diff --git a/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/Internal.hs b/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/Internal.hs
index b0a8ee74e..5341e1122 100644
--- a/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/Internal.hs
+++ b/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/Internal.hs
@@ -207,7 +207,7 @@ toVar ::
 toVar witness = runHash @(Just (Order a)) $ witness $ \case
   SysVar (InVar inV) -> merkleHash inV
   SysVar (NewVar newV) -> M newV
-  ConstVar cV -> merkleHash cV
+  ConstVar cV -> fromConstant cV
 
 ----------------------------- Evaluation functions -----------------------------
 
diff --git a/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/MerkleHash.hs b/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/MerkleHash.hs
index bb4021150..98b5709b4 100644
--- a/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/MerkleHash.hs
+++ b/src/ZkFold/Symbolic/Compiler/ArithmeticCircuit/MerkleHash.hs
@@ -17,7 +17,7 @@ import           ZkFold.Base.Data.ByteString     (toByteString)
 
 newtype MerkleHash (n :: Maybe Natural) = M { runHash :: ByteString }
 
-data Prec = Add | Mul | Div | Mod | Exp deriving (Generic, Binary)
+data Prec = Add | Mul | Div | Mod | Exp | Const deriving (Generic, Binary)
 
 merkleHash :: Binary a => a -> MerkleHash n
 merkleHash = M . hash . toByteString
@@ -34,7 +34,7 @@ instance {-# OVERLAPPING #-} FromConstant (MerkleHash n) (MerkleHash n)
 instance {-# OVERLAPPING #-} Scale (MerkleHash n) (MerkleHash n)
 
 instance Binary a => FromConstant a (MerkleHash n) where
-  fromConstant = merkleHash
+  fromConstant x = merkleHash (Const, x)
 
 instance Binary a => Scale a (MerkleHash n)