fix warnings (and disable some)

yesod/Devel.hs

@@ -30,10 +30,11 @@ import           System.Process (createProcess, proc, terminateProcess, readProc
                                            waitForProcess, rawSystem, runInteractiveProcess)
 import           System.IO (hClose, hIsEOF, hGetLine, stdout, stderr, hPutStrLn)
 
-import Build (recompDeps, getDeps, isNewerThan)
-import GhcBuild (getBuildFlags, buildPackage)
+import           Build (recompDeps, getDeps, isNewerThan)
+import           GhcBuild (getBuildFlags, buildPackage)
 
 import qualified Config as GHC
+import           SrcLoc (Located)
 
 lockFile :: FilePath
 lockFile = "dist/devel-terminate"
@@ -90,7 +91,7 @@ devel isCabalDev passThroughArgs = do
     mainLoop :: [FilePath] -> FilePath -> IO ()
     mainLoop hsSourceDirs cabal = do
        ghcVer <- ghcVersion
-       rebuildCabal cmd
+       _ <- rebuildCabal cmd
        pkgArgs <- ghcPackageArgs isCabalDev ghcVer
        rebuild <- mkRebuild ghcVer cabal cmd
        let devArgs = pkgArgs ++ ["devel.hs"] ++ passThroughArgs
@@ -132,10 +133,12 @@ mkRebuild ghcVer cabalFile cabalCmd
                   putStrLn "WARNING: yesod is compiled with a different ghc version, falling back to cabal"
                   rebuildCabal cabalCmd
 
+rebuildGhc :: [Located String] -> IO Bool
 rebuildGhc bf = do
   putStrLn "Rebuilding application... (GHC API)"
   buildPackage bf
 
+rebuildCabal :: String -> IO Bool
 rebuildCabal cmd = do
   putStrLn "Rebuilding application... (cabal)"
   exit <- rawSystemFilter cmd ["build"]

yesod/GhcBuild.hs

@@ -1,4 +1,14 @@
-{-# LANGUAGE CPP, ScopedTypeVariables #-}
+{-# OPTIONS_GHC -fno-warn-unused-do-bind #-}
+{-# OPTIONS_GHC -fno-warn-unused-binds #-}
+{-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-# OPTIONS_GHC -fno-warn-unused-matches #-}
+{-
+  There is a lot of code copied from GHC here, and some conditional
+  compilation. Instead of fixing all warnings and making it much more
+  difficult to compare the code to the original, just ignore unused
+  binds and imports.
+-}
+{-# LANGUAGE CPP, ScopedTypeVariables, PatternGuards #-}
 
 {-
   build package with the GHC API
@@ -43,6 +53,7 @@ buildPackage a = buildPackage' a `Ex.catch` \(e::Ex.SomeException) -> do
   putStrLn ("exception building package: " ++ show e)
   return False
 
+buildPackage' :: [Located String] -> IO Bool
 buildPackage' argv2 = do
   (mode, argv3, modeFlagWarnings) <- parseModeFlags argv2
   GHC.runGhc (Just libdir) $ do
@@ -85,12 +96,13 @@ buildPackage' argv2 = do
       else liftIO linkPkg >> return True
 
 -- fixme, find default ar and ld versions
+linkPkg :: IO ()
 linkPkg = do
   arargs <- fmap read $ readFile "dist/arargs.txt"
   rawSystem "ar" arargs
   ldargs <- fmap read $ readFile "dist/ldargs.txt"
   rawSystem "ld" ldargs
-
+  return ()
 
 --------------------------------------------------------------------------------------------
 -- stuff below copied from ghc main.hs