Replace hand-written recursion with forAllBases

Author: snarang181

clang/lib/Sema/SemaTypeTraits.cpp

@@ -2353,32 +2353,17 @@ static void DiagnoseNonStandardLayoutReason(Sema &SemaRef, SourceLocation Loc,
           << Field->getType() << Field->getSourceRange();
     }
   }
-
-  //  if this class and an indirect base
-  // both have non-static data members, grab the first such base.
+  // find any indirect base classes that have fields
   if (D->hasDirectFields()) {
-    SmallVector<const CXXRecordDecl *, 4> Records;
-
-    // Recursive lambda to collect all bases that declare fields
-    std::function<void(const CXXRecordDecl *)> collect =
-        [&](const CXXRecordDecl *R) {
-          for (const CXXBaseSpecifier &B : R->bases()) {
-            const auto *BR = B.getType()->getAsCXXRecordDecl();
-            if (!BR || !BR->hasDefinition())
-              continue;
-            if (BR->hasDirectFields())
-              Records.push_back(BR);
-            // Recurse into the base class.
-            collect(BR);
-          }
-        };
-
-    // Collect all bases that declare fields.
-    collect(D);
-
-    // If more than one record has fields, then the layout is non-standard.
-    if (!Records.empty()) {
-      const CXXRecordDecl *Indirect = Records.front();
+    const CXXRecordDecl *Indirect = nullptr;
+    D->forallBases([&](const CXXRecordDecl *BaseDef) {
+      if (BaseDef->hasDirectFields()) {
+        Indirect = BaseDef;
+        return false; // stop traversal
+      }
+      return true; // continue to the next base
+    });
+    if (Indirect) {
       SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
           << diag::TraitNotSatisfiedReason::IndirectBaseWithFields << Indirect
           << Indirect->getSourceRange();