[clang] 38832a8 - [clang] fix obtaining EnumDecl for UsingEnumDecl (#156127)

[via cfe-commits]

Author: Matheus Izvekov
Date: 2025-08-30T01:06:48Z
New Revision: 38832a8443d76ce96b7e893a80538b9c3515a22a

URL: https://github.com/llvm/llvm-project/commit/38832a8443d76ce96b7e893a80538b9c3515a22a
DIFF: https://github.com/llvm/llvm-project/commit/38832a8443d76ce96b7e893a80538b9c3515a22a.diff

LOG: [clang] fix obtaining EnumDecl for UsingEnumDecl (#156127)

Use the castAs acessor for the type for a UsingEnumDecl, as it can be
sugar for an EnumType.

Fixes a regression reported here:
https://github.com/llvm/llvm-project/pull/155313#issuecomment-3238482327

Since this regression was never released, there are no release notes.

Added: 
    

Modified: 
    clang/include/clang/AST/DeclCXX.h
    clang/test/SemaTemplate/using-decl.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/AST/DeclCXX.h b/clang/include/clang/AST/DeclCXX.h
index 00d8f724671f1..8802664031d37 100644
--- a/clang/include/clang/AST/DeclCXX.h
+++ b/clang/include/clang/AST/DeclCXX.h
@@ -3826,7 +3826,7 @@ class UsingEnumDecl : public BaseUsingDecl, public Mergeable<UsingEnumDecl> {
 
 public:
   EnumDecl *getEnumDecl() const {
-    return cast<clang::EnumType>(EnumType->getType())->getOriginalDecl();
+    return EnumType->getType()->castAs<clang::EnumType>()->getOriginalDecl();
   }
 
   static UsingEnumDecl *Create(ASTContext &C, DeclContext *DC,

diff  --git a/clang/test/SemaTemplate/using-decl.cpp b/clang/test/SemaTemplate/using-decl.cpp
index 1ef2a2dfaa019..d54d3a3f3ea9e 100644
--- a/clang/test/SemaTemplate/using-decl.cpp
+++ b/clang/test/SemaTemplate/using-decl.cpp
@@ -14,3 +14,15 @@ namespace UsingInGenericLambda {
   }
   void e() { c<int>(); }
 }
+
+namespace UsingUsingEnum {
+  namespace foo {
+    enum class EnumOne {};
+  }
+  using foo::EnumOne;
+
+  template <class> void t() {
+    using enum EnumOne;
+  }
+  template void t<void>();
+} // namespace UsingUsingEnum