diff --git a/core/src/Streamly/Internal/Data/Array/Type.hs b/core/src/Streamly/Internal/Data/Array/Type.hs
index 1d26d4143..fbc4cf14c 100644
--- a/core/src/Streamly/Internal/Data/Array/Type.hs
+++ b/core/src/Streamly/Internal/Data/Array/Type.hs
@@ -329,7 +329,12 @@ isPinned = MA.isPinned . unsafeThaw
 -- would make a copy on every splice operation, instead use the
 -- 'fromChunksK' operation to combine n immutable arrays.
 {-# INLINE splice #-}
-splice :: MonadIO m => Array a -> Array a -> m (Array a)
+splice :: (MonadIO m
+#ifdef DEVBUILD
+    , Unbox a
+#endif
+    )
+    => Array a -> Array a -> m (Array a)
 splice arr1 arr2 =
     unsafeFreeze <$> MA.spliceCopy (unsafeThaw arr1) (unsafeThaw arr2)
 
diff --git a/src/Streamly/Internal/Data/SmallArray/Type.hs b/src/Streamly/Internal/Data/SmallArray/Type.hs
index 0dc3d40d1..32b21f6af 100644
--- a/src/Streamly/Internal/Data/SmallArray/Type.hs
+++ b/src/Streamly/Internal/Data/SmallArray/Type.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE UnboxedTuples #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE NoMonoLocalBinds #-}
 
 -- |
 -- Module : Data.Primitive.SmallArray