X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreSubst.lhs;h=8306c04611d997fda09fbdb9f3ce0dc31c05dadf;hb=940524aec90652b5ef81789c9a453c57c0e42cc9;hp=321ea8fc3603a37936a9a8ea9db6983815cc956a;hpb=94b170a053c161d1e0cc4418b37a6a4807872a5f;p=ghc-hetmet.git

diff --git a/compiler/coreSyn/CoreSubst.lhs b/compiler/coreSyn/CoreSubst.lhs
index 321ea8f..8306c04 100644
--- a/compiler/coreSyn/CoreSubst.lhs
+++ b/compiler/coreSyn/CoreSubst.lhs
@@ -16,7 +16,8 @@ module CoreSubst (
 
 	emptySubst, mkEmptySubst, mkSubst, substInScope, isEmptySubst, 
  	extendIdSubst, extendIdSubstList, extendTvSubst, extendTvSubstList,
-	extendInScope, extendInScopeIds,
+	extendSubstList, zapSubstEnv,
+	extendInScope, extendInScopeList, extendInScopeIds, 
 	isInScope,
 
 	-- Binders
@@ -56,6 +57,7 @@ import FastTypes
 \begin{code}
 data Subst 
   = Subst InScopeSet	-- Variables in in scope (both Ids and TyVars)
+			-- *after* applying the substitution
 	  IdSubstEnv	-- Substitution for Ids
 	  TvSubstEnv	-- Substitution for TyVars
 
@@ -144,8 +146,8 @@ mkSubst in_scope tvs ids = Subst in_scope ids tvs
 substInScope :: Subst -> InScopeSet
 substInScope (Subst in_scope _ _) = in_scope
 
--- zapSubstEnv :: Subst -> Subst
--- zapSubstEnv (Subst in_scope _ _) = Subst in_scope emptyVarEnv emptyVarEnv
+zapSubstEnv :: Subst -> Subst
+zapSubstEnv (Subst in_scope _ _) = Subst in_scope emptyVarEnv emptyVarEnv
 
 -- ToDo: add an ASSERT that fvs(subst-result) is already in the in-scope set
 extendIdSubst :: Subst -> Id -> CoreExpr -> Subst
@@ -160,6 +162,14 @@ extendTvSubst (Subst in_scope ids tvs) v r = Subst in_scope ids (extendVarEnv tv
 extendTvSubstList :: Subst -> [(TyVar,Type)] -> Subst
 extendTvSubstList (Subst in_scope ids tvs) prs = Subst in_scope ids (extendVarEnvList tvs prs)
 
+extendSubstList :: Subst -> [(Var,CoreArg)] -> Subst
+extendSubstList subst [] 
+  = subst
+extendSubstList (Subst in_scope ids tvs) ((tv,Type ty):prs)
+  = ASSERT( isTyVar tv ) extendSubstList (Subst in_scope ids (extendVarEnv tvs tv ty)) prs
+extendSubstList (Subst in_scope ids tvs) ((id,expr):prs)
+  = ASSERT( isId id ) extendSubstList (Subst in_scope (extendVarEnv ids id expr) tvs) prs
+
 lookupIdSubst :: Subst -> Id -> CoreExpr
 lookupIdSubst (Subst in_scope ids tvs) v 
   | not (isLocalId v) = Var v
@@ -181,6 +191,11 @@ extendInScope (Subst in_scope ids tvs) v
   = Subst (in_scope `extendInScopeSet` v) 
 	  (ids `delVarEnv` v) (tvs `delVarEnv` v)
 
+extendInScopeList :: Subst -> [Var] -> Subst
+extendInScopeList (Subst in_scope ids tvs) vs
+  = Subst (in_scope `extendInScopeSetList` vs) 
+	  (ids `delVarEnvList` vs) (tvs `delVarEnvList` vs)
+
 extendInScopeIds :: Subst -> [Id] -> Subst
 extendInScopeIds (Subst in_scope ids tvs) vs 
   = Subst (in_scope `extendInScopeSetList` vs) 
@@ -292,6 +307,7 @@ substRecBndrs subst bndrs
 substIdBndr :: Subst		-- Substitution to use for the IdInfo
 	    -> Subst -> Id 	-- Substitition and Id to transform
 	    -> (Subst, Id)	-- Transformed pair
+				-- NB: unfolding may be zapped
 
 substIdBndr rec_subst subst@(Subst in_scope env tvs) old_id
   = (Subst (in_scope `extendInScopeSet` new_id) new_env tvs, new_id)
@@ -309,6 +325,7 @@ substIdBndr rec_subst subst@(Subst in_scope env tvs) old_id
 	-- rec_subst, when dealing with a mutually-recursive group
     new_id = maybeModifyIdInfo mb_new_info id2
     mb_new_info = substIdInfo rec_subst (idInfo id2)
+	-- NB: unfolding info may be zapped
 
 	-- Extend the substitution if the unique has changed
 	-- See the notes with substTyVarBndr for the delVarEnv