Replace fromJust with fromJustNote everywhere

Language/Haskell/GhcMod/Browse.hs

@@ -3,6 +3,7 @@ module Language.Haskell.GhcMod.Browse (
     BrowseOpts(..)
   ) where
 
+import Safe
 import Control.Applicative
 import Control.Exception (SomeException(..))
 import Data.Char
@@ -49,7 +50,7 @@ browse opts pkgmdl = do
     goHomeModule = runGmlT [Right mdlname] $ do
       processExports opts =<< tryModuleInfo =<< G.findModule mdlname Nothing
 
-    tryModuleInfo m = fromJust <$> G.getModuleInfo m
+    tryModuleInfo m = fromJustNote "browse, tryModuleInfo" <$> G.getModuleInfo m
 
     (mpkg, mdl) = splitPkgMdl pkgmdl
     mdlname = G.mkModuleName mdl

Language/Haskell/GhcMod/Cradle.hs

@@ -19,6 +19,7 @@ import Language.Haskell.GhcMod.Stack
 import Language.Haskell.GhcMod.Logging
 import Language.Haskell.GhcMod.Error
 
+import Safe
 import Control.Applicative
 import Control.Monad.Trans.Maybe
 import Data.Maybe
@@ -46,7 +47,7 @@ findCradle' dir = run $
          , sandboxCradle dir
          , plainCradle dir
          ]
- where run a = fillTempDir =<< (fromJust <$> runMaybeT a)
+ where run a = fillTempDir =<< (fromJustNote "findCradle'" <$> runMaybeT a)
 
 findSpecCradle :: (GmLog m, IOish m, GmOut m) => FilePath -> m Cradle
 findSpecCradle dir = do

Language/Haskell/GhcMod/Monad/Types.hs

@@ -73,6 +73,8 @@ import Language.Haskell.GhcMod.Monad.Out
 import Language.Haskell.GhcMod.Monad.Newtypes
 import Language.Haskell.GhcMod.Monad.Orphans ()
 
+import Safe
+
 import GHC
 import DynFlags
 import Exception
@@ -116,13 +118,13 @@ instance (MonadIO m, MonadBaseControl IO m) => GhcMonad (GmlT m) where
 -- | Get the underlying GHC session
 gmlGetSession :: (MonadIO m, MonadBaseControl IO m) => GmlT m HscEnv
 gmlGetSession = do
-        ref <- gmgsSession . fromJust . gmGhcSession <$> gmsGet
+        ref <- gmgsSession . fromJustNote "gmlGetSession" . gmGhcSession <$> gmsGet
         liftIO $ readIORef ref
 
 -- | Set the underlying GHC session
 gmlSetSession :: (MonadIO m, MonadBaseControl IO m) => HscEnv -> GmlT m ()
 gmlSetSession a = do
-        ref <- gmgsSession . fromJust . gmGhcSession <$> gmsGet
+        ref <- gmgsSession . fromJustNote "gmlSetSession" . gmGhcSession <$> gmsGet
         liftIO $ flip writeIORef a ref
 
 instance GhcMonad LightGhc where

Language/Haskell/GhcMod/Stack.hs

@@ -16,7 +16,7 @@
 
 module Language.Haskell.GhcMod.Stack where
 
-
+import Safe
 import Control.Applicative
 import Control.Exception as E
 import Control.Monad
@@ -51,7 +51,7 @@ patchStackPrograms _crdl progs = return progs
 getStackEnv :: (IOish m, GmOut m, GmLog m) => FilePath -> m (Maybe StackEnv)
 getStackEnv projdir = U.withDirectory_ projdir $ runMaybeT $ do
     env <- map (liToTup . splitOn ": ") . lines <$> readStack ["path"]
-    let look k = fromJust $ lookup k env
+    let look k = fromJustNote "getStackEnv" $ lookup k env
     return StackEnv {
         seDistDir       = look "dist-dir"
       , seBinPath       = splitSearchPath $ look "bin-path"

Language/Haskell/GhcMod/Target.hs

@@ -40,6 +40,7 @@ import Language.Haskell.GhcMod.LightGhc
 import Language.Haskell.GhcMod.CustomPackageDb
 import Language.Haskell.GhcMod.Output
 
+import Safe
 import Data.Maybe
 import Data.Monoid as Monoid
 import Data.Either
@@ -188,13 +189,13 @@ targetGhcOptions crdl sefnmn = do
             let cns = filter (/= ChSetupHsName) $ Map.keys mcs
 
             gmLog GmDebug "" $ strDoc $ "Could not find a component assignment, falling back to picking library component in cabal file."
-            return $ gmcGhcOpts $ fromJust $ Map.lookup (head cns) mcs
+            return $ gmcGhcOpts $ fromJustNote "targetGhcOptions, no-assignment" $ Map.lookup (head cns) mcs
           else do
             when noCandidates $
               throwError $ GMECabalCompAssignment mdlcs
 
             let cn = pickComponent candidates
-            return $ gmcGhcOpts $ fromJust $ Map.lookup cn mcs
+            return $ gmcGhcOpts $ fromJustNote "targetGhcOptions" $ Map.lookup cn mcs
 
 resolvedComponentsCache :: IOish m => FilePath ->
     Cached (GhcModT m) GhcModState

Setup.hs

@@ -8,6 +8,7 @@ import Distribution.Simple.InstallDirs as ID
 import Distribution.Simple.LocalBuildInfo
 import Distribution.PackageDescription
 
+import Safe
 import Control.Arrow
 import Control.Applicative
 import Control.Monad
@@ -99,7 +100,7 @@ xInstallTarget pd lbi fn = do
         libexecdir'      = fromPathTemplate (libexecdir idirtpl)
 
         pd_extended      = onlyExePackageDesc [exe] pd
-        install_target   = fromJust $ installTarget exe
+        install_target   = fromJustNote "xInstallTarget" $ installTarget exe
         install_target'  = ID.substPathTemplate env install_target
         -- $libexec isn't a real thing :/ so we have to simulate it
         install_target'' = substLibExec' libexecdir' install_target'

ghc-mod.cabal

@@ -186,6 +186,7 @@ Library
                       , fclabels          == 2.0.*
                       , extra             == 1.4.*
                       , pipes             == 4.1.*
+                      , safe              < 0.4 && >= 0.3.9
   if impl(ghc < 7.8)
     Build-Depends:      convertible
   if impl(ghc < 7.5)