Drop pre-AMP compatibility CPP conditionals

Since GHC 8.1/8.2 only needs to be bootstrap-able by GHC 7.10 and
GHC 8.0 (and GHC 8.2), we can now finally drop all that pre-AMP
compatibility CPP-mess for good!

Reviewers: austin, goldfire, bgamari

Subscribers: goldfire, thomie, erikd

Differential Revision: https://phabricator.haskell.org/D1724

compiler/basicTypes/ConLike.hs

@@ -39,9 +39,6 @@ import Type (mkTyConApp)
 import Data.Function (on)
 import qualified Data.Data as Data
 import qualified Data.Typeable
-#if __GLASGOW_HASKELL__ <= 708
-import Control.Applicative ((<$>))
-#endif
 
 {-
 ************************************************************************

compiler/basicTypes/FieldLabel.hs

@@ -56,7 +56,6 @@ Of course, datatypes with no constructors cannot have any fields.
 
 -}
 
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE DeriveFoldable #-}
@@ -79,11 +78,6 @@ import Binary
 
 import Data.Data
 
-#if __GLASGOW_HASKELL__ < 709
-import Data.Foldable ( Foldable )
-import Data.Traversable ( Traversable )
-#endif
-
 -- | Field labels are just represented as strings;
 -- they are not necessarily unique (even within a module)
 type FieldLabelString = FastString

compiler/basicTypes/SrcLoc.hs

 -- (c) The University of Glasgow, 1992-2006
 
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE DeriveFunctor      #-}
@@ -85,10 +84,6 @@ import Util
 import Outputable
 import FastString
 
-#if __GLASGOW_HASKELL__ < 709
-import Data.Foldable ( Foldable )
-import Data.Traversable ( Traversable )
-#endif
 import Data.Bits
 import Data.Data
 import Data.List

compiler/cmm/CmmLayoutStack.hs

@@ -33,9 +33,7 @@ import Data.Bits
 import Data.List (nub)
 import Control.Monad (liftM)
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 #include "HsVersions.h"
 

compiler/cmm/CmmLint.hs

@@ -5,7 +5,7 @@
 -- CmmLint: checking the correctness of Cmm statements and expressions
 --
 -----------------------------------------------------------------------------
-{-# LANGUAGE GADTs, CPP #-}
+{-# LANGUAGE GADTs #-}
 module CmmLint (
     cmmLint, cmmLintGraph
   ) where
@@ -22,9 +22,6 @@ import Outputable
 import DynFlags
 
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 -- Things to check:
 --     - invariant on CmmBlock in CmmExpr (see comment there)

compiler/cmm/PprC.hs

@@ -55,10 +55,6 @@ import Data.Word
 import System.IO
 import qualified Data.Map as Map
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
-
 import qualified Data.Array.Unsafe as U ( castSTUArray )
 import Data.Array.ST
 

compiler/codeGen/StgCmmBind.hs

@@ -52,9 +52,7 @@ import DynFlags
 
 import Control.Monad
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 ------------------------------------------------------------------------
 --              Top-level bindings

compiler/codeGen/StgCmmExpr.hs

@@ -50,9 +50,7 @@ import Outputable
 import Control.Monad (unless,void)
 import Control.Arrow (first)
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 ------------------------------------------------------------------------
 --              cgExpr: the main function

compiler/codeGen/StgCmmExtCode.hs

-{-# LANGUAGE CPP #-}
-
 -- | Our extended FCode monad.
 
 -- We add a mapping from names to CmmExpr, to support local variable names in
@@ -54,9 +52,6 @@ import UniqFM
 import Unique
 
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 -- | The environment contains variable definitions or blockids.
 data Named

compiler/codeGen/StgCmmForeign.hs

@@ -45,11 +45,7 @@ import BasicTypes
 
 import Control.Monad
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding( succ, (<*>) )
-#else
-import Prelude hiding( succ )
-#endif
 
 -----------------------------------------------------------------------------
 -- Code generation for Foreign Calls

compiler/codeGen/StgCmmHeap.hs

@@ -48,9 +48,7 @@ import DynFlags
 import FastString( mkFastString, fsLit )
 import Panic( sorry )
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 import Control.Monad (when)
 import Data.Maybe (isJust)

compiler/codeGen/StgCmmLayout.hs

@@ -25,9 +25,7 @@ module StgCmmLayout (
 
 #include "HsVersions.h"
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 import StgCmmClosure
 import StgCmmEnv

compiler/codeGen/StgCmmPrim.hs

@@ -43,9 +43,7 @@ import FastString
 import Outputable
 import Util
 
-#if __GLASGOW_HASKELL__ >= 709
 import Prelude hiding ((<*>))
-#endif
 
 import Data.Bits ((.&.), bit)
 import Control.Monad (liftM, when)

compiler/coreSyn/CorePrep.hs

@@ -61,10 +61,6 @@ import MonadUtils       ( mapAccumLM )
 import Data.List        ( mapAccumL )
 import Control.Monad
 
-#if __GLASGOW_HASKELL__ < 710
-import Control.Applicative
-#endif
-
 {-
 -- ---------------------------------------------------------------------------
 -- Overview

compiler/coreSyn/MkCore.hs

@@ -80,9 +80,6 @@ import DynFlags
 import Data.List
 
 import Data.Char        ( ord )
-#if __GLASGOW_HASKELL__ < 709
-import Data.Word        ( Word )
-#endif
 
 infixl 4 `mkCoreApp`, `mkCoreApps`
 

compiler/deSugar/MatchLit.hs

@@ -47,9 +47,6 @@ import qualified GHC.LanguageExtensions as LangExt
 
 import Control.Monad
 import Data.Int
-#if __GLASGOW_HASKELL__ < 709
-import Data.Traversable (traverse)
-#endif
 import Data.Word
 
 {-

compiler/deSugar/PmExpr.hs

@@ -25,9 +25,6 @@ import SrcLoc
 import FastString -- sLit
 import VarSet
 
-#if __GLASGOW_HASKELL__ < 709
-import Data.Functor ((<$>))
-#endif
 import Data.Maybe (mapMaybe)
 import Data.List (groupBy, sortBy, nubBy)
 import Control.Monad.Trans.State.Lazy

compiler/ghci/ByteCodeAsm.hs

@@ -36,9 +36,6 @@ import Util
 -- From iserv
 import SizedSeq
 
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 import Control.Monad
 import Control.Monad.ST ( runST )
 import Control.Monad.Trans.Class

compiler/ghci/ByteCodeGen.hs

@@ -47,10 +47,6 @@ import OrdList
 
 import Data.List
 import Foreign
-
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 import Control.Monad
 import Data.Char
 

compiler/ghci/RtClosureInspect.hs

@@ -68,15 +68,8 @@ import Data.Array.Base
 import Data.Ix
 import Data.List
 import qualified Data.Sequence as Seq
-#if __GLASGOW_HASKELL__ < 709
-import Data.Monoid (mappend)
-#endif
 import Data.Sequence (viewl, ViewL(..))
-#if __GLASGOW_HASKELL__ >= 709
 import Foreign
-#else
-import Foreign.Safe
-#endif
 import System.IO.Unsafe
 
 ---------------------------------------------

compiler/hsSyn/Convert.hs

@@ -6,7 +6,6 @@
 This module converts Template Haskell syntax into HsSyn
 -}
 
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
 module Convert( convertToHsExpr, convertToPat, convertToHsDecls,
@@ -39,9 +38,6 @@ import MonadUtils ( foldrM )
 
 import qualified Data.ByteString as BS
 import Control.Monad( unless, liftM, ap )
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 import Data.Char ( chr )
 import Data.Word ( Word8 )

compiler/hsSyn/HsBinds.hs

@@ -13,7 +13,6 @@ Datatype for: @BindGroup@, @Bind@, @Sig@, @Bind@.
 {-# LANGUAGE UndecidableInstances #-} -- Note [Pass sensitive types]
                                       -- in module PlaceHolder
 {-# LANGUAGE ConstraintKinds #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE BangPatterns #-}
 
 module HsBinds where
@@ -44,11 +43,6 @@ import Data.Data hiding ( Fixity )
 import Data.List hiding ( foldr )
 import Data.Ord
 import Data.Foldable ( Foldable(..) )
-#if __GLASGOW_HASKELL__ < 709
-import Data.Traversable ( Traversable(..) )
-import Data.Monoid ( mappend )
-import Control.Applicative hiding (empty)
-#endif
 
 {-
 ************************************************************************
@@ -1029,8 +1023,6 @@ instance Foldable HsPatSynDetails where
     foldr1 f (RecordPatSyn args) =
       Data.List.foldr1 f (map (Data.Foldable.foldr1 f) args)
 
--- TODO: After a few more versions, we should probably use these.
-#if __GLASGOW_HASKELL__ >= 709
     length (InfixPatSyn _ _) = 2
     length (PrefixPatSyn args) = Data.List.length args
     length (RecordPatSyn args) = Data.List.length args
@@ -1042,7 +1034,6 @@ instance Foldable HsPatSynDetails where
     toList (InfixPatSyn left right) = [left, right]
     toList (PrefixPatSyn args) = args
     toList (RecordPatSyn args) = foldMap toList args
-#endif
 
 instance Traversable HsPatSynDetails where
     traverse f (InfixPatSyn left right) = InfixPatSyn <$> f left <*> f right

compiler/hsSyn/HsDecls.hs

@@ -3,7 +3,6 @@
 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 -}
 
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable, DeriveFunctor, DeriveFoldable,
              DeriveTraversable #-}
 {-# LANGUAGE StandaloneDeriving #-}
@@ -110,10 +109,6 @@ import FastString
 import Bag
 import Data.Maybe ( fromMaybe )
 import Data.Data        hiding (TyCon,Fixity)
-#if __GLASGOW_HASKELL__ < 709
-import Data.Foldable ( Foldable )
-import Data.Traversable ( Traversable )
-#endif
 
 {-
 ************************************************************************

compiler/hsSyn/HsUtils.hs

@@ -115,11 +115,6 @@ import Data.Either
 import Data.Function
 import Data.List
 
-#if __GLASGOW_HASKELL__ < 709
-import Data.Foldable ( foldMap )
-import Data.Monoid ( mempty, mappend )
-#endif
-
 {-
 ************************************************************************
 *                                                                      *

compiler/iface/TcIface.hs

@@ -72,9 +72,6 @@ import ListSetOps
 import Data.List
 import Control.Monad
 import qualified Data.Map as Map
-#if __GLASGOW_HASKELL__ < 709
-import Data.Traversable ( traverse )
-#endif
 
 {-
 This module takes

compiler/llvmGen/LlvmCodeGen/Base.hs

@@ -57,9 +57,6 @@ import ErrUtils
 import qualified Stream
 
 import Control.Monad (ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 -- ----------------------------------------------------------------------------
 -- * Some Data Types

compiler/llvmGen/LlvmCodeGen/CodeGen.hs

@@ -34,10 +34,6 @@ import Util
 import Control.Monad.Trans.Class
 import Control.Monad.Trans.Writer
 
-#if MIN_VERSION_base(4,8,0)
-#else
-import Data.Monoid ( Monoid, mappend, mempty )
-#endif
 #if __GLASGOW_HASKELL__ > 710
 import Data.Semigroup   ( Semigroup )
 import qualified Data.Semigroup as Semigroup

compiler/main/CmdLineParser.hs

@@ -33,9 +33,6 @@ import Data.Function
 import Data.List
 
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 --------------------------------------------------------
 --         The Flag and OptKind types

compiler/main/DynFlags.hs

@@ -182,9 +182,7 @@ import Control.Monad
 import Control.Monad.Trans.Class
 import Control.Monad.Trans.Writer
 import Control.Monad.Trans.Reader
-#if MIN_VERSION_transformers(0,4,0)
 import Control.Monad.Trans.Except
-#endif
 import Control.Exception (throwIO)
 
 import Data.Bits
@@ -195,7 +193,6 @@ import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Monoid (Monoid)
 import Data.Word
 import System.FilePath
 import System.Directory
@@ -850,10 +847,8 @@ instance (Monad m, HasDynFlags m) => HasDynFlags (ReaderT a m) where
 instance (Monad m, HasDynFlags m) => HasDynFlags (MaybeT m) where
     getDynFlags = lift getDynFlags
 
-#if MIN_VERSION_transformers(0,4,0)
 instance (Monad m, HasDynFlags m) => HasDynFlags (ExceptT e m) where
     getDynFlags = lift getDynFlags
-#endif
 
 class ContainsDynFlags t where
     extractDynFlags :: t -> DynFlags

compiler/main/GHC.hs

@@ -450,12 +450,7 @@ runGhc mb_top_dir ghc = do
 -- to this function will create a new session which should not be shared among
 -- several threads.
 
-#if __GLASGOW_HASKELL__ < 710
--- Pre-AMP change
-runGhcT :: (ExceptionMonad m, Functor m) =>
-#else
-runGhcT :: (ExceptionMonad m) =>
-#endif
+runGhcT :: ExceptionMonad m =>
            Maybe FilePath  -- ^ See argument to 'initGhcMonad'.
         -> GhcT m a        -- ^ The action to perform.
         -> m a

compiler/main/GhcMonad.hs

@@ -188,12 +188,7 @@ instance ExceptionMonad m => ExceptionMonad (GhcT m) where
 instance MonadIO m => HasDynFlags (GhcT m) where
   getDynFlags = GhcT $ \(Session r) -> liftM hsc_dflags (liftIO $ readIORef r)
 
-#if __GLASGOW_HASKELL__ < 710
--- Pre-AMP change
-instance (ExceptionMonad m, Functor m) => GhcMonad (GhcT m) where
-#else
-instance (ExceptionMonad m) => GhcMonad (GhcT m) where
-#endif
+instance ExceptionMonad m => GhcMonad (GhcT m) where
   getSession = GhcT $ \(Session r) -> liftIO $ readIORef r
   setSession s' = GhcT $ \(Session r) -> liftIO $ writeIORef r s'
 

compiler/main/Packages.hs

@@ -77,9 +77,6 @@ import Data.Char ( toUpper )
 import Data.List as List
 import Data.Map (Map)
 import Data.Set (Set)
-#if __GLASGOW_HASKELL__ < 709
-import Data.Monoid hiding ((<>))
-#endif
 #if __GLASGOW_HASKELL__ > 710
 import Data.Semigroup   ( Semigroup )
 import qualified Data.Semigroup as Semigroup

compiler/nativeGen/AsmCodeGen.hs

@@ -84,9 +84,6 @@ import Data.List
 import Data.Maybe
 import Data.Ord         ( comparing )
 import Control.Exception
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 import Control.Monad
 import System.IO
 

compiler/nativeGen/NCGMonad.hs

@@ -52,9 +52,6 @@ import DynFlags
 import Module
 
 import Control.Monad    ( liftM, ap )
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative ( Applicative(..) )
-#endif
 
 import Compiler.Hoopl   ( LabelMap, Label )
 

compiler/nativeGen/RegAlloc/Linear/State.hs

 {-# LANGUAGE UnboxedTuples #-}
-{-# LANGUAGE CPP #-}
 
 -- | State monad for the linear register allocator.
 
@@ -44,9 +43,6 @@ import Unique
 import UniqSupply
 
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 -- | The register allocator monad type.
 newtype RegM freeRegs a

compiler/parser/Lexer.x

@@ -74,9 +74,6 @@ module Lexer (
   ) where
 
 -- base
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative
-#endif
 import Control.Monad
 #if __GLASGOW_HASKELL__ > 710
 import Control.Monad.Fail

compiler/parser/RdrHsSyn.hs

@@ -95,11 +95,7 @@ import Data.List
 import qualified GHC.LanguageExtensions as LangExt
 import MonadUtils
 
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative ((<$>))
-#endif
 import Control.Monad
-
 import Text.ParserCombinators.ReadP as ReadP
 import Data.Char
 

compiler/prelude/PrelRules.hs

@@ -47,11 +47,7 @@ import Platform
 import Util
 import Coercion     (mkUnbranchedAxInstCo,mkSymCo,Role(..))
 
-#if __GLASGOW_HASKELL__ >= 709
 import Control.Applicative ( Alternative(..) )
-#else
-import Control.Applicative ( Applicative(..), Alternative(..) )
-#endif
 
 import Control.Monad
 #if __GLASGOW_HASKELL__ > 710

compiler/profiling/SCCfinal.hs

@@ -37,9 +37,6 @@ import SrcLoc
 import Util
 
 import Control.Monad (liftM, ap)
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 
 stgMassageForProfiling
         :: DynFlags

compiler/rename/RnBinds.hs

@@ -9,8 +9,6 @@ type-synonym declarations; those cannot be done at this stage because
 they may be affected by renaming (which isn't fully worked out yet).
 -}
 
-{-# LANGUAGE CPP #-}
-
 module RnBinds (
    -- Renaming top-level bindings
    rnTopBindsLHS, rnTopBindsRHS, rnValBindsRHS,
@@ -53,9 +51,6 @@ import qualified GHC.LanguageExtensions as LangExt
 
 import Control.Monad
 import Data.List        ( partition, sort )
-#if __GLASGOW_HASKELL__ < 709
-import Data.Traversable ( traverse )
-#endif
 
 {-
 -- ToDo: Put the annotations into the monad, so that they arrive in the proper

compiler/rename/RnSource.hs

@@ -54,9 +54,6 @@ import Control.Monad
 import Data.List ( sortBy )
 import Maybes( orElse, mapMaybe )
 import qualified Data.Set as Set ( difference, fromList, toList, null )
-#if __GLASGOW_HASKELL__ < 709
-import Data.Traversable (traverse)
-#endif
 
 {-
 @rnSourceDecl@ `renames' declarations.

compiler/rename/RnTypes.hs

@@ -58,10 +58,6 @@ import qualified GHC.LanguageExtensions as LangExt
 import Data.List        ( (\\), nubBy, partition )
 import Control.Monad    ( unless, when )
 
-#if __GLASGOW_HASKELL__ < 709
-import Data.Monoid      ( mappend, mempty, mconcat )
-#endif
-
 #include "HsVersions.h"
 
 {-

compiler/specialise/Specialise.hs

@@ -36,9 +36,6 @@ import Outputable
 import FastString
 import State
 
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative (Applicative(..))
-#endif
 import Control.Monad
 #if __GLASGOW_HASKELL__ > 710
 import qualified Control.Monad.Fail as MonadFail

compiler/stgSyn/StgLint.hs

@@ -26,9 +26,6 @@ import Util
 import SrcLoc
 import Outputable
 import FastString
-#if __GLASGOW_HASKELL__ < 709
-import Control.Applicative ( Applicative(..) )
-#endif
 import Control.Monad
 import Data.Function
 

compiler/typecheck/FamInst.hs

@@ -44,11 +44,6 @@ import Control.Monad
 import Data.Map (Map)
 import qualified Data.Map as Map
 
-#if __GLASGOW_HASKELL__ < 709
-import Prelude hiding ( and )
-import Data.Foldable ( and )
-#endif
-
 #include "HsVersions.h"
 
 {-

compiler/typecheck/FunDeps.hs

@@ -39,12 +39,6 @@ import Data.List        ( nubBy )
 import Data.Maybe
 import Data.Foldable    ( fold )
 
-#if __GLASGOW_HASKELL__ < 709
-import Prelude hiding ( and )
-import Control.Applicative ( (<$>) )
-import Data.Foldable       ( and )
-#endif
-
 {-
 ************************************************************************
 *                                                                      *

compiler/typecheck/TcCanonical.hs

@@ -39,13 +39,7 @@ import Data.List  ( zip4, foldl' )