Add two new helper instances for Has

src/Nix/Reduce.hs

@@ -15,7 +15,6 @@
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TupleSections #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE ViewPatterns #-}
@@ -72,9 +71,6 @@ newtype Reducer m a = Reducer
               MonadReader (Maybe FilePath, Scopes (Reducer m) NExprLoc),
               MonadState (HashMap FilePath NExprLoc))
 
-instance Has (Maybe FilePath, Scopes m v) (Scopes m v) where
-    hasLens f (x, y) = (x,) <$> f y
-
 -- gatherNames :: NExprLoc -> HashSet VarName
 -- gatherNames = cata $ \case
 --     NSym_ _ var -> S.singleton var

src/Nix/Utils.hs

@@ -108,6 +108,12 @@ class Has a b where
 instance Has a a where
     hasLens f = f
 
+instance Has (a, b) a where
+    hasLens f (x, y) = (, y) <$> f x
+
+instance Has (a, b) b where
+    hasLens f (x, y) = (x,) <$> f y
+
 toEncodingSorted :: A.Value -> A.Encoding
 toEncodingSorted = \case
     A.Object m ->