diff --git a/gibbon-compiler/src/Gibbon/L1/GenSML.hs b/gibbon-compiler/src/Gibbon/L1/GenSML.hs
index fd2f78d4e..1c06a7e5d 100644
--- a/gibbon-compiler/src/Gibbon/L1/GenSML.hs
+++ b/gibbon-compiler/src/Gibbon/L1/GenSML.hs
@@ -391,7 +391,7 @@ printerTy1 ty1 d = case ty1 of
     where
       ppSub (i, x) = hsep
         [ "val _ ="
-        , printerTy1 x ("x__" <> int i)
+        , printerTy1 x $ "x__" <> int i
         , "val _ = print \" \""
         ]
   SymDictTy _m_var _ut -> _