diff --git a/Cabal-QuickCheck/src/Test/QuickCheck/GenericArbitrary.hs b/Cabal-QuickCheck/src/Test/QuickCheck/GenericArbitrary.hs
index 29f0b5d85e9..0a9f92be693 100644
--- a/Cabal-QuickCheck/src/Test/QuickCheck/GenericArbitrary.hs
+++ b/Cabal-QuickCheck/src/Test/QuickCheck/GenericArbitrary.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP              #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs            #-}
 {-# LANGUAGE TypeOperators #-}
diff --git a/Cabal-syntax/src/Distribution/Compat/Graph.hs b/Cabal-syntax/src/Distribution/Compat/Graph.hs
index 1a6de3a571b..7b99ae031ed 100644
--- a/Cabal-syntax/src/Distribution/Compat/Graph.hs
+++ b/Cabal-syntax/src/Distribution/Compat/Graph.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE ScopedTypeVariables #-}
diff --git a/Cabal-syntax/src/Distribution/Compat/Newtype.hs b/Cabal-syntax/src/Distribution/Compat/Newtype.hs
index 56f55a9282b..abd8d6225a0 100644
--- a/Cabal-syntax/src/Distribution/Compat/Newtype.hs
+++ b/Cabal-syntax/src/Distribution/Compat/Newtype.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DefaultSignatures #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FunctionalDependencies #-}
@@ -32,7 +31,6 @@ import Data.Monoid (Endo (..), Product (..), Sum (..))
 -- Another approach would be to use @TypeFamilies@ (and possibly
 -- compute inner type using "GHC.Generics"), but we think @FunctionalDependencies@
 -- version gives cleaner type signatures.
-{- FOURMOLU_DISABLE -}
 class Newtype o n | n -> o where
   pack :: o -> n
   default pack :: Coercible o n => o -> n
@@ -41,7 +39,6 @@ class Newtype o n | n -> o where
   unpack :: n -> o
   default unpack :: Coercible n o => n -> o
   unpack = coerce
-{- FOURMOLU_ENABLE -}
 
 instance Newtype a (Identity a)
 instance Newtype a (Sum a)
diff --git a/Cabal-syntax/src/Distribution/Compat/Prelude.hs b/Cabal-syntax/src/Distribution/Compat/Prelude.hs
index 2d6f92b5da6..cabbf8cac2c 100644
--- a/Cabal-syntax/src/Distribution/Compat/Prelude.hs
+++ b/Cabal-syntax/src/Distribution/Compat/Prelude.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE Trustworthy #-}
@@ -180,23 +179,25 @@ module Distribution.Compat.Prelude
   , traceShowM
   ) where
 
--- We also could hide few partial function
-{- FOURMOLU_DISABLE -}
-import Prelude                       as BasePrelude hiding
-    ( mapM, mapM_, sequence, any, all, head, tail, last, init
-    -- partial functions
-    , read
-    , foldr1, foldl1
-    -- As of base 4.11.0.0 Prelude exports part of Semigroup(..).
-    -- Hide this so we instead rely on Distribution.Compat.Semigroup.
-    , Semigroup(..)
-    , Word
-    -- We hide them, as we import only some members
-    , Traversable, traverse, sequenceA
-    , Foldable(..)
-    )
-{- FOURMOLU_ENABLE -}
 import Data.Foldable as BasePrelude (elem, foldl, maximum, minimum, product, sum)
+import Prelude as BasePrelude hiding
+  ( Foldable (..)
+  , Semigroup (..)
+  , Traversable
+  , Word
+  , all
+  , any
+  , head
+  , init
+  , last
+  , mapM
+  , mapM_
+  , read
+  , sequence
+  , sequenceA
+  , tail
+  , traverse
+  )
 
 -- AMP
 import Data.Foldable
diff --git a/Cabal-syntax/src/Distribution/Fields/ParseResult.hs b/Cabal-syntax/src/Distribution/Fields/ParseResult.hs
index aad7de2737a..912ea7fb02f 100644
--- a/Cabal-syntax/src/Distribution/Fields/ParseResult.hs
+++ b/Cabal-syntax/src/Distribution/Fields/ParseResult.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 
diff --git a/Cabal-syntax/src/Distribution/Parsec.hs b/Cabal-syntax/src/Distribution/Parsec.hs
index 3bf62597222..d0197616fd6 100644
--- a/Cabal-syntax/src/Distribution/Parsec.hs
+++ b/Cabal-syntax/src/Distribution/Parsec.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE RankNTypes #-}
diff --git a/Cabal-syntax/src/Distribution/System.hs b/Cabal-syntax/src/Distribution/System.hs
index 1bf6d598d03..e6b87a3cbb7 100644
--- a/Cabal-syntax/src/Distribution/System.hs
+++ b/Cabal-syntax/src/Distribution/System.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE FlexibleContexts #-}
diff --git a/Cabal-tests/tests/UnitTests/Distribution/Utils/CharSet.hs b/Cabal-tests/tests/UnitTests/Distribution/Utils/CharSet.hs
index a7d629ccb08..9efa58cc672 100644
--- a/Cabal-tests/tests/UnitTests/Distribution/Utils/CharSet.hs
+++ b/Cabal-tests/tests/UnitTests/Distribution/Utils/CharSet.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 module UnitTests.Distribution.Utils.CharSet where
 
 import Prelude hiding (Foldable(..))
diff --git a/Cabal/src/Distribution/Compat/Async.hs b/Cabal/src/Distribution/Compat/Async.hs
index d21c19d9cff..2194aa42c4b 100644
--- a/Cabal/src/Distribution/Compat/Async.hs
+++ b/Cabal/src/Distribution/Compat/Async.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 
 -- | 'Async', yet using 'MVar's.
@@ -146,13 +145,11 @@ data AsyncCancelled = AsyncCancelled
     , Typeable
     )
 
-{- FOURMOLU_DISABLE -}
 instance Exception AsyncCancelled where
   -- wraps in SomeAsyncException
   -- See https://github.com/ghc/ghc/commit/756a970eacbb6a19230ee3ba57e24999e4157b09
   fromException = asyncExceptionFromException
   toException = asyncExceptionToException
-{- FOURMOLU_ENABLE -}
 
 -- | Cancel an asynchronous action
 --
diff --git a/Cabal/src/Distribution/Compat/ResponseFile.hs b/Cabal/src/Distribution/Compat/ResponseFile.hs
index 8619ae56962..568e659c094 100644
--- a/Cabal/src/Distribution/Compat/ResponseFile.hs
+++ b/Cabal/src/Distribution/Compat/ResponseFile.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 
diff --git a/Cabal/src/Distribution/Compat/Stack.hs b/Cabal/src/Distribution/Compat/Stack.hs
index 616a66d090d..425e53a990e 100644
--- a/Cabal/src/Distribution/Compat/Stack.hs
+++ b/Cabal/src/Distribution/Compat/Stack.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE ImplicitParams #-}
 {-# LANGUAGE RankNTypes #-}
 
diff --git a/cabal-install/src/Distribution/Client/FileMonitor.hs b/cabal-install/src/Distribution/Client/FileMonitor.hs
index 0872a9a9504..281c6215486 100644
--- a/cabal-install/src/Distribution/Client/FileMonitor.hs
+++ b/cabal-install/src/Distribution/Client/FileMonitor.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
diff --git a/cabal-install/src/Distribution/Client/ProjectConfig.hs b/cabal-install/src/Distribution/Client/ProjectConfig.hs
index 06f4e4e555d..92c101438f3 100644
--- a/cabal-install/src/Distribution/Client/ProjectConfig.hs
+++ b/cabal-install/src/Distribution/Client/ProjectConfig.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
diff --git a/cabal-install/src/Distribution/Client/Security/HTTP.hs b/cabal-install/src/Distribution/Client/Security/HTTP.hs
index 941d0b28dab..dfe96a7a28a 100644
--- a/cabal-install/src/Distribution/Client/Security/HTTP.hs
+++ b/cabal-install/src/Distribution/Client/Security/HTTP.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
diff --git a/cabal-install/src/Distribution/Deprecated/ParseUtils.hs b/cabal-install/src/Distribution/Deprecated/ParseUtils.hs
index 2b48a5df504..e432b0a2333 100644
--- a/cabal-install/src/Distribution/Deprecated/ParseUtils.hs
+++ b/cabal-install/src/Distribution/Deprecated/ParseUtils.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE Rank2Types #-}
 -----------------------------------------------------------------------------
 -- This module is meant to be local-only to Distribution...
@@ -121,14 +120,12 @@ instance Applicative ParseResult where
   pure = ParseOk []
   (<*>) = ap
 
-{- FOURMOLU_DISABLE -}
 instance Monad ParseResult where
   return = pure
   ParseFailed err >>= _ = ParseFailed err
   ParseOk ws x >>= f = case f x of
     ParseFailed err -> ParseFailed err
     ParseOk ws' x' -> ParseOk (ws' ++ ws) x'
-{- FOURMOLU_ENABLE -}
 
 instance Foldable ParseResult where
   foldMap _ (ParseFailed _) = mempty
diff --git a/cabal-install/tests/UnitTests/Distribution/Client/UserConfig.hs b/cabal-install/tests/UnitTests/Distribution/Client/UserConfig.hs
index 91ed61c86cd..a9cb90c64f1 100644
--- a/cabal-install/tests/UnitTests/Distribution/Client/UserConfig.hs
+++ b/cabal-install/tests/UnitTests/Distribution/Client/UserConfig.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
-
 module UnitTests.Distribution.Client.UserConfig
   ( tests
   ) where
diff --git a/cabal-install/tests/UnitTests/Distribution/Solver/Types/OptionalStanza.hs b/cabal-install/tests/UnitTests/Distribution/Solver/Types/OptionalStanza.hs
index 3e2959b01f2..61f94ea28b4 100644
--- a/cabal-install/tests/UnitTests/Distribution/Solver/Types/OptionalStanza.hs
+++ b/cabal-install/tests/UnitTests/Distribution/Solver/Types/OptionalStanza.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
-
 module UnitTests.Distribution.Solver.Types.OptionalStanza
   ( tests
   ) where
diff --git a/cabal-testsuite/src/Test/Cabal/TestCode.hs b/cabal-testsuite/src/Test/Cabal/TestCode.hs
index 2dbd6afd189..e4e466b815c 100644
--- a/cabal-testsuite/src/Test/Cabal/TestCode.hs
+++ b/cabal-testsuite/src/Test/Cabal/TestCode.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP                #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 -- | Exception type like 'ExitCode' but with more information
 -- than just integer.