Initial implementation of case splitting

- It doesn't handle vars correctly yet

Language/Haskell/GhcMod/Gap.hs

@@ -23,6 +23,7 @@ module Language.Haskell.GhcMod.Gap (
   , HasType(..)
   , errorMsgSpan
   , typeForUser
+  , nameForUser
   , deSugar
   , showDocWith
   , GapThing(..)
@@ -47,6 +48,7 @@ import HscTypes
 import Language.Haskell.GhcMod.GHCChoice
 import Language.Haskell.GhcMod.Types
 import NameSet
+import OccName
 import Outputable
 import PprTyThing
 import StringBuffer
@@ -337,6 +339,13 @@ typeForUser = pprTypeForUser
 typeForUser = pprTypeForUser False
 #endif
 
+nameForUser :: Name -> SDoc
+#if __GLASGOW_HASKELL__ >= 708
+nameForUser = pprOccName . getOccName
+#else
+nameForUser = pprOccName False . getOccName
+#endif
+
 deSugar :: TypecheckedModule -> LHsExpr Id -> HscEnv
          -> IO (Maybe CoreExpr)
 #if __GLASGOW_HASKELL__ >= 708