "-main-file-name" "main.cpp" "-mrelocation-model" "static" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-mllvm" "-treat-scalable-fixed-error-as-warning" "-debugger-tuning=gdb" "-fcoverage-compilation-dir=/tmp/test-clang-ast-crash/build" "-resource-dir" "/tmp/test-clang-ast-crash/build/lib/clang/15.0.0" "-internal-isystem" "/usr/lib64/gcc/x86_64-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0" "-internal-isystem" "/usr/lib64/gcc/x86_64-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0/x86_64-pc-linux-gnu" "-internal-isystem" "/usr/lib64/gcc/x86_64-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0/backward" "-internal-isystem" "/tmp/test-clang-ast-crash/build/lib/clang/15.0.0/include" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/usr/lib64/gcc/x86_64-pc-linux-gnu/11.1.0/../../../../x86_64-pc-linux-gnu/include" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-std=c++20" "-fdeprecated-macro" "-fdebug-compilation-dir=/tmp/test-clang-ast-crash/build" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fcxx-exceptions" "-fexceptions" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-o" "main.o" "-x" "c++" "/home/user/dev/tmp/source/main.cpp"
 "/tmp/test-clang-ast-crash/build/bin/clang-13" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-obj" "-mrelax-all" "--mrelax-relocations" "-disable-free" "-clear-ast-before-backend" "-main-file-name" "main.cpp" "-mrelocation-model" "static" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-mllvm" "-treat-scalable-fixed-error-as-warning" "-debugger-tuning=gdb" "-fcoverage-compilation-dir=/tmp/test-clang-ast-crash/build" "-std=c++20" "-fdeprecated-macro" "-fdebug-compilation-dir=/tmp/test-clang-ast-crash/build" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fcxx-exceptions" "-fexceptions" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-x" "c++" "main-4e7a5b.cpp"

clang++: /tmp/test-clang-ast-crash/clang/lib/AST/ExprConstant.cpp:3314: bool evaluateVarDeclInit((anonymous namespace)::EvalInfo &, const clang::Expr *, const clang::VarDecl *, (anonymous namespace)::CallStackFrame *, unsigned int, clang::APValue *&): Assertion `!VD->mightBeUsableInConstantExpressions(Info.Ctx)' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: ./bin/clang++ -c /home/user/dev/tmp/source/main.cpp -std=c++20
1.      /home/user/dev/tmp/source/main.cpp:121:17: current parser token ';'
2.      /home/user/dev/tmp/source/main.cpp:118:1: parsing struct/union/class body 'Foo'
3.      /home/user/dev/tmp/source/main.cpp:119:13: parsing function body 'Foo::bar'
4.      /home/user/dev/tmp/source/main.cpp:119:13: in compound statement ('{}')
 #0 0x0000000001d47af3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (./bin/clang+++0x1d47af3)
 #1 0x0000000001d4589e llvm::sys::RunSignalHandlers() (./bin/clang+++0x1d4589e)
 #2 0x0000000001cc2fe3 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) CrashRecoveryContext.cpp:0:0
 #3 0x0000000001cc318e CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #4 0x00007fe9b9a1a870 __restore_rt sigaction.c:0:0
 #5 0x00007fe9b9461d22 raise (/usr/lib/libc.so.6+0x3cd22)
 #6 0x00007fe9b944b862 abort (/usr/lib/libc.so.6+0x26862)
 #7 0x00007fe9b944b747 _nl_load_domain.cold loadmsgcat.c:0:0
 #8 0x00007fe9b945a616 (/usr/lib/libc.so.6+0x35616)
 #9 0x00000000045d73d3 (./bin/clang+++0x45d73d3)
#10 0x000000000462e33b (anonymous namespace)::LValueExprEvaluator::VisitVarDecl(clang::Expr const*, clang::VarDecl const*) ExprConstant.cpp:0:0
#11 0x00000000045d1f65 (anonymous namespace)::LValueExprEvaluator::VisitMemberExpr(clang::MemberExpr const*) ExprConstant.cpp:0:0
#12 0x00000000045c2f91 EvaluateLValue(clang::Expr const*, (anonymous namespace)::LValue&, (anonymous namespace)::EvalInfo&, bool) ExprConstant.cpp:0:0
#13 0x00000000045c92a0 Evaluate(clang::APValue&, (anonymous namespace)::EvalInfo&, clang::Expr const*) ExprConstant.cpp:0:0
#14 0x00000000045c6561 EvaluateAsRValue((anonymous namespace)::EvalInfo&, clang::Expr const*, clang::APValue&) ExprConstant.cpp:0:0
#15 0x00000000045c1bd7 clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult&, clang::ASTContext const&, bool) const (./bin/clang+++0x45c1bd7)
#16 0x00000000045c2976 clang::Expr::EvaluateAsFloat(llvm::APFloat&, clang::ASTContext const&, clang::Expr::SideEffectsKind, bool) const (./bin/clang+++0x45c2976)
#17 0x0000000003a4a00f DiagnoseFloatingImpCast(clang::Sema&, clang::Expr*, clang::QualType, clang::SourceLocation) SemaChecking.cpp:0:0
#18 0x0000000003a4875e CheckImplicitConversion(clang::Sema&, clang::Expr*, clang::QualType, clang::SourceLocation, bool*, bool) SemaChecking.cpp:0:0
#19 0x0000000003a3d0da AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) SemaChecking.cpp:0:0
#20 0x0000000003a400b0 clang::Sema::CheckCompletedExpr(clang::Expr*, clang::SourceLocation, bool) (./bin/clang+++0x3a400b0)
#21 0x0000000003d72c86 clang::Sema::ActOnFinishFullExpr(clang::Expr*, clang::SourceLocation, bool, bool) (./bin/clang+++0x3d72c86)
#22 0x0000000003f9d593 clang::Sema::BuildReturnStmt(clang::SourceLocation, clang::Expr*, bool) (./bin/clang+++0x3f9d593)
#23 0x0000000003f9ca02 clang::Sema::ActOnReturnStmt(clang::SourceLocation, clang::Expr*, clang::Scope*) (./bin/clang+++0x3f9ca02)
#24 0x0000000003989388 clang::Parser::ParseReturnStatement() (./bin/clang+++0x3989388)
#25 0x00000000039825c0 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributesWithRange&) (./bin/clang+++0x39825c0)
#26 0x0000000003981dd3 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (./bin/clang+++0x3981dd3)
#27 0x000000000398b611 clang::Parser::ParseCompoundStatementBody(bool) (./bin/clang+++0x398b611)
#28 0x000000000398c4b0 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (./bin/clang+++0x398c4b0)
#29 0x00000000038dad0f clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (./bin/clang+++0x38dad0f)
#30 0x00000000038d915a clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (./bin/clang+++0x38d915a)
#31 0x000000000390f47a clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributesWithRange&, unsigned int, clang::Decl*) (./bin/clang+++0x390f47a)
#32 0x000000000390c6c5 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributesWithRange&) (./bin/clang+++0x390c6c5)
#33 0x00000000038e98aa clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*) (./bin/clang+++0x38e98aa)
#34 0x0000000003994aa5 clang::Parser::ParseSingleDeclarationAfterTemplate(clang::DeclaratorContext, clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (./bin/clang+++0x3994aa5)
#35 0x0000000003993bc7 clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (./bin/clang+++0x3993bc7)
#36 0x000000000399346e clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (./bin/clang+++0x399346e)
#37 0x00000000038e87e5 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributesWithRange&, clang::SourceLocation*) (./bin/clang+++0x38e87e5)
#38 0x00000000038cbf9a clang::Parser::ParseExternalDeclaration(clang::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) (./bin/clang+++0x38cbf9a)
#39 0x00000000038ca7a8 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, bool) (./bin/clang+++0x38ca7a8)
#40 0x00000000038c4bbd clang::ParseAST(clang::Sema&, bool, bool) (./bin/clang+++0x38c4bbd)
#41 0x00000000026dcb00 clang::FrontendAction::Execute() (./bin/clang+++0x26dcb00)
#42 0x0000000002654d8f clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (./bin/clang+++0x2654d8f)
#43 0x000000000279d7e3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (./bin/clang+++0x279d7e3)
#44 0x0000000000a12e81 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (./bin/clang+++0xa12e81)
#45 0x0000000000a10880 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#46 0x00000000024e08f2 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, bool*) const::$_1>(long) Job.cpp:0:0
#47 0x0000000001cc2ef7 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (./bin/clang+++0x1cc2ef7)
#48 0x00000000024e0330 clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, bool*) const (./bin/clang+++0x24e0330)
#49 0x00000000024a73e8 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&) const (./bin/clang+++0x24a73e8)
#50 0x00000000024a76b7 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const (./bin/clang+++0x24a76b7)
#51 0x00000000024c18e1 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) (./bin/clang+++0x24c18e1)
#52 0x0000000000a10131 main (./bin/clang+++0xa10131)
#53 0x00007fe9b944cb25 __libc_start_main (/usr/lib/libc.so.6+0x27b25)
#54 0x0000000000a0d61e _start (./bin/clang+++0xa0d61e)
clang-13: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 15.0.0 (https://github.com/llvm/llvm-project.git fc604825ec0a6ed164e9d047ca1489eb7f0fbf39)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /tmp/test-clang-ast-crash/build/./bin

[5chmidti]

Also to note: clang on godbolt does not seem to crash (https://godbolt.org/z/Ghv13deM8), as well as the clang 13 versions provided by my distro (manjaro).

Can be closed if you consider it user/setup error while building.

[llvmbot]

@llvm/issue-subscribers-bug

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[5chmidti]

Closing.
Tested with locally build clang-14 compiler and it works (tag: llvmorg-14.0.0), there was probably something under active development that temporarily broke this for me.

[DimitryAndric]

This problem still occurs on main as of d119c38 (llvmorg-17-init-14883-gd119c386cd7):

Command:

$ ~/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang -cc1 -S -std=c++17 pr53598.cpp

Assertion:

Assertion failed: (!VD->mightBeUsableInConstantExpressions(Info.Ctx))
function evaluateVarDeclInit, file /home/dim/src/llvm/llvm-project/clang/lib/AST/ExprConstant.cpp, line 3314.

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: /home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang -cc1 -S -std=c++17 pr53598.cpp
1.      pr53598.cpp:9:17: current parser token ';'
2.      pr53598.cpp:6:1: parsing struct/union/class body 'Foo'
3.      pr53598.cpp:7:13: parsing function body 'Foo::bar'
4.      pr53598.cpp:7:13: in compound statement ('{}')
 #0 0x00000000042e3ac7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x42e3ac7)
 #1 0x00000000042e18a8 llvm::sys::RunSignalHandlers() (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x42e18a8)
 #2 0x00000000042e42a0 SignalHandler(int) Signals.cpp:0:0
 #3 0x0000000829d3ba3e handle_signal /usr/src/lib/libthr/thread/thr_sig.c:0:3
 #4 0x0000000829d3aff9 thr_sighandler /usr/src/lib/libthr/thread/thr_sig.c:247:1
 #5 0x0000000828842903 ([vdso]+0x2d3)
 #6 0x000000082dcc697a __sys_thr_kill /usr/obj/usr/src/lib/libc/thr_kill.S:4:0
 #7 0x000000082dc3f954 __raise /usr/src/lib/libc/gen/raise.c:0:10
 #8 0x000000082dcf03e9 abort /usr/src/lib/libc/stdlib/abort.c:73:17
 #9 0x000000082dc22a41 (/lib/libc.so.7+0x93a41)
#10 0x0000000006a779a6 (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x6a779a6)
#11 0x0000000006acd7dd (anonymous namespace)::LValueExprEvaluator::VisitVarDecl(clang::Expr const*, clang::VarDecl const*) ExprConstant.cpp:0:0
#12 0x0000000006a72854 (anonymous namespace)::LValueExprEvaluator::VisitMemberExpr(clang::MemberExpr const*) ExprConstant.cpp:0:0
#13 0x0000000006a6657b EvaluateLValue(clang::Expr const*, (anonymous namespace)::LValue&, (anonymous namespace)::EvalInfo&, bool) ExprConstant.cpp:0:0
#14 0x0000000006a6b449 Evaluate(clang::APValue&, (anonymous namespace)::EvalInfo&, clang::Expr const*) ExprConstant.cpp:0:0
#15 0x0000000006a691a8 EvaluateAsRValue((anonymous namespace)::EvalInfo&, clang::Expr const*, clang::APValue&) ExprConstant.cpp:0:0
#16 0x0000000006a6549c clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult&, clang::ASTContext const&, bool) const (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x6a6549c)
#17 0x0000000006a6612a clang::Expr::EvaluateAsFloat(llvm::APFloat&, clang::ASTContext const&, clang::Expr::SideEffectsKind, bool) const (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x6a6612a)
#18 0x0000000005ddfcf4 DiagnoseFloatingImpCast(clang::Sema&, clang::Expr*, clang::QualType, clang::SourceLocation) SemaChecking.cpp:0:0
#19 0x0000000005dde453 CheckImplicitConversion(clang::Sema&, clang::Expr*, clang::QualType, clang::SourceLocation, bool*, bool) SemaChecking.cpp:0:0
#20 0x0000000005dd0c5f AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) SemaChecking.cpp:0:0
#21 0x0000000005dd3b9e clang::Sema::CheckCompletedExpr(clang::Expr*, clang::SourceLocation, bool) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5dd3b9e)
#22 0x000000000621f11d clang::Sema::ActOnFinishFullExpr(clang::Expr*, clang::SourceLocation, bool, bool, bool) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x621f11d)
#23 0x000000000645bb5d clang::Sema::BuildReturnStmt(clang::SourceLocation, clang::Expr*, bool) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x645bb5d)
#24 0x000000000645b047 clang::Sema::ActOnReturnStmt(clang::SourceLocation, clang::Expr*, clang::Scope*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x645b047)
#25 0x0000000005ca1c9d clang::Parser::ParseReturnStatement() (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5ca1c9d)
#26 0x0000000005c9b122 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c9b122)
#27 0x0000000005c9a2e9 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c9a2e9)
#28 0x0000000005ca4140 clang::Parser::ParseCompoundStatementBody(bool) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5ca4140)
#29 0x0000000005ca505e clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5ca505e)
#30 0x0000000005c980ab clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c980ab)
#31 0x0000000005c966ba clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c966ba)
#32 0x0000000005c3d17b clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c3d17b)
#33 0x0000000005c3aaa0 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c3aaa0)
#34 0x0000000005c5dae3 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c5dae3)
#35 0x0000000005c8c48c clang::Parser::ParseSingleDeclarationAfterTemplate(clang::DeclaratorContext, clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c8c48c)
#36 0x0000000005c8b50a clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c8b50a)
#37 0x0000000005c8adfc clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c8adfc)
#38 0x0000000005c57b2b clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5c57b2b)
#39 0x0000000005be88e0 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5be88e0)
#40 0x0000000005be696f clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5be696f)
#41 0x0000000005be0ece clang::ParseAST(clang::Sema&, bool, bool) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x5be0ece)
#42 0x0000000004d791e3 clang::FrontendAction::Execute() (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x4d791e3)
#43 0x0000000004cfc9bf clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x4cfc9bf)
#44 0x0000000004e4cb24 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x4e4cb24)
#45 0x00000000028be79b cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x28be79b)
#46 0x00000000028ba054 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#47 0x00000000028b8eea clang_main(int, char**, llvm::ToolContext const&) (/home/dim/ins/llvmorg-17-init-14883-gd119c386cd7/bin/clang+0x28b8eea)
Abort trap

As far as I can determine, this has been introduced in 00068c4 (llvmorg-11-init-20261-g00068c452a5) by @zygoloid. The problem was reported earlier in Bugzilla by @sks75220, and it got migrated as #46209.

In that bug a review https://reviews.llvm.org/D86649 was posted, but that review was never completed, and this problem still exists in main as of 2023-06-18, so I am reopening this issue.

[DimitryAndric]

Note the problem only occurs when assertions are enabled, so this can't be tested on godbolt. :)

[shafik]

It can be tested on godbolt, it has an assertions build of trunk: https://godbolt.org/z/ETs7hzTYn

[DimitryAndric]

It can be tested on godbolt, it has an assertions build of trunk: https://godbolt.org/z/ETs7hzTYn

Ah, there is actually an "assertions trunk" setting there, I was not aware of it. Thanks!