Clang crashes with ICE when concept constraint uses incomplete requires block with ellipsis since version 20 with -std=c++20 #138820

mariete1223 · 2025-05-07T08:14:37Z

Using a concept with a requires clause that includes an incomplete expression using ellipsis (...) results in an internal compiler error (ICE)

Assertion

No assertion arises

Program

int a;
template<typename T>
concept atomicish = requires() {
  {
    a
   ...
  };
};
atomicish<int> f();

Stack dump

Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-20.1.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-14.2.0 -fcolor-diagnostics -fno-crash-diagnostics -x c++ -std=c++20 <source>
1.	<source>:9:16: current parser token 'f'
 #0 0x0000000003a59568 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x3a59568)
 #1 0x0000000003a576ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x3a576ac)
 #2 0x00000000039a69e8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000070092b642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000000000742ef29 clang::Expr::IgnoreParenImpCasts() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x742ef29)
 #5 0x00000000065c1b26 clang::ActionResult<clang::Expr*, true> calculateConstraintSatisfaction<calculateConstraintSatisfaction(clang::Sema&, clang::NamedDecl const*, clang::SourceLocation, clang::MultiLevelTemplateArgumentList const&, clang::Expr const*, clang::ConstraintSatisfaction&)::ConstraintEvaluator>(clang::Sema&, clang::Expr const*, clang::ConstraintSatisfaction&, calculateConstraintSatisfaction(clang::Sema&, clang::NamedDecl const*, clang::SourceLocation, clang::MultiLevelTemplateArgumentList const&, clang::Expr const*, clang::ConstraintSatisfaction&)::ConstraintEvaluator const&) SemaConcept.cpp:0:0
 #6 0x00000000065c484a CheckConstraintSatisfaction(clang::Sema&, clang::NamedDecl const*, llvm::ArrayRef<clang::Expr const*>, llvm::SmallVectorImpl<clang::Expr*>&, clang::MultiLevelTemplateArgumentList const&, clang::SourceRange, clang::ConstraintSatisfaction&) SemaConcept.cpp:0:0
 #7 0x00000000065c4d97 clang::Sema::CheckConstraintSatisfaction(clang::NamedDecl const*, llvm::ArrayRef<clang::Expr const*>, llvm::SmallVectorImpl<clang::Expr*>&, clang::MultiLevelTemplateArgumentList const&, clang::SourceRange, clang::ConstraintSatisfaction&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x65c4d97)
 #8 0x0000000006ced338 clang::Sema::CheckConceptTemplateId(clang::CXXScopeSpec const&, clang::SourceLocation, clang::DeclarationNameInfo const&, clang::NamedDecl*, clang::ConceptDecl*, clang::TemplateArgumentListInfo const*) (.constprop.0) SemaTemplate.cpp:0:0
 #9 0x0000000006ceeb06 clang::Sema::BuildTemplateIdExpr(clang::CXXScopeSpec const&, clang::SourceLocation, clang::LookupResult&, bool, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x6ceeb06)
#10 0x00000000067f9e35 clang::Sema::ActOnIdExpression(clang::Scope*, clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, bool, bool, clang::CorrectionCandidateCallback*, bool, clang::Token*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x67f9e35)
#11 0x000000000636ab85 clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&, bool, clang::Token&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x636ab85)
#12 0x000000000636ae10 clang::Parser::ParseCXXIdExpression(bool) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x636ae10)
#13 0x000000000634ae63 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634ae63)
#14 0x000000000634bf45 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634bf45)
#15 0x000000000634c46a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634c46a)
#16 0x000000000634c639 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634c639)
#17 0x00000000063518d9 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63518d9)
#18 0x00000000063625f0 clang::Parser::ParseRequiresExpression() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63625f0)
#19 0x000000000634b3ee clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634b3ee)
#20 0x0000000006359b86 clang::Parser::ParseConstraintExpression() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x6359b86)
#21 0x00000000063ee95b clang::Parser::ParseConceptDefinition(clang::Parser::ParsedTemplateInfo const&, clang::SourceLocation&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63ee95b)
#22 0x00000000063f6cf1 clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63f6cf1)
#23 0x00000000063f6e4f clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63f6e4f)
#24 0x000000000631dd02 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x631dd02)
#25 0x00000000062d39fa clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62d39fa)
#26 0x00000000062d5268 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62d5268)
#27 0x00000000062c38ca clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62c38ca)
#28 0x00000000043aa295 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43aa295)
#29 0x0000000004682ca1 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x4682ca1)
#30 0x000000000460260b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x460260b)
#31 0x000000000476e173 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x476e173)
#32 0x0000000000d116c1 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd116c1)
#33 0x0000000000d09eed ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#34 0x00000000043f5b49 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
#35 0x00000000039a6e13 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x39a6e13)
#36 0x00000000043f5d69 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
#37 0x00000000043b9ebd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43b9ebd)
#38 0x00000000043bae51 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43bae51)
#39 0x00000000043c51ec clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43c51ec)
#40 0x0000000000d0e391 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd0e391)
#41 0x0000000000bd3bc4 main (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xbd3bc4)
#42 0x000070092b629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#43 0x000070092b629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#44 0x0000000000d09985 _start (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd09985)

To quickly reproduce

It only happens in version 20 and current with -std=c++20 flag

https://gcc.godbolt.org/z/x47naqv91

The text was updated successfully, but these errors were encountered:

llvmbot · 2025-05-07T10:33:13Z

@llvm/issue-subscribers-clang-frontend

Author: None (mariete1223)

Using a concept with a requires clause that includes an incomplete expression using ellipsis (...) results in an internal compiler error (ICE)

Assertion

No assertion arises

Program

int a;
template&lt;typename T&gt;
concept atomicish = requires() {
  {
    a
   ...
  };
};
atomicish&lt;int&gt; f();

Stack dump

Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-20.1.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-14.2.0 -fcolor-diagnostics -fno-crash-diagnostics -x c++ -std=c++20 &lt;source&gt;
1.	&lt;source&gt;:9:16: current parser token 'f'
 #<!-- -->0 0x0000000003a59568 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x3a59568)
 #<!-- -->1 0x0000000003a576ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x3a576ac)
 #<!-- -->2 0x00000000039a69e8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x000070092b642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->4 0x000000000742ef29 clang::Expr::IgnoreParenImpCasts() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x742ef29)
 #<!-- -->5 0x00000000065c1b26 clang::ActionResult&lt;clang::Expr*, true&gt; calculateConstraintSatisfaction&lt;calculateConstraintSatisfaction(clang::Sema&amp;, clang::NamedDecl const*, clang::SourceLocation, clang::MultiLevelTemplateArgumentList const&amp;, clang::Expr const*, clang::ConstraintSatisfaction&amp;)::ConstraintEvaluator&gt;(clang::Sema&amp;, clang::Expr const*, clang::ConstraintSatisfaction&amp;, calculateConstraintSatisfaction(clang::Sema&amp;, clang::NamedDecl const*, clang::SourceLocation, clang::MultiLevelTemplateArgumentList const&amp;, clang::Expr const*, clang::ConstraintSatisfaction&amp;)::ConstraintEvaluator const&amp;) SemaConcept.cpp:0:0
 #<!-- -->6 0x00000000065c484a CheckConstraintSatisfaction(clang::Sema&amp;, clang::NamedDecl const*, llvm::ArrayRef&lt;clang::Expr const*&gt;, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, clang::MultiLevelTemplateArgumentList const&amp;, clang::SourceRange, clang::ConstraintSatisfaction&amp;) SemaConcept.cpp:0:0
 #<!-- -->7 0x00000000065c4d97 clang::Sema::CheckConstraintSatisfaction(clang::NamedDecl const*, llvm::ArrayRef&lt;clang::Expr const*&gt;, llvm::SmallVectorImpl&lt;clang::Expr*&gt;&amp;, clang::MultiLevelTemplateArgumentList const&amp;, clang::SourceRange, clang::ConstraintSatisfaction&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x65c4d97)
 #<!-- -->8 0x0000000006ced338 clang::Sema::CheckConceptTemplateId(clang::CXXScopeSpec const&amp;, clang::SourceLocation, clang::DeclarationNameInfo const&amp;, clang::NamedDecl*, clang::ConceptDecl*, clang::TemplateArgumentListInfo const*) (.constprop.0) SemaTemplate.cpp:0:0
 #<!-- -->9 0x0000000006ceeb06 clang::Sema::BuildTemplateIdExpr(clang::CXXScopeSpec const&amp;, clang::SourceLocation, clang::LookupResult&amp;, bool, clang::TemplateArgumentListInfo const*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x6ceeb06)
#<!-- -->10 0x00000000067f9e35 clang::Sema::ActOnIdExpression(clang::Scope*, clang::CXXScopeSpec&amp;, clang::SourceLocation, clang::UnqualifiedId&amp;, bool, bool, clang::CorrectionCandidateCallback*, bool, clang::Token*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x67f9e35)
#<!-- -->11 0x000000000636ab85 clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&amp;, bool, clang::Token&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x636ab85)
#<!-- -->12 0x000000000636ae10 clang::Parser::ParseCXXIdExpression(bool) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x636ae10)
#<!-- -->13 0x000000000634ae63 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&amp;, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634ae63)
#<!-- -->14 0x000000000634bf45 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&amp;, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634bf45)
#<!-- -->15 0x000000000634c46a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634c46a)
#<!-- -->16 0x000000000634c639 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634c639)
#<!-- -->17 0x00000000063518d9 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63518d9)
#<!-- -->18 0x00000000063625f0 clang::Parser::ParseRequiresExpression() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63625f0)
#<!-- -->19 0x000000000634b3ee clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&amp;, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x634b3ee)
#<!-- -->20 0x0000000006359b86 clang::Parser::ParseConstraintExpression() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x6359b86)
#<!-- -->21 0x00000000063ee95b clang::Parser::ParseConceptDefinition(clang::Parser::ParsedTemplateInfo const&amp;, clang::SourceLocation&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63ee95b)
#<!-- -->22 0x00000000063f6cf1 clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&amp;, clang::ParsedAttributes&amp;, clang::AccessSpecifier) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63f6cf1)
#<!-- -->23 0x00000000063f6e4f clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&amp;, clang::ParsedAttributes&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x63f6e4f)
#<!-- -->24 0x000000000631dd02 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&amp;, clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::SourceLocation*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x631dd02)
#<!-- -->25 0x00000000062d39fa clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62d39fa)
#<!-- -->26 0x00000000062d5268 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&lt;clang::DeclGroupRef&gt;&amp;, clang::Sema::ModuleImportState&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62d5268)
#<!-- -->27 0x00000000062c38ca clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x62c38ca)
#<!-- -->28 0x00000000043aa295 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43aa295)
#<!-- -->29 0x0000000004682ca1 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x4682ca1)
#<!-- -->30 0x000000000460260b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x460260b)
#<!-- -->31 0x000000000476e173 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x476e173)
#<!-- -->32 0x0000000000d116c1 cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd116c1)
#<!-- -->33 0x0000000000d09eed ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->34 0x00000000043f5b49 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const::'lambda'()&gt;(long) Job.cpp:0:0
#<!-- -->35 0x00000000039a6e13 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x39a6e13)
#<!-- -->36 0x00000000043f5d69 clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->37 0x00000000043b9ebd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43b9ebd)
#<!-- -->38 0x00000000043bae51 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;, bool) const (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43bae51)
#<!-- -->39 0x00000000043c51ec clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0x43c51ec)
#<!-- -->40 0x0000000000d0e391 clang_main(int, char**, llvm::ToolContext const&amp;) (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd0e391)
#<!-- -->41 0x0000000000bd3bc4 main (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xbd3bc4)
#<!-- -->42 0x000070092b629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->43 0x000070092b629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->44 0x0000000000d09985 _start (/opt/compiler-explorer/clang-20.1.0/bin/clang+++0xd09985)

To quickly reproduce

It only happens in version 20 and current with -std=c++20 flag

https://gcc.godbolt.org/z/x47naqv91

We were previously recovering a bit too hard; consumeClose() would skip to a recovery point, then we would call skipToEnd() to skip to another recovery point. Needless to say, the follow-on diagnostics were not great. But also, follow-on diagnostics were crashing due to unexpected null constraint expressions. Now we only recover once. Fixes llvm#138820

We were previously recovering a bit too hard; consumeClose() would skip to a recovery point, then we would call skipToEnd() to skip to another recovery point. Needless to say, the follow-on diagnostics were not great. But also, follow-on diagnostics were crashing due to unexpected null constraint expressions. Now we only recover once. Fixes #138820

llvmbot added the clang Clang issues not falling into any other category label May 7, 2025

mariete1223 mentioned this issue May 7, 2025

ICE with concept pack expansion + std::swap in C++20 constraint expressions with -std=c++20 since clang 20 #138823

Open

frederick-vs-ja added clang:frontend Language frontend issues, e.g. anything involving "Sema" crash-on-invalid concepts C++20 concepts regression:20 Regression in 20 release and removed clang Clang issues not falling into any other category labels May 7, 2025

AaronBallman added the confirmed Verified by a second party label May 7, 2025

AaronBallman mentioned this issue May 7, 2025

[C++20] Fix crash with invalid concept requirement #138877

Merged

AaronBallman closed this as completed in #138877 May 7, 2025

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Clang crashes with ICE when concept constraint uses incomplete requires block with ellipsis since version 20 with -std=c++20 #138820

Clang crashes with ICE when concept constraint uses incomplete requires block with ellipsis since version 20 with -std=c++20 #138820

mariete1223 commented May 7, 2025

llvmbot commented May 7, 2025

Assertion

Program

Stack dump

To quickly reproduce

Clang crashes with ICE when concept constraint uses incomplete requires block with ellipsis since version 20 with -std=c++20 #138820

Clang crashes with ICE when concept constraint uses incomplete requires block with ellipsis since version 20 with -std=c++20 #138820

Comments

mariete1223 commented May 7, 2025

Assertion

Program

Stack dump

To quickly reproduce

llvmbot commented May 7, 2025

Assertion

Program

Stack dump

To quickly reproduce