Do type refinement in TcIface

[ghc-hetmet.git] / ghc / compiler / types / Unify.lhs

diff --git a/ghc/compiler/types/Unify.lhs b/ghc/compiler/types/Unify.lhs
index 1443498..f60c7be 100644 (file)
--- a/ghc/compiler/types/Unify.lhs
+++ b/ghc/compiler/types/Unify.lhs
@@ -21,7 +21,7 @@ import VarSet
 import Kind            ( isSubKind )
 import Type            ( typeKind, tyVarsOfType, tyVarsOfTypes, tyVarsOfTheta, mkTyVarTys,
                          TvSubstEnv, emptyTvSubstEnv, TvSubst(..), substTy, tcEqTypeX,
-                         tcView )
+                         mkOpenTvSubst, tcView )
 import TypeRep          ( Type(..), PredType(..), funTyCon )
 import DataCon                 ( DataCon, dataConInstResTy )
 import Util            ( snocView )
@@ -222,8 +222,7 @@ tcUnifyTys bind_fn tys1 tys2
     tvs2 = tyVarsOfTypes tys2
 
 ----------------------------
-coreRefineTys :: InScopeSet            -- Superset of free vars of either type
-             -> DataCon -> [TyVar]     -- Case pattern (con tv1 .. tvn ...)
+coreRefineTys :: DataCon -> [TyVar]    -- Case pattern (con tv1 .. tvn ...)
              -> Type                   -- Type of scrutinee
              -> Maybe TypeRefinement
 
@@ -234,13 +233,13 @@ type TypeRefinement = (TvSubstEnv, Bool)
        -- for already-in-scope type variables
 
 -- Used by Core Lint and the simplifier.
-coreRefineTys in_scope con tvs scrut_ty
+coreRefineTys con tvs scrut_ty
   = maybeErrToMaybe $ initUM (tryToBind tv_set) $
     do {       -- Run the unifier, starting with an empty env
        ; subst_env <- unify emptyTvSubstEnv pat_res_ty scrut_ty
 
        -- Find the fixed point of the resulting non-idempotent substitution
-       ; let subst           = TvSubst in_scope subst_env_fixpt
+       ; let subst           = mkOpenTvSubst subst_env_fixpt
              subst_env_fixpt = mapVarEnv (substTy subst) subst_env
                
        ; return (subst_env_fixpt, all_bound_here subst_env) }