{-# LANGUAGE CPP #-}
module VarSet (
VarSet, IdSet, TyVarSet, CoVarSet, TyCoVarSet,
emptyVarSet, unitVarSet, mkVarSet,
extendVarSet, extendVarSetList,
elemVarSet, subVarSet,
unionVarSet, unionVarSets, mapUnionVarSet,
intersectVarSet, intersectsVarSet, disjointVarSet,
isEmptyVarSet, delVarSet, delVarSetList, delVarSetByKey,
minusVarSet, filterVarSet, mapVarSet,
anyVarSet, allVarSet,
transCloVarSet, fixVarSet,
lookupVarSet_Directly, lookupVarSet, lookupVarSetByName,
sizeVarSet, seqVarSet,
elemVarSetByKey, partitionVarSet,
pluralVarSet, pprVarSet,
DVarSet, DIdSet, DTyVarSet, DTyCoVarSet,
emptyDVarSet, unitDVarSet, mkDVarSet,
extendDVarSet, extendDVarSetList,
elemDVarSet, dVarSetElems, subDVarSet,
unionDVarSet, unionDVarSets, mapUnionDVarSet,
intersectDVarSet, dVarSetIntersectVarSet,
intersectsDVarSet, disjointDVarSet,
isEmptyDVarSet, delDVarSet, delDVarSetList,
minusDVarSet, foldDVarSet, filterDVarSet, mapDVarSet,
dVarSetMinusVarSet, anyDVarSet, allDVarSet,
transCloDVarSet,
sizeDVarSet, seqDVarSet,
partitionDVarSet,
dVarSetToVarSet,
) where
#include "HsVersions.h"
import GhcPrelude
import Var ( Var, TyVar, CoVar, TyCoVar, Id )
import Unique
import Name ( Name )
import UniqSet
import UniqDSet
import UniqFM( disjointUFM, pluralUFM, pprUFM )
import UniqDFM( disjointUDFM, udfmToUfm, anyUDFM, allUDFM )
import Outputable (SDoc)
type VarSet = UniqSet Var
type IdSet = UniqSet Id
type TyVarSet = UniqSet TyVar
type CoVarSet = UniqSet CoVar
type TyCoVarSet = UniqSet TyCoVar
emptyVarSet :: VarSet
intersectVarSet :: VarSet -> VarSet -> VarSet
unionVarSet :: VarSet -> VarSet -> VarSet
unionVarSets :: [VarSet] -> VarSet
mapUnionVarSet :: (a -> VarSet) -> [a] -> VarSet
unitVarSet :: Var -> VarSet
extendVarSet :: VarSet -> Var -> VarSet
extendVarSetList:: VarSet -> [Var] -> VarSet
elemVarSet :: Var -> VarSet -> Bool
delVarSet :: VarSet -> Var -> VarSet
delVarSetList :: VarSet -> [Var] -> VarSet
minusVarSet :: VarSet -> VarSet -> VarSet
isEmptyVarSet :: VarSet -> Bool
mkVarSet :: [Var] -> VarSet
lookupVarSet_Directly :: VarSet -> Unique -> Maybe Var
lookupVarSet :: VarSet -> Var -> Maybe Var
lookupVarSetByName :: VarSet -> Name -> Maybe Var
sizeVarSet :: VarSet -> Int
filterVarSet :: (Var -> Bool) -> VarSet -> VarSet
delVarSetByKey :: VarSet -> Unique -> VarSet
elemVarSetByKey :: Unique -> VarSet -> Bool
partitionVarSet :: (Var -> Bool) -> VarSet -> (VarSet, VarSet)
emptyVarSet :: VarSet
emptyVarSet = VarSet
forall a. UniqSet a
emptyUniqSet
unitVarSet :: Var -> VarSet
unitVarSet = Var -> VarSet
forall a. Uniquable a => a -> UniqSet a
unitUniqSet
extendVarSet :: VarSet -> Var -> VarSet
extendVarSet = VarSet -> Var -> VarSet
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
addOneToUniqSet
extendVarSetList :: VarSet -> [Var] -> VarSet
extendVarSetList= VarSet -> [Var] -> VarSet
forall a. Uniquable a => UniqSet a -> [a] -> UniqSet a
addListToUniqSet
intersectVarSet :: VarSet -> VarSet -> VarSet
intersectVarSet = VarSet -> VarSet -> VarSet
forall a. UniqSet a -> UniqSet a -> UniqSet a
intersectUniqSets
intersectsVarSet:: VarSet -> VarSet -> Bool
disjointVarSet :: VarSet -> VarSet -> Bool
subVarSet :: VarSet -> VarSet -> Bool
unionVarSet :: VarSet -> VarSet -> VarSet
unionVarSet = VarSet -> VarSet -> VarSet
forall a. UniqSet a -> UniqSet a -> UniqSet a
unionUniqSets
unionVarSets :: [VarSet] -> VarSet
unionVarSets = [VarSet] -> VarSet
forall a. [UniqSet a] -> UniqSet a
unionManyUniqSets
elemVarSet :: Var -> VarSet -> Bool
elemVarSet = Var -> VarSet -> Bool
forall a. Uniquable a => a -> UniqSet a -> Bool
elementOfUniqSet
minusVarSet :: VarSet -> VarSet -> VarSet
minusVarSet = VarSet -> VarSet -> VarSet
forall a. UniqSet a -> UniqSet a -> UniqSet a
minusUniqSet
delVarSet :: VarSet -> Var -> VarSet
delVarSet = VarSet -> Var -> VarSet
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet
delVarSetList :: VarSet -> [Var] -> VarSet
delVarSetList = VarSet -> [Var] -> VarSet
forall a. Uniquable a => UniqSet a -> [a] -> UniqSet a
delListFromUniqSet
isEmptyVarSet :: VarSet -> Bool
isEmptyVarSet = VarSet -> Bool
forall a. UniqSet a -> Bool
isEmptyUniqSet
mkVarSet :: [Var] -> VarSet
mkVarSet = [Var] -> VarSet
forall a. Uniquable a => [a] -> UniqSet a
mkUniqSet
lookupVarSet_Directly :: VarSet -> Unique -> Maybe Var
lookupVarSet_Directly = VarSet -> Unique -> Maybe Var
forall a. UniqSet a -> Unique -> Maybe a
lookupUniqSet_Directly
lookupVarSet :: VarSet -> Var -> Maybe Var
lookupVarSet = VarSet -> Var -> Maybe Var
forall a b. Uniquable a => UniqSet b -> a -> Maybe b
lookupUniqSet
lookupVarSetByName :: VarSet -> Name -> Maybe Var
lookupVarSetByName = VarSet -> Name -> Maybe Var
forall a b. Uniquable a => UniqSet b -> a -> Maybe b
lookupUniqSet
sizeVarSet :: VarSet -> Int
sizeVarSet = VarSet -> Int
forall a. UniqSet a -> Int
sizeUniqSet
filterVarSet :: (Var -> Bool) -> VarSet -> VarSet
filterVarSet = (Var -> Bool) -> VarSet -> VarSet
forall a. (a -> Bool) -> UniqSet a -> UniqSet a
filterUniqSet
delVarSetByKey :: VarSet -> Unique -> VarSet
delVarSetByKey = VarSet -> Unique -> VarSet
forall a. UniqSet a -> Unique -> UniqSet a
delOneFromUniqSet_Directly
elemVarSetByKey :: Unique -> VarSet -> Bool
elemVarSetByKey = Unique -> VarSet -> Bool
forall a. Unique -> UniqSet a -> Bool
elemUniqSet_Directly
partitionVarSet :: (Var -> Bool) -> VarSet -> (VarSet, VarSet)
partitionVarSet = (Var -> Bool) -> VarSet -> (VarSet, VarSet)
forall a. (a -> Bool) -> UniqSet a -> (UniqSet a, UniqSet a)
partitionUniqSet
mapUnionVarSet :: (a -> VarSet) -> [a] -> VarSet
mapUnionVarSet a -> VarSet
get_set [a]
xs = (a -> VarSet -> VarSet) -> VarSet -> [a] -> VarSet
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (VarSet -> VarSet -> VarSet
unionVarSet (VarSet -> VarSet -> VarSet)
-> (a -> VarSet) -> a -> VarSet -> VarSet
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> VarSet
get_set) VarSet
emptyVarSet [a]
xs
intersectsVarSet :: VarSet -> VarSet -> Bool
intersectsVarSet VarSet
s1 VarSet
s2 = Bool -> Bool
not (VarSet
s1 VarSet -> VarSet -> Bool
`disjointVarSet` VarSet
s2)
disjointVarSet :: VarSet -> VarSet -> Bool
disjointVarSet VarSet
s1 VarSet
s2 = UniqFM Var -> UniqFM Var -> Bool
forall elt1 elt2. UniqFM elt1 -> UniqFM elt2 -> Bool
disjointUFM (VarSet -> UniqFM Var
forall a. UniqSet a -> UniqFM a
getUniqSet VarSet
s1) (VarSet -> UniqFM Var
forall a. UniqSet a -> UniqFM a
getUniqSet VarSet
s2)
subVarSet :: VarSet -> VarSet -> Bool
subVarSet VarSet
s1 VarSet
s2 = VarSet -> Bool
isEmptyVarSet (VarSet
s1 VarSet -> VarSet -> VarSet
`minusVarSet` VarSet
s2)
anyVarSet :: (Var -> Bool) -> VarSet -> Bool
anyVarSet :: (Var -> Bool) -> VarSet -> Bool
anyVarSet = (Var -> Bool) -> VarSet -> Bool
forall a. (a -> Bool) -> UniqSet a -> Bool
uniqSetAny
allVarSet :: (Var -> Bool) -> VarSet -> Bool
allVarSet :: (Var -> Bool) -> VarSet -> Bool
allVarSet = (Var -> Bool) -> VarSet -> Bool
forall a. (a -> Bool) -> UniqSet a -> Bool
uniqSetAll
mapVarSet :: Uniquable b => (a -> b) -> UniqSet a -> UniqSet b
mapVarSet :: (a -> b) -> UniqSet a -> UniqSet b
mapVarSet = (a -> b) -> UniqSet a -> UniqSet b
forall b a. Uniquable b => (a -> b) -> UniqSet a -> UniqSet b
mapUniqSet
fixVarSet :: (VarSet -> VarSet)
-> VarSet -> VarSet
fixVarSet :: (VarSet -> VarSet) -> VarSet -> VarSet
fixVarSet VarSet -> VarSet
fn VarSet
vars
| VarSet
new_vars VarSet -> VarSet -> Bool
`subVarSet` VarSet
vars = VarSet
vars
| Bool
otherwise = (VarSet -> VarSet) -> VarSet -> VarSet
fixVarSet VarSet -> VarSet
fn VarSet
new_vars
where
new_vars :: VarSet
new_vars = VarSet -> VarSet
fn VarSet
vars
transCloVarSet :: (VarSet -> VarSet)
-> VarSet -> VarSet
transCloVarSet :: (VarSet -> VarSet) -> VarSet -> VarSet
transCloVarSet VarSet -> VarSet
fn VarSet
seeds
= VarSet -> VarSet -> VarSet
go VarSet
seeds VarSet
seeds
where
go :: VarSet
-> VarSet
-> VarSet
go :: VarSet -> VarSet -> VarSet
go VarSet
acc VarSet
candidates
| VarSet -> Bool
isEmptyVarSet VarSet
new_vs = VarSet
acc
| Bool
otherwise = VarSet -> VarSet -> VarSet
go (VarSet
acc VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
new_vs) VarSet
new_vs
where
new_vs :: VarSet
new_vs = VarSet -> VarSet
fn VarSet
candidates VarSet -> VarSet -> VarSet
`minusVarSet` VarSet
acc
seqVarSet :: VarSet -> ()
seqVarSet :: VarSet -> ()
seqVarSet VarSet
s = VarSet -> Int
sizeVarSet VarSet
s Int -> () -> ()
`seq` ()
pluralVarSet :: VarSet -> SDoc
pluralVarSet :: VarSet -> SDoc
pluralVarSet = UniqFM Var -> SDoc
forall a. UniqFM a -> SDoc
pluralUFM (UniqFM Var -> SDoc) -> (VarSet -> UniqFM Var) -> VarSet -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. VarSet -> UniqFM Var
forall a. UniqSet a -> UniqFM a
getUniqSet
pprVarSet :: VarSet
-> ([Var] -> SDoc)
-> SDoc
pprVarSet :: VarSet -> ([Var] -> SDoc) -> SDoc
pprVarSet = UniqFM Var -> ([Var] -> SDoc) -> SDoc
forall a. UniqFM a -> ([a] -> SDoc) -> SDoc
pprUFM (UniqFM Var -> ([Var] -> SDoc) -> SDoc)
-> (VarSet -> UniqFM Var) -> VarSet -> ([Var] -> SDoc) -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. VarSet -> UniqFM Var
forall a. UniqSet a -> UniqFM a
getUniqSet
type DVarSet = UniqDSet Var
type DIdSet = UniqDSet Id
type DTyVarSet = UniqDSet TyVar
type DTyCoVarSet = UniqDSet TyCoVar
emptyDVarSet :: DVarSet
emptyDVarSet :: DVarSet
emptyDVarSet = DVarSet
forall a. UniqDSet a
emptyUniqDSet
unitDVarSet :: Var -> DVarSet
unitDVarSet :: Var -> DVarSet
unitDVarSet = Var -> DVarSet
forall a. Uniquable a => a -> UniqDSet a
unitUniqDSet
mkDVarSet :: [Var] -> DVarSet
mkDVarSet :: [Var] -> DVarSet
mkDVarSet = [Var] -> DVarSet
forall a. Uniquable a => [a] -> UniqDSet a
mkUniqDSet
extendDVarSet :: DVarSet -> Var -> DVarSet
extendDVarSet :: DVarSet -> Var -> DVarSet
extendDVarSet = DVarSet -> Var -> DVarSet
forall a. Uniquable a => UniqDSet a -> a -> UniqDSet a
addOneToUniqDSet
elemDVarSet :: Var -> DVarSet -> Bool
elemDVarSet :: Var -> DVarSet -> Bool
elemDVarSet = Var -> DVarSet -> Bool
forall a. Uniquable a => a -> UniqDSet a -> Bool
elementOfUniqDSet
dVarSetElems :: DVarSet -> [Var]
dVarSetElems :: DVarSet -> [Var]
dVarSetElems = DVarSet -> [Var]
forall a. UniqDSet a -> [a]
uniqDSetToList
subDVarSet :: DVarSet -> DVarSet -> Bool
subDVarSet :: DVarSet -> DVarSet -> Bool
subDVarSet DVarSet
s1 DVarSet
s2 = DVarSet -> Bool
isEmptyDVarSet (DVarSet
s1 DVarSet -> DVarSet -> DVarSet
`minusDVarSet` DVarSet
s2)
unionDVarSet :: DVarSet -> DVarSet -> DVarSet
unionDVarSet :: DVarSet -> DVarSet -> DVarSet
unionDVarSet = DVarSet -> DVarSet -> DVarSet
forall a. UniqDSet a -> UniqDSet a -> UniqDSet a
unionUniqDSets
unionDVarSets :: [DVarSet] -> DVarSet
unionDVarSets :: [DVarSet] -> DVarSet
unionDVarSets = [DVarSet] -> DVarSet
forall a. [UniqDSet a] -> UniqDSet a
unionManyUniqDSets
mapUnionDVarSet :: (a -> DVarSet) -> [a] -> DVarSet
mapUnionDVarSet :: (a -> DVarSet) -> [a] -> DVarSet
mapUnionDVarSet a -> DVarSet
get_set [a]
xs = (a -> DVarSet -> DVarSet) -> DVarSet -> [a] -> DVarSet
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (DVarSet -> DVarSet -> DVarSet
unionDVarSet (DVarSet -> DVarSet -> DVarSet)
-> (a -> DVarSet) -> a -> DVarSet -> DVarSet
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> DVarSet
get_set) DVarSet
emptyDVarSet [a]
xs
intersectDVarSet :: DVarSet -> DVarSet -> DVarSet
intersectDVarSet :: DVarSet -> DVarSet -> DVarSet
intersectDVarSet = DVarSet -> DVarSet -> DVarSet
forall a. UniqDSet a -> UniqDSet a -> UniqDSet a
intersectUniqDSets
dVarSetIntersectVarSet :: DVarSet -> VarSet -> DVarSet
dVarSetIntersectVarSet :: DVarSet -> VarSet -> DVarSet
dVarSetIntersectVarSet = DVarSet -> VarSet -> DVarSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
uniqDSetIntersectUniqSet
disjointDVarSet :: DVarSet -> DVarSet -> Bool
disjointDVarSet :: DVarSet -> DVarSet -> Bool
disjointDVarSet DVarSet
s1 DVarSet
s2 = UniqDFM Var -> UniqDFM Var -> Bool
forall elt. UniqDFM elt -> UniqDFM elt -> Bool
disjointUDFM (DVarSet -> UniqDFM Var
forall a. UniqDSet a -> UniqDFM a
getUniqDSet DVarSet
s1) (DVarSet -> UniqDFM Var
forall a. UniqDSet a -> UniqDFM a
getUniqDSet DVarSet
s2)
intersectsDVarSet :: DVarSet -> DVarSet -> Bool
intersectsDVarSet :: DVarSet -> DVarSet -> Bool
intersectsDVarSet DVarSet
s1 DVarSet
s2 = Bool -> Bool
not (DVarSet
s1 DVarSet -> DVarSet -> Bool
`disjointDVarSet` DVarSet
s2)
isEmptyDVarSet :: DVarSet -> Bool
isEmptyDVarSet :: DVarSet -> Bool
isEmptyDVarSet = DVarSet -> Bool
forall a. UniqDSet a -> Bool
isEmptyUniqDSet
delDVarSet :: DVarSet -> Var -> DVarSet
delDVarSet :: DVarSet -> Var -> DVarSet
delDVarSet = DVarSet -> Var -> DVarSet
forall a. Uniquable a => UniqDSet a -> a -> UniqDSet a
delOneFromUniqDSet
minusDVarSet :: DVarSet -> DVarSet -> DVarSet
minusDVarSet :: DVarSet -> DVarSet -> DVarSet
minusDVarSet = DVarSet -> DVarSet -> DVarSet
forall a. UniqDSet a -> UniqDSet a -> UniqDSet a
minusUniqDSet
dVarSetMinusVarSet :: DVarSet -> VarSet -> DVarSet
dVarSetMinusVarSet :: DVarSet -> VarSet -> DVarSet
dVarSetMinusVarSet = DVarSet -> VarSet -> DVarSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
uniqDSetMinusUniqSet
foldDVarSet :: (Var -> a -> a) -> a -> DVarSet -> a
foldDVarSet :: (Var -> a -> a) -> a -> DVarSet -> a
foldDVarSet = (Var -> a -> a) -> a -> DVarSet -> a
forall a b. (a -> b -> b) -> b -> UniqDSet a -> b
foldUniqDSet
anyDVarSet :: (Var -> Bool) -> DVarSet -> Bool
anyDVarSet :: (Var -> Bool) -> DVarSet -> Bool
anyDVarSet Var -> Bool
p = (Var -> Bool) -> UniqDFM Var -> Bool
forall elt. (elt -> Bool) -> UniqDFM elt -> Bool
anyUDFM Var -> Bool
p (UniqDFM Var -> Bool)
-> (DVarSet -> UniqDFM Var) -> DVarSet -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DVarSet -> UniqDFM Var
forall a. UniqDSet a -> UniqDFM a
getUniqDSet
allDVarSet :: (Var -> Bool) -> DVarSet -> Bool
allDVarSet :: (Var -> Bool) -> DVarSet -> Bool
allDVarSet Var -> Bool
p = (Var -> Bool) -> UniqDFM Var -> Bool
forall elt. (elt -> Bool) -> UniqDFM elt -> Bool
allUDFM Var -> Bool
p (UniqDFM Var -> Bool)
-> (DVarSet -> UniqDFM Var) -> DVarSet -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DVarSet -> UniqDFM Var
forall a. UniqDSet a -> UniqDFM a
getUniqDSet
mapDVarSet :: Uniquable b => (a -> b) -> UniqDSet a -> UniqDSet b
mapDVarSet :: (a -> b) -> UniqDSet a -> UniqDSet b
mapDVarSet = (a -> b) -> UniqDSet a -> UniqDSet b
forall b a. Uniquable b => (a -> b) -> UniqDSet a -> UniqDSet b
mapUniqDSet
filterDVarSet :: (Var -> Bool) -> DVarSet -> DVarSet
filterDVarSet :: (Var -> Bool) -> DVarSet -> DVarSet
filterDVarSet = (Var -> Bool) -> DVarSet -> DVarSet
forall a. (a -> Bool) -> UniqDSet a -> UniqDSet a
filterUniqDSet
sizeDVarSet :: DVarSet -> Int
sizeDVarSet :: DVarSet -> Int
sizeDVarSet = DVarSet -> Int
forall a. UniqDSet a -> Int
sizeUniqDSet
partitionDVarSet :: (Var -> Bool) -> DVarSet -> (DVarSet, DVarSet)
partitionDVarSet :: (Var -> Bool) -> DVarSet -> (DVarSet, DVarSet)
partitionDVarSet = (Var -> Bool) -> DVarSet -> (DVarSet, DVarSet)
forall a. (a -> Bool) -> UniqDSet a -> (UniqDSet a, UniqDSet a)
partitionUniqDSet
delDVarSetList :: DVarSet -> [Var] -> DVarSet
delDVarSetList :: DVarSet -> [Var] -> DVarSet
delDVarSetList = DVarSet -> [Var] -> DVarSet
forall a. Uniquable a => UniqDSet a -> [a] -> UniqDSet a
delListFromUniqDSet
seqDVarSet :: DVarSet -> ()
seqDVarSet :: DVarSet -> ()
seqDVarSet DVarSet
s = DVarSet -> Int
sizeDVarSet DVarSet
s Int -> () -> ()
`seq` ()
extendDVarSetList :: DVarSet -> [Var] -> DVarSet
extendDVarSetList :: DVarSet -> [Var] -> DVarSet
extendDVarSetList = DVarSet -> [Var] -> DVarSet
forall a. Uniquable a => UniqDSet a -> [a] -> UniqDSet a
addListToUniqDSet
dVarSetToVarSet :: DVarSet -> VarSet
dVarSetToVarSet :: DVarSet -> VarSet
dVarSetToVarSet = UniqFM Var -> VarSet
forall a. UniqFM a -> UniqSet a
unsafeUFMToUniqSet (UniqFM Var -> VarSet)
-> (DVarSet -> UniqFM Var) -> DVarSet -> VarSet
forall b c a. (b -> c) -> (a -> b) -> a -> c
. UniqDFM Var -> UniqFM Var
forall elt. UniqDFM elt -> UniqFM elt
udfmToUfm (UniqDFM Var -> UniqFM Var)
-> (DVarSet -> UniqDFM Var) -> DVarSet -> UniqFM Var
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DVarSet -> UniqDFM Var
forall a. UniqDSet a -> UniqDFM a
getUniqDSet
transCloDVarSet :: (DVarSet -> DVarSet)
-> DVarSet -> DVarSet
transCloDVarSet :: (DVarSet -> DVarSet) -> DVarSet -> DVarSet
transCloDVarSet DVarSet -> DVarSet
fn DVarSet
seeds
= DVarSet -> DVarSet -> DVarSet
go DVarSet
seeds DVarSet
seeds
where
go :: DVarSet
-> DVarSet
-> DVarSet
go :: DVarSet -> DVarSet -> DVarSet
go DVarSet
acc DVarSet
candidates
| DVarSet -> Bool
isEmptyDVarSet DVarSet
new_vs = DVarSet
acc
| Bool
otherwise = DVarSet -> DVarSet -> DVarSet
go (DVarSet
acc DVarSet -> DVarSet -> DVarSet
`unionDVarSet` DVarSet
new_vs) DVarSet
new_vs
where
new_vs :: DVarSet
new_vs = DVarSet -> DVarSet
fn DVarSet
candidates DVarSet -> DVarSet -> DVarSet
`minusDVarSet` DVarSet
acc