X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypes%2FType.lhs;h=242e6035694fcef8e1f287a26b499809f2c5fdc1;hp=fd275da20458eac892841ad1d8b90b9253c0e1ce;hb=064812423073e89805c16311728cfded5d50e306;hpb=455302c1fd5dba0047e76ad83ec21d2edb9864de

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index fd275da..242e603 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -123,7 +123,8 @@ module Type (
 	emptyTvSubstEnv, emptyTvSubst,
 	
 	mkTvSubst, mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst, notElemTvSubst,
-	getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope, extendTvInScopeList,
+	getTvSubstEnv, setTvSubstEnv, zapTvSubstEnv, getTvInScope, 
+        extendTvInScope, extendTvInScopeList,
  	extendTvSubst, extendTvSubstList, isInScope, composeTvSubst, zipTyEnv,
         isEmptyTvSubst,
 
@@ -1437,6 +1438,9 @@ notElemTvSubst tv (TvSubst _ env) = not (tv `elemVarEnv` env)
 setTvSubstEnv :: TvSubst -> TvSubstEnv -> TvSubst
 setTvSubstEnv (TvSubst in_scope _) env = TvSubst in_scope env
 
+zapTvSubstEnv :: TvSubst -> TvSubst
+zapTvSubstEnv (TvSubst in_scope _) = TvSubst in_scope emptyVarEnv
+
 extendTvInScope :: TvSubst -> Var -> TvSubst
 extendTvInScope (TvSubst in_scope env) var = TvSubst (extendInScopeSet in_scope var) env