[commit: ghc] master: Simplify implementation of wWarningFlags (76aaa6e)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/76aaa6eed264ac2398753a09418c6e1374244ff6/ghc

>---------------------------------------------------------------

commit 76aaa6eed264ac2398753a09418c6e1374244ff6
Author: Matthew Pickering <matthewtpickering at gmail.com>
Date:   Fri Oct 7 15:19:56 2016 +0100

    Simplify implementation of wWarningFlags


>---------------------------------------------------------------

76aaa6eed264ac2398753a09418c6e1374244ff6
 compiler/main/DynFlags.hs | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 63bb0ef..b78d665 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -186,6 +186,7 @@ import Control.Monad.Trans.Reader
 import Control.Monad.Trans.Except
 import Control.Exception (throwIO)
 
+import Data.Ord
 import Data.Bits
 import Data.Char
 import Data.Int
@@ -2295,7 +2296,7 @@ flagsPackage = map snd package_flags_deps
 
 type FlagMaker m = String -> OptKind m -> Flag m
 type DynFlagMaker = FlagMaker (CmdLineP DynFlags)
-data Deprecation = Deprecated | NotDeprecated
+data Deprecation = NotDeprecated | Deprecated deriving (Eq, Ord)
 
 -- Make a non-deprecated flag
 make_ord_flag :: DynFlagMaker -> String -> OptKind (CmdLineP DynFlags)
@@ -3236,15 +3237,7 @@ flagSpecOf flag = listToMaybe $ filter check wWarningFlags
 
 -- | These @-W\<blah\>@ flags can all be reversed with @-Wno-\<blah\>@
 wWarningFlags :: [FlagSpec WarningFlag]
-wWarningFlags = wWarningFlagsDepsCurrent ++ wWarningFlagsDepsDeprecated
-  where
-    deprecatedWFlags = filter (not . isCurr) wWarningFlagsDeps
-    currentWFlags = filter isCurr wWarningFlagsDeps
-    wWarningFlagsDepsCurrent = map snd currentWFlags
-    wWarningFlagsDepsDeprecated = map snd deprecatedWFlags
-
-    isCurr ( Deprecated , _ ) = False
-    isCurr _ = True
+wWarningFlags = map snd (sortBy (comparing fst) wWarningFlagsDeps)
 
 wWarningFlagsDeps :: [(Deprecation, FlagSpec WarningFlag)]
 wWarningFlagsDeps = [