diff --git a/Language/Haskell/GhcMod/Boot.hs b/Language/Haskell/GhcMod/Boot.hs
index 7399de1..b4652c7 100644
--- a/Language/Haskell/GhcMod/Boot.hs
+++ b/Language/Haskell/GhcMod/Boot.hs
@@ -7,12 +7,13 @@ import Language.Haskell.GhcMod.Flag
 import Language.Haskell.GhcMod.Lang
 import Language.Haskell.GhcMod.Monad
 import Language.Haskell.GhcMod.Modules
+import Language.Haskell.GhcMod.Types (defaultBrowseOpts)
 
 -- | Printing necessary information for front-end booting.
 boot :: IOish m => GhcModT m String
 boot = concat <$> sequence ms
   where
-    ms = [modules False, languages, flags, concat <$> mapM (browse (BrowseOpts False False False)) preBrowsedModules]
+    ms = [modules False, languages, flags, concat <$> mapM (browse defaultBrowseOpts) preBrowsedModules]
 
 preBrowsedModules :: [String]
 preBrowsedModules = [
diff --git a/Language/Haskell/GhcMod/Browse.hs b/Language/Haskell/GhcMod/Browse.hs
index 05bc969..882e4ac 100644
--- a/Language/Haskell/GhcMod/Browse.hs
+++ b/Language/Haskell/GhcMod/Browse.hs
@@ -11,6 +11,7 @@ import Data.List
 import Data.Maybe
 import FastString
 import GHC
+import HscTypes
 import qualified GHC as G
 import Language.Haskell.GhcMod.Convert
 import Language.Haskell.GhcMod.Doc (showPage, styleUnqualified)
@@ -96,14 +97,20 @@ showExport opt minfo e = do
     mqualified = (G.moduleNameString (G.moduleName $ G.nameModule e) ++ ".") `justIf` optBrowseQualified opt
     mtype :: m (Maybe String)
     mtype
-      | optBrowseDetailed opt = do
+      | optBrowseDetailed opt || optBrowseParents opt = do
         tyInfo <- G.modInfoLookupName minfo e
         -- If nothing found, load dependent module and lookup global
         tyResult <- maybe (inOtherModule e) (return . Just) tyInfo
         dflag <- G.getSessionDynFlags
-        return $ do
-          typeName <- tyResult >>= showThing dflag
-          (" :: " ++ typeName) `justIf` optBrowseDetailed opt
+        let sig = do
+                    typeName <- tyResult >>= showThing dflag
+                    (" :: " ++ typeName) `justIf` optBrowseDetailed opt
+        let parent = do
+                    thing <- fmap getOccString $ tyResult >>= tyThingParent_maybe
+                    (" -- from:" ++ thing) `justIf` optBrowseParents opt
+        return $ case concat $ catMaybes [sig, parent] of
+                    [] -> Nothing
+                    x  -> Just x
       | otherwise = return Nothing
     formatOp nm
       | null nm    = error "formatOp"
diff --git a/Language/Haskell/GhcMod/CaseSplit.hs b/Language/Haskell/GhcMod/CaseSplit.hs
index a327dd4..d3ea112 100644
--- a/Language/Haskell/GhcMod/CaseSplit.hs
+++ b/Language/Haskell/GhcMod/CaseSplit.hs
@@ -29,6 +29,7 @@ import Language.Haskell.GhcMod.Logging
 import Language.Haskell.GhcMod.Types
 import Language.Haskell.GhcMod.Utils (withMappedFile)
 import Language.Haskell.GhcMod.FileMapping (fileModSummaryWithMapping)
+import Control.DeepSeq
 
 ----------------------------------------------------------------
 -- CASE SPLITTING
@@ -55,19 +56,17 @@ splits file lineNo colNo =
       style <- getStyle
       dflag <- G.getSessionDynFlags
       modSum <- fileModSummaryWithMapping (cradleCurrentDir crdl </> file)
-      whenFound' oopts (getSrcSpanTypeForSplit modSum lineNo colNo) $ \x -> case x of
-        (SplitInfo varName bndLoc (varLoc,varT) _matches) -> do
-          let varName' = showName dflag style varName  -- Convert name to string
+      whenFound' oopts (getSrcSpanTypeForSplit modSum lineNo colNo) $ \x -> do
+          let (varName, bndLoc, (varLoc,varT))
+                | (SplitInfo vn bl vlvt _matches) <- x
+                = (vn, bl, vlvt)
+                | (TySplitInfo vn bl vlvt) <- x
+                = (vn, bl, vlvt)
+              varName' = showName dflag style varName  -- Convert name to string
           t <- withMappedFile file $ \file' ->
                 genCaseSplitTextFile file' (SplitToTextInfo varName' bndLoc varLoc $
                                              getTyCons dflag style varName varT)
-          return (fourInts bndLoc, t)
-        (TySplitInfo varName bndLoc (varLoc,varT)) -> do
-          let varName' = showName dflag style varName  -- Convert name to string
-          t <- withMappedFile file $ \file' ->
-                genCaseSplitTextFile file' (SplitToTextInfo varName' bndLoc varLoc $
-                                             getTyCons dflag style varName varT)
-          return (fourInts bndLoc, t)
+          return $!! (fourInts bndLoc, t)
  where
    handler (SomeException ex) = do
      gmLog GmException "splits" $
@@ -215,8 +214,8 @@ genCaseSplitTextFile file info = liftIO $ do
   return $ getCaseSplitText (T.lines t) info
 
 getCaseSplitText :: [T.Text] -> SplitToTextInfo -> String
-getCaseSplitText t (SplitToTextInfo { sVarName = sVN, sBindingSpan = sBS
-                                       , sVarSpan = sVS, sTycons = sT })  =
+getCaseSplitText t SplitToTextInfo{ sVarName = sVN, sBindingSpan = sBS
+                                       , sVarSpan = sVS, sTycons = sT }  =
   let bindingText = getBindingText t sBS
       difference  = srcSpanDifference sBS sVS
       replaced    = map (replaceVarWithTyCon bindingText difference sVN) sT
diff --git a/Language/Haskell/GhcMod/Gap.hs b/Language/Haskell/GhcMod/Gap.hs
index 3e74c67..ab897a1 100644
--- a/Language/Haskell/GhcMod/Gap.hs
+++ b/Language/Haskell/GhcMod/Gap.hs
@@ -44,6 +44,7 @@ module Language.Haskell.GhcMod.Gap (
   , Language.Haskell.GhcMod.Gap.isSynTyCon
   , parseModuleHeader
   , mkErrStyle'
+  , everythingStagedWithContext
   ) where
 
 import Control.Applicative hiding (empty)
@@ -115,6 +116,8 @@ import Lexer as L
 import Parser
 import SrcLoc
 import Packages
+import Data.Generics (GenericQ, extQ, gmapQ)
+import GHC.SYB.Utils (Stage(..))
 
 import Language.Haskell.GhcMod.Types (Expression(..))
 import Prelude
@@ -607,3 +610,20 @@ instance NFData ByteString where
   rnf Empty       = ()
   rnf (Chunk _ b) = rnf b
 #endif
+
+-- | Like 'everything', but avoid known potholes, based on the 'Stage' that
+--   generated the Ast.
+everythingStagedWithContext :: Stage -> s -> (r -> r -> r) -> r -> GenericQ (s -> (r, s)) -> GenericQ r
+everythingStagedWithContext stage s0 f z q x
+  | (const False
+#if __GLASGOW_HASKELL__ <= 708
+      `extQ` postTcType
+#endif
+      `extQ` fixity `extQ` nameSet) x = z
+  | otherwise = foldl f r (gmapQ (everythingStagedWithContext stage s' f z q) x)
+  where nameSet    = const (stage `elem` [Parser,TypeChecker]) :: NameSet -> Bool
+#if __GLASGOW_HASKELL__ <= 708
+        postTcType = const (stage<TypeChecker)                 :: PostTcType -> Bool
+#endif
+        fixity     = const (stage<Renamer)                     :: GHC.Fixity -> Bool
+        (r, s') = q x s0
diff --git a/Language/Haskell/GhcMod/Info.hs b/Language/Haskell/GhcMod/Info.hs
index 31a8eab..dc18f7c 100644
--- a/Language/Haskell/GhcMod/Info.hs
+++ b/Language/Haskell/GhcMod/Info.hs
@@ -5,10 +5,9 @@ module Language.Haskell.GhcMod.Info (
 
 import Data.Function (on)
 import Data.List (sortBy)
-import Data.Maybe (catMaybes)
 import System.FilePath
 import Exception (ghandle, SomeException(..))
-import GHC (GhcMonad, LHsBind, LHsExpr, LPat, Id, TypecheckedModule(..), SrcSpan, Type)
+import GHC (GhcMonad, SrcSpan)
 import Prelude
 import qualified GHC as G
 import qualified Language.Haskell.GhcMod.Gap as Gap
@@ -53,17 +52,18 @@ info file expr =
 
 -- | Obtaining type of a target expression. (GHCi's type:)
 types :: IOish m
-      => FilePath     -- ^ A target file.
+      => Bool         -- ^ Include constraints into type signature
+      -> FilePath     -- ^ A target file.
       -> Int          -- ^ Line number.
       -> Int          -- ^ Column number.
       -> GhcModT m String
-types file lineNo colNo =
+types withConstraints file lineNo colNo =
   ghandle handler $
     runGmlT' [Left file] deferErrors $
       withInteractiveContext $ do
         crdl         <- cradle
         modSum       <- fileModSummaryWithMapping (cradleCurrentDir crdl </> file)
-        srcSpanTypes <- getSrcSpanType modSum lineNo colNo
+        srcSpanTypes <- getSrcSpanType withConstraints modSum lineNo colNo
         dflag        <- G.getSessionDynFlags
         st           <- getStyle
         convert' $ map (toTup dflag st) $ sortBy (cmp `on` fst) srcSpanTypes
@@ -72,14 +72,8 @@ types file lineNo colNo =
      gmLog GmException "types" $ showDoc ex
      return []
 
-getSrcSpanType :: GhcMonad m => G.ModSummary -> Int -> Int -> m [(SrcSpan, Type)]
-getSrcSpanType modSum lineNo colNo = do
-  p <- G.parseModule modSum
-  tcm@TypecheckedModule{tm_typechecked_source = tcs} <- G.typecheckModule p
-  let bs = listifySpans tcs (lineNo, colNo) :: [LHsBind Id]
-      es = listifySpans tcs (lineNo, colNo) :: [LHsExpr Id]
-      ps = listifySpans tcs (lineNo, colNo) :: [LPat Id]
-  bts <- mapM (getType tcm) bs
-  ets <- mapM (getType tcm) es
-  pts <- mapM (getType tcm) ps
-  return $ catMaybes $ concat [ets, bts, pts]
+getSrcSpanType :: (GhcMonad m) => Bool -> G.ModSummary -> Int -> Int -> m [(SrcSpan, G.Type)]
+getSrcSpanType withConstraints modSum lineNo colNo =
+  G.parseModule modSum
+  >>= G.typecheckModule
+  >>= flip (collectSpansTypes withConstraints) (lineNo, colNo)
diff --git a/Language/Haskell/GhcMod/SrcUtils.hs b/Language/Haskell/GhcMod/SrcUtils.hs
index 0938f81..961bfae 100644
--- a/Language/Haskell/GhcMod/SrcUtils.hs
+++ b/Language/Haskell/GhcMod/SrcUtils.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE TupleSections, FlexibleInstances, Rank2Types #-}
+{-# LANGUAGE TupleSections, FlexibleInstances, Rank2Types, ImpredicativeTypes #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 module Language.Haskell.GhcMod.SrcUtils where
@@ -6,11 +6,14 @@ module Language.Haskell.GhcMod.SrcUtils where
 import Control.Applicative
 import CoreUtils (exprType)
 import Data.Generics
-import Data.Maybe (fromMaybe)
+import Data.Maybe
 import Data.Ord as O
 import GHC (LHsExpr, LPat, Id, DynFlags, SrcSpan, Type, Located, ParsedSource, RenamedSource, TypecheckedSource, GenLocated(L))
+import Var (Var)
 import qualified GHC as G
-import GHC.SYB.Utils (Stage(..), everythingStaged)
+import qualified Var as G
+import qualified Type as G
+import GHC.SYB.Utils
 import GhcMonad
 import qualified Language.Haskell.Exts.Annotated as HE
 import Language.Haskell.GhcMod.Doc
@@ -20,6 +23,10 @@ import OccName (OccName)
 import Outputable (PprStyle)
 import TcHsSyn (hsPatType)
 import Prelude
+import Control.Monad
+import Data.List (nub)
+import Control.Arrow
+import qualified Data.Map as M
 
 ----------------------------------------------------------------
 
@@ -34,6 +41,82 @@ instance HasType (LPat Id) where
 
 ----------------------------------------------------------------
 
+-- | Stores mapping from monomorphic to polymorphic types
+type CstGenQS = M.Map Var Type
+-- | Generic type to simplify SYB definition
+type CstGenQT a = forall m. GhcMonad m => a Id -> CstGenQS -> (m [(SrcSpan, Type)], CstGenQS)
+
+collectSpansTypes :: (GhcMonad m) => Bool -> G.TypecheckedModule -> (Int, Int) -> m [(SrcSpan, Type)]
+collectSpansTypes withConstraints tcs lc =
+  -- This walks AST top-down, left-to-right, while carrying CstGenQS down the tree
+  -- (but not left-to-right)
+  everythingStagedWithContext TypeChecker M.empty (liftM2 (++))
+    (return [])
+    ((return [],)
+      `mkQ`  (hsBind    :: CstGenQT G.LHsBind) -- matches on binds
+      `extQ` (genericCT :: CstGenQT G.LHsExpr) -- matches on expressions
+      `extQ` (genericCT :: CstGenQT G.LPat) -- matches on patterns
+      )
+    (G.tm_typechecked_source tcs)
+  where
+    -- Helper function to insert mapping into CstGenQS
+    insExp x = M.insert (G.abe_mono x) (G.varType $ G.abe_poly x)
+    -- If there is AbsBinds here, insert mapping into CstGenQS if needed
+    hsBind (L _ G.AbsBinds{abs_exports = es'}) s
+      | withConstraints = (return [], foldr insExp s es')
+      | otherwise       = (return [], s)
+    -- Otherwise, it's the same as other cases
+    hsBind x s = genericCT x s
+    -- Generic SYB function to get type
+    genericCT x s
+      | withConstraints
+      = (maybe [] (uncurry $ constrainedType (collectBinders x) s) <$> getType' x, s)
+      | otherwise = (maybeToList <$> getType' x, s)
+    -- Collects everything with Id from LHsBind, LHsExpr, or LPat
+    collectBinders :: Data a => a -> [Id]
+    collectBinders = listifyStaged TypeChecker (const True)
+    -- Gets monomorphic type with location
+    getType' x@(L spn _)
+      | G.isGoodSrcSpan spn && spn `G.spans` lc
+      = getType tcs x
+      | otherwise = return Nothing
+    -- Gets constrained type
+    constrainedType :: [Var] -- ^ Binders in expression, i.e. anything with Id
+                    -> CstGenQS -- ^ Map from Id to polymorphic type
+                    -> SrcSpan -- ^ extent of expression, copied to result
+                    -> Type -- ^ monomorphic type
+                    -> [(SrcSpan, Type)] -- ^ result
+    constrainedType pids s spn genTyp =
+      let
+        -- runs build on every binder.
+        ctys  = mapMaybe build (nub pids)
+        -- Computes constrained type for x. Returns (constraints, substitutions)
+        -- Substitutions are needed because type variables don't match
+        -- between polymorphic and monomorphic types.
+        -- E.g. poly type might be `Monad m => m ()`, while monomorphic might be `f ()`
+        build x | Just cti <- x `M.lookup` s
+                = let
+                    (preds', ctt) = getPreds cti
+                    -- list of type variables in monomorphic type
+                    vts = listifyStaged TypeChecker G.isTyVar $ G.varType x
+                    -- list of type variables in polymorphic type
+                    tvm = listifyStaged TypeChecker G.isTyVarTy ctt
+                  in Just (preds', zip vts tvm)
+                | otherwise = Nothing
+        -- list of constraints
+        preds = concatMap fst ctys
+        -- Type variable substitutions
+        subs  = G.mkTopTvSubst $ concatMap snd ctys
+        -- Constrained type
+        ty    = G.substTy subs $ G.mkFunTys preds genTyp
+      in [(spn, ty)]
+    -- Splits a given type into list of constraints and simple type. Drops foralls.
+    getPreds :: Type -> ([Type], Type)
+    getPreds x | G.isForAllTy x = getPreds $ G.dropForAlls x
+               | Just (c, t) <- G.splitFunTy_maybe x
+               , G.isPredTy c = first (c:) $ getPreds t
+               | otherwise = ([], x)
+
 listifySpans :: Typeable a => TypecheckedSource -> (Int, Int) -> [Located a]
 listifySpans tcs lc = listifyStaged TypeChecker p tcs
   where
diff --git a/Language/Haskell/GhcMod/Types.hs b/Language/Haskell/GhcMod/Types.hs
index 2281ba9..7b4a8d1 100644
--- a/Language/Haskell/GhcMod/Types.hs
+++ b/Language/Haskell/GhcMod/Types.hs
@@ -71,7 +71,7 @@ data OutputStyle = LispStyle  -- ^ S expression style.
 newtype LineSeparator = LineSeparator String deriving (Show)
 
 data FileMapping =  FileMapping {fmPath :: FilePath, fmTemp :: Bool}
-                  deriving Show
+                  deriving (Eq, Show)
 
 type FileMappingMap = Map FilePath FileMapping
 
@@ -388,13 +388,15 @@ data BrowseOpts = BrowseOpts {
         -- ^ If 'True', "browseWith" also returns operators.
       , optBrowseDetailed       :: Bool
         -- ^ If 'True', "browseWith" also returns types.
+      , optBrowseParents        :: Bool
+        -- ^ If 'True', "browseWith" also returns parents.
       , optBrowseQualified      :: Bool
         -- ^ If 'True', "browseWith" will return fully qualified name
     } deriving (Show)
 
 -- | Default "BrowseOpts" instance
 defaultBrowseOpts :: BrowseOpts
-defaultBrowseOpts = BrowseOpts False False False
+defaultBrowseOpts = BrowseOpts False False False False
 
 mkLabel ''GhcModCaches
 mkLabel ''GhcModState
diff --git a/Language/Haskell/GhcMod/World.hs b/Language/Haskell/GhcMod/World.hs
index 74ed5a2..d166b49 100644
--- a/Language/Haskell/GhcMod/World.hs
+++ b/Language/Haskell/GhcMod/World.hs
@@ -19,6 +19,7 @@ data World = World {
   , worldCabalFile     :: Maybe TimedFile
   , worldCabalConfig   :: Maybe TimedFile
   , worldCabalSandboxConfig :: Maybe TimedFile
+  , worldMappedFiles   :: FileMappingMap
   } deriving (Eq)
 
 timedPackageCaches :: IOish m => GhcModT m [TimedFile]
@@ -34,12 +35,14 @@ getCurrentWorld = do
     mCabalFile   <- liftIO $ timeFile `traverse` cradleCabalFile crdl
     mCabalConfig <- liftIO $ timeMaybe (setupConfigFile crdl)
     mCabalSandboxConfig <- liftIO $ timeMaybe (sandboxConfigFile crdl)
+    mFileMap     <- getMMappedFiles
 
     return World {
         worldPackageCaches = pkgCaches
       , worldCabalFile     = mCabalFile
       , worldCabalConfig   = mCabalConfig
       , worldCabalSandboxConfig = mCabalSandboxConfig
+      , worldMappedFiles   = mFileMap
       }
 
 didWorldChange :: IOish m => World -> GhcModT m Bool
diff --git a/ghc-mod.cabal b/ghc-mod.cabal
index 82b2261..c112995 100644
--- a/ghc-mod.cabal
+++ b/ghc-mod.cabal
@@ -165,7 +165,7 @@ Library
                       , bytestring        < 0.11
                       , binary            < 0.9 && >= 0.5.1.0
                       , containers        < 0.6
-                      , cabal-helper      < 0.8 && >= 0.7.0.1
+                      , cabal-helper      < 0.8 && >= 0.7.1.0
                       , deepseq           < 1.5
                       , directory         < 1.3
                       , filepath          < 1.5
diff --git a/src/GHCMod.hs b/src/GHCMod.hs
index 713d567..ed28d56 100644
--- a/src/GHCMod.hs
+++ b/src/GHCMod.hs
@@ -151,7 +151,7 @@ ghcCommands (CmdBrowse opts ms) = concat <$> browse opts `mapM` ms
 ghcCommands (CmdCheck files) = checkSyntax files
 ghcCommands (CmdExpand files) = expandTemplate files
 ghcCommands (CmdInfo file symb) = info file $ Expression symb
-ghcCommands (CmdType file (line, col)) = types file line col
+ghcCommands (CmdType wCon file (line, col)) = types wCon file line col
 ghcCommands (CmdSplit file (line, col)) = splits file line col
 ghcCommands (CmdSig file (line, col)) = sig file line col
 ghcCommands (CmdAuto file (line, col)) = auto file line col
diff --git a/src/GHCMod/Options/Commands.hs b/src/GHCMod/Options/Commands.hs
index a2ab3c0..688905f 100644
--- a/src/GHCMod/Options/Commands.hs
+++ b/src/GHCMod/Options/Commands.hs
@@ -51,7 +51,7 @@ data GhcModCommands =
   | CmdCheck [FilePath]
   | CmdExpand [FilePath]
   | CmdInfo FilePath Symbol
-  | CmdType FilePath Point
+  | CmdType Bool FilePath Point
   | CmdSplit FilePath Point
   | CmdSig FilePath Point
   | CmdAuto FilePath Point
@@ -215,12 +215,12 @@ interactiveCommandsSpec =
 strArg :: String -> Parser String
 strArg = argument str . metavar
 
-filesArgsSpec :: ([String] -> b) -> Parser b
-filesArgsSpec x = x <$> some (strArg "FILES..")
+filesArgsSpec :: Parser ([String] -> b) -> Parser b
+filesArgsSpec x = x <*> some (strArg "FILES..")
 
-locArgSpec :: (String -> (Int, Int) -> b) -> Parser b
+locArgSpec :: Parser (String -> (Int, Int) -> b) -> Parser b
 locArgSpec x = x
-  <$> strArg "FILE"
+  <*> strArg "FILE"
   <*> ( (,)
         <$> argument int (metavar "LINE")
         <*> argument int (metavar "COL")
@@ -255,23 +255,31 @@ browseArgSpec = CmdBrowse
             $$  long "detailed"
             <=> short 'd'
             <=> help "Print symbols with accompanying signature"
+        <*> switch
+            $$  long "parents"
+            <=> short 'p'
+            <=> help "Print symbols parents"
         <*> switch
             $$  long "qualified"
             <=> short 'q'
             <=> help "Qualify symbols"
       )
   <*> some (strArg "MODULE")
-debugComponentArgSpec = filesArgsSpec CmdDebugComponent
-checkArgSpec = filesArgsSpec CmdCheck
-expandArgSpec = filesArgsSpec CmdExpand
+debugComponentArgSpec = filesArgsSpec (pure CmdDebugComponent)
+checkArgSpec = filesArgsSpec (pure CmdCheck)
+expandArgSpec = filesArgsSpec (pure CmdExpand)
 infoArgSpec = CmdInfo
     <$> strArg "FILE"
     <*> strArg "SYMBOL"
-typeArgSpec = locArgSpec CmdType
-autoArgSpec = locArgSpec CmdAuto
-splitArgSpec = locArgSpec CmdSplit
-sigArgSpec = locArgSpec CmdSig
-refineArgSpec = locArgSpec CmdRefine <*> strArg "SYMBOL"
+typeArgSpec = locArgSpec $ CmdType <$>
+        switch
+          $$  long "constraints"
+          <=> short 'c'
+          <=> help "Include constraints into type signature"
+autoArgSpec = locArgSpec (pure CmdAuto)
+splitArgSpec = locArgSpec (pure CmdSplit)
+sigArgSpec = locArgSpec (pure CmdSig)
+refineArgSpec = locArgSpec (pure CmdRefine) <*> strArg "SYMBOL"
 mapArgSpec = CmdMapFile <$> strArg "FILE"
 unmapArgSpec = CmdUnmapFile <$> strArg "FILE"
 legacyInteractiveArgSpec = const CmdLegacyInteractive <$>
diff --git a/test/CaseSplitSpec.hs b/test/CaseSplitSpec.hs
index 5e5db3f..4cec78b 100644
--- a/test/CaseSplitSpec.hs
+++ b/test/CaseSplitSpec.hs
@@ -39,3 +39,8 @@ spec = do
                 res `shouldBe` "38 21 38 59"++
                         " \"mlReverse' Nil accum = _mlReverse_body\NUL"++
                         "                    mlReverse' (Cons xs'1 xs'2) accum = _mlReverse_body\"\n"
+
+        it "doesn't crash when source doesn't make sense" $
+            withDirectory_ "test/data/case-split" $ do
+                res <- runD $ splits "Crash.hs" 4 6
+                res `shouldBe` []
diff --git a/test/FileMappingSpec.hs b/test/FileMappingSpec.hs
index d6ba1bb..9598fb6 100644
--- a/test/FileMappingSpec.hs
+++ b/test/FileMappingSpec.hs
@@ -134,13 +134,19 @@ spec = do
             let tdir = "test/data/file-mapping"
             res <- runD' tdir $ do
               loadMappedFile "File.hs" "File_Redir_Lint.hs"
-              types "File.hs" 4 12
+              types False "File.hs" 4 12
             res `shouldBe` "4 12 4 15 \"a -> a -> a\"\n4 12 4 17 \"a -> a\"\n4 12 4 19 \"a\"\n4 1 4 19 \"a -> a -> a\"\n"
+        it "shows types of the expression with constraints for redirected files" $ do
+            let tdir = "test/data/file-mapping"
+            res <- runD' tdir $ do
+              loadMappedFile "File.hs" "File_Redir_Lint.hs"
+              types True "File.hs" 4 12
+            res `shouldBe` "4 12 4 15 \"a -> a -> a\"\n4 12 4 17 \"a -> a\"\n4 12 4 19 \"a\"\n4 1 4 19 \"Num a => a -> a -> a\"\n"
         it "shows types of the expression for in-memory files" $ do
             let tdir = "test/data/file-mapping"
             res <- runD' tdir $ do
               loadMappedFileSource "File.hs" "main = putStrLn \"Hello!\""
-              types "File.hs" 1 14
+              types False "File.hs" 1 14
             res `shouldBe` "1 8 1 16 \"String -> IO ()\"\n1 8 1 25 \"IO ()\"\n1 1 1 25 \"IO ()\"\n"
         it "shows info for the expression for redirected files" $ do
             let tdir = "test/data/file-mapping"
@@ -234,7 +240,7 @@ spec = do
                        ,("Bar.hs", tmpdir </> "Bar_Redir.hs")]
               res <- run defaultOptions $ do
                 mapM_ (uncurry loadMappedFile) fm
-                types "Bar.hs" 5 1
+                types False "Bar.hs" 5 1
               res `shouldBe` unlines ["5 1 5 20 \"[Char]\""]
         it "works with a memory module using TemplateHaskell" $ do
           srcFoo <- readFile "test/data/template-haskell/Foo.hs"
@@ -244,5 +250,5 @@ spec = do
                      ,("Bar.hs", srcBar)]
             res <- run defaultOptions $ do
               mapM_ (uncurry loadMappedFileSource) fm
-              types "Bar.hs" 5 1
+              types False "Bar.hs" 5 1
             res `shouldBe` unlines ["5 1 5 20 \"[Char]\""]
diff --git a/test/InfoSpec.hs b/test/InfoSpec.hs
index 3bdd5ae..d084b9a 100644
--- a/test/InfoSpec.hs
+++ b/test/InfoSpec.hs
@@ -19,17 +19,22 @@ spec = do
     describe "types" $ do
         it "shows types of the expression and its outers" $ do
             let tdir = "test/data/ghc-mod-check"
-            res <- runD' tdir $ types "lib/Data/Foo.hs" 9 5
+            res <- runD' tdir $ types False "lib/Data/Foo.hs" 9 5
             res `shouldBe` "9 5 11 40 \"Int -> a -> a -> a\"\n7 1 11 40 \"Int -> Integer\"\n"
 
+        it "shows types of the expression with constraints and its outers" $ do
+            let tdir = "test/data/ghc-mod-check"
+            res <- runD' tdir $ types True "lib/Data/Foo.hs" 9 5
+            res `shouldBe` "9 5 11 40 \"Num a => Int -> a -> a -> a\"\n7 1 11 40 \"Int -> Integer\"\n"
+
         it "works with a module using TemplateHaskell" $ do
             let tdir = "test/data/template-haskell"
-            res <- runD' tdir $ types "Bar.hs" 5 1
+            res <- runD' tdir $ types False "Bar.hs" 5 1
             res `shouldBe` unlines ["5 1 5 20 \"[Char]\""]
 
         it "works with a module that imports another module using TemplateHaskell" $ do
             let tdir = "test/data/template-haskell"
-            res <- runD' tdir $ types "ImportsTH.hs" 3 8
+            res <- runD' tdir $ types False "ImportsTH.hs" 3 8
             res `shouldBe` unlines ["3 8 3 16 \"String -> IO ()\"", "3 8 3 20 \"IO ()\"", "3 1 3 20 \"IO ()\""]
 
     describe "info" $ do
diff --git a/test/data/case-split/Crash.hs b/test/data/case-split/Crash.hs
new file mode 100644
index 0000000..7ee88cb
--- /dev/null
+++ b/test/data/case-split/Crash.hs
@@ -0,0 +1,4 @@
+module Crash where
+
+test :: Maybe a
+test x = undefined