[clang++] Assertion `!Packs.empty() && "Pack expansion without unexpanded packs?"' failed.

[yijan4845]

This testcase is generated by a fuzzer.

Compiler Explorer: https://godbolt.org/z/Mfb3s14Td

This valid code will crash on Clang Assertion Trunk. It seems that this goes back to clang-12:

template <class...> struct Tuple {
  template <class _Up> Tuple(_Up);
};
template <int> using ElementType = int;
template <int... fields>
Tuple<ElementType<fields>...> Parser();
struct Helper { Helper(Tuple<>, Tuple<>); };
struct D : Helper {
  D() : Helper(Parser<>, Parser<>) {}
};

Stack dump:

clang++: /root/llvm-project/clang/lib/Sema/SemaTemplateDeduction.cpp:762: unsigned int {anonymous}::PackDeductionScope::addPacks(clang::TemplateArgument): Assertion `!Packs.empty() && "Pack expansion without unexpanded packs?"' 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: /opt/compiler-explorer/clang-assertions-12.0.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-10.3.0 -fcolor-diagnostics -fno-crash-diagnostics <source>
1.	<source>:9:36: current parser token '{'
2.	<source>:8:1: parsing struct/union/class body 'D'
 #0 0x000056e61da32001 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3606001)
 #1 0x000056e61da2fcb4 llvm::sys::RunSignalHandlers() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3603cb4)
 #2 0x000056e61da2ff51 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3603f51)
 #3 0x000056e61d98e6a8 CrashRecoverySignalHandler(int) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x35626a8)
 #4 0x000072d340442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #5 0x000072d3404969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #6 0x000072d340442476 raise (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #7 0x000072d3404287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #8 0x000072d34042871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #9 0x000072d340439e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#10 0x000056e62037ef85 (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f52f85)
#11 0x000056e62037fa23 DeduceTemplateArguments(clang::Sema&, clang::TemplateParameterList*, clang::TemplateSpecializationType const*, clang::QualType, clang::sema::TemplateDeductionInfo&, llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f53a23)
#12 0x000056e62037bf06 DeduceTemplateArgumentsByTypeMatch(clang::Sema&, clang::TemplateParameterList*, clang::QualType, clang::QualType, clang::sema::TemplateDeductionInfo&, llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&, unsigned int, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f4ff06)
#13 0x000056e62037b3fa DeduceTemplateArgumentsByTypeMatch(clang::Sema&, clang::TemplateParameterList*, clang::QualType, clang::QualType, clang::sema::TemplateDeductionInfo&, llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&, unsigned int, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f4f3fa)
#14 0x000056e620382eb4 clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*, clang::TemplateArgumentListInfo*, clang::QualType, clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f56eb4)
#15 0x000056e6201f9a4f clang::Sema::ResolveAddressOfOverloadedFunction(clang::Expr*, clang::QualType, bool, clang::DeclAccessPair&, bool*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dcda4f)
#16 0x000056e6201fbb6a IsStandardConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::StandardConversionSequence&, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dcfb6a)
#17 0x000056e620207fb3 TryImplicitConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddbfb3)
#18 0x000056e620202364 TryCopyInitialization(clang::Sema&, clang::Expr*, clang::QualType, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd6364)
#19 0x000056e62020429d clang::Sema::AddOverloadCandidate(clang::FunctionDecl*, clang::DeclAccessPair, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool, bool, bool, clang::CallExpr::ADLCallKind, llvm::MutableArrayRef<clang::ImplicitConversionSequence>, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd829d)
#20 0x000056e620204db0 clang::Sema::AddTemplateOverloadCandidate(clang::FunctionTemplateDecl*, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool, bool, clang::CallExpr::ADLCallKind, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd8db0)
#21 0x000056e6202076e6 IsUserDefinedConversion(clang::Sema&, clang::Expr*, clang::QualType, clang::UserDefinedConversionSequence&, clang::OverloadCandidateSet&, clang::Sema::AllowedExplicit, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddb6e6)
#22 0x000056e620207bc5 TryUserDefinedConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (.constprop.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddbbc5)
#23 0x000056e6202081e6 TryImplicitConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddc1e6)
#24 0x000056e620202364 TryCopyInitialization(clang::Sema&, clang::Expr*, clang::QualType, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd6364)
#25 0x000056e62020429d clang::Sema::AddOverloadCandidate(clang::FunctionDecl*, clang::DeclAccessPair, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool, bool, bool, clang::CallExpr::ADLCallKind, llvm::MutableArrayRef<clang::ImplicitConversionSequence>, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd829d)
#26 0x000056e6200a191a ResolveConstructorOverload(clang::Sema&, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, clang::QualType, clang::DeclContextLookupResult, clang::OverloadCandidate*&, bool, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c7591a)
#27 0x000056e6200b2aa9 TryConstructorInitialization(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType, clang::QualType, clang::InitializationSequence&, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c86aa9)
#28 0x000056e6200b594d clang::InitializationSequence::InitializeFrom(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, bool, bool) (.localalias) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c8994d)
#29 0x000056e61fe039b2 clang::Sema::BuildBaseInitializer(clang::QualType, clang::TypeSourceInfo*, clang::Expr*, clang::CXXRecordDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x59d79b2)
#30 0x000056e61fe03d2b clang::Sema::BuildMemInitializer(clang::Decl*, clang::Scope*, clang::CXXScopeSpec&, clang::IdentifierInfo*, clang::OpaquePtr<clang::QualType>, clang::DeclSpec const&, clang::SourceLocation, clang::Expr*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x59d7d2b)
#31 0x000056e61faf3016 clang::Parser::ParseMemInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56c7016)
#32 0x000056e61faf60fb clang::Parser::ParseConstructorInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56ca0fb)
#33 0x000056e61fabe518 clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5692518)
#34 0x000056e61fabe04d clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x569204d)
#35 0x000056e61fb0209e clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::Parser::ParsedAttributesWithRange&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56d609e)
#36 0x000056e61fb043d5 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::Parser::ParsedAttributesWithRange&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56d83d5)
#37 0x000056e61fadf9b5 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56b39b5)
#38 0x000056e61fab4473 clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5688473)
#39 0x000056e61fab4d21 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5688d21)
#40 0x000056e61fabb210 clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) (.localalias) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x568f210)
#41 0x000056e61fabc158 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5690158)
#42 0x000056e61faaf319 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5683319)
#43 0x000056e61eab7b28 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x468bb28)
#44 0x000056e61e3b10c9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3f850c9)
#45 0x000056e61e35068e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3f2468e)
#46 0x000056e61e4873c0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x405b3c0)
#47 0x000056e61b4f911d cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10cd11d)
#48 0x000056e61b4f5818 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10c9818)
#49 0x000056e61e1f5d29 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::'lambda'()>(long) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3dc9d29)
#50 0x000056e61d98e82c llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x356282c)
#51 0x000056e61e1f68c7 clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, bool*) const (.part.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3dca8c7)
#52 0x000056e61e1c96db clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&) const (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3d9d6db)
#53 0x000056e61e1ca1f9 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3d9e1f9)
#54 0x000056e61e1d50b9 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3da90b9)
#55 0x000056e61b42e90d main (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x100290d)
#56 0x000072d340429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#57 0x000072d340429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#58 0x000056e61b4f536e _start (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10c936e)
clang-12: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Yihan Yang (yijan4845)

**This testcase is generated by a fuzzer.**

Compiler Explorer: https://godbolt.org/z/Mfb3s14Td

This valid code will crash on Clang Assertion Trunk. It seems that this goes back to clang-12:

template <class...> struct Tuple {
  template <class _Up> Tuple(_Up);
};
template <int> using ElementType = int;
template <int... fields>
Tuple<ElementType<fields>...> Parser();
struct Helper { Helper(Tuple<>, Tuple<>); };
struct D : Helper {
  D() : Helper(Parser<>, Parser<>) {}
};

Stack dump:

clang++: /root/llvm-project/clang/lib/Sema/SemaTemplateDeduction.cpp:762: unsigned int {anonymous}::PackDeductionScope::addPacks(clang::TemplateArgument): Assertion `!Packs.empty() && "Pack expansion without unexpanded packs?"' 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: /opt/compiler-explorer/clang-assertions-12.0.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-10.3.0 -fcolor-diagnostics -fno-crash-diagnostics <source>
1.	<source>:9:36: current parser token '{'
2.	<source>:8:1: parsing struct/union/class body 'D'
 #<!-- -->0 0x000056e61da32001 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3606001)
 #<!-- -->1 0x000056e61da2fcb4 llvm::sys::RunSignalHandlers() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3603cb4)
 #<!-- -->2 0x000056e61da2ff51 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3603f51)
 #<!-- -->3 0x000056e61d98e6a8 CrashRecoverySignalHandler(int) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x35626a8)
 #<!-- -->4 0x000072d340442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->5 0x000072d3404969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #<!-- -->6 0x000072d340442476 raise (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #<!-- -->7 0x000072d3404287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #<!-- -->8 0x000072d34042871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #<!-- -->9 0x000072d340439e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#<!-- -->10 0x000056e62037ef85 (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f52f85)
#<!-- -->11 0x000056e62037fa23 DeduceTemplateArguments(clang::Sema&amp;, clang::TemplateParameterList*, clang::TemplateSpecializationType const*, clang::QualType, clang::sema::TemplateDeductionInfo&amp;, llvm::SmallVectorImpl&lt;clang::DeducedTemplateArgument&gt;&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f53a23)
#<!-- -->12 0x000056e62037bf06 DeduceTemplateArgumentsByTypeMatch(clang::Sema&amp;, clang::TemplateParameterList*, clang::QualType, clang::QualType, clang::sema::TemplateDeductionInfo&amp;, llvm::SmallVectorImpl&lt;clang::DeducedTemplateArgument&gt;&amp;, unsigned int, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f4ff06)
#<!-- -->13 0x000056e62037b3fa DeduceTemplateArgumentsByTypeMatch(clang::Sema&amp;, clang::TemplateParameterList*, clang::QualType, clang::QualType, clang::sema::TemplateDeductionInfo&amp;, llvm::SmallVectorImpl&lt;clang::DeducedTemplateArgument&gt;&amp;, unsigned int, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f4f3fa)
#<!-- -->14 0x000056e620382eb4 clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*, clang::TemplateArgumentListInfo*, clang::QualType, clang::FunctionDecl*&amp;, clang::sema::TemplateDeductionInfo&amp;, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5f56eb4)
#<!-- -->15 0x000056e6201f9a4f clang::Sema::ResolveAddressOfOverloadedFunction(clang::Expr*, clang::QualType, bool, clang::DeclAccessPair&amp;, bool*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dcda4f)
#<!-- -->16 0x000056e6201fbb6a IsStandardConversion(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, clang::StandardConversionSequence&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dcfb6a)
#<!-- -->17 0x000056e620207fb3 TryImplicitConversion(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddbfb3)
#<!-- -->18 0x000056e620202364 TryCopyInitialization(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd6364)
#<!-- -->19 0x000056e62020429d clang::Sema::AddOverloadCandidate(clang::FunctionDecl*, clang::DeclAccessPair, llvm::ArrayRef&lt;clang::Expr*&gt;, clang::OverloadCandidateSet&amp;, bool, bool, bool, bool, clang::CallExpr::ADLCallKind, llvm::MutableArrayRef&lt;clang::ImplicitConversionSequence&gt;, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd829d)
#<!-- -->20 0x000056e620204db0 clang::Sema::AddTemplateOverloadCandidate(clang::FunctionTemplateDecl*, clang::DeclAccessPair, clang::TemplateArgumentListInfo*, llvm::ArrayRef&lt;clang::Expr*&gt;, clang::OverloadCandidateSet&amp;, bool, bool, bool, clang::CallExpr::ADLCallKind, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd8db0)
#<!-- -->21 0x000056e6202076e6 IsUserDefinedConversion(clang::Sema&amp;, clang::Expr*, clang::QualType, clang::UserDefinedConversionSequence&amp;, clang::OverloadCandidateSet&amp;, clang::Sema::AllowedExplicit, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddb6e6)
#<!-- -->22 0x000056e620207bc5 TryUserDefinedConversion(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (.constprop.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddbbc5)
#<!-- -->23 0x000056e6202081e6 TryImplicitConversion(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5ddc1e6)
#<!-- -->24 0x000056e620202364 TryCopyInitialization(clang::Sema&amp;, clang::Expr*, clang::QualType, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd6364)
#<!-- -->25 0x000056e62020429d clang::Sema::AddOverloadCandidate(clang::FunctionDecl*, clang::DeclAccessPair, llvm::ArrayRef&lt;clang::Expr*&gt;, clang::OverloadCandidateSet&amp;, bool, bool, bool, bool, clang::CallExpr::ADLCallKind, llvm::MutableArrayRef&lt;clang::ImplicitConversionSequence&gt;, clang::OverloadCandidateParamOrder) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5dd829d)
#<!-- -->26 0x000056e6200a191a ResolveConstructorOverload(clang::Sema&amp;, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::OverloadCandidateSet&amp;, clang::QualType, clang::DeclContextLookupResult, clang::OverloadCandidate*&amp;, bool, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c7591a)
#<!-- -->27 0x000056e6200b2aa9 TryConstructorInitialization(clang::Sema&amp;, clang::InitializedEntity const&amp;, clang::InitializationKind const&amp;, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::QualType, clang::QualType, clang::InitializationSequence&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c86aa9)
#<!-- -->28 0x000056e6200b594d clang::InitializationSequence::InitializeFrom(clang::Sema&amp;, clang::InitializedEntity const&amp;, clang::InitializationKind const&amp;, llvm::MutableArrayRef&lt;clang::Expr*&gt;, bool, bool) (.localalias) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5c8994d)
#<!-- -->29 0x000056e61fe039b2 clang::Sema::BuildBaseInitializer(clang::QualType, clang::TypeSourceInfo*, clang::Expr*, clang::CXXRecordDecl*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x59d79b2)
#<!-- -->30 0x000056e61fe03d2b clang::Sema::BuildMemInitializer(clang::Decl*, clang::Scope*, clang::CXXScopeSpec&amp;, clang::IdentifierInfo*, clang::OpaquePtr&lt;clang::QualType&gt;, clang::DeclSpec const&amp;, clang::SourceLocation, clang::Expr*, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x59d7d2b)
#<!-- -->31 0x000056e61faf3016 clang::Parser::ParseMemInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56c7016)
#<!-- -->32 0x000056e61faf60fb clang::Parser::ParseConstructorInitializer(clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56ca0fb)
#<!-- -->33 0x000056e61fabe518 clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5692518)
#<!-- -->34 0x000056e61fabe04d clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x569204d)
#<!-- -->35 0x000056e61fb0209e clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::Parser::ParsedAttributesWithRange&amp;, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56d609e)
#<!-- -->36 0x000056e61fb043d5 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&amp;, clang::Parser::ParsedTemplateInfo const&amp;, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::Parser::ParsedAttributesWithRange&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56d83d5)
#<!-- -->37 0x000056e61fadf9b5 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&amp;, clang::Parser::ParsedTemplateInfo const&amp;, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x56b39b5)
#<!-- -->38 0x000056e61fab4473 clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&amp;, clang::ParsingDeclSpec&amp;, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5688473)
#<!-- -->39 0x000056e61fab4d21 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&amp;, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5688d21)
#<!-- -->40 0x000056e61fabb210 clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&amp;, clang::ParsingDeclSpec*) (.localalias) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x568f210)
#<!-- -->41 0x000056e61fabc158 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&lt;clang::DeclGroupRef&gt;&amp;, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5690158)
#<!-- -->42 0x000056e61faaf319 clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x5683319)
#<!-- -->43 0x000056e61eab7b28 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x468bb28)
#<!-- -->44 0x000056e61e3b10c9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3f850c9)
#<!-- -->45 0x000056e61e35068e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3f2468e)
#<!-- -->46 0x000056e61e4873c0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x405b3c0)
#<!-- -->47 0x000056e61b4f911d cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10cd11d)
#<!-- -->48 0x000056e61b4f5818 ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10c9818)
#<!-- -->49 0x000056e61e1f5d29 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;llvm::Optional&lt;llvm::StringRef&gt; &gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;*, bool*) const::'lambda'()&gt;(long) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3dc9d29)
#<!-- -->50 0x000056e61d98e82c llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x356282c)
#<!-- -->51 0x000056e61e1f68c7 clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;llvm::Optional&lt;llvm::StringRef&gt; &gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;*, bool*) const (.part.0) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3dca8c7)
#<!-- -->52 0x000056e61e1c96db clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;) const (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3d9d6db)
#<!-- -->53 0x000056e61e1ca1f9 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt; &gt;&amp;) const (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3d9e1f9)
#<!-- -->54 0x000056e61e1d50b9 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt; &gt;&amp;) (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x3da90b9)
#<!-- -->55 0x000056e61b42e90d main (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x100290d)
#<!-- -->56 0x000072d340429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->57 0x000072d340429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->58 0x000056e61b4f536e _start (/opt/compiler-explorer/clang-assertions-12.0.0/bin/clang+++0x10c936e)
clang-12: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

[shafik]

Looks very similar to: #100095

CC @mizvekov

[shafik]

@yijan4845 it would be helpful to try and look or related issues, often the backtrace won't exactly match so they are exact duplicates but often linking related issues with similar backtraces could help in debugging or writing best test cases when submitting a fix.

[yijan4845]

@yijan4845 it would be helpful to try and look or related issues, often the backtrace won't exactly match so they are exact duplicates but often linking related issues with similar backtraces could help in debugging or writing best test cases when submitting a fix.

Sure, I'll attach the the related issues found when checking for the duplicate.