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[Clang]: clang crashed with `Assertion 'idx < size()' failed` in `clang::Sema::tryCaptureVariable` when try to capture variable with function parameter scope in a trailing noexcept expression #97453

Open RungeCC opened 6 days ago

RungeCC commented 6 days ago

Reproducer:

// clang++ -std=c++26 -fsyntax-only main.cpp
struct X {
    constexpr auto ICE(int&& that)
    noexcept(noexcept(
        [that]() {}
    ));
};

Assertions:

clang++: /root/llvm-project/llvm/include/llvm/ADT/SmallVector.h:304: 
T& llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::operator[]
(llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type) 
[with T = clang::sema::FunctionScopeInfo*; <template-parameter-1-2> = void; 
llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::reference = 
clang::sema::FunctionScopeInfo*&; llvm::SmallVectorTemplateCommon<T, <template-
parameter-1-2> >::size_type = long unsigned int]: Assertion `idx < size()' failed.

Stacktrace:


Stack dump:
0.  Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++26 -fsyntax-only <source>
1.  <source>:4:15: current parser token '('
2.  <source>:1:1: parsing struct/union/class body 'X'
3.  <source>:4:9: lambda expression parsing
 #0 0x0000000003a34ff8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a34ff8)
 #1 0x0000000003a32cdc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a32cdc)
 #2 0x0000000003978a78 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000075b989a42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000075b989a969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x000075b989a42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x000075b989a287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000075b989a2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x000075b989a39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006953f82 clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6953f82)
#10 0x00000000069544af clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69544af)
#11 0x0000000006bd3817 clang::Sema::ActOnLambdaExpressionAfterIntroducer(clang::LambdaIntroducer&, clang::Scope*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6bd3817)
#12 0x0000000006455b30 clang::Parser::ParseLambdaExpressionAfterIntroducer(clang::LambdaIntroducer&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6455b30)
#13 0x00000000064578eb clang::Parser::ParseLambdaExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64578eb)
#14 0x0000000006436195 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6436195)
#15 0x0000000006437cba clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6437cba)
#16 0x0000000006437e59 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6437e59)
#17 0x000000000643c829 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x643c829)
#18 0x0000000006436070 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6436070)
#19 0x0000000006443c96 clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6443c96)
#20 0x000000000641cfe9 clang::Parser::tryParseExceptionSpecification(bool, clang::SourceRange&, llvm::SmallVectorImpl<clang::OpaquePtr<clang::QualType>>&, llvm::SmallVectorImpl<clang::SourceRange>&, clang::ActionResult<clang::Expr*, true>&, llvm::SmallVector<clang::Token, 4u>*&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x641cfe9)
#21 0x00000000063e653d clang::Parser::ParseLexedMethodDeclaration(clang::Parser::LateParsedMethodDeclaration&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63e653d)
#22 0x00000000063dbd8d clang::Parser::ParseLexedMethodDeclarations(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63dbd8d)
#23 0x000000000642beff clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642beff)
#24 0x000000000642e640 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642e640)
#25 0x0000000006403ff5 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6403ff5)
#26 0x00000000063bf787 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63bf787)
#27 0x00000000063c01ee clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c01ee)
#28 0x00000000063c6917 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c6917)
#29 0x00000000063c782f clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c782f)
#30 0x00000000063c7cf0 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c7cf0)
#31 0x00000000063bafcc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63bafcc)
#32 0x00000000045a8239 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x45a8239)
#33 0x000000000452e14e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x452e14e)
#34 0x000000000469073e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x469073e)
#35 0x0000000000c70665 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc70665)
#36 0x0000000000c6988a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#37 0x0000000004364859 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#38 0x0000000003978f24 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3978f24)
#39 0x0000000004364e4f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#40 0x000000000432a895 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x432a895)
#41 0x000000000432b2fd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x432b2fd)
#42 0x0000000004332d15 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4332d15)
#43 0x0000000000c6da35 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc6da35)
#44 0x0000000000b45d34 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xb45d34)
#45 0x000075b989a29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#46 0x000075b989a29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#47 0x0000000000c6933e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc6933e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

Online compiler (https://godbolt.org/z/cYPohaMe9).

Note

struct X {
    constexpr auto ICE(int&& that)
    noexcept(noexcept(
        [that=that]() {}
    ));
};

Clang error:

<source>:4:15: error: reference to local variable 'that' declared in enclosing function 'X::ICE'
    4 |         [that=that]() {}
      |               ^
<source>:2:30: note: 'that' declared here
    2 |     constexpr auto ICE(int&& that)
      |

Additional Reproducer

// clang++ -std=c++26 -fsyntax-only main.cpp
struct X1 {
    constexpr auto ICE(int&& that)
    noexcept(requires {
        [that]() {};
    });
};

struct X2 {
    constexpr auto ICE(auto&& that)
    noexcept([that](){return false;}());
};
llvmbot commented 6 days ago

@llvm/issue-subscribers-clang-frontend

Author: Runge (RungeCC)

Reproducer: ```c++ // clang++ -std=c++26 -fsyntax-only main.cpp struct X { constexpr auto ICE(int&& that) noexcept(noexcept( [that]() {} )); }; ``` Assertions: ``` clang++: /root/llvm-project/llvm/include/llvm/ADT/SmallVector.h:304: T& llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::operator[] (llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type) [with T = clang::sema::FunctionScopeInfo*; <template-parameter-1-2> = void; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::reference = clang::sema::FunctionScopeInfo*&; llvm::SmallVectorTemplateCommon<T, <template- parameter-1-2> >::size_type = long unsigned int]: Assertion `idx < size()' failed. ``` Stacktrace: ``` Stack dump: 0. Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++26 -fsyntax-only <source> 1. <source>:4:15: current parser token '(' 2. <source>:1:1: parsing struct/union/class body 'X' 3. <source>:4:9: lambda expression parsing #0 0x0000000003a34ff8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a34ff8) #1 0x0000000003a32cdc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a32cdc) #2 0x0000000003978a78 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0 #3 0x000075b989a42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520) #4 0x000075b989a969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc) #5 0x000075b989a42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476) #6 0x000075b989a287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3) #7 0x000075b989a2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b) #8 0x000075b989a39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96) #9 0x0000000006953f82 clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation, bool, clang::QualType&, clang::QualType&, unsigned int const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6953f82) #10 0x00000000069544af clang::Sema::tryCaptureVariable(clang::ValueDecl*, clang::SourceLocation, clang::Sema::TryCaptureKind, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69544af) #11 0x0000000006bd3817 clang::Sema::ActOnLambdaExpressionAfterIntroducer(clang::LambdaIntroducer&, clang::Scope*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6bd3817) #12 0x0000000006455b30 clang::Parser::ParseLambdaExpressionAfterIntroducer(clang::LambdaIntroducer&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6455b30) #13 0x00000000064578eb clang::Parser::ParseLambdaExpression() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64578eb) #14 0x0000000006436195 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6436195) #15 0x0000000006437cba clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6437cba) #16 0x0000000006437e59 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6437e59) #17 0x000000000643c829 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x643c829) #18 0x0000000006436070 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6436070) #19 0x0000000006443c96 clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6443c96) #20 0x000000000641cfe9 clang::Parser::tryParseExceptionSpecification(bool, clang::SourceRange&, llvm::SmallVectorImpl<clang::OpaquePtr<clang::QualType>>&, llvm::SmallVectorImpl<clang::SourceRange>&, clang::ActionResult<clang::Expr*, true>&, llvm::SmallVector<clang::Token, 4u>*&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x641cfe9) #21 0x00000000063e653d clang::Parser::ParseLexedMethodDeclaration(clang::Parser::LateParsedMethodDeclaration&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63e653d) #22 0x00000000063dbd8d clang::Parser::ParseLexedMethodDeclarations(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63dbd8d) #23 0x000000000642beff clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642beff) #24 0x000000000642e640 clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642e640) #25 0x0000000006403ff5 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6403ff5) #26 0x00000000063bf787 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63bf787) #27 0x00000000063c01ee clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c01ee) #28 0x00000000063c6917 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c6917) #29 0x00000000063c782f clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c782f) #30 0x00000000063c7cf0 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c7cf0) #31 0x00000000063bafcc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63bafcc) #32 0x00000000045a8239 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x45a8239) #33 0x000000000452e14e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x452e14e) #34 0x000000000469073e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x469073e) #35 0x0000000000c70665 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc70665) #36 0x0000000000c6988a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0 #37 0x0000000004364859 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0 #38 0x0000000003978f24 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3978f24) #39 0x0000000004364e4f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0 #40 0x000000000432a895 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x432a895) #41 0x000000000432b2fd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x432b2fd) #42 0x0000000004332d15 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4332d15) #43 0x0000000000c6da35 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc6da35) #44 0x0000000000b45d34 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xb45d34) #45 0x000075b989a29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90) #46 0x000075b989a29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40) #47 0x0000000000c6933e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc6933e) clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation) Compiler returned: 134 ``` Online compiler (https://godbolt.org/z/cYPohaMe9). - clang version: trunk and 18. - gcc (trunl and 14) compiles successfully. - msvc compiles successfully. - reproduced with flag -fsyntax-only so maybe a frontend issue. ## Note - Note that only clang emits an error in this init-capture case (https://godbolt.org/z/4EzzMfjG3), both gcc and msvc accept it, it seems that clang rejected valid code. ```c++ struct X { constexpr auto ICE(int&& that) noexcept(noexcept( [that=that]() {} )); }; ``` Clang error: ``` <source>:4:15: error: reference to local variable 'that' declared in enclosing function 'X::ICE' 4 | [that=that]() {} | ^ <source>:2:30: note: 'that' declared here 2 | constexpr auto ICE(int&& that) | ```
shafik commented 6 days ago

Confirmed

zyn0217 commented 6 days ago

@cor3ntin You're right, here is the case that falls out of the fix of 'skipping past the requires expressions'. We need a generic approach then.