treewide: clean-up of #ifdef macros

This type of #ifdef use is undocumented.

It can be explained as IF Cabal env does not load/link the package, then Cabal
does not provides this variable `MIN_VERSION_serialise`

So this expression determines is package provided by Cabal.
b60a15d

Which was done to not load serialize for GHCJS build:
ba0dc19
(look at the `.cabal` `!impl` `GHCJS` switch)

So this macros can be reduced now.

Yeeting `datasize` circa 2016.

Author: Anton-Latukha

src/Nix/Effects.hs

@@ -105,13 +105,9 @@ class
 instance MonadIntrospect IO where
   recursiveSize =
 #ifdef MIN_VERSION_ghc_datasize
-#if MIN_VERSION_ghc_datasize(0,2,0)
     recursiveSize
 #else
-      \_ -> pure 0
-#endif
-#else
-      \_ -> pure 0
+    \_ -> pure 0
 #endif
 
 deriving

src/Nix/Effects/Basic.hs

@@ -31,10 +31,8 @@ import           Nix.Value
 import           Nix.Value.Monad
 
 #ifdef MIN_VERSION_ghc_datasize
-#if MIN_VERSION_ghc_datasize(0,2,0)
 import           GHC.DataSize
 #endif
-#endif
 
 defaultMakeAbsolutePath :: MonadNix e t f m => FilePath -> m FilePath
 defaultMakeAbsolutePath origPath = do

src/Nix/Exec.hs

@@ -43,15 +43,11 @@ import           Nix.Value
 import           Nix.Value.Equal
 import           Nix.Value.Monad
 import           Prettyprinter
-#ifdef MIN_VERSION_pretty_show
 import qualified Text.Show.Pretty              as PS
-#endif
 
 #ifdef MIN_VERSION_ghc_datasize
-#if MIN_VERSION_ghc_datasize(0,2,0)
 import           GHC.DataSize
 #endif
-#endif
 
 type MonadCited t f m =
   ( HasCitations m (NValue t f m) t
@@ -514,11 +510,7 @@ addTracing k v = do
           if verbose opts >= Chatty
             then
               pretty $
-#ifdef MIN_VERSION_pretty_show
                 PS.ppShow $ void x
-#else
-                show $ void x
-#endif
             else prettyNix $ Fix $ Fix (NSym "?") <$ x
         msg x = pretty ("eval: " <> replicate depth ' ') <> x
       loc <- renderLocation span $ msg rendered <> " ...\n"

src/Nix/Render/Frame.hs

@@ -26,9 +26,7 @@ import           Nix.Value
 import           Prettyprinter       hiding ( list )
 import qualified Text.Show                 as Text
 import           Text.Megaparsec.Pos        ( sourcePosPretty)
-#ifdef MIN_VERSION_pretty_show
 import qualified Text.Show.Pretty          as PS
-#endif
 
 renderFrames
   :: forall v t f e m ann
@@ -153,11 +151,7 @@ renderExpr _level longLabel shortLabel e@(AnnE _ x) = do
   opts :: Options <- asks (view hasLens)
   let rendered
           | verbose opts >= DebugInfo =
-#ifdef MIN_VERSION_pretty_show
               pretty (PS.ppShow (stripAnnotation e))
-#else
-              pretty (show (stripAnnotation e))
-#endif
           | verbose opts >= Chatty = prettyNix (stripAnnotation e)
           | otherwise = prettyNix (Fix (Fix (NSym "<?>") <$ x))
   pure $

src/Nix/String/Coerce.hs

@@ -12,10 +12,8 @@ import           Nix.Value
 import           Nix.Value.Monad
 
 #ifdef MIN_VERSION_ghc_datasize
-#if MIN_VERSION_ghc_datasize(0,2,0)
 import           GHC.DataSize
 #endif
-#endif
 
 -- | Data type to avoid boolean blindness on what used to be called coerceMore
 data CoercionLevel