remove ugly nhc98 cpp+defaulting hack - use explicit typesig instead

Distribution/Simple/Haddock.hs

-{-# LANGUAGE CPP #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Distribution.Simple.Haddock
@@ -99,10 +98,6 @@ import System.FilePath((</>), (<.>), splitFileName, splitExtension,
 import System.IO (hClose, hPutStrLn)
 import Distribution.Version
 
-#ifdef __NHC__
-default (Integer,Double,Version)
-#endif
-
 -- --------------------------------------------------------------------------
 -- Haddock support
 
@@ -169,7 +164,8 @@ haddock pkg_descr lbi suffixes flags = do
 
     when isVersion2 $ do
       strHadGhcVers <- rawSystemProgramStdout verbosity confHaddock ["--ghc-version"]
-      let mHadGhcVers = simpleParse strHadGhcVers
+      let mHadGhcVers :: Maybe Version
+          mHadGhcVers = simpleParse strHadGhcVers
       when (mHadGhcVers == Nothing) $ die "Could not get GHC version from Haddock"
       when (fromJust mHadGhcVers /= compilerVersion comp) $
         die "Haddock's internal GHC version must match the configured GHC version"

Distribution/Simple/Program.hs

-{-# LANGUAGE CPP #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Distribution.Simple.Program
@@ -100,10 +99,6 @@ import System.IO.Error (try)
 import Control.Monad (join, foldM)
 import Control.Exception as Exception (catch)
 
-#ifdef __NHC__
-default (Integer,Double,Version)
-#endif
-
 -- | Represents a program which can be configured.
 data Program = Program {
         -- | The simple name of the program, eg. ghc
@@ -188,7 +183,8 @@ findProgramVersion :: ProgArg            -- ^ version args
 findProgramVersion versionArg selectVersion verbosity path = do
   str <- rawSystemStdout verbosity path [versionArg]
          `Exception.catch` \_ -> return ""
-  let version = simpleParse (selectVersion str)
+  let version :: Maybe Version
+      version = simpleParse (selectVersion str)
   case version of
       Nothing -> warn verbosity $ "cannot determine version of " ++ path
                                ++ " :\n" ++ show str