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Concept checking assertion in Clang 16 #64086

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alexolog opened this issue Jul 24, 2023 · 12 comments · Fixed by #76967
Closed

Concept checking assertion in Clang 16 #64086

alexolog opened this issue Jul 24, 2023 · 12 comments · Fixed by #76967
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@LYP951018
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c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" concepts C++20 concepts confirmed Verified by a second party crash Prefer [crash-on-valid] or [crash-on-invalid] lambda C++11 lambda expressions

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@alexolog
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alexolog commented Jul 24, 2023 •
edited
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Clang 14: https://godbolt.org/z/T7vY6Ydcq OK
Clang 15: https://godbolt.org/z/cYse4o87b OK
Clang 16: https://godbolt.org/z/eoTzGe413 Boom!

Context: https://stackoverflow.com/q/76741924/181238
@EugeneZelenko EugeneZelenko added c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" confirmed Verified by a second party crash Prefer [crash-on-valid] or [crash-on-invalid] lambda C++11 lambda expressions and removed new issue labels Jul 24, 2023
@EugeneZelenko
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Also crashes in main: https://godbolt.org/z/GGMv4Kz6q

@llvmbot
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llvmbot commented Jul 24, 2023

@llvm/issue-subscribers-c-20

@llvmbot
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llvmbot commented Jul 24, 2023

@llvm/issue-subscribers-clang-frontend

@AaronBallman
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Well this is neat. When trying to reduce the test case, you can remove the include to concepts and the assert still triggers, and you can remove use of std::cout and the assert still triggers, but when you remove the include to iostreams (despite not using it anywhere in the test), the assert disappears.

https://godbolt.org/z/6n8nG99Eo

@AaronBallman AaronBallman added the concepts C++20 concepts label Jul 25, 2023
@AaronBallman
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For reference, the assertion is:

clang++: /root/llvm-project/clang/include/clang/AST/ExprConcepts.h:101: bool clang::ConceptSpecializationExpr::isSatisfied() const: Assertion `!isValueDependent() && "isSatisfied called on a dependent ConceptSpecializationExpr"' failed.
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-assertions-16.0.0/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-12.2.0 -fcolor-diagnostics -fno-crash-diagnostics -DEXPLODE -std=c++20 -stdlib=libc++ -Wall -Wextra -O3 <source>
1.	<source>:41:62: current parser token ')'
2.	<source>:27:1: parsing struct/union/class body 'Thing'
3.	<source>:29:22: parsing function body 'Thing::foo'
4.	<source>:29:22: in compound statement ('{}')
5.	<source>:40:16: in compound statement ('{}')
6.	<source>:30:24: instantiating function definition 'Thing::foo(char)::(anonymous class)::operator()<&S::getS1>'
 #0 0x000055c2a782e32f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x412e32f)
 #1 0x000055c2a782c2cc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x412c2cc)
 #2 0x000055c2a7778fb8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f61642c3420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f6163d9000b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f6163d6f859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f6163d6f729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f6163d80fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x000055c2aa4de9ad clang::Sema::BuildExprRequirement(clang::Expr*, bool, clang::SourceLocation, clang::concepts::ExprRequirement::ReturnTypeRequirement) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6dde9ad)
 #9 0x000055c2aa996e28 (anonymous namespace)::TemplateInstantiator::TransformExprRequirement(clang::concepts::ExprRequirement*) SemaTemplateInstantiate.cpp:0:0
#10 0x000055c2aa9b3cb8 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformRequiresExpr(clang::RequiresExpr*) SemaTemplateInstantiate.cpp:0:0
#11 0x000055c2aa9b511e (anonymous namespace)::TemplateInstantiator::TransformRequiresExpr(clang::RequiresExpr*) SemaTemplateInstantiate.cpp:0:0
#12 0x000055c2aa9893eb clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#13 0x000055c2aa98d948 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCondition(clang::SourceLocation, clang::VarDecl*, clang::Expr*, clang::Sema::ConditionKind) SemaTemplateInstantiate.cpp:0:0
#14 0x000055c2aa9c11af clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformIfStmt(clang::IfStmt*) SemaTemplateInstantiate.cpp:0:0
#15 0x000055c2aa9bfb39 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#16 0x000055c2aa988a57 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformLambdaExpr(clang::LambdaExpr*) SemaTemplateInstantiate.cpp:0:0
#17 0x000055c2aa98962a clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) SemaTemplateInstantiate.cpp:0:0
#18 0x000055c2aa98a0e8 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformInitializer(clang::Expr*, bool) (.part.0) SemaTemplateInstantiate.cpp:0:0
#19 0x000055c2aa98a46c clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformReturnStmt(clang::ReturnStmt*) SemaTemplateInstantiate.cpp:0:0
#20 0x000055c2aa9bfb39 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) SemaTemplateInstantiate.cpp:0:0
#21 0x000055c2aa9c517e clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x72c517e)
#22 0x000055c2aaa12d4a clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x7312d4a)
#23 0x000055c2a9ff9595 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x68f9595)
#24 0x000055c2aa90073f clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x720073f)
#25 0x000055c2aa3b361a clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRef<clang::SourceLocation>, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6cb361a)
#26 0x000055c2aa77ac08 clang::Sema::BuildCallToMemberFunction(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x707ac08)
#27 0x000055c2aa41515d clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6d1515d)
#28 0x000055c2aa43837b clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6d3837b)
#29 0x000055c2a9f1bed9 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x681bed9)
#30 0x000055c2a9f14027 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6814027)
#31 0x000055c2a9f1710b clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x681710b)
#32 0x000055c2a9f171ad clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x68171ad)
#33 0x000055c2a9f18ebc clang::Parser::ParseRHSOfBinaryExpression(clang::ActionResult<clang::Expr*, true>, clang::prec::Level) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6818ebc)
#34 0x000055c2a9f1b45d clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x681b45d)
#35 0x000055c2a9f95d7e clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6895d7e)
#36 0x000055c2a9f8c3ec clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688c3ec)
#37 0x000055c2a9f8d2f5 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688d2f5)
#38 0x000055c2a9f8fe58 clang::Parser::ParseStatement(clang::SourceLocation*, clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688fe58)
#39 0x000055c2a9f949c8 clang::Parser::ParseCaseStatement(clang::Parser::ParsedStmtContext, bool, clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x68949c8)
#40 0x000055c2a9f8be43 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688be43)
#41 0x000055c2a9f8d2f5 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688d2f5)
#42 0x000055c2a9f8e2ca clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688e2ca)
#43 0x000055c2a9f8e966 clang::Parser::ParseCompoundStatement(bool, unsigned int) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688e966)
#44 0x000055c2a9f8b597 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688b597)
#45 0x000055c2a9f8d2f5 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688d2f5)
#46 0x000055c2a9f8fe58 clang::Parser::ParseStatement(clang::SourceLocation*, clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688fe58)
#47 0x000055c2a9f91f0e clang::Parser::ParseSwitchStatement(clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x6891f0e)
#48 0x000055c2a9f8bcfc clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688bcfc)
#49 0x000055c2a9f8d2f5 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688d2f5)
#50 0x000055c2a9f8e2ca clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688e2ca)
#51 0x000055c2a9f8fc7a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x688fc7a)
#52 0x000055c2a9ec0d3a clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67c0d3a)
#53 0x000055c2a9ec0a1d clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67c0a1d)
#54 0x000055c2a9f0b71a clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x680b71a)
#55 0x000055c2a9f0d7dd clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x680d7dd)
#56 0x000055c2a9eddd60 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67ddd60)
#57 0x000055c2a9eb3e0b clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67b3e0b)
#58 0x000055c2a9eb472f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) Parser.cpp:0:0
#59 0x000055c2a9eb9e89 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67b9e89)
#60 0x000055c2a9ebae2d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67bae2d)
#61 0x000055c2a9eaf1ba clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x67af1ba)
#62 0x000055c2a8bb03c8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x54b03c8)
#63 0x000055c2a841b659 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4d1b659)
#64 0x000055c2a83a21ee clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4ca21ee)
#65 0x000055c2a8502a83 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4e02a83)
#66 0x000055c2a4c592a6 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x15592a6)
#67 0x000055c2a4c55397 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#68 0x000055c2a820a3b9 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
#69 0x000055c2a77794a0 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x40794a0)
#70 0x000055c2a820ac6f 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
#71 0x000055c2a81d330c clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4ad330c)
#72 0x000055c2a81d3d8d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4ad3d8d)
#73 0x000055c2a81dcf5c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x4adcf5c)
#74 0x000055c2a4c579f2 clang_main(int, char**) (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x15579f2)
#75 0x00007f6163d71083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#76 0x000055c2a4c5007e _start (/opt/compiler-explorer/clang-assertions-16.0.0/bin/clang+++0x155007e)
clang-16: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

@cor3ntin
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I suspect this is one more case of trying to instantiate lambda body too early, @erichkeane is meaning to get to that at some point

@AaronBallman
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AaronBallman commented Jul 25, 2023 •
edited by usx95
Loading

I've gotten it reduced further to:

struct S1 {
    int f1() { return 1; }
};

template <typename T>
concept C = true;

void foo() {
  auto make_caller = []<auto member> {
    return [](S1* ps) {
      if constexpr (requires { { (ps->*member)() } -> C; })
        ;
    };
  };
    
  auto* caller = make_caller.operator()<&S1::f1>();
}

https://godbolt.org/z/oKPTvPzo3

@AaronBallman AaronBallman changed the title Lambda breaks clang 16 Concept checking assertion in Clang 16 Jul 25, 2023
@alexolog
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Removing the return value from the requires seems to work:
https://godbolt.org/z/6f8n9efMe

@danakj
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danakj commented Aug 4, 2023

I have another case of this assertion here, which is concepts + partial specialization: #49570 (comment)

@danakj
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danakj commented Aug 4, 2023

Oh ok mine is lambda related too, but the concept on the specialization somehow is needed to trigger it as well. But using a template function instead of a lambda prevents the crash there as well.

danakj added a commit to danakj/subspace that referenced this issue Aug 4, 2023
@danakj
Avoid lambda to work around clang assertion failure
8f9ff3c 
Using a lambda in a requires clause can cause clang to assert, so
move to a named function instead.

Clang bug: llvm/llvm-project#64086
danakj added a commit to danakj/subspace that referenced this issue Aug 4, 2023
@danakj
Avoid lambda to work around clang assertion failure
a3d651e 
Using a lambda in a requires clause can cause clang to assert, so
move to a named function instead.

Clang bug: llvm/llvm-project#64086
danakj added a commit to chromium/subspace that referenced this issue Aug 6, 2023
@danakj
Avoid lambda to work around clang assertion failure
0b5fb15 
Using a lambda in a requires clause can cause clang to assert, so
move to a named function instead.

Clang bug: llvm/llvm-project#64086
@ecatmur
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ecatmur commented Aug 17, 2023

Looks similar to #63808

@LYP951018
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I am trying to fix this bug. It seems that the template argument depth passed in when instantiating ReturnTypeRequirement is wrong.

@LYP951018 LYP951018 self-assigned this Dec 26, 2023
@LYP951018 LYP951018 mentioned this issue Jan 4, 2024
Merged
LYP951018 added a commit that referenced this issue Jan 4, 2024
@LYP951018
[Clang] Fix the instantiation of return type requirements in lambda b…
e78a1f4 
…odies (#76967)

Currently, due to the incomplete implementation of p0588r1, the
instantiation of lambda expressions leads to the instantiation of the
body. And `EvaluateConstraints` is false during the instantiation of the
body, which causes crashes during the instantiation of the return type
requirement:

```cpp
template<typename T> concept doesnt_matter = true;

template<class T>
concept test = 
    []{
        return requires(T t) {
            { t } -> doesnt_matter; // crash
        };
    }();

static_assert(test<int>);
```

Although a complete implementation of p0588r1 can solve these crashes,
it will take some time. Therefore, this pull request aims to fix these
crashes first.

Fixes #63808
Fixes #64607
Fixes #64086
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c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" concepts C++20 concepts confirmed Verified by a second party crash Prefer [crash-on-valid] or [crash-on-invalid] lambda C++11 lambda expressions
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[Clang] Fix the instantiation of return type requirements in lambda bodies LYP951018/llvm-project
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@danakj @ecatmur @cor3ntin @alexolog @AaronBallman @LYP951018 @EugeneZelenko @llvmbot