diff --git a/src/StreamJsonRpc.Analyzers/ProxyGenerator.cs b/src/StreamJsonRpc.Analyzers/ProxyGenerator.cs
index 4ec1a958..ae4edf42 100644
--- a/src/StreamJsonRpc.Analyzers/ProxyGenerator.cs
+++ b/src/StreamJsonRpc.Analyzers/ProxyGenerator.cs
@@ -396,7 +396,10 @@ private static IEnumerable<INamedTypeSymbol[]> ExpandInterfaceToGroups(INamedTyp
             yield return [primary];
 
             // And if RpcMarshalable optional interfaces were specified, add them to another group.
-            yield return [primary, .. optionalMarshalableInterfaces];
+            if (optionalMarshalableInterfaces.Count > 0)
+            {
+                yield return [primary, .. optionalMarshalableInterfaces];
+            }
         }
     }