diff --git a/headed-megaparsec.cabal b/headed-megaparsec.cabal
--- a/headed-megaparsec.cabal
+++ b/headed-megaparsec.cabal
@@ -1,33 +1,71 @@
-name: headed-megaparsec
-version: 0.2.1.2
-category: Parsers, Parsing, Megaparsec
-synopsis: More informative parser
-homepage: https://github.com/nikita-volkov/headed-megaparsec
-bug-reports: https://github.com/nikita-volkov/headed-megaparsec/issues
-author: Nikita Volkov <nikita.y.volkov@mail.ru>
-maintainer: Nikita Volkov <nikita.y.volkov@mail.ru>
-copyright: (c) 2019, Nikita Volkov
-license: MIT
-license-file: LICENSE
-build-type: Simple
-cabal-version: >=1.10
+cabal-version: 3.0
+name:          headed-megaparsec
+version:       0.2.1.3
+category:      Parsers, Parsing, Megaparsec
+synopsis:      More informative parser
+homepage:      https://github.com/nikita-volkov/headed-megaparsec
+bug-reports:   https://github.com/nikita-volkov/headed-megaparsec/issues
+author:        Nikita Volkov <nikita.y.volkov@mail.ru>
+maintainer:    Nikita Volkov <nikita.y.volkov@mail.ru>
+copyright:     (c) 2019, Nikita Volkov
+license:       MIT
+license-file:  LICENSE
 
 source-repository head
-  type: git
+  type:     git
   location: git://github.com/nikita-volkov/headed-megaparsec.git
 
 library
-  hs-source-dirs: library
-  default-extensions: ApplicativeDo, Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFoldable, DeriveFunctor, DeriveGeneric, DeriveTraversable, DuplicateRecordFields, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples
-  default-language: Haskell2010
-  exposed-modules:
-    HeadedMegaparsec
+  hs-source-dirs:     library
+  default-extensions:
+    NoImplicitPrelude
+    NoMonomorphismRestriction
+    ApplicativeDo
+    Arrows
+    BangPatterns
+    ConstraintKinds
+    DataKinds
+    DefaultSignatures
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveTraversable
+    DuplicateRecordFields
+    EmptyDataDecls
+    FlexibleContexts
+    FlexibleInstances
+    FunctionalDependencies
+    GADTs
+    GeneralizedNewtypeDeriving
+    LambdaCase
+    LiberalTypeSynonyms
+    MagicHash
+    MultiParamTypeClasses
+    MultiWayIf
+    OverloadedStrings
+    ParallelListComp
+    PatternGuards
+    QuasiQuotes
+    RankNTypes
+    RecordWildCards
+    ScopedTypeVariables
+    StandaloneDeriving
+    TemplateHaskell
+    TupleSections
+    TypeFamilies
+    TypeOperators
+    UnboxedTuples
+
+  default-language:   Haskell2010
+  exposed-modules:    HeadedMegaparsec
   other-modules:
     HeadedMegaparsec.Megaparsec
     HeadedMegaparsec.Prelude
+
   build-depends:
-    base >=4.13 && <5,
-    case-insensitive >=1.2 && <2,
-    megaparsec >=9.2 && <10,
-    parser-combinators >=1.3 && <1.4,
-    selective >=0.7 && <0.8
+    , base >=4.13 && <5
+    , case-insensitive >=1.2 && <2
+    , megaparsec >=9.2 && <10
+    , parser-combinators >=1.3 && <1.4
+    , selective >=0.7 && <0.8
diff --git a/library/HeadedMegaparsec.hs b/library/HeadedMegaparsec.hs
--- a/library/HeadedMegaparsec.hs
+++ b/library/HeadedMegaparsec.hs
@@ -114,12 +114,14 @@
         junction2 <- p2
         case junction2 of
           Left a -> return (Left (aToB a))
-          Right tailP2 -> return $
-            Right $ do
+          Right tailP2 -> return
+            $ Right
+            $ do
               a <- tailP2
               return (aToB a)
-      Right tailP1 -> return $
-        Right $ do
+      Right tailP1 -> return
+        $ Right
+        $ do
           aToB <- tailP1
           junction2 <- p2
           case junction2 of
@@ -139,8 +141,9 @@
           case junction2 of
             Left aToB -> return (Left (aToB a))
             Right tailP2 -> return (Right (fmap ($ a) tailP2))
-      Right tailP1 -> return $
-        Right $ do
+      Right tailP1 -> return
+        $ Right
+        $ do
           eitherAOrB <- tailP1
           case eitherAOrB of
             Right b -> return b
@@ -156,8 +159,9 @@
     junction1 <- p1
     case junction1 of
       Left a -> case k2 a of HeadedParsec p2 -> p2
-      Right tailP1 -> return $
-        Right $ do
+      Right tailP1 -> return
+        $ Right
+        $ do
           a <- tailP1
           Megaparsec.contPossibly $ case k2 a of HeadedParsec p2 -> p2
 
@@ -234,8 +238,9 @@
       if pred a
         then return (Left a)
         else fail (err a)
-    Right tailP -> return $
-      Right $ do
+    Right tailP -> return
+      $ Right
+      $ do
         a <- tailP
         if pred a
           then return a
diff --git a/library/HeadedMegaparsec/Prelude.hs b/library/HeadedMegaparsec/Prelude.hs
--- a/library/HeadedMegaparsec/Prelude.hs
+++ b/library/HeadedMegaparsec/Prelude.hs
@@ -27,7 +27,7 @@
 import Data.Fixed as Exports
 import Data.Foldable as Exports
 import Data.Function as Exports hiding (id, (.))
-import Data.Functor as Exports
+import Data.Functor as Exports hiding (unzip)
 import Data.Functor.Identity as Exports
 import Data.IORef as Exports
 import Data.Int as Exports