Remove unused dependency

Clean up unused dedendencies, remove all uses of `RecordWildCards` and `GADTs` (the former of which
made it tougher to see when fields weren't being used and made code in general less readable to me).

Author: harpocrates

language-rust.cabal

@@ -1,6 +1,6 @@
 name:                language-rust
 version:             0.1.0.0
-synopsis:            Haskell library for parsing and pretty printing Rust code.
+synopsis:            Haskell library for parsing and pretty printing Rust source code.
 -- description:         
 homepage:            https://github.com/harpocrates/language-rust
 license:             BSD3
@@ -32,10 +32,9 @@ library
                        Language.Rust.Data.InputStream
   -- other-modules:
 
-  other-extensions:    RecordWildCards
-                     , OverloadedStrings
+  other-extensions:    OverloadedStrings
+                     , OverloadedLists
                      , DuplicateRecordFields
-                     , GADTs
                      , InstanceSigs
                      , CPP
                      , DeriveFunctor

src/Language/Rust/Data/Position.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE RecordWildCards, DeriveFunctor #-}
+{-# LANGUAGE DeriveFunctor #-}
 
 module Language.Rust.Data.Position where
 
@@ -36,22 +36,22 @@ initPos = Position 0 1 1
 -- | advance column
 incPos :: Position -> Int -> Position
 incPos NoPosition _ = NoPosition
-incPos Position{..} offset = Position (absoluteOffset + offset) (row + offset) col
+incPos p@Position{ absoluteOffset = a, row = r } offset = p { absoluteOffset = a + offset, row = r + offset }
 
 -- | advance to the next line
 retPos :: Position -> Position
 retPos NoPosition = NoPosition
-retPos Position{..} = Position (absoluteOffset + 1) (row + 1) 1
+retPos (Position a r _) = Position { absoluteOffset = a + 1, row = r + 1, col = 1 }
 
 -- | advance just the offset
 incOffset :: Position -> Int -> Position
 incOffset NoPosition _ = NoPosition
-incOffset Position{..} offset = Position (absoluteOffset + offset) row col
+incOffset p@Position{ absoluteOffset = a } offset = p { absoluteOffset = a + offset }
 
 
 instance Show Position where
   show NoPosition = "$"
-  show Position{..} = show row ++ ":" ++ show col
+  show (Position _ r c) = show r ++ ":" ++ show c
 
 
 type ExpnId = Int -- https://docs.serde.rs/syntex_pos/struct.ExpnId.html
@@ -78,7 +78,7 @@ instance Monoid Span where
   s1 `mappend` s2 = Span (lo s1 `minPos` lo s2) (hi s1 `maxPos` hi s2)
 
 instance Show Span where
-  show (Span lo hi) = show lo ++ " - " ++ show hi
+  show (Span lo' hi') = show lo' ++ " - " ++ show hi'
 
 -- | A "tagging" of something with a 'Span' that describes its extent
 data Spanned a = Spanned { unspan :: a, span :: Span } deriving (Functor)

src/Language/Rust/Parser/ParseMonad.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE InstanceSigs, RecordWildCards, PatternSynonyms #-}
+{-# LANGUAGE InstanceSigs, PatternSynonyms #-}
 
 module Language.Rust.Parser.ParseMonad where
 
@@ -92,7 +92,7 @@ setPosition pos = P (\s -> Ok () s{ curPos = pos })
 
 -- | retrieve the input stream of the parser
 getInput :: P InputStream
-getInput = P $ (\s@PState{ curInput = i } -> Ok i s)
+getInput = P (\s@PState{ curInput = i } -> Ok i s)
 
 -- | set the input stream of the parser
 setInput :: InputStream -> P ()

src/Language/Rust/Syntax/AST.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE DuplicateRecordFields, DeriveFunctor, GADTs, PatternSynonyms #-}
+{-# LANGUAGE DuplicateRecordFields, DeriveFunctor, PatternSynonyms #-}
 
 module Language.Rust.Syntax.AST where