[clang] [Clang][Sema] set declaration invalid earlier to prevent crash in calculating record layout (PR #87173)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Qizhi Hu (jcsxky)

<details>
<summary>Changes</summary>

Try to fix https://github.com/llvm/llvm-project/issues/75221
This crash caused by calculating record layout which contains a field declaration with dependent type. Make it invalid when report diagnose to prevent this crash. Set the record declaration incomplete bypass the assertion and restore the status when finish setting it invalid.

---
Full diff: https://github.com/llvm/llvm-project/pull/87173.diff


3 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+2) 
- (modified) clang/lib/Sema/SemaType.cpp (+3) 
- (added) clang/test/SemaCXX/PR75221.cpp (+7) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 37b843915a0dee..20578c9b60e33c 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -465,6 +465,8 @@ Bug Fixes to C++ Support
   following the first `::` were ignored).
 - Fix an out-of-bounds crash when checking the validity of template partial specializations. (part of #GH86757).
 - Fix an issue caused by not handling invalid cases when substituting into the parameter mapping of a constraint. Fixes (#GH86757).
+- Fix a crash caused by defined struct in a type alias template when the structure
+  has fields with dependent type. Fixes (#GH75221).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index fd94caa4e1d449..973ad20c943bde 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -3899,6 +3899,9 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
       SemaRef.Diag(OwnedTagDecl->getLocation(), DiagID)
           << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
       D.setInvalidType(true);
+      OwnedTagDecl->setCompleteDefinition(false);
+      OwnedTagDecl->setInvalidDecl();
+      OwnedTagDecl->setCompleteDefinition();
     }
   }
 
diff --git a/clang/test/SemaCXX/PR75221.cpp b/clang/test/SemaCXX/PR75221.cpp
new file mode 100644
index 00000000000000..08b7a06676a8a5
--- /dev/null
+++ b/clang/test/SemaCXX/PR75221.cpp
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -verify -std=c++11 -fsyntax-only %s
+// expected-no-diagnostics
+
+template <class T> using foo = struct foo {
+  T size = 0;
+};
+foo a;

``````````

</details>


https://github.com/llvm/llvm-project/pull/87173