[project @ 2000-08-01 09:08:25 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcImprove.lhs

diff --git a/ghc/compiler/typecheck/TcImprove.lhs b/ghc/compiler/typecheck/TcImprove.lhs
index 7ba6d21..9093ccb 100644 (file)
--- a/ghc/compiler/typecheck/TcImprove.lhs
+++ b/ghc/compiler/typecheck/TcImprove.lhs
@@ -6,7 +6,7 @@ module TcImprove ( tcImprove ) where
 import Name            ( Name )
 import Class           ( Class, FunDep, className, classExtraBigSig )
 import Unify           ( unifyTyListsX, matchTys )
-import Subst           ( mkSubst, substTy )
+import Subst           ( mkSubst, emptyInScopeSet, substTy )
 import TcEnv           ( tcGetInstEnv, classInstEnv )
 import TcMonad
 import TcType          ( TcType, TcTyVar, TcTyVarSet, zonkTcType, zonkTcTypes )
@@ -104,8 +104,9 @@ checkFd free (t_x, t_y) (s_x, s_y)
   = zonkUnifyTys free t_x s_x `thenTc` \ msubst ->
     case msubst of
       Just subst ->
-       let t_y' = map (substTy (mkSubst emptyVarEnv subst)) t_y
-           s_y' = map (substTy (mkSubst emptyVarEnv subst)) s_y
+       let full_subst = mkSubst emptyInScopeSet subst
+           t_y' = map (substTy full_subst) t_y
+           s_y' = map (substTy full_subst) s_y
        in
            zonkEqTys t_y' s_y' `thenTc` \ eq ->
            if eq then