Export `Monoid(..)`/`Foldable(..)`/`Traversable(..)` from Prelude

This finally exposes also the methods of these 3 classes in the Prelude
in order to allow to define basic class instances w/o needing imports.

This almost completes the primary goal of #9586

NOTE: `fold`, `foldl'`, `foldr'`, and `toList` are not exposed yet,
      as they require upstream fixes for at least `containers` and
      `bytestring`, and are not required for defining basic instances.

Reviewed By: ekmett, austin

Differential Revision: https://phabricator.haskell.org/D236

13 files changed, 32 insertions, 4 deletions

diff --git a/compiler/deSugar/MatchLit.lhs b/compiler/deSugar/MatchLit.lhs
index f404997c9f..5a247177a3 100644
--- a/compiler/deSugar/MatchLit.lhs
+++ b/compiler/deSugar/MatchLit.lhs
@@ -46,7 +46,9 @@ import FastString
 import Control.Monad
 
 import Data.Int
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable (traverse)
+#endif
 import Data.Word
 \end{code}
 
diff --git a/compiler/ghci/RtClosureInspect.hs b/compiler/ghci/RtClosureInspect.hs
index dde813d31d..0b69492b0a 100644
--- a/compiler/ghci/RtClosureInspect.hs
+++ b/compiler/ghci/RtClosureInspect.hs
@@ -65,7 +65,9 @@ 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(..))
 import Foreign.Safe
 import System.IO.Unsafe
diff --git a/compiler/hsSyn/HsBinds.lhs b/compiler/hsSyn/HsBinds.lhs
index 5ebada6e9c..e6d0c0ecd5 100644
--- a/compiler/hsSyn/HsBinds.lhs
+++ b/compiler/hsSyn/HsBinds.lhs
@@ -41,10 +41,10 @@ import BooleanFormula (BooleanFormula)
 import Data.Data hiding ( Fixity )
 import Data.List
 import Data.Ord
+#if __GLASGOW_HASKELL__ < 709
 import Data.Foldable ( Foldable(..) )
 import Data.Traversable ( Traversable(..) )
 import Data.Monoid ( mappend )
-#if __GLASGOW_HASKELL__ < 709
 import Control.Applicative hiding (empty)
 #else
 import Control.Applicative ((<$>))
diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index 37b65b01af..293e8c9c4c 100644
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -72,7 +72,9 @@ import FastString
 
 import Control.Monad
 import qualified Data.Map as Map
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable ( traverse )
+#endif
 \end{code}
 
 This module takes
diff --git a/compiler/main/Packages.lhs b/compiler/main/Packages.lhs
index a6a61e9534..93370d47b3 100644
--- a/compiler/main/Packages.lhs
+++ b/compiler/main/Packages.lhs
@@ -73,7 +73,9 @@ import qualified System.FilePath.Posix as FilePath.Posix
 import Control.Monad
 import Data.List as List
 import Data.Map (Map)
+#if __GLASGOW_HASKELL__ < 709
 import Data.Monoid hiding ((<>))
+#endif
 import qualified Data.Map as Map
 import qualified FiniteMap as Map
 import qualified Data.Set as Set
diff --git a/compiler/rename/RnBinds.lhs b/compiler/rename/RnBinds.lhs
index dfbde13ded..f76090f3d9 100644
--- a/compiler/rename/RnBinds.lhs
+++ b/compiler/rename/RnBinds.lhs
@@ -9,6 +9,7 @@ type-synonym declarations; those cannot be done at this stage because
 they may be affected by renaming (which isn't fully worked out yet).
 
 \begin{code}
+{-# LANGUAGE CPP #-}
 {-# OPTIONS_GHC -fno-warn-tabs #-}
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and
@@ -55,7 +56,9 @@ import FastString
 import Data.List        ( partition, sort )
 import Maybes           ( orElse )
 import Control.Monad
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable ( traverse )
+#endif
 \end{code}
 
 -- ToDo: Put the annotations into the monad, so that they arrive in the proper
diff --git a/compiler/rename/RnSource.lhs b/compiler/rename/RnSource.lhs
index 4af8be32fd..6aa666642f 100644
--- a/compiler/rename/RnSource.lhs
+++ b/compiler/rename/RnSource.lhs
@@ -48,7 +48,9 @@ import Util             ( mapSnd )
 
 import Control.Monad
 import Data.List( partition, sortBy )
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable (traverse)
+#endif
 import Maybes( orElse, mapMaybe )
 \end{code}
 
diff --git a/compiler/typecheck/TcEvidence.lhs b/compiler/typecheck/TcEvidence.lhs
index 8b64d2408b..468f9c3956 100644
--- a/compiler/typecheck/TcEvidence.lhs
+++ b/compiler/typecheck/TcEvidence.lhs
@@ -50,7 +50,9 @@ import Util
 import Bag
 import Pair
 import Control.Applicative
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable (traverse, sequenceA)
+#endif
 import qualified Data.Data as Data 
 import Outputable
 import FastString
diff --git a/compiler/typecheck/TcHsSyn.lhs b/compiler/typecheck/TcHsSyn.lhs
index f4d5cf262c..b19bfbbdc1 100644
--- a/compiler/typecheck/TcHsSyn.lhs
+++ b/compiler/typecheck/TcHsSyn.lhs
@@ -58,7 +58,9 @@ import Bag
 import FastString
 import Outputable
 import Util
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable ( traverse )
+#endif
 \end{code}
 
 %************************************************************************
diff --git a/compiler/typecheck/TcPatSyn.lhs b/compiler/typecheck/TcPatSyn.lhs
index 6ae3ba0153..9b2b5110f4 100644
--- a/compiler/typecheck/TcPatSyn.lhs
+++ b/compiler/typecheck/TcPatSyn.lhs
@@ -30,7 +30,9 @@ import BasicTypes
 import TcSimplify
 import TcType
 import VarSet
+#if __GLASGOW_HASKELL__ < 709
 import Data.Monoid
+#endif
 import Bag
 import TcEvidence
 import BuildTyCl
diff --git a/compiler/types/Coercion.lhs b/compiler/types/Coercion.lhs
index fc6c8a7669..36eb711bdc 100644
--- a/compiler/types/Coercion.lhs
+++ b/compiler/types/Coercion.lhs
@@ -102,7 +102,9 @@ import Pair
 import SrcLoc
 import PrelNames        ( funTyConKey, eqPrimTyConKey, eqReprPrimTyConKey )
 import Control.Applicative
+#if __GLASGOW_HASKELL__ < 709
 import Data.Traversable (traverse, sequenceA)
+#endif
 import FastString
 import ListSetOps
 
diff --git a/compiler/utils/Pair.lhs b/compiler/utils/Pair.lhs
index ca7c2a7f8e..529ba669ea 100644
--- a/compiler/utils/Pair.lhs
+++ b/compiler/utils/Pair.lhs
@@ -10,10 +10,12 @@ module Pair ( Pair(..), unPair, toPair, swap ) where
 #include "HsVersions.h"
 
 import Outputable
-import Data.Monoid
 import Control.Applicative
+#if __GLASGOW_HASKELL__ < 709
 import Data.Foldable
+import Data.Monoid
 import Data.Traversable
+#endif
 
 data Pair a = Pair { pFst :: a, pSnd :: a }
 -- Note that Pair is a *unary* type constructor
@@ -46,4 +48,4 @@ toPair (x,y) = Pair x y
 
 swap :: Pair a -> Pair a
 swap (Pair x y) = Pair y x
-\end{code}
\ No newline at end of file
+\end{code}
diff --git a/compiler/utils/UniqFM.lhs b/compiler/utils/UniqFM.lhs
index d8e08f599a..c941ce8884 100644
--- a/compiler/utils/UniqFM.lhs
+++ b/compiler/utils/UniqFM.lhs
@@ -20,7 +20,10 @@ and ``addToUFM\_C'' and ``Data.IntMap.insertWith'' differ in the order
 of arguments of combining function.
 
 \begin{code}
-{-# LANGUAGE DeriveTraversable, DeriveDataTypeable, GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE DeriveTraversable #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# OPTIONS_GHC -Wall #-}
 
 module UniqFM (
@@ -76,7 +79,9 @@ import qualified Data.Foldable as Foldable
 import qualified Data.Traversable as Traversable
 import Data.Typeable
 import Data.Data
+#if __GLASGOW_HASKELL__ < 709
 import Data.Monoid
+#endif
 \end{code}
 
 %************************************************************************