Refactor module imports in base

This commit removes a couple of

  {-# OPTIONS_GHC -fno-warn-unused-imports #-}

by cleaning up the imports, as well as ensuring that all modules in the
GHC.* hierarchy avoid importing the `Prelude` module to clean-up the
import graph a bit.

12 files changed, 29 insertions, 29 deletions

diff --git a/libraries/base/Control/Concurrent.hs b/libraries/base/Control/Concurrent.hs
index c12fef54b0..702d0bb3b4 100644
--- a/libraries/base/Control/Concurrent.hs
+++ b/libraries/base/Control/Concurrent.hs
@@ -4,7 +4,6 @@
            , UnboxedTuples
            , ScopedTypeVariables
   #-}
-{-# OPTIONS_GHC -fno-warn-unused-imports #-}
 {-# OPTIONS_GHC -fno-warn-deprecations #-}
 -- kludge for the Control.Concurrent.QSem, Control.Concurrent.QSemN
 -- and Control.Concurrent.SampleVar imports.
@@ -106,11 +105,9 @@ module Control.Concurrent (
 
 import Control.Exception.Base as Exception
 
-import GHC.Exception
 import GHC.Conc hiding (threadWaitRead, threadWaitWrite,
                         threadWaitReadSTM, threadWaitWriteSTM)
-import qualified GHC.Conc
-import GHC.IO           ( IO(..), unsafeInterleaveIO, unsafeUnmask )
+import GHC.IO           ( unsafeUnmask )
 import GHC.IORef        ( newIORef, readIORef, writeIORef )
 import GHC.Base
 
@@ -122,6 +119,8 @@ import Foreign.C.Types
 import Foreign.C
 import System.IO
 import Data.Functor ( void )
+#else
+import qualified GHC.Conc
 #endif
 
 import Control.Concurrent.MVar
diff --git a/libraries/base/Data/Tuple.hs b/libraries/base/Data/Tuple.hs
index ec8478a6ff..d8bccf3364 100644
--- a/libraries/base/Data/Tuple.hs
+++ b/libraries/base/Data/Tuple.hs
@@ -1,7 +1,5 @@
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE NoImplicitPrelude #-}
-{-# OPTIONS_GHC -fno-warn-unused-imports #-}
--- XXX -fno-warn-unused-imports needed for the GHC.Tuple import below. Sigh.
 
 -----------------------------------------------------------------------------
 -- |
@@ -23,20 +21,9 @@ module Data.Tuple
   , curry
   , uncurry
   , swap
-  )
-    where
+  ) where
 
-import GHC.Base
--- We need to depend on GHC.Base so that
--- a) so that we get GHC.Classes, GHC.Types
-
--- b) so that GHC.Base.inline is available, which is used
---    when expanding instance declarations
-
-import GHC.Tuple
--- We must import GHC.Tuple, to ensure sure that the
--- data constructors of `(,)' are in scope when we do
--- the standalone deriving instance for Eq (a,b) etc
+import GHC.Base ()      -- Note [Depend on GHC.Tuple]
 
 default ()              -- Double isn't available yet
 
diff --git a/libraries/base/GHC/ConsoleHandler.hs b/libraries/base/GHC/ConsoleHandler.hs
index 4eaa434186..9c3ed9eb5b 100644
--- a/libraries/base/GHC/ConsoleHandler.hs
+++ b/libraries/base/GHC/ConsoleHandler.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE CPP #-}
 
@@ -20,6 +21,8 @@
 module GHC.ConsoleHandler
 #if !defined(mingw32_HOST_OS) && !defined(__HADDOCK__)
         where
+
+import GHC.Base ()  -- dummy dependency
 #else /* whole file */
         ( Handler(..)
         , installHandler
@@ -38,6 +41,7 @@ Note: this #include is inside a Haskell comment
       by GHC
 -}
 
+import GHC.Base
 import Foreign
 import Foreign.C
 import GHC.IO.FD
diff --git a/libraries/base/GHC/Constants.hs b/libraries/base/GHC/Constants.hs
index c2e01a3e62..32bbf01747 100644
--- a/libraries/base/GHC/Constants.hs
+++ b/libraries/base/GHC/Constants.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE Trustworthy #-}
 
 module GHC.Constants where
@@ -6,3 +7,4 @@ module GHC.Constants where
 -- We probably want to include the constants in platformConstants somehow
 -- instead.
 
+import GHC.Base () -- dummy dependency
diff --git a/libraries/base/GHC/Environment.hs b/libraries/base/GHC/Environment.hs
index 39b472913a..f5f5629ffa 100644
--- a/libraries/base/GHC/Environment.hs
+++ b/libraries/base/GHC/Environment.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE CPP #-}
 
@@ -5,6 +6,8 @@ module GHC.Environment (getFullArgs) where
 
 import Foreign
 import Foreign.C
+import GHC.Base
+import GHC.Real ( fromIntegral )
 
 #ifdef mingw32_HOST_OS
 import GHC.IO (finally)
@@ -40,9 +43,8 @@ foreign import WINDOWS_CCONV unsafe "windows.h CommandLineToArgvW"
 foreign import WINDOWS_CCONV unsafe "Windows.h LocalFree"
     c_LocalFree :: Ptr a -> IO (Ptr a)
 #else
-import Control.Monad
-
 import GHC.IO.Encoding
+import GHC.Num
 import qualified GHC.Foreign as GHC
 
 getFullArgs :: IO [String]
diff --git a/libraries/base/GHC/Event.hs b/libraries/base/GHC/Event.hs
index 9746bc7f2e..3dcf3098b4 100644
--- a/libraries/base/GHC/Event.hs
+++ b/libraries/base/GHC/Event.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE Trustworthy #-}
 
 -- ----------------------------------------------------------------------------
diff --git a/libraries/base/GHC/Int.hs b/libraries/base/GHC/Int.hs
index b8e05e2c5b..5cb6ceb7ff 100644
--- a/libraries/base/GHC/Int.hs
+++ b/libraries/base/GHC/Int.hs
@@ -39,7 +39,6 @@ import GHC.Read
 import GHC.Arr
 import GHC.Word hiding (uncheckedShiftL64#, uncheckedShiftRL64#)
 import GHC.Show
-import GHC.Float ()     -- for RealFrac methods
 import Data.Typeable
 
 
diff --git a/libraries/base/GHC/PArr.hs b/libraries/base/GHC/PArr.hs
index d569acab28..e15e87ea17 100644
--- a/libraries/base/GHC/PArr.hs
+++ b/libraries/base/GHC/PArr.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE ParallelArrays, MagicHash #-}
 {-# OPTIONS_GHC -funbox-strict-fields #-}
diff --git a/libraries/base/GHC/Profiling.hs b/libraries/base/GHC/Profiling.hs
index c0322187cb..0bedcb18fa 100644
--- a/libraries/base/GHC/Profiling.hs
+++ b/libraries/base/GHC/Profiling.hs
@@ -1,5 +1,9 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+
 -- | /Since: 4.7.0.0/
 module GHC.Profiling where
 
+import GHC.Base
+
 foreign import ccall startProfTimer :: IO ()
 foreign import ccall stopProfTimer :: IO ()
diff --git a/libraries/base/GHC/Stats.hsc b/libraries/base/GHC/Stats.hsc
index 11e31b9821..1a895b5815 100644
--- a/libraries/base/GHC/Stats.hsc
+++ b/libraries/base/GHC/Stats.hsc
@@ -1,4 +1,5 @@
-{-# LANGUAGE Safe #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# OPTIONS_GHC -funbox-strict-fields #-}
 
@@ -19,6 +20,9 @@ module GHC.Stats
 
 import Control.Monad
 import Data.Int
+import GHC.Base
+import GHC.Read ( Read )
+import GHC.Show ( Show )
 import GHC.IO.Exception
 import Foreign.Marshal.Alloc
 import Foreign.Storable
diff --git a/libraries/base/GHC/TopHandler.lhs b/libraries/base/GHC/TopHandler.lhs
index ee8e792e26..cdca26205c 100644
--- a/libraries/base/GHC/TopHandler.lhs
+++ b/libraries/base/GHC/TopHandler.lhs
@@ -5,7 +5,6 @@
            , MagicHash
            , UnboxedTuples
   #-}
-{-# OPTIONS_GHC -fno-warn-unused-imports #-}
 {-# OPTIONS_HADDOCK hide #-}
 
 -----------------------------------------------------------------------------
@@ -34,23 +33,22 @@ module GHC.TopHandler (
 
 import Control.Exception
 import Data.Maybe
-import Data.Dynamic (toDyn)
 
 import Foreign
 import Foreign.C
 import GHC.Base
 import GHC.Conc hiding (throwTo)
-import GHC.Num
 import GHC.Real
-import GHC.MVar
 import GHC.IO
 import GHC.IO.Handle.FD
 import GHC.IO.Handle
 import GHC.IO.Exception
 import GHC.Weak
-import Data.Typeable
+
 #if defined(mingw32_HOST_OS)
 import GHC.ConsoleHandler
+#else
+import Data.Dynamic (toDyn)
 #endif
 
 -- | 'runMainIO' is wrapped around 'Main.main' (or whatever main is
diff --git a/libraries/base/GHC/Word.hs b/libraries/base/GHC/Word.hs
index b2c70a2dcd..5351c0b94d 100644
--- a/libraries/base/GHC/Word.hs
+++ b/libraries/base/GHC/Word.hs
@@ -42,7 +42,6 @@ import GHC.Real
 import GHC.Read
 import GHC.Arr
 import GHC.Show
-import GHC.Float ()     -- for RealFrac methods
 
 ------------------------------------------------------------------------
 -- type Word8