| Issue |
176629
|
| Summary |
clang-tidy 21.1.6 crashes (SIGSEGV) in VarTemplateSpecializationDecl during static analyzer on C++23 modules
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
joseph-wardle
|
**Summary**
`clang-tidy` crashes with SIGSEGV while analyzing a C++23 project that uses modules (`.cppm`). Crash occurs during static analyzer (PaddingChecker) and appears related to `VarTemplateSpecializationDecl::getMostRecentDecl()`.
**Steps to reproduce**
1. Configure the project (CMake generates `build/dev` and `compile_commands.json`)
2. Run:
```
rg --files -0 -g '*.{c,cc,cpp,cxx,cppm,ixx}' -g '!build/**' -g '!third_party/**' | \
xargs -0 clang-tidy -p build/dev
```
In my run, clang-tidy is invoked as:
```
clang-tidy -p build/dev examples/sandbox/main.cpp src/physics/physics_system.cppm src/scene/camera.cppm src/scene/pose_channel.cppm src/scene/render_view.cppm src/scene/shapes.cppm src/scene/physics_view.cppm src/scene/entity.cppm src/scene/scene.cppm src/render/render_system.cppm src/math/mat4.cppm src/render/render_targets.cppm src/math/mat3.cppm src/render/pipeline.cppm src/math/vec4.cppm src/render/render_device.cppm src/math/vec3.cppm src/render/fly_camera.cppm src/math/vec2.cppm src/render/types.cppm src/math/quat.cppm src/math/constants.cppm src/core/app.cppm src/core/logging.cppm src/core/time.cppm src/core/types.cppm src/render/render_context.cppm src/platform/input.cppm src/platform/platform.cppm src/platform/window.cppm src/render/passes/post_pass.cppm src/render/passes/world_grid_pass.cppm src/render/passes/geometry_pass.cppm
```
Crash happens on the first file processed: `examples/sandbox/main.cpp`.
**Backtrace (trimmed)**
```
#4 clang::Redeclarable<clang::VarDecl>::getFirstDecl()
#5 clang::Redeclarable<clang::VarDecl>::getMostRecentDecl()
#6 clang::VarTemplateSpecializationDecl::getMostRecentDecl()
#7 clang::RedeclarableTemplateDecl::SpecIterator<...>::operator*() const
#8 TraverseTemplateInstantiations
#9 clang::DynamicRecursiveASTVisitorBase<false>::TraverseTemplateInstantiations(...)
#10 TraverseVarTemplateDecl
...
#24 _checkDecl<(anonymous namespace)::PaddingChecker>
#25 clang::ento::CheckerManager::runCheckersOnASTDecl(...)
...
#55 clang::tidy::runClangTidy(...)
#56 clang::tidy::clangTidyMain(...)
```
**Environment**
- OS: Arch Linux (rolling)
- clang-tidy version:
```
LLVM (http://llvm.org/):
LLVM version 21.1.6
Optimized build.
```
The main file itself is extremely simple:
```cpp
import std;
import javelin.core.types;
import javelin.core.app;
using namespace javelin;
int main() {
App app{};
app.run("[hardcoded filepath]");
return 0;
}
```
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