diff --git a/src/Data/Aeson/Local.hs b/src/Data/Aeson/Local.hs
index f3c8e17..d5c5e92 100644
--- a/src/Data/Aeson/Local.hs
+++ b/src/Data/Aeson/Local.hs
@@ -72,5 +72,5 @@ renderURI u = uriToString id u ""
 
 infixr 8 .=?
 (.=?) :: ToJSON v => Text -> Maybe v -> Series
-k .=? Nothing  = mempty
+_ .=? Nothing  = mempty
 k .=? (Just v) = k .= v