diff --git a/bsonmacros/src/main/scala/me/sgrouples/rogue/cc/macros/MacroBsonFormatDerivingQuotes.scala b/bsonmacros/src/main/scala/me/sgrouples/rogue/cc/macros/MacroBsonFormatDerivingQuotes.scala
index f1d2609..3400287 100644
--- a/bsonmacros/src/main/scala/me/sgrouples/rogue/cc/macros/MacroBsonFormatDerivingQuotes.scala
+++ b/bsonmacros/src/main/scala/me/sgrouples/rogue/cc/macros/MacroBsonFormatDerivingQuotes.scala
@@ -167,7 +167,7 @@ object MacroBsonFormatDerivingImpl:
               fieldsVec
             }.toVector //why no vector?
 
-            override def flds: Map[String, BsonFormat[?]] =
+            override val flds: Map[String, BsonFormat[?]] =
               ${ fldsFormatsMap } ++ (${ fldsFormatsMap }
                 .map { case (name, f) => subfields(name, f) })
                 .flatten