{TH, Exec}: use patterns for Fix

Author: Anton-Latukha

src/Nix/Exec.hs

@@ -141,7 +141,7 @@ currentPos :: forall e m . (MonadReader e m, Has e SrcSpan) => m SrcSpan
 currentPos = asks $ view hasLens
 
 wrapExprLoc :: SrcSpan -> NExprLocF r -> NExprLoc
-wrapExprLoc span x = Fix $ Fix (NSymAnnF span "<?>") <$ x
+wrapExprLoc span x = Fix $ NSymAnn span "<?>" <$ x
 {-# inline wrapExprLoc #-}
 
 --  2021-01-07: NOTE: This instance belongs to be beside MonadEval type class.
@@ -155,7 +155,7 @@ instance MonadNix e t f m => MonadEval (NValue t f m) m where
     scope <- currentScopes
     evalError @(NValue t f m) $ SynHole $
       SynHoleInfo
-        { _synHoleInfo_expr  = Fix $ NSynHoleAnnF span name
+        { _synHoleInfo_expr  = NSynHoleAnn span name
         , _synHoleInfo_scope = scope
         }
 

src/Nix/TH.hs

@@ -5,7 +5,7 @@
 
 module Nix.TH where
 
-import           Data.Fix                       ( Fix(..) )
+import           Data.Fix                       ( Fix(unFix) )
 import           Data.Generics.Aliases          ( extQ )
 import qualified Data.Set                      as Set
 import           Language.Haskell.TH
@@ -130,24 +130,24 @@ instance ToExpr NExprLoc where
   toExpr = id
 
 instance ToExpr VarName where
-  toExpr = Fix . NSymAnnF nullSpan
+  toExpr = NSymAnn nullSpan
 
 instance ToExpr Int where
-  toExpr = Fix . NConstantAnnF nullSpan . NInt . fromIntegral
+  toExpr = NConstantAnn nullSpan . NInt . fromIntegral
 
 instance ToExpr Integer where
-  toExpr = Fix . NConstantAnnF nullSpan . NInt
+  toExpr = NConstantAnn nullSpan . NInt
 
 instance ToExpr Float where
-  toExpr = Fix . NConstantAnnF nullSpan . NFloat
+  toExpr = NConstantAnn nullSpan . NFloat
 
 metaExp :: Set VarName -> NExprLoc -> Maybe ExpQ
-metaExp fvs (Fix (NSymAnnF _ x)) | x `Set.member` fvs =
+metaExp fvs (NSymAnn _ x) | x `Set.member` fvs =
   pure [| toExpr $(varE (mkName $ toString x)) |]
 metaExp _ _ = Nothing
 
 metaPat :: Set VarName -> NExprLoc -> Maybe PatQ
-metaPat fvs (Fix (NSymAnnF _ x)) | x `Set.member` fvs =
+metaPat fvs (NSymAnn _ x) | x `Set.member` fvs =
   pure $ varP $ mkName $ toString x
 metaPat _ _ = Nothing