| Issue |
202879
|
| Summary |
[clang]Assertion failure in InitListChecker with malformed class template specialization and CTAD
|
| Labels |
|
| Assignees |
|
| Reporter |
Attacker23
|
The following ill-formed code triggers a clang assertion failure since **12.0.0**:
```cpp
template<>
template<class T>
struct X<int> {
T a;
};
//X x1(0); //error
//X<int> x2{0}; //error
X x3{0}; //crash
```
https://godbolt.org/z/c6rze5xbn
**Clang attempts to perform aggregate CTAD on a malformed class template specialization, but internal deduction state (AggrDeductionCandidateParamTypes) is not initialized, leading to an assertion failure.**
* Direct initialization with CTAD (X x1(0)) does not trigger the crash.
* Explicit template arguments with list-initialization (X<int> x2{0}) does not trigger the crash — no CTAD path is entered.
<details>
<summary>Output:</summary>
<pre><code>
'<'source'>':3:8: error: explicit specialization of undeclared template struct 'X'
3 | struct X<int> {
| ^~~~~~
'<'source'>':1:1: error: extraneous 'template<>' in declaration of struct 'X'
1 | template<>
| ^
clang++: /root/llvm-project/llvm/tools/clang/lib/Sema/SemaInit.cpp:1558: void {anonymous}::InitListChecker::CheckSubElementType(const clang::InitializedEntity&, clang::InitListExpr*, clang::QualType, unsigned int&, clang::InitListExpr*, unsigned int&, bool): Assertion `AggrDeductionCandidateParamTypes' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and dumped files.
Stack dump:
0. Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1. <source>:9:8: current parser token ';'
#0 0x0000000004385c18 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4385c18)
#1 0x0000000004382a54 llvm::sys::RunSignalHandlers() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4382a54)
#2 0x0000000004383074 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4383074)
#3 0x00000000042bf2f8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#4 0x00007403a1c45330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
#5 0x00007403a1c9eb2c pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x9eb2c)
#6 0x00007403a1c4527e raise (/lib/x86_64-linux-gnu/libc.so.6+0x4527e)
#7 0x00007403a1c288ff abort (/lib/x86_64-linux-gnu/libc.so.6+0x288ff)
#8 0x00007403a1c2881b (/lib/x86_64-linux-gnu/libc.so.6+0x2881b)
#9 0x00007403a1c3b517 (/lib/x86_64-linux-gnu/libc.so.6+0x3b517)
#10 0x0000000007322dd8 (anonymous namespace)::InitListChecker::CheckSubElementType(clang::InitializedEntity const&, clang::InitListExpr*, clang::QualType, unsigned int&, clang::InitListExpr*, unsigned int&, bool) SemaInit.cpp:0:0
#11 0x00000000073235d1 (anonymous namespace)::InitListChecker::CheckStructUnionTypes(clang::InitializedEntity const&, clang::InitListExpr*, clang::QualType, llvm::iterator_range<clang::CXXBaseSpecifier const*>, clang::DeclContext::specific_decl_iterator<clang::FieldDecl>, bool, unsigned int&, clang::InitListExpr*, unsigned int&, bool) SemaInit.cpp:0:0
#12 0x00000000073207ce (anonymous namespace)::InitListChecker::CheckListElementTypes(clang::InitializedEntity const&, clang::InitListExpr*, clang::QualType&, bool, unsigned int&, clang::InitListExpr*, unsigned int&, bool) (.constprop.0) SemaInit.cpp:0:0
#13 0x000000000730e3da (anonymous namespace)::InitListChecker::CheckExplicitInitList(clang::InitializedEntity const&, clang::InitListExpr*, clang::QualType&, clang::InitListExpr*, bool) (.constprop.0) SemaInit.cpp:0:0
#14 0x000000000730edf7 (anonymous namespace)::InitListChecker::InitListChecker(clang::Sema&, clang::InitializedEntity const&, clang::InitListExpr*, clang::QualType&, bool, bool, bool, llvm::SmallVectorImpl<clang::QualType>*) SemaInit.cpp:0:0
#15 0x000000000730f6b8 TryListInitialization(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, clang::InitListExpr*, clang::InitializationSequence&, bool) SemaInit.cpp:0:0
#16 0x0000000007310f44 clang::InitializationSequence::InitializeFrom(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x7310f44)
#17 0x000000000702d1ca clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x702d1ca)
#18 0x0000000006c70c34 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c70c34)
#19 0x0000000006c7e54a clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c7e54a)
#20 0x0000000006c3b31b clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c3b31b)
#21 0x0000000006c3bb1f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c3bb1f)
#22 0x0000000006c435d1 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c435d1)
#23 0x0000000006c444e5 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c444e5)
#24 0x0000000006c253ca clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6c253ca)
#25 0x0000000004e72a68 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4e72a68)
#26 0x00000000051a9458 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x51a9458)
#27 0x0000000005126c9d clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5126c9d)
#28 0x00000000052a803d clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52a803d)
#29 0x0000000000e21efc cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xe21efc)
#30 0x0000000000e18b9a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) driver.cpp:0:0
#31 0x0000000000e18d1d int llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::callback_fn<clang_main(int, char**, llvm::ToolContext const&)::'lambda'(llvm::SmallVectorImpl<char const*>&)>(long, llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#32 0x0000000004ee4b39 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
#33 0x00000000042bf734 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x42bf734)
#34 0x0000000004ee5186 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
#35 0x0000000004ea2102 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ea2102)
#36 0x0000000004ea30ae 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+++0x4ea30ae)
#37 0x0000000004eab3a5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4eab3a5)
#38 0x0000000000e1e432 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xe1e432)
#39 0x0000000000cc210a main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcc210a)
#40 0x00007403a1c2a1ca (/lib/x86_64-linux-gnu/libc.so.6+0x2a1ca)
#41 0x00007403a1c2a28b __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28b)
#42 0x0000000000e18545 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xe18545)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)
Compiler returned: 134
</code></pre>
</details>
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