Refactor SetLevels.abstractVars

This patch is pure refactoring: using utility functions
rather than special-purpose code, especially for closeOverKinds

1 files changed, 6 insertions, 14 deletions

diff --git a/compiler/simplCore/SetLevels.hs b/compiler/simplCore/SetLevels.hs
index 25b20188e6..65f771306e 100644
--- a/compiler/simplCore/SetLevels.hs
+++ b/compiler/simplCore/SetLevels.hs
@@ -88,6 +88,7 @@ import Demand           ( StrictSig, Demand, isStrictDmd, splitStrictSig, increa
 import Name             ( getOccName, mkSystemVarName )
 import OccName          ( occNameString )
 import Type             ( Type, mkLamTypes, splitTyConApp_maybe, tyCoVarsOfType )
+import TyCoRep          ( closeOverKindsDSet )
 import BasicTypes       ( Arity, RecFlag(..), isRec )
 import DataCon          ( dataConOrigResTy )
 import TysWiredIn
@@ -1558,17 +1559,14 @@ abstractVars :: Level -> LevelEnv -> DVarSet -> [OutVar]
         -- Uniques are not deterministic.
 abstractVars dest_lvl (LE { le_subst = subst, le_lvl_env = lvl_env }) in_fvs
   =  -- NB: sortQuantVars might not put duplicates next to each other
-    map zap $ sortQuantVars $ uniq
-    [out_var | out_fv  <- dVarSetElems (substDVarSet subst in_fvs)
-             , out_var <- dVarSetElems (close out_fv)
-             , abstract_me out_var ]
+    map zap $ sortQuantVars $
+    filter abstract_me      $
+    dVarSetElems            $
+    closeOverKindsDSet      $
+    substDVarSet subst in_fvs
         -- NB: it's important to call abstract_me only on the OutIds the
         -- come from substDVarSet (not on fv, which is an InId)
   where
-    uniq :: [Var] -> [Var]
-        -- Remove duplicates, preserving order
-    uniq = dVarSetElems . mkDVarSet
-
     abstract_me v = case lookupVarEnv lvl_env v of
                         Just lvl -> dest_lvl `ltLvl` lvl
                         Nothing  -> False
@@ -1581,12 +1579,6 @@ abstractVars dest_lvl (LE { le_subst = subst, le_lvl_env = lvl_env }) in_fvs
                      setIdInfo v vanillaIdInfo
           | otherwise = v
 
-    close :: Var -> DVarSet  -- Close over variables free in the type
-                             -- Result includes the input variable itself
-    close v = foldDVarSet (unionDVarSet . close)
-                          (unitDVarSet v)
-                          (fvDVarSet $ varTypeTyCoFVs v)
-
 type LvlM result = UniqSM result
 
 initLvl :: UniqSupply -> UniqSM a -> a