Properly ppr InstEqs in wanteds of implication constraints

[ghc-hetmet.git] / compiler / coreSyn / CoreSubst.lhs

diff --git a/compiler/coreSyn/CoreSubst.lhs b/compiler/coreSyn/CoreSubst.lhs
index 321ea8f..9cedf2d 100644 (file)
--- a/compiler/coreSyn/CoreSubst.lhs
+++ b/compiler/coreSyn/CoreSubst.lhs
@@ -6,6 +6,13 @@
 Utility functions on @Core@ syntax
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module CoreSubst (
        -- Substitution stuff
        Subst, TvSubstEnv, IdSubstEnv, InScopeSet,
@@ -16,7 +23,8 @@ module CoreSubst (
 
        emptySubst, mkEmptySubst, mkSubst, substInScope, isEmptySubst, 
        extendIdSubst, extendIdSubstList, extendTvSubst, extendTvSubstList,
-       extendInScope, extendInScopeIds,
+       extendSubstList, zapSubstEnv,
+       extendInScope, extendInScopeList, extendInScopeIds, 
        isInScope,
 
        -- Binders
@@ -44,6 +52,8 @@ import Outputable
 import PprCore         ()              -- Instances
 import Util
 import FastTypes
+
+import Data.List
 \end{code}
 
 
@@ -56,6 +66,7 @@ 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 +155,8 @@ 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 +171,14 @@ 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 +200,11 @@ 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 +316,7 @@ 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)
@@ -308,7 +333,8 @@ substIdBndr rec_subst subst@(Subst in_scope env tvs) old_id
        -- The lazy-set is because we're in a loop here, with 
        -- rec_subst, when dealing with a mutually-recursive group
     new_id = maybeModifyIdInfo mb_new_info id2
-    mb_new_info = substIdInfo rec_subst (idInfo id2)
+    mb_new_info = substIdInfo rec_subst id2 (idInfo id2)
+       -- NB: unfolding info may be zapped
 
        -- Extend the substitution if the unique has changed
        -- See the notes with substTyVarBndr for the delVarEnv
@@ -350,7 +376,7 @@ clone_id rec_subst subst@(Subst in_scope env tvs) (old_id, uniq)
   where
     id1            = setVarUnique old_id uniq
     id2     = substIdType subst id1
-    new_id  = maybeModifyIdInfo (substIdInfo rec_subst (idInfo old_id)) id2
+    new_id  = maybeModifyIdInfo (substIdInfo rec_subst id2 (idInfo old_id)) id2
     new_env = extendVarEnv env old_id (Var new_id)
 \end{code}
 
@@ -395,11 +421,11 @@ substIdType subst@(Subst in_scope id_env tv_env) id
     old_ty = idType id
 
 ------------------
-substIdInfo :: Subst -> IdInfo -> Maybe IdInfo
+substIdInfo :: Subst -> Id -> IdInfo -> Maybe IdInfo
 -- Always zaps the unfolding, to save substitution work
-substIdInfo  subst info
+substIdInfo subst new_id info
   | nothing_to_do = Nothing
-  | otherwise     = Just (info `setSpecInfo`             substSpec  subst old_rules
+  | otherwise     = Just (info `setSpecInfo`             substSpec subst new_id old_rules
                               `setWorkerInfo`    substWorker subst old_wrkr
                               `setUnfoldingInfo` noUnfolding)
   where
@@ -426,19 +452,21 @@ substWorker subst (HasWorker w a)
                                --  via postInlineUnconditionally, hence warning)
 
 ------------------
-substSpec :: Subst -> SpecInfo -> SpecInfo
+substSpec :: Subst -> Id -> SpecInfo -> SpecInfo
 
-substSpec subst spec@(SpecInfo rules rhs_fvs)
+substSpec subst new_fn spec@(SpecInfo rules rhs_fvs)
   | isEmptySubst subst
   = spec
   | otherwise
   = seqSpecInfo new_rules `seq` new_rules
   where
+    new_name = idName new_fn
     new_rules = SpecInfo (map do_subst rules) (substVarSet subst rhs_fvs)
 
     do_subst rule@(BuiltinRule {}) = rule
     do_subst rule@(Rule { ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs })
-       = rule { ru_bndrs = bndrs',
+       = rule { ru_bndrs = bndrs', 
+                ru_fn = new_name,      -- Important: the function may have changed its name!
                 ru_args  = map (substExpr subst') args,
                 ru_rhs   = substExpr subst' rhs }
        where