Merge branch 'file-redirection-2' of https://github.com/atom-haskell/ghc-mod

Language/Haskell/GhcMod/Utils.hs

@@ -27,6 +27,9 @@ import Control.Applicative
 import Data.Char
 import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
+import Data.Either (rights)
+import Data.List (inits)
+import System.FilePath (joinPath, splitPath, normalise)
 import Exception
 import Language.Haskell.GhcMod.Error
 import Language.Haskell.GhcMod.Types
@@ -170,12 +173,18 @@ withMappedFile file action = getCanonicalFileNameSafe file >>= lookupMMappedFile
 
 getCanonicalFileNameSafe :: (IOish m, GmEnv m) => FilePath -> m FilePath
 getCanonicalFileNameSafe fn = do
-  crdl <- cradle
-  let ccfn = cradleRootDir crdl </> fn
-  fex <- liftIO $ doesFileExist ccfn
-  if fex
-    then liftIO $ canonicalizePath ccfn
-    else return ccfn
+  let fn' = normalise fn
+  pl <- liftIO $ rights <$> (mapM ((try :: IO FilePath -> IO (Either SomeException FilePath)) . canonicalizePath . joinPath) $ reverse $ inits $ splitPath' fn')
+  return $
+    if (length pl > 0)
+    then joinPath $ (head pl):(drop (length pl - 1) (splitPath fn'))
+    else error "Current dir doesn't seem to exist?"
+  where
+#if __GLASGOW_HASKELL__ < 710
+    splitPath' = (".":) . splitPath
+#else
+    splitPath' = splitPath
+#endif
 
 mkRevRedirMapFunc :: (Functor m, GmState m, GmEnv m) => m (FilePath -> FilePath)
 mkRevRedirMapFunc = do