Structured binding packs ICE

[stripe2933]

After some experiments using recently merged structured binding packs PR, I found this ICE. Compiler Explorer

#include <format>
#include <print>
#include <type_traits>

#define FWD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)

template <typename T> requires std::is_aggregate_v<std::remove_cvref_t<T>>
[[nodiscard]] constexpr auto as_tuple(T &&v) {
    auto &&[...xs] = FWD(v);
    return std::forward_as_tuple(FWD(xs)...);
}

template <typename T, typename CharT>
    requires std::is_aggregate_v<T>
struct std::formatter<T, CharT> : formatter<decltype(as_tuple(std::declval<const T>())), CharT> {
    constexpr auto format(const T &v, std::format_context &ctx) const {
        return formatter<decltype(as_tuple(std::declval<const T>())), CharT>::format(as_tuple(v), ctx);
    }
};

struct Person {
    std::string name;
    int age;
};

int main() {
    std::println("{}", Person { .name = "Lee Kyoungheon", .age = 23 });
}

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-trunk-20250130/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir /app/output.s- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name example.cpp -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -fno-verbose-asm -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debug-info-kind=constructor -dwarf-version=4 -debugger-tuning=gdb -fdebug-compilation-dir=/app -fcoverage-compilation-dir=/app -resource-dir /opt/compiler-explorer/clang-trunk-20250130/lib/clang/21 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/bin/../include/x86_64-unknown-linux-gnu/c++/v1 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/15.0.1/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=c++26 -fdeprecated-macro -ferror-limit 19 -fgnuc-version=4.2.1 -fno-implicit-modules -fskip-odr-check-in-gmf -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/example-7e79d0.o -x c++ <source>
1.	<source>:27:70: current parser token ')'
2.	<source>:26:12: parsing function body 'main'
3.	<source>:26:12: in compound statement ('{}')
4.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:368:13: instantiating function definition 'std::basic_format_string<char, Person>::basic_format_string<char[3]>'
5.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:386:85: instantiating variable definition 'std::basic_format_string<char, Person>::__handles_'
6.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:94:40: instantiating function definition 'std::__format::__compile_time_handle<char>::__enable<Person>'
7.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/formatter.h:34:29: instantiating class definition 'std::formatter<Person>'
8.	<source>:8:30: instantiating function definition 'as_tuple<Person>'
  #0 0x0000000003b04c78 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x3b04c78)
  #1 0x0000000003b02824 SignalHandler(int) Signals.cpp:0:0
  #2 0x00007d05a1642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
  #3 0x00000000068c3448 clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68c3448)
  #4 0x00000000068c82dd 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-trunk-20250130/bin/clang-21+0x68c82dd)
  #5 0x00000000068ced17 clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::SourceLocation, clang::CXXScopeSpec const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68ced17)
  #6 0x00000000067e43d3 CheckBindingsCount(clang::Sema&, clang::DecompositionDecl*, clang::QualType, llvm::ArrayRef<clang::BindingDecl*>, unsigned int) SemaDeclCXX.cpp:0:0
  #7 0x00000000067e4dd1 checkMemberDecomposition(clang::Sema&, llvm::ArrayRef<clang::BindingDecl*>, clang::ValueDecl*, clang::QualType, clang::CXXRecordDecl const*) SemaDeclCXX.cpp:0:0
  #8 0x00000000067f24b4 clang::Sema::CheckCompleteDecompositionDeclaration(clang::DecompositionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x67f24b4)
  #9 0x0000000006758191 clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6758191)
 #10 0x000000000675d10c clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x675d10c)
 #11 0x0000000006f767d8 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f767d8)
 #12 0x0000000006fbcbb2 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&, llvm::SmallVector<clang::Sema::LateInstantiatedAttribute, 16u>*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbcbb2)
 #13 0x0000000006fc9233 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef<clang::BindingDecl*>*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9233)
 #14 0x0000000006fc9f7e clang::TemplateDeclInstantiator::VisitDecompositionDecl(clang::DecompositionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9f7e)
 #15 0x0000000006fd6793 void llvm::function_ref<void ()>::callback_fn<clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)::'lambda'()>(long) SemaTemplateInstantiateDecl.cpp:0:0
 #16 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #17 0x0000000006f74c9a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f74c9a)
 #18 0x0000000006ee6150 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
 #19 0x0000000006f4dc55 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #20 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
 #21 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
 #22 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #23 0x0000000006e40421 clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6e40421)
 #24 0x000000000689d5f7 clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef<clang::SourceLocation>, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x689d5f7)
 #25 0x0000000006cb272c FinishOverloadedCallExpr(clang::Sema&, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
 #26 0x0000000006cb35fc clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6cb35fc)
 #27 0x00000000068f6738 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f6738)
 #28 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
 #29 0x0000000006f270a7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #30 0x0000000006f199f4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #31 0x0000000006f14671 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeLocBuilder&, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #32 0x0000000006f17be7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeSourceInfo*) SemaTemplateInstantiate.cpp:0:0
 #33 0x0000000006f2db91 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformTemplateArgument(clang::TemplateArgumentLoc const&, clang::TemplateArgumentLoc&, bool) SemaTemplateInstantiate.cpp:0:0
 #34 0x0000000006f32fc5 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformTemplateSpecializationType(clang::TypeLocBuilder&, clang::TemplateSpecializationTypeLoc, clang::TemplateName) SemaTemplateInstantiate.cpp:0:0
 #35 0x0000000006f157e9 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeLocBuilder&, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #36 0x0000000006f3e03e clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformElaboratedType(clang::TypeLocBuilder&, clang::ElaboratedTypeLoc) SemaTemplateInstantiate.cpp:0:0
 #37 0x0000000006f149b2 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeLocBuilder&, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #38 0x0000000006f17be7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformType(clang::TypeSourceInfo*) SemaTemplateInstantiate.cpp:0:0
 #39 0x0000000006f3841f clang::Sema::SubstType(clang::TypeSourceInfo*, clang::MultiLevelTemplateArgumentList const&, clang::SourceLocation, clang::DeclarationName, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f3841f)
 #40 0x0000000006f38885 clang::Sema::SubstBaseSpecifiers(clang::CXXRecordDecl*, clang::CXXRecordDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f38885)
 #41 0x0000000006f39184 clang::Sema::InstantiateClass(clang::SourceLocation, clang::CXXRecordDecl*, clang::CXXRecordDecl*, clang::MultiLevelTemplateArgumentList const&, clang::TemplateSpecializationKind, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f39184)
 #42 0x0000000006f6f1e7 clang::Sema::InstantiateClassTemplateSpecialization(clang::SourceLocation, clang::ClassTemplateSpecializationDecl*, clang::TemplateSpecializationKind, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f6f1e7)
 #43 0x0000000006fe7265 void llvm::function_ref<void ()>::callback_fn<clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*)::'lambda'()>(long) SemaType.cpp:0:0
 #44 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #45 0x0000000006ff67b5 clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff67b5)
 #46 0x0000000006ff6835 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff6835)
 #47 0x0000000006ff6cc0 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, unsigned int) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff6cc0)
 #48 0x0000000006759781 clang::Sema::ActOnUninitializedDecl(clang::Decl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6759781)
 #49 0x0000000006f76749 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f76749)
 #50 0x0000000006fbcbb2 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&, llvm::SmallVector<clang::Sema::LateInstantiatedAttribute, 16u>*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbcbb2)
 #51 0x0000000006fc9233 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef<clang::BindingDecl*>*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9233)
 #52 0x0000000006fd6557 void llvm::function_ref<void ()>::callback_fn<clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)::'lambda'()>(long) SemaTemplateInstantiateDecl.cpp:0:0
 #53 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #54 0x0000000006f74c9a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f74c9a)
 #55 0x0000000006ee6150 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
 #56 0x0000000006f4dc55 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #57 0x0000000006f55e01 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
 #58 0x0000000006f1a468 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #59 0x0000000006f1c365 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
 #60 0x0000000006f29529 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformBinaryOperator(clang::BinaryOperator*) SemaTemplateInstantiate.cpp:0:0
 #61 0x0000000006f19738 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #62 0x0000000006f4d199 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
 #63 0x0000000006f4dc55 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #64 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
 #65 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
 #66 0x00000000068d933d void llvm::function_ref<void ()>::callback_fn<clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool)::'lambda'()>(long) SemaExpr.cpp:0:0
 #67 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #68 0x00000000068d8bc4 clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68d8bc4)
 #69 0x00000000068d9919 MarkExprReferenced(clang::Sema&, clang::SourceLocation, clang::Decl*, clang::Expr*, bool, llvm::DenseMap<clang::VarDecl const*, int, llvm::DenseMapInfo<clang::VarDecl const*, void>, llvm::detail::DenseMapPair<clang::VarDecl const*, int>>&) SemaExpr.cpp:0:0
 #70 0x0000000006a215d4 clang::Sema::BuildMemberExpr(clang::Expr*, bool, clang::SourceLocation, clang::NestedNameSpecifierLoc, clang::SourceLocation, clang::ValueDecl*, clang::DeclAccessPair, bool, clang::DeclarationNameInfo const&, clang::QualType, clang::ExprValueKind, clang::ExprObjectKind, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a215d4)
 #71 0x0000000006c777d6 clang::Sema::FixOverloadedFunctionReference(clang::Expr*, clang::DeclAccessPair, clang::FunctionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6c777d6)
 #72 0x0000000006ca9cfd clang::Sema::BuildCallToMemberFunction(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ca9cfd)
 #73 0x00000000068f60d6 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f60d6)
 #74 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
 #75 0x0000000006f270a7 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #76 0x0000000006f199f4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #77 0x0000000006f4d199 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
 #78 0x0000000006f5251b clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformIfStmt(clang::IfStmt*) SemaTemplateInstantiate.cpp:0:0
 #79 0x0000000006f4dc55 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #80 0x0000000006f55e01 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
 #81 0x0000000006f1a468 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #82 0x0000000006f26fa4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #83 0x0000000006f199f4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #84 0x0000000006f1bc6d clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl<clang::Expr*>&, bool*) SemaTemplateInstantiate.cpp:0:0
 #85 0x0000000006f1de4c clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitListExpr(clang::InitListExpr*) SemaTemplateInstantiate.cpp:0:0
 #86 0x0000000006f19c51 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #87 0x0000000006f1c365 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
 #88 0x0000000006f1c734 clang::Sema::SubstInitializer(clang::Expr*, clang::MultiLevelTemplateArgumentList const&, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f1c734)
 #89 0x0000000006f76628 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f76628)
 #90 0x0000000006fbf34c clang::Sema::InstantiateVariableDefinition(clang::SourceLocation, clang::VarDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbf34c)
 #91 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #92 0x00000000068c7af8 DoMarkVarDeclReferenced(clang::Sema&, clang::SourceLocation, clang::VarDecl*, clang::Expr*, llvm::DenseMap<clang::VarDecl const*, int, llvm::DenseMapInfo<clang::VarDecl const*, void>, llvm::detail::DenseMapPair<clang::VarDecl const*, int>>&) SemaExpr.cpp:0:0
 #93 0x00000000068d9858 MarkExprReferenced(clang::Sema&, clang::SourceLocation, clang::Decl*, clang::Expr*, bool, llvm::DenseMap<clang::VarDecl const*, int, llvm::DenseMapInfo<clang::VarDecl const*, void>, llvm::detail::DenseMapPair<clang::VarDecl const*, int>>&) SemaExpr.cpp:0:0
 #94 0x00000000068c8346 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-trunk-20250130/bin/clang-21+0x68c8346)
 #95 0x00000000068c886f 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-trunk-20250130/bin/clang-21+0x68c886f)
 #96 0x00000000068cd9fe clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68cd9fe)
 #97 0x0000000006f3bd73 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclRefExpr(clang::DeclRefExpr*) SemaTemplateInstantiate.cpp:0:0
 #98 0x0000000006f19ae5 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #99 0x0000000006f42345 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCXXDependentScopeMemberExpr(clang::CXXDependentScopeMemberExpr*) SemaTemplateInstantiate.cpp:0:0
#100 0x0000000006f19929 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#101 0x0000000006f26fa4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#102 0x0000000006f199f4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#103 0x0000000006f1bd0b clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl<clang::Expr*>&, bool*) SemaTemplateInstantiate.cpp:0:0
#104 0x0000000006f1de4c clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitListExpr(clang::InitListExpr*) SemaTemplateInstantiate.cpp:0:0
#105 0x0000000006f19c51 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#106 0x0000000006f1c365 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
#107 0x0000000006f1ba57 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl<clang::Expr*>&, bool*) SemaTemplateInstantiate.cpp:0:0
#108 0x0000000006f382a6 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCXXUnresolvedConstructExpr(clang::CXXUnresolvedConstructExpr*) SemaTemplateInstantiate.cpp:0:0
#109 0x0000000006f199b8 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#110 0x0000000006f1c365 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
#111 0x0000000006f1ba57 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl<clang::Expr*>&, bool*) SemaTemplateInstantiate.cpp:0:0
#112 0x0000000006f27019 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#113 0x0000000006f199f4 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#114 0x0000000006f4d199 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt(clang::Stmt*, clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
#115 0x0000000006f4dc55 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#116 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
#117 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
#118 0x00000000068d933d void llvm::function_ref<void ()>::callback_fn<clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool)::'lambda'()>(long) SemaExpr.cpp:0:0
#119 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
#120 0x00000000068d8bc4 clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68d8bc4)
#121 0x000000000681395d clang::Sema::BuildCXXConstructExpr(clang::SourceLocation, clang::QualType, clang::NamedDecl*, clang::CXXConstructorDecl*, llvm::MutableArrayRef<clang::Expr*>, bool, bool, bool, bool, clang::CXXConstructionKind, clang::SourceRange) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x681395d)
#122 0x0000000006a8d79e clang::InitializationSequence::Perform(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a8d79e)
#123 0x0000000006a989bd clang::Sema::PerformCopyInitialization(clang::InitializedEntity const&, clang::SourceLocation, clang::ActionResult<clang::Expr*, true>, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a989bd)
#124 0x00000000068f75b0 clang::Sema::GatherArgumentsForCall(clang::SourceLocation, clang::FunctionDecl*, clang::FunctionProtoType const*, unsigned int, llvm::ArrayRef<clang::Expr*>, llvm::SmallVectorImpl<clang::Expr*>&, clang::Sema::VariadicCallType, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f75b0)
#125 0x00000000068f80e7 clang::Sema::ConvertArgumentsForCall(clang::CallExpr*, clang::Expr*, clang::FunctionDecl*, clang::FunctionProtoType const*, llvm::ArrayRef<clang::Expr*>, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f80e7)
#126 0x00000000068f9f64 clang::Sema::BuildResolvedCallExpr(clang::Expr*, clang::NamedDecl*, clang::SourceLocation, llvm::ArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, clang::CallExpr::ADLCallKind) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f9f64)
#127 0x0000000006cb2596 FinishOverloadedCallExpr(clang::Sema&, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
#128 0x0000000006cb35fc clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6cb35fc)
#129 0x00000000068f6738 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f6738)
#130 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
#131 0x000000000642a957 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x642a957)
#132 0x0000000006422e91 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6422e91)
#133 0x00000000064250ca clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64250ca)
#134 0x0000000006425299 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6425299)
#135 0x000000000642a539 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x642a539)
#136 0x00000000064b7d37 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64b7d37)
#137 0x00000000064ab4c7 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ab4c7)
#138 0x00000000064abebd clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64abebd)
#139 0x00000000064ad1d4 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ad1d4)
#140 0x00000000064ae38a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ae38a)
#141 0x00000000063a98d6 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a98d6)
#142 0x00000000063f39bf clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63f39bf)
#143 0x00000000063a1e97 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a1e97)
#144 0x00000000063a2cae clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a2cae)
#145 0x00000000063ac5b2 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63ac5b2)
#146 0x00000000063ade48 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63ade48)
#147 0x000000000639c4ea clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x639c4ea)
#148 0x0000000004457225 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x4457225)
#149 0x000000000472f911 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x472f911)
#150 0x00000000046af09b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x46af09b)
#151 0x000000000481af83 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x481af83)
#152 0x0000000000d54831 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd54831)
#153 0x0000000000d4d03d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#154 0x0000000000d4fe1e clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd4fe1e)
#155 0x0000000000c16a74 main (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xc16a74)
#156 0x00007d05a1629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#157 0x00007d05a1629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#158 0x0000000000d4cad5 _start (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd4cad5)
clang++: error: unable to execute command: Segmentation fault (core dumped)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)

When I changed decltype(as_tuple(std::declval<const T>())) to std::tuple<const std::string&&, const int&&>, it compiles well.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: LEE KYOUNGHEON (stripe2933)

After some experiments using recently merged structured binding packs PR, I found this ICE. [Compiler Explorer](https://godbolt.org/z/9dMa74sEv)

#include <format>
#include <print>
#include <type_traits>

#define FWD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)

template <typename T> requires std::is_aggregate_v<std::remove_cvref_t<T>>
[[nodiscard]] constexpr auto as_tuple(T &&v) {
    auto &&[...xs] = FWD(v);
    return std::forward_as_tuple(FWD(xs)...);
}

template <typename T, typename CharT>
    requires std::is_aggregate_v<T>
struct std::formatter<T, CharT> : formatter<decltype(as_tuple(std::declval<T>())), CharT> {
    constexpr auto format(const T &v, std::format_context &ctx) const {
        return formatter<decltype(as_tuple(std::declval<T>()))>::format(as_tuple(v), ctx);
    }
};

struct Person {
    std::string name;
    int age;
};

int main() {
    std::println("{}", Person { .name = "lee kyoungheon", .age = 23 });
}

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-trunk-20250130/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir /app/output.s- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name example.cpp -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -fno-verbose-asm -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debug-info-kind=constructor -dwarf-version=4 -debugger-tuning=gdb -fdebug-compilation-dir=/app -fcoverage-compilation-dir=/app -resource-dir /opt/compiler-explorer/clang-trunk-20250130/lib/clang/21 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/bin/../include/x86_64-unknown-linux-gnu/c++/v1 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1 -internal-isystem /opt/compiler-explorer/clang-trunk-20250130/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/15.0.1/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=c++26 -fdeprecated-macro -ferror-limit 19 -fgnuc-version=4.2.1 -fno-implicit-modules -fskip-odr-check-in-gmf -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/example-7e79d0.o -x c++ <source>
1.	<source>:27:70: current parser token ')'
2.	<source>:26:12: parsing function body 'main'
3.	<source>:26:12: in compound statement ('{}')
4.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:368:13: instantiating function definition 'std::basic_format_string<char, Person>::basic_format_string<char[3]>'
5.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:386:85: instantiating variable definition 'std::basic_format_string<char, Person>::__handles_'
6.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/format_functions.h:94:40: instantiating function definition 'std::__format::__compile_time_handle<char>::__enable<Person>'
7.	/opt/compiler-explorer/clang-trunk-20250130/bin/../include/c++/v1/__format/formatter.h:34:29: instantiating class definition 'std::formatter<Person>'
8.	<source>:8:30: instantiating function definition 'as_tuple<Person>'
  #<!-- -->0 0x0000000003b04c78 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x3b04c78)
  #<!-- -->1 0x0000000003b02824 SignalHandler(int) Signals.cpp:0:0
  #<!-- -->2 0x00007d05a1642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
  #<!-- -->3 0x00000000068c3448 clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&amp;, clang::QualType&amp;, unsigned int const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68c3448)
  #<!-- -->4 0x00000000068c82dd clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::DeclarationNameInfo const&amp;, clang::NestedNameSpecifierLoc, clang::NamedDecl*, clang::SourceLocation, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68c82dd)
  #<!-- -->5 0x00000000068ced17 clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::SourceLocation, clang::CXXScopeSpec const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68ced17)
  #<!-- -->6 0x00000000067e43d3 CheckBindingsCount(clang::Sema&amp;, clang::DecompositionDecl*, clang::QualType, llvm::ArrayRef&lt;clang::BindingDecl*&gt;, unsigned int) SemaDeclCXX.cpp:0:0
  #<!-- -->7 0x00000000067e4dd1 checkMemberDecomposition(clang::Sema&amp;, llvm::ArrayRef&lt;clang::BindingDecl*&gt;, clang::ValueDecl*, clang::QualType, clang::CXXRecordDecl const*) SemaDeclCXX.cpp:0:0
  #<!-- -->8 0x00000000067f24b4 clang::Sema::CheckCompleteDecompositionDeclaration(clang::DecompositionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x67f24b4)
  #<!-- -->9 0x0000000006758191 clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6758191)
 #<!-- -->10 0x000000000675d10c clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x675d10c)
 #<!-- -->11 0x0000000006f767d8 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f767d8)
 #<!-- -->12 0x0000000006fbcbb2 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&amp;, llvm::SmallVector&lt;clang::Sema::LateInstantiatedAttribute, 16u&gt;*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbcbb2)
 #<!-- -->13 0x0000000006fc9233 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef&lt;clang::BindingDecl*&gt;*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9233)
 #<!-- -->14 0x0000000006fc9f7e clang::TemplateDeclInstantiator::VisitDecompositionDecl(clang::DecompositionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9f7e)
 #<!-- -->15 0x0000000006fd6793 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&amp;)::'lambda'()&gt;(long) SemaTemplateInstantiateDecl.cpp:0:0
 #<!-- -->16 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->17 0x0000000006f74c9a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f74c9a)
 #<!-- -->18 0x0000000006ee6150 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->19 0x0000000006f4dc55 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->20 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
 #<!-- -->21 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
 #<!-- -->22 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->23 0x0000000006e40421 clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6e40421)
 #<!-- -->24 0x000000000689d5f7 clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef&lt;clang::SourceLocation&gt;, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x689d5f7)
 #<!-- -->25 0x0000000006cb272c FinishOverloadedCallExpr(clang::Sema&amp;, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
 #<!-- -->26 0x0000000006cb35fc clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6cb35fc)
 #<!-- -->27 0x00000000068f6738 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f6738)
 #<!-- -->28 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
 #<!-- -->29 0x0000000006f270a7 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->30 0x0000000006f199f4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->31 0x0000000006f14671 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformType(clang::TypeLocBuilder&amp;, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->32 0x0000000006f17be7 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformType(clang::TypeSourceInfo*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->33 0x0000000006f2db91 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformTemplateArgument(clang::TemplateArgumentLoc const&amp;, clang::TemplateArgumentLoc&amp;, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->34 0x0000000006f32fc5 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformTemplateSpecializationType(clang::TypeLocBuilder&amp;, clang::TemplateSpecializationTypeLoc, clang::TemplateName) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->35 0x0000000006f157e9 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformType(clang::TypeLocBuilder&amp;, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->36 0x0000000006f3e03e clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformElaboratedType(clang::TypeLocBuilder&amp;, clang::ElaboratedTypeLoc) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->37 0x0000000006f149b2 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformType(clang::TypeLocBuilder&amp;, clang::TypeLoc) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->38 0x0000000006f17be7 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformType(clang::TypeSourceInfo*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->39 0x0000000006f3841f clang::Sema::SubstType(clang::TypeSourceInfo*, clang::MultiLevelTemplateArgumentList const&amp;, clang::SourceLocation, clang::DeclarationName, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f3841f)
 #<!-- -->40 0x0000000006f38885 clang::Sema::SubstBaseSpecifiers(clang::CXXRecordDecl*, clang::CXXRecordDecl*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f38885)
 #<!-- -->41 0x0000000006f39184 clang::Sema::InstantiateClass(clang::SourceLocation, clang::CXXRecordDecl*, clang::CXXRecordDecl*, clang::MultiLevelTemplateArgumentList const&amp;, clang::TemplateSpecializationKind, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f39184)
 #<!-- -->42 0x0000000006f6f1e7 clang::Sema::InstantiateClassTemplateSpecialization(clang::SourceLocation, clang::ClassTemplateSpecializationDecl*, clang::TemplateSpecializationKind, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f6f1e7)
 #<!-- -->43 0x0000000006fe7265 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*)::'lambda'()&gt;(long) SemaType.cpp:0:0
 #<!-- -->44 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->45 0x0000000006ff67b5 clang::Sema::RequireCompleteTypeImpl(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff67b5)
 #<!-- -->46 0x0000000006ff6835 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, clang::Sema::TypeDiagnoser&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff6835)
 #<!-- -->47 0x0000000006ff6cc0 clang::Sema::RequireCompleteType(clang::SourceLocation, clang::QualType, clang::Sema::CompleteTypeKind, unsigned int) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ff6cc0)
 #<!-- -->48 0x0000000006759781 clang::Sema::ActOnUninitializedDecl(clang::Decl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6759781)
 #<!-- -->49 0x0000000006f76749 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f76749)
 #<!-- -->50 0x0000000006fbcbb2 clang::Sema::BuildVariableInstantiation(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&amp;, llvm::SmallVector&lt;clang::Sema::LateInstantiatedAttribute, 16u&gt;*, clang::DeclContext*, clang::LocalInstantiationScope*, bool, clang::VarTemplateSpecializationDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbcbb2)
 #<!-- -->51 0x0000000006fc9233 clang::TemplateDeclInstantiator::VisitVarDecl(clang::VarDecl*, bool, llvm::ArrayRef&lt;clang::BindingDecl*&gt;*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc9233)
 #<!-- -->52 0x0000000006fd6557 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&amp;)::'lambda'()&gt;(long) SemaTemplateInstantiateDecl.cpp:0:0
 #<!-- -->53 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->54 0x0000000006f74c9a clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f74c9a)
 #<!-- -->55 0x0000000006ee6150 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformDeclStmt(clang::DeclStmt*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->56 0x0000000006f4dc55 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->57 0x0000000006f55e01 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->58 0x0000000006f1a468 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->59 0x0000000006f1c365 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->60 0x0000000006f29529 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformBinaryOperator(clang::BinaryOperator*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->61 0x0000000006f19738 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->62 0x0000000006f4d199 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformStmt(clang::Stmt*, clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->63 0x0000000006f4dc55 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->64 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
 #<!-- -->65 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
 #<!-- -->66 0x00000000068d933d void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool)::'lambda'()&gt;(long) SemaExpr.cpp:0:0
 #<!-- -->67 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->68 0x00000000068d8bc4 clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68d8bc4)
 #<!-- -->69 0x00000000068d9919 MarkExprReferenced(clang::Sema&amp;, clang::SourceLocation, clang::Decl*, clang::Expr*, bool, llvm::DenseMap&lt;clang::VarDecl const*, int, llvm::DenseMapInfo&lt;clang::VarDecl const*, void&gt;, llvm::detail::DenseMapPair&lt;clang::VarDecl const*, int&gt;&gt;&amp;) SemaExpr.cpp:0:0
 #<!-- -->70 0x0000000006a215d4 clang::Sema::BuildMemberExpr(clang::Expr*, bool, clang::SourceLocation, clang::NestedNameSpecifierLoc, clang::SourceLocation, clang::ValueDecl*, clang::DeclAccessPair, bool, clang::DeclarationNameInfo const&amp;, clang::QualType, clang::ExprValueKind, clang::ExprObjectKind, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a215d4)
 #<!-- -->71 0x0000000006c777d6 clang::Sema::FixOverloadedFunctionReference(clang::Expr*, clang::DeclAccessPair, clang::FunctionDecl*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6c777d6)
 #<!-- -->72 0x0000000006ca9cfd clang::Sema::BuildCallToMemberFunction(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6ca9cfd)
 #<!-- -->73 0x00000000068f60d6 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f60d6)
 #<!-- -->74 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
 #<!-- -->75 0x0000000006f270a7 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->76 0x0000000006f199f4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->77 0x0000000006f4d199 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformStmt(clang::Stmt*, clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->78 0x0000000006f5251b clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformIfStmt(clang::IfStmt*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->79 0x0000000006f4dc55 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->80 0x0000000006f55e01 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->81 0x0000000006f1a468 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->82 0x0000000006f26fa4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->83 0x0000000006f199f4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->84 0x0000000006f1bc6d clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, bool*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->85 0x0000000006f1de4c clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitListExpr(clang::InitListExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->86 0x0000000006f19c51 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->87 0x0000000006f1c365 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->88 0x0000000006f1c734 clang::Sema::SubstInitializer(clang::Expr*, clang::MultiLevelTemplateArgumentList const&amp;, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f1c734)
 #<!-- -->89 0x0000000006f76628 clang::Sema::InstantiateVariableInitializer(clang::VarDecl*, clang::VarDecl*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f76628)
 #<!-- -->90 0x0000000006fbf34c clang::Sema::InstantiateVariableDefinition(clang::SourceLocation, clang::VarDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fbf34c)
 #<!-- -->91 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
 #<!-- -->92 0x00000000068c7af8 DoMarkVarDeclReferenced(clang::Sema&amp;, clang::SourceLocation, clang::VarDecl*, clang::Expr*, llvm::DenseMap&lt;clang::VarDecl const*, int, llvm::DenseMapInfo&lt;clang::VarDecl const*, void&gt;, llvm::detail::DenseMapPair&lt;clang::VarDecl const*, int&gt;&gt;&amp;) SemaExpr.cpp:0:0
 #<!-- -->93 0x00000000068d9858 MarkExprReferenced(clang::Sema&amp;, clang::SourceLocation, clang::Decl*, clang::Expr*, bool, llvm::DenseMap&lt;clang::VarDecl const*, int, llvm::DenseMapInfo&lt;clang::VarDecl const*, void&gt;, llvm::detail::DenseMapPair&lt;clang::VarDecl const*, int&gt;&gt;&amp;) SemaExpr.cpp:0:0
 #<!-- -->94 0x00000000068c8346 clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::DeclarationNameInfo const&amp;, clang::NestedNameSpecifierLoc, clang::NamedDecl*, clang::SourceLocation, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68c8346)
 #<!-- -->95 0x00000000068c886f clang::Sema::BuildDeclRefExpr(clang::ValueDecl*, clang::QualType, clang::ExprValueKind, clang::DeclarationNameInfo const&amp;, clang::CXXScopeSpec const*, clang::NamedDecl*, clang::SourceLocation, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68c886f)
 #<!-- -->96 0x00000000068cd9fe clang::Sema::BuildDeclarationNameExpr(clang::CXXScopeSpec const&amp;, clang::DeclarationNameInfo const&amp;, clang::NamedDecl*, clang::NamedDecl*, clang::TemplateArgumentListInfo const*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68cd9fe)
 #<!-- -->97 0x0000000006f3bd73 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformDeclRefExpr(clang::DeclRefExpr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->98 0x0000000006f19ae5 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
 #<!-- -->99 0x0000000006f42345 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCXXDependentScopeMemberExpr(clang::CXXDependentScopeMemberExpr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->100 0x0000000006f19929 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->101 0x0000000006f26fa4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->102 0x0000000006f199f4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->103 0x0000000006f1bd0b clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, bool*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->104 0x0000000006f1de4c clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitListExpr(clang::InitListExpr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->105 0x0000000006f19c51 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->106 0x0000000006f1c365 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
#<!-- -->107 0x0000000006f1ba57 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, bool*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->108 0x0000000006f382a6 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCXXUnresolvedConstructExpr(clang::CXXUnresolvedConstructExpr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->109 0x0000000006f199b8 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->110 0x0000000006f1c365 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformInitializer(clang::Expr*, bool) SemaTemplateInstantiate.cpp:0:0
#<!-- -->111 0x0000000006f1ba57 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExprs(clang::Expr* const*, unsigned int, bool, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, bool*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->112 0x0000000006f27019 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCallExpr(clang::CallExpr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->113 0x0000000006f199f4 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#<!-- -->114 0x0000000006f4d199 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformStmt(clang::Stmt*, clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::StmtDiscardKind) SemaTemplateInstantiate.cpp:0:0
#<!-- -->115 0x0000000006f4dc55 clang::TreeTransform&lt;(anonymous namespace)::TemplateInstantiator&gt;::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#<!-- -->116 0x0000000006f5461b clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6f5461b)
#<!-- -->117 0x0000000006fc1c4f clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6fc1c4f)
#<!-- -->118 0x00000000068d933d void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool)::'lambda'()&gt;(long) SemaExpr.cpp:0:0
#<!-- -->119 0x0000000007b32531 clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x7b32531)
#<!-- -->120 0x00000000068d8bc4 clang::Sema::MarkFunctionReferenced(clang::SourceLocation, clang::FunctionDecl*, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68d8bc4)
#<!-- -->121 0x000000000681395d clang::Sema::BuildCXXConstructExpr(clang::SourceLocation, clang::QualType, clang::NamedDecl*, clang::CXXConstructorDecl*, llvm::MutableArrayRef&lt;clang::Expr*&gt;, bool, bool, bool, bool, clang::CXXConstructionKind, clang::SourceRange) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x681395d)
#<!-- -->122 0x0000000006a8d79e clang::InitializationSequence::Perform(clang::Sema&amp;, clang::InitializedEntity const&amp;, clang::InitializationKind const&amp;, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::QualType*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a8d79e)
#<!-- -->123 0x0000000006a989bd clang::Sema::PerformCopyInitialization(clang::InitializedEntity const&amp;, clang::SourceLocation, clang::ActionResult&lt;clang::Expr*, true&gt;, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6a989bd)
#<!-- -->124 0x00000000068f75b0 clang::Sema::GatherArgumentsForCall(clang::SourceLocation, clang::FunctionDecl*, clang::FunctionProtoType const*, unsigned int, llvm::ArrayRef&lt;clang::Expr*&gt;, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, clang::Sema::VariadicCallType, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f75b0)
#<!-- -->125 0x00000000068f80e7 clang::Sema::ConvertArgumentsForCall(clang::CallExpr*, clang::Expr*, clang::FunctionDecl*, clang::FunctionProtoType const*, llvm::ArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f80e7)
#<!-- -->126 0x00000000068f9f64 clang::Sema::BuildResolvedCallExpr(clang::Expr*, clang::NamedDecl*, clang::SourceLocation, llvm::ArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, clang::CallExpr::ADLCallKind) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f9f64)
#<!-- -->127 0x0000000006cb2596 FinishOverloadedCallExpr(clang::Sema&amp;, clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, clang::OverloadCandidateSet*, clang::OverloadCandidate**, clang::OverloadingResult, bool) SemaOverload.cpp:0:0
#<!-- -->128 0x0000000006cb35fc clang::Sema::BuildOverloadedCallExpr(clang::Scope*, clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6cb35fc)
#<!-- -->129 0x00000000068f6738 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68f6738)
#<!-- -->130 0x00000000068fad8c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x68fad8c)
#<!-- -->131 0x000000000642a957 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult&lt;clang::Expr*, true&gt;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x642a957)
#<!-- -->132 0x0000000006422e91 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&amp;, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6422e91)
#<!-- -->133 0x00000000064250ca clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64250ca)
#<!-- -->134 0x0000000006425299 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x6425299)
#<!-- -->135 0x000000000642a539 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x642a539)
#<!-- -->136 0x00000000064b7d37 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64b7d37)
#<!-- -->137 0x00000000064ab4c7 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector&lt;clang::Stmt*, 32u&gt;&amp;, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ab4c7)
#<!-- -->138 0x00000000064abebd clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector&lt;clang::Stmt*, 32u&gt;&amp;, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64abebd)
#<!-- -->139 0x00000000064ad1d4 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ad1d4)
#<!-- -->140 0x00000000064ae38a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x64ae38a)
#<!-- -->141 0x00000000063a98d6 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&amp;, clang::Parser::ParsedTemplateInfo const&amp;, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a98d6)
#<!-- -->142 0x00000000063f39bf clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&amp;, clang::DeclaratorContext, clang::ParsedAttributes&amp;, clang::Parser::ParsedTemplateInfo&amp;, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63f39bf)
#<!-- -->143 0x00000000063a1e97 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec&amp;, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a1e97)
#<!-- -->144 0x00000000063a2cae clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63a2cae)
#<!-- -->145 0x00000000063ac5b2 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63ac5b2)
#<!-- -->146 0x00000000063ade48 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&lt;clang::DeclGroupRef&gt;&amp;, clang::Sema::ModuleImportState&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x63ade48)
#<!-- -->147 0x000000000639c4ea clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x639c4ea)
#<!-- -->148 0x0000000004457225 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x4457225)
#<!-- -->149 0x000000000472f911 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x472f911)
#<!-- -->150 0x00000000046af09b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x46af09b)
#<!-- -->151 0x000000000481af83 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0x481af83)
#<!-- -->152 0x0000000000d54831 cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd54831)
#<!-- -->153 0x0000000000d4d03d ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->154 0x0000000000d4fe1e clang_main(int, char**, llvm::ToolContext const&amp;) (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd4fe1e)
#<!-- -->155 0x0000000000c16a74 main (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xc16a74)
#<!-- -->156 0x00007d05a1629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->157 0x00007d05a1629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->158 0x0000000000d4cad5 _start (/opt/compiler-explorer/clang-trunk-20250130/bin/clang-21+0xd4cad5)
clang++: error: unable to execute command: Segmentation fault (core dumped)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)

When I changed decltype(as_tuple(std::declval<T>())) to std::tuple<const std::string&&, const int&&>, it compiles well.

[cor3ntin]

@ricejasonf @zyn0217 I haven't figured out yet if it's a lambda bug or pack bug but I figure that might be of interest to both of you

[ricejasonf]

I can look at this possibly this weekend. The stack trace looks familiar like when the BindingDecl's Decomp was not set.

[Sirraide]

Just ran into this as well; this crashes in seemingly the same place (https://godbolt.org/z/GqEjMKb8c):

struct S {
    int a, b, c;
};

auto X = [] <typename = void> () {
    auto [...pack] = S{};
};

[Sirraide]

Also, here’s a link to @stripe2933’s example with assertions enabled; it seems to be the same assertion: https://godbolt.org/z/rxx19zdxf