GHC.Word: Move Read instances to GHC.Read

Test Plan: Validate

Reviewers: hvr, austin, bgamari

Reviewed By: hvr

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3353

3 files changed, 27 insertions, 24 deletions

diff --git a/libraries/base/Data/Word.hs b/libraries/base/Data/Word.hs
index f20844f991..b341f9c4bc 100644
--- a/libraries/base/Data/Word.hs
+++ b/libraries/base/Data/Word.hs
@@ -6,7 +6,7 @@
 -- Module      :  Data.Word
 -- Copyright   :  (c) The University of Glasgow 2001
 -- License     :  BSD-style (see the file libraries/base/LICENSE)
--- 
+--
 -- Maintainer  :  libraries@haskell.org
 -- Stability   :  experimental
 -- Portability :  portable
@@ -31,6 +31,7 @@ module Data.Word
         ) where
 
 import GHC.Word
+import GHC.Read () -- Need the `Read` instance for types defined in `GHC.Word`.
 
 {- $notes
 
@@ -55,6 +56,6 @@ import GHC.Word
   of the type result in a zero result.  This is contrary to the
   behaviour in C, which is undefined; a common interpretation is to
   truncate the shift count to the width of the type, for example @1 \<\<
-  32 == 1@ in some C implementations. 
+  32 == 1@ in some C implementations.
 -}
 
diff --git a/libraries/base/GHC/Read.hs b/libraries/base/GHC/Read.hs
index ad505bb106..49c0606878 100644
--- a/libraries/base/GHC/Read.hs
+++ b/libraries/base/GHC/Read.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE Trustworthy #-}
-{-# LANGUAGE NoImplicitPrelude, StandaloneDeriving, ScopedTypeVariables #-}
+{-# LANGUAGE CPP, NoImplicitPrelude, StandaloneDeriving, ScopedTypeVariables #-}
 {-# OPTIONS_HADDOCK hide #-}
 
 -----------------------------------------------------------------------------
@@ -42,6 +42,8 @@ module GHC.Read
   )
  where
 
+#include "MachDeps.h"
+
 import qualified Text.ParserCombinators.ReadP as P
 
 import Text.ParserCombinators.ReadP
@@ -66,6 +68,7 @@ import GHC.Float
 import GHC.Show
 import GHC.Base
 import GHC.Arr
+import GHC.Word
 
 
 -- | @'readParen' 'True' p@ parses what @p@ parses, but surrounded with
@@ -521,6 +524,26 @@ instance Read Word where
     readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]
 
 -- | @since 2.01
+instance Read Word8 where
+    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
+
+-- | @since 2.01
+instance Read Word16 where
+    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
+
+-- | @since 2.01
+instance Read Word32 where
+#if WORD_SIZE_IN_BITS < 33
+    readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]
+#else
+    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
+#endif
+
+-- | @since 2.01
+instance Read Word64 where
+    readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]
+
+-- | @since 2.01
 instance Read Integer where
   readPrec     = readNumber convertInt
   readListPrec = readListPrecDefault
diff --git a/libraries/base/GHC/Word.hs b/libraries/base/GHC/Word.hs
index d4a5536275..1df9d14693 100644
--- a/libraries/base/GHC/Word.hs
+++ b/libraries/base/GHC/Word.hs
@@ -51,7 +51,6 @@ import GHC.Base
 import GHC.Enum
 import GHC.Num
 import GHC.Real
-import GHC.Read
 import GHC.Arr
 import GHC.Show
 
@@ -165,10 +164,6 @@ instance Ix Word8 where
     inRange (m,n) i     = m <= i && i <= n
 
 -- | @since 2.01
-instance Read Word8 where
-    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
-
--- | @since 2.01
 instance Bits Word8 where
     {-# INLINE shift #-}
     {-# INLINE bit #-}
@@ -353,10 +348,6 @@ instance Ix Word16 where
     inRange (m,n) i     = m <= i && i <= n
 
 -- | @since 2.01
-instance Read Word16 where
-    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
-
--- | @since 2.01
 instance Bits Word16 where
     {-# INLINE shift #-}
     {-# INLINE bit #-}
@@ -657,14 +648,6 @@ instance Ix Word32 where
     unsafeIndex (m,_) i = fromIntegral (i - m)
     inRange (m,n) i     = m <= i && i <= n
 
--- | @since 2.01
-instance Read Word32 where
-#if WORD_SIZE_IN_BITS < 33
-    readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]
-#else
-    readsPrec p s = [(fromIntegral (x::Int), r) | (x, r) <- readsPrec p s]
-#endif
-
 -- | Reverse order of bytes in 'Word32'.
 --
 -- @since 4.7.0.0
@@ -979,10 +962,6 @@ instance Ix Word64 where
     unsafeIndex (m,_) i = fromIntegral (i - m)
     inRange (m,n) i     = m <= i && i <= n
 
--- | @since 2.01
-instance Read Word64 where
-    readsPrec p s = [(fromInteger x, r) | (x, r) <- readsPrec p s]
-
 -- | Reverse order of bytes in 'Word64'.
 --
 -- @since 4.7.0.0