diff --git a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs
index 399b893e8e8e90..b1f71a7372804a 100644
--- a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs
+++ b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs
@@ -67,7 +67,7 @@ private sealed class SyntaxReceiver : ISyntaxReceiver
 
             public void OnVisitSyntaxNode(SyntaxNode syntaxNode)
             {
-                if (syntaxNode is ClassDeclarationSyntax cds)
+                if (syntaxNode is ClassDeclarationSyntax { AttributeLists.Count: > 0, BaseList.Types.Count: > 0 } cds)
                 {
                     (ClassDeclarationSyntaxList ??= new List<ClassDeclarationSyntax>()).Add(cds);
                 }