\begin{code}
module Type (
-- re-exports from TypeRep:
- Type,
- Kind, TyVarSubst,
-
- superKind, superBoxity, -- :: SuperKind
-
- boxedKind, -- :: Kind :: BX
- anyBoxKind, -- :: Kind :: BX
- typeCon, -- :: KindCon :: BX -> KX
- anyBoxCon, -- :: KindCon :: BX
-
- boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
-
- mkArrowKind, mkArrowKinds, -- mentioned below: hasMoreBoxityInfo,
-
+ Type, PredType, ThetaType,
+ Kind, TyVarSubst,
+
+ TyThing(..), isTyClThing,
+
+ superKind, superBoxity, -- KX and BX respectively
+ liftedBoxity, unliftedBoxity, -- :: BX
+ openKindCon, -- :: KX
+ typeCon, -- :: BX -> KX
+ liftedTypeKind, unliftedTypeKind, openTypeKind, -- :: KX
+ mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX
+ isTypeKind, isAnyTypeKind,
funTyCon,
-- exports from this module:
- hasMoreBoxityInfo,
+ hasMoreBoxityInfo, defaultKind,
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
- mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
- funResultTy, funArgTy, zipFunTys,
-
- mkTyConApp, mkTyConTy, splitTyConApp_maybe,
- splitAlgTyConApp_maybe, splitAlgTyConApp,
- mkDictTy, mkDictTys, mkPredTy, splitPredTy_maybe, splitDictTy_maybe, isDictTy,
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys,
+ funResultTy, funArgTy, zipFunTys, isFunTy,
- mkSynTy, isSynTy, deNoteType,
+ mkGenTyConApp, mkTyConApp, mkTyConTy,
+ tyConAppTyCon, tyConAppArgs,
+ splitTyConApp_maybe, splitTyConApp,
- repType, splitRepFunTys, splitNewType_maybe, typePrimRep,
+ mkSynTy,
- UsageAnn(..), mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
- mkUsForAllTy, mkUsForAllTys, splitUsForAllTys, substUsTy,
+ repType, typePrimRep,
mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
- applyTy, applyTys, hoistForAllTys,
+ applyTy, applyTys, isForAllTy, dropForAlls,
- TauType, RhoType, SigmaType, PredType(..), ThetaType,
- ClassPred, ClassContext, mkClassPred,
- getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
- isTauTy, mkRhoTy, splitRhoTy,
- mkSigmaTy, isSigmaTy, splitSigmaTy,
+ -- Source types
+ SourceType(..), sourceTypeRep, mkPredTy, mkPredTys,
+
+ -- Newtypes
+ splitNewType_maybe,
-- Lifting and boxity
- isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
+ isUnLiftedType, isUnboxedTupleType, isAlgType, isStrictType, isPrimitiveType,
-- Free variables
tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
- namesOfType, typeKind, addFreeTyVars,
+ typeKind, addFreeTyVars,
-- Tidying up for printing
- tidyType, tidyTypes,
- tidyOpenType, tidyOpenTypes,
- tidyTyVar, tidyTyVars,
- tidyTopType,
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVarBndr, tidyFreeTyVars,
+ tidyOpenTyVar, tidyOpenTyVars,
+ tidyTopType, tidyPred,
+
+ -- Comparison
+ eqType, eqKind,
-- Seq
seqType, seqTypes
-- Other imports:
-import {-# SOURCE #-} DataCon( DataCon, dataConRepType )
-import {-# SOURCE #-} PprType( pprType, pprPred ) -- Only called in debug messages
-import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
+import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
+import {-# SOURCE #-} Subst ( substTyWith )
-- friends:
-import Var ( TyVar, Var, UVar,
- tyVarKind, tyVarName, setTyVarName, isId, idType,
- )
+import Var ( Id, TyVar, tyVarKind, tyVarName, setTyVarName )
import VarEnv
import VarSet
-import Name ( Name, NamedThing(..), mkLocalName, tidyOccName
- )
-import NameSet
-import Class ( classTyCon, Class, ClassPred, ClassContext )
-import TyCon ( TyCon,
+import Name ( NamedThing(..), mkInternalName, tidyOccName )
+import Class ( Class, classTyCon )
+import TyCon ( TyCon, isRecursiveTyCon, isPrimTyCon,
isUnboxedTupleTyCon, isUnLiftedTyCon,
- isFunTyCon, isDataTyCon, isNewTyCon, newTyConRep,
- isAlgTyCon, isSynTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn,
- tyConPrimRep, tyConClass_maybe
+ isFunTyCon, isNewTyCon, newTyConRep,
+ isAlgTyCon, isSynTyCon, tyConArity,
+ tyConKind, getSynTyConDefn,
+ tyConPrimRep,
)
-- others
+import CmdLineOpts ( opt_DictsStrict )
import SrcLoc ( noSrcLoc )
-import Maybes ( maybeToBool )
-import PrimRep ( PrimRep(..), isFollowableRep )
+import PrimRep ( PrimRep(..) )
import Unique ( Uniquable(..) )
-import Util ( mapAccumL, seqList )
+import Util ( mapAccumL, seqList, lengthIs, snocView )
import Outputable
import UniqSet ( sizeUniqSet ) -- Should come via VarSet
+import Maybe ( isJust )
+\end{code}
+
+
+%************************************************************************
+%* *
+ TyThing
+%* *
+%************************************************************************
+
+\begin{code}
+data TyThing = AnId Id
+ | ATyCon TyCon
+ | AClass Class
+
+isTyClThing :: TyThing -> Bool
+isTyClThing (ATyCon _) = True
+isTyClThing (AClass _) = True
+isTyClThing (AnId _) = False
+
+instance NamedThing TyThing where
+ getName (AnId id) = getName id
+ getName (ATyCon tc) = getName tc
+ getName (AClass cl) = getName cl
\end{code}
\begin{code}
hasMoreBoxityInfo :: Kind -> Kind -> Bool
+-- (k1 `hasMoreBoxityInfo` k2) checks that k1 <: k2
hasMoreBoxityInfo k1 k2
- | k2 == openTypeKind = ASSERT( is_type_kind k1) True
- | otherwise = k1 == k2
+ | k2 `eqKind` openTypeKind = isAnyTypeKind k1
+ | otherwise = k1 `eqKind` k2
where
- -- Returns true for things of form (Type x)
- is_type_kind k = case splitTyConApp_maybe k of
- Just (tc,[_]) -> tc == typeCon
- Nothing -> False
+
+isAnyTypeKind :: Kind -> Bool
+-- True of kind * and *# and ?
+isAnyTypeKind (TyConApp tc _) = tc == typeCon || tc == openKindCon
+isAnyTypeKind (NoteTy _ k) = isAnyTypeKind k
+isAnyTypeKind other = False
+
+isTypeKind :: Kind -> Bool
+-- True of kind * and *#
+isTypeKind (TyConApp tc _) = tc == typeCon
+isTypeKind (NoteTy _ k) = isTypeKind k
+isTypeKind other = False
+
+defaultKind :: Kind -> Kind
+-- Used when generalising: default kind '?' to '*'
+defaultKind kind | kind `eqKind` openTypeKind = liftedTypeKind
+ | otherwise = kind
\end{code}
mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
getTyVar :: String -> Type -> TyVar
-getTyVar msg (TyVarTy tv) = tv
-getTyVar msg (NoteTy _ t) = getTyVar msg t
-getTyVar msg other = panic ("getTyVar: " ++ msg)
+getTyVar msg (TyVarTy tv) = tv
+getTyVar msg (SourceTy p) = getTyVar msg (sourceTypeRep p)
+getTyVar msg (NoteTy _ t) = getTyVar msg t
+getTyVar msg other = panic ("getTyVar: " ++ msg)
getTyVar_maybe :: Type -> Maybe TyVar
-getTyVar_maybe (TyVarTy tv) = Just tv
-getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
-getTyVar_maybe other = Nothing
+getTyVar_maybe (TyVarTy tv) = Just tv
+getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
+getTyVar_maybe (SourceTy p) = getTyVar_maybe (sourceTypeRep p)
+getTyVar_maybe other = Nothing
isTyVarTy :: Type -> Bool
-isTyVarTy (TyVarTy tv) = True
-isTyVarTy (NoteTy _ ty) = isTyVarTy ty
-isTyVarTy other = False
+isTyVarTy (TyVarTy tv) = True
+isTyVarTy (NoteTy _ ty) = isTyVarTy ty
+isTyVarTy (SourceTy p) = isTyVarTy (sourceTypeRep p)
+isTyVarTy other = False
\end{code}
invariant: use it.
\begin{code}
-mkAppTy orig_ty1 orig_ty2 = ASSERT2( isNotUsgTy orig_ty1 && isNotUsgTy orig_ty2, pprType orig_ty1 <+> text "to" <+> pprType orig_ty2 )
- mk_app orig_ty1
+mkAppTy orig_ty1 orig_ty2
+ = ASSERT( not (isSourceTy orig_ty1) ) -- Source types are of kind *
+ mk_app orig_ty1
where
mk_app (NoteTy _ ty1) = mk_app ty1
- mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
+ mk_app (TyConApp tc tys) = mkGenTyConApp tc (tys ++ [orig_ty2])
mk_app ty1 = AppTy orig_ty1 orig_ty2
+ -- We call mkGenTyConApp because the TyConApp could be an
+ -- under-saturated type synonym. GHC allows that; e.g.
+ -- type Foo k = k a -> k a
+ -- type Id x = x
+ -- foo :: Foo Id -> Foo Id
+ --
+ -- Here Id is partially applied in the type sig for Foo,
+ -- but once the type synonyms are expanded all is well
mkAppTys :: Type -> [Type] -> Type
mkAppTys orig_ty1 [] = orig_ty1
-- This check for an empty list of type arguments
- -- avoids the needless of a type synonym constructor.
+ -- avoids the needless loss of a type synonym constructor.
-- For example: mkAppTys Rational []
-- returns to (Ratio Integer), which has needlessly lost
-- the Rational part.
-mkAppTys orig_ty1 orig_tys2 = ASSERT2( isNotUsgTy orig_ty1, pprType orig_ty1 )
- mk_app orig_ty1
+mkAppTys orig_ty1 orig_tys2
+ = ASSERT( not (isSourceTy orig_ty1) ) -- Source types are of kind *
+ mk_app orig_ty1
where
mk_app (NoteTy _ ty1) = mk_app ty1
mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ orig_tys2)
- mk_app ty1 = ASSERT2( all isNotUsgTy orig_tys2, pprType orig_ty1 <+> text "to" <+> hsep (map pprType orig_tys2) )
- foldl AppTy orig_ty1 orig_tys2
+ mk_app ty1 = foldl AppTy orig_ty1 orig_tys2
splitAppTy_maybe :: Type -> Maybe (Type, Type)
splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2)
splitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2)
splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
-splitAppTy_maybe (TyConApp tc []) = Nothing
-splitAppTy_maybe (TyConApp tc tys) = split tys []
- where
- split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
- split (ty:tys) acc = split tys (ty:acc)
-
-splitAppTy_maybe other = Nothing
+splitAppTy_maybe (SourceTy p) = splitAppTy_maybe (sourceTypeRep p)
+splitAppTy_maybe (TyConApp tc tys) = case snocView tys of
+ Nothing -> Nothing
+ Just (tys',ty') -> Just (TyConApp tc tys', ty')
+splitAppTy_maybe other = Nothing
splitAppTy :: Type -> (Type, Type)
splitAppTy ty = case splitAppTy_maybe ty of
where
split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
split orig_ty (NoteTy _ ty) args = split orig_ty ty args
+ split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args
split orig_ty (FunTy ty1 ty2) args = ASSERT( null args )
(TyConApp funTyCon [], [ty1,ty2])
split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
mkFunTys :: [Type] -> Type -> Type
mkFunTys tys ty = foldr FunTy ty tys
+isFunTy :: Type -> Bool
+isFunTy ty = isJust (splitFunTy_maybe ty)
+
splitFunTy :: Type -> (Type, Type)
splitFunTy (FunTy arg res) = (arg, res)
splitFunTy (NoteTy _ ty) = splitFunTy ty
+splitFunTy (SourceTy p) = splitFunTy (sourceTypeRep p)
splitFunTy_maybe :: Type -> Maybe (Type, Type)
-splitFunTy_maybe (FunTy arg res) = Just (arg, res)
-splitFunTy_maybe (NoteTy (IPNote _) ty) = Nothing
-splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
-splitFunTy_maybe other = Nothing
+splitFunTy_maybe (FunTy arg res) = Just (arg, res)
+splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
+splitFunTy_maybe (SourceTy p) = splitFunTy_maybe (sourceTypeRep p)
+splitFunTy_maybe other = Nothing
splitFunTys :: Type -> ([Type], Type)
splitFunTys ty = split [] ty ty
where
split args orig_ty (FunTy arg res) = split (arg:args) res res
- split args orig_ty (NoteTy (IPNote _) ty)
- = (reverse args, orig_ty)
split args orig_ty (NoteTy _ ty) = split args orig_ty ty
+ split args orig_ty (SourceTy p) = split args orig_ty (sourceTypeRep p)
split args orig_ty ty = (reverse args, orig_ty)
-splitFunTysN :: String -> Int -> Type -> ([Type], Type)
-splitFunTysN msg orig_n orig_ty = split orig_n [] orig_ty orig_ty
- where
- split 0 args syn_ty ty = (reverse args, syn_ty)
- split n args syn_ty (FunTy arg res) = split (n-1) (arg:args) res res
- split n args syn_ty (NoteTy _ ty) = split n args syn_ty ty
- split n args syn_ty ty = pprPanic ("splitFunTysN: " ++ msg) (int orig_n <+> pprType orig_ty)
-
zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
zipFunTys orig_xs orig_ty = split [] orig_xs orig_ty orig_ty
where
split acc [] nty ty = (reverse acc, nty)
split acc (x:xs) nty (FunTy arg res) = split ((x,arg):acc) xs res res
split acc xs nty (NoteTy _ ty) = split acc xs nty ty
+ split acc xs nty (SourceTy p) = split acc xs nty (sourceTypeRep p)
split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty)
funResultTy :: Type -> Type
funResultTy (FunTy arg res) = res
funResultTy (NoteTy _ ty) = funResultTy ty
+funResultTy (SourceTy p) = funResultTy (sourceTypeRep p)
funResultTy ty = pprPanic "funResultTy" (pprType ty)
funArgTy :: Type -> Type
funArgTy (FunTy arg res) = arg
funArgTy (NoteTy _ ty) = funArgTy ty
+funArgTy (SourceTy p) = funArgTy (sourceTypeRep p)
funArgTy ty = pprPanic "funArgTy" (pprType ty)
\end{code}
---------------------------------------------------------------------
TyConApp
~~~~~~~~
+@mkTyConApp@ is a key function, because it builds a TyConApp, FunTy or SourceTy,
+as apppropriate.
\begin{code}
+mkGenTyConApp :: TyCon -> [Type] -> Type
+mkGenTyConApp tc tys
+ | isSynTyCon tc = mkSynTy tc tys
+ | otherwise = mkTyConApp tc tys
+
mkTyConApp :: TyCon -> [Type] -> Type
+-- Assumes TyCon is not a SynTyCon; use mkSynTy instead for those
mkTyConApp tycon tys
- | isFunTyCon tycon && length tys == 2
- = case tys of
- (ty1:ty2:_) -> FunTy ty1 ty2
+ | isFunTyCon tycon, [ty1,ty2] <- tys
+ = FunTy ty1 ty2
+
+ | isNewTyCon tycon, -- A saturated newtype application;
+ not (isRecursiveTyCon tycon), -- Not recursive (we don't use SourceTypes for them)
+ tys `lengthIs` tyConArity tycon -- use the SourceType form
+ = SourceTy (NType tycon tys)
| otherwise
= ASSERT(not (isSynTyCon tycon))
-- mean a distinct type, but all other type-constructor applications
-- including functions are returned as Just ..
-splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
-splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
-splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
-splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty
-splitTyConApp_maybe other = Nothing
-
--- splitAlgTyConApp_maybe looks for
--- *saturated* applications of *algebraic* data types
--- "Algebraic" => newtype, data type, or dictionary (not function types)
--- We return the constructors too, so there had better be some.
-
-splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
-splitAlgTyConApp_maybe (TyConApp tc tys)
- | isAlgTyCon tc &&
- tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
-splitAlgTyConApp_maybe (NoteTy (IPNote _) ty)
- = Nothing
-splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
-splitAlgTyConApp_maybe other = Nothing
-
-splitAlgTyConApp :: Type -> (TyCon, [Type], [DataCon])
- -- Here the "algebraic" property is an *assertion*
-splitAlgTyConApp (TyConApp tc tys) = ASSERT( isAlgTyCon tc && tyConArity tc == length tys )
- (tc, tys, tyConDataCons tc)
-splitAlgTyConApp (NoteTy _ ty) = splitAlgTyConApp ty
-#ifdef DEBUG
-splitAlgTyConApp ty = pprPanic "splitAlgTyConApp" (pprType ty)
-#endif
-\end{code}
-
-"Dictionary" types are just ordinary data types, but you can
-tell from the type constructor whether it's a dictionary or not.
-
-\begin{code}
-mkDictTy :: Class -> [Type] -> Type
-mkDictTy clas tys = TyConApp (classTyCon clas) tys
+tyConAppTyCon :: Type -> TyCon
+tyConAppTyCon ty = fst (splitTyConApp ty)
-mkDictTys :: ClassContext -> [Type]
-mkDictTys cxt = [mkDictTy cls tys | (cls,tys) <- cxt]
+tyConAppArgs :: Type -> [Type]
+tyConAppArgs ty = snd (splitTyConApp ty)
-mkPredTy :: PredType -> Type
-mkPredTy (Class clas tys) = TyConApp (classTyCon clas) tys
-mkPredTy (IParam n ty) = NoteTy (IPNote n) ty
+splitTyConApp :: Type -> (TyCon, [Type])
+splitTyConApp ty = case splitTyConApp_maybe ty of
+ Just stuff -> stuff
+ Nothing -> pprPanic "splitTyConApp" (pprType ty)
-splitPredTy_maybe :: Type -> Maybe PredType
-splitPredTy_maybe (TyConApp tc tys)
- | maybeToBool maybe_class
- && tyConArity tc == length tys = Just (Class clas tys)
- where
- maybe_class = tyConClass_maybe tc
- Just clas = maybe_class
-
-splitPredTy_maybe (NoteTy (IPNote n) ty)
- = Just (IParam n ty)
-splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
-splitPredTy_maybe other = Nothing
-
-splitDictTy_maybe :: Type -> Maybe (Class, [Type])
-splitDictTy_maybe ty
- = case splitPredTy_maybe ty of
- Just p -> getClassTys_maybe p
- Nothing -> Nothing
-
-isDictTy :: Type -> Bool
- -- This version is slightly more efficient than (maybeToBool . splitDictTy)
-isDictTy (TyConApp tc tys)
- | maybeToBool (tyConClass_maybe tc)
- && tyConArity tc == length tys
- = True
-isDictTy (NoteTy _ ty) = isDictTy ty
-isDictTy other = False
+splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
+splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
+splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
+splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty
+splitTyConApp_maybe (SourceTy p) = splitTyConApp_maybe (sourceTypeRep p)
+splitTyConApp_maybe other = Nothing
\end{code}
+
---------------------------------------------------------------------
SynTy
~~~~~
\begin{code}
-mkSynTy syn_tycon tys
- = ASSERT( isSynTyCon syn_tycon )
- ASSERT( isNotUsgTy body )
- ASSERT( length tyvars == length tys )
- NoteTy (SynNote (TyConApp syn_tycon tys))
- (substTy (mkTyVarSubst tyvars tys) body)
+mkSynTy tycon tys
+ | n_args == arity -- Exactly saturated
+ = mk_syn tys
+ | n_args > arity -- Over-saturated
+ = case splitAt arity tys of { (as,bs) -> mkAppTys (mk_syn as) bs }
+ -- Its important to use mkAppTys, rather than (foldl AppTy),
+ -- because (mk_syn as) might well return a partially-applied
+ -- type constructor; indeed, usually will!
+ | otherwise -- Un-saturated
+ = TyConApp tycon tys
+ -- For the un-saturated case we build TyConApp directly
+ -- (mkTyConApp ASSERTs that the tc isn't a SynTyCon).
+ -- Here we are relying on checkValidType to find
+ -- the error. What we can't do is use mkSynTy with
+ -- too few arg tys, because that is utterly bogus.
+
where
- (tyvars, body) = getSynTyConDefn syn_tycon
-
-isSynTy (NoteTy (SynNote _) _) = True
-isSynTy other = False
-
-deNoteType :: Type -> Type
- -- Sorry for the cute name
-deNoteType ty@(TyVarTy tyvar) = ty
-deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
-deNoteType (NoteTy _ ty) = deNoteType ty
-deNoteType (AppTy fun arg) = AppTy (deNoteType fun) (deNoteType arg)
-deNoteType (FunTy fun arg) = FunTy (deNoteType fun) (deNoteType arg)
-deNoteType (ForAllTy tv ty) = ForAllTy tv (deNoteType ty)
+ mk_syn tys = NoteTy (SynNote (TyConApp tycon tys))
+ (substTyWith tyvars tys body)
+
+ (tyvars, body) = ASSERT( isSynTyCon tycon ) getSynTyConDefn tycon
+ arity = tyConArity tycon
+ n_args = length tys
\end{code}
Notes on type synonyms
Representation types
~~~~~~~~~~~~~~~~~~~~
-
repType looks through
(a) for-alls, and
- (b) newtypes
- (c) synonyms
-It's useful in the back end where we're not
-interested in newtypes anymore.
+ (b) synonyms
+ (c) predicates
+ (d) usage annotations
+ (e) [recursive] newtypes
+It's useful in the back end.
+
+Remember, non-recursive newtypes get expanded as part of the SourceTy case,
+but recursive ones are represented by TyConApps and have to be expanded
+by steam.
\begin{code}
repType :: Type -> Type
-repType (ForAllTy _ ty) = repType ty
-repType (NoteTy _ ty) = repType ty
-repType ty = case splitNewType_maybe ty of
- Just ty' -> repType ty' -- Still re-apply repType in case of for-all
- Nothing -> ty
-
-splitRepFunTys :: Type -> ([Type], Type)
--- Like splitFunTys, but looks through newtypes and for-alls
-splitRepFunTys ty = split [] (repType ty)
- where
- split args (FunTy arg res) = split (arg:args) (repType res)
- split args ty = (reverse args, ty)
+repType (ForAllTy _ ty) = repType ty
+repType (NoteTy _ ty) = repType ty
+repType (SourceTy p) = repType (sourceTypeRep p)
+repType (TyConApp tc tys) | isNewTyCon tc && tys `lengthIs` tyConArity tc
+ = repType (newTypeRep tc tys)
+repType ty = ty
+
typePrimRep :: Type -> PrimRep
typePrimRep ty = case repType ty of
FunTy _ _ -> PtrRep
AppTy _ _ -> PtrRep -- ??
TyVarTy _ -> PtrRep
-
-splitNewType_maybe :: Type -> Maybe Type
--- Find the representation of a newtype, if it is one
--- Looks through multiple levels of newtype, but does not look through for-alls
-splitNewType_maybe (NoteTy (IPNote _) ty)
- = Nothing
-splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
-splitNewType_maybe (TyConApp tc tys) = case newTyConRep tc of
- Just rep_ty -> ASSERT( length tys == tyConArity tc )
- -- The assert should hold because repType should
- -- only be applied to *types* (of kind *)
- Just (applyTys rep_ty tys)
- Nothing -> Nothing
-splitNewType_maybe other = Nothing
\end{code}
---------------------------------------------------------------------
- UsgNote
- ~~~~~~~
-
-NB: Invariant: if present, usage note is at the very top of the type.
-This should be carefully preserved.
-
-In some parts of the compiler, comments use the _Once Upon a
-Polymorphic Type_ (POPL'99) usage of "rho = generalised
-usage-annotated type; sigma = usage-annotated type; tau =
-usage-annotated type except on top"; unfortunately this conflicts with
-the rho/tau/theta/sigma usage in the rest of the compiler. (KSW
-1999-07)
-
-\begin{code}
-mkUsgTy :: UsageAnn -> Type -> Type
-#ifndef USMANY
-mkUsgTy UsMany ty = ASSERT2( isNotUsgTy ty, pprType ty )
- ty
-#endif
-mkUsgTy usg ty = ASSERT2( isNotUsgTy ty, pprType ty )
- NoteTy (UsgNote usg) ty
-
--- The isUsgTy function is utterly useless if UsManys are omitted.
--- Be warned! KSW 1999-04.
-isUsgTy :: Type -> Bool
-#ifndef USMANY
-isUsgTy _ = True
-#else
-isUsgTy (NoteTy (UsgForAll _) ty) = isUsgTy ty
-isUsgTy (NoteTy (UsgNote _) _ ) = True
-isUsgTy other = False
-#endif
-
--- The isNotUsgTy function may return a false True if UsManys are omitted;
--- in other words, A SSERT( isNotUsgTy ty ) may be useful but
--- A SSERT( not (isNotUsg ty) ) is asking for trouble. KSW 1999-04.
-isNotUsgTy :: Type -> Bool
-isNotUsgTy (NoteTy (UsgForAll _) _) = False
-isNotUsgTy (NoteTy (UsgNote _) _) = False
-isNotUsgTy other = True
-
--- splitUsgTy_maybe is not exported, since it is meaningless if
--- UsManys are omitted. It is used in several places in this module,
--- however. KSW 1999-04.
-splitUsgTy_maybe :: Type -> Maybe (UsageAnn,Type)
-splitUsgTy_maybe (NoteTy (UsgNote usg) ty2) = ASSERT( isNotUsgTy ty2 )
- Just (usg,ty2)
-splitUsgTy_maybe ty@(NoteTy (UsgForAll _) _) = pprPanic "splitUsgTy_maybe:" $ pprType ty
-splitUsgTy_maybe ty = Nothing
-
-splitUsgTy :: Type -> (UsageAnn,Type)
-splitUsgTy ty = case splitUsgTy_maybe ty of
- Just ans -> ans
- Nothing ->
-#ifndef USMANY
- (UsMany,ty)
-#else
- pprPanic "splitUsgTy: no usage annot:" $ pprType ty
-#endif
-
-tyUsg :: Type -> UsageAnn
-tyUsg = fst . splitUsgTy
-
-unUsgTy :: Type -> Type
--- strip outer usage annotation if present
-unUsgTy ty = case splitUsgTy_maybe ty of
- Just (_,ty1) -> ASSERT2( isNotUsgTy ty1, pprType ty )
- ty1
- Nothing -> ty
-
-mkUsForAllTy :: UVar -> Type -> Type
-mkUsForAllTy uv ty = NoteTy (UsgForAll uv) ty
-
-mkUsForAllTys :: [UVar] -> Type -> Type
-mkUsForAllTys uvs ty = foldr (NoteTy . UsgForAll) ty uvs
-
-splitUsForAllTys :: Type -> ([UVar],Type)
-splitUsForAllTys ty = split ty []
- where split (NoteTy (UsgForAll u) ty) uvs = split ty (u:uvs)
- split other_ty uvs = (reverse uvs, other_ty)
-
-substUsTy :: VarEnv UsageAnn -> Type -> Type
--- assumes range is fresh uvars, so no conflicts
-substUsTy ve (NoteTy note@(UsgNote (UsVar u))
- ty ) = NoteTy (case lookupVarEnv ve u of
- Just ua -> UsgNote ua
- Nothing -> note)
- (substUsTy ve ty)
-substUsTy ve (NoteTy note@(UsgNote _) ty ) = NoteTy note (substUsTy ve ty)
-substUsTy ve (NoteTy note@(UsgForAll _) ty ) = NoteTy note (substUsTy ve ty)
-substUsTy ve (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1))
- (substUsTy ve ty2)
-substUsTy ve (NoteTy note@(FTVNote _) ty ) = NoteTy note (substUsTy ve ty)
-substUsTy ve ty@(TyVarTy _ ) = ty
-substUsTy ve (AppTy ty1 ty2) = AppTy (substUsTy ve ty1)
- (substUsTy ve ty2)
-substUsTy ve (FunTy ty1 ty2) = FunTy (substUsTy ve ty1)
- (substUsTy ve ty2)
-substUsTy ve (TyConApp tyc tys) = TyConApp tyc (map (substUsTy ve) tys)
-substUsTy ve (ForAllTy yv ty ) = ForAllTy yv (substUsTy ve ty)
-\end{code}
-
-
----------------------------------------------------------------------
ForAllTy
~~~~~~~~
-We need to be clever here with usage annotations; they need to be
-lifted or lowered through the forall as appropriate.
-
\begin{code}
mkForAllTy :: TyVar -> Type -> Type
-mkForAllTy tyvar ty = case splitUsgTy_maybe ty of
- Just (usg,ty') -> NoteTy (UsgNote usg)
- (ForAllTy tyvar ty')
- Nothing -> ForAllTy tyvar ty
+mkForAllTy tyvar ty
+ = mkForAllTys [tyvar] ty
mkForAllTys :: [TyVar] -> Type -> Type
-mkForAllTys tyvars ty = case splitUsgTy_maybe ty of
- Just (usg,ty') -> NoteTy (UsgNote usg)
- (foldr ForAllTy ty' tyvars)
- Nothing -> foldr ForAllTy ty tyvars
+mkForAllTys tyvars ty = foldr ForAllTy ty tyvars
+
+isForAllTy :: Type -> Bool
+isForAllTy (NoteTy _ ty) = isForAllTy ty
+isForAllTy (ForAllTy _ _) = True
+isForAllTy other_ty = False
splitForAllTy_maybe :: Type -> Maybe (TyVar, Type)
-splitForAllTy_maybe ty = case splitUsgTy_maybe ty of
- Just (usg,ty') -> do (tyvar,ty'') <- splitFAT_m ty'
- return (tyvar, NoteTy (UsgNote usg) ty'')
- Nothing -> splitFAT_m ty
+splitForAllTy_maybe ty = splitFAT_m ty
where
- splitFAT_m (NoteTy (IPNote _) ty) = Nothing
splitFAT_m (NoteTy _ ty) = splitFAT_m ty
+ splitFAT_m (SourceTy p) = splitFAT_m (sourceTypeRep p)
splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
splitFAT_m _ = Nothing
splitForAllTys :: Type -> ([TyVar], Type)
-splitForAllTys ty = case splitUsgTy_maybe ty of
- Just (usg,ty') -> let (tvs,ty'') = split ty' ty' []
- in (tvs, NoteTy (UsgNote usg) ty'')
- Nothing -> split ty ty []
+splitForAllTys ty = split ty ty []
where
split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
- split orig_ty (NoteTy (IPNote _) ty) tvs = (reverse tvs, orig_ty)
split orig_ty (NoteTy _ ty) tvs = split orig_ty ty tvs
+ split orig_ty (SourceTy p) tvs = split orig_ty (sourceTypeRep p) tvs
split orig_ty t tvs = (reverse tvs, orig_ty)
+
+dropForAlls :: Type -> Type
+dropForAlls ty = snd (splitForAllTys ty)
\end{code}
-- (mkPiType now in CoreUtils)
-Applying a for-all to its arguments
+Applying a for-all to its arguments. Lift usage annotation as required.
\begin{code}
applyTy :: Type -> Type -> Type
-applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
-applyTy (NoteTy note@(UsgForAll _) fun) arg = NoteTy note (applyTy fun arg)
-applyTy (NoteTy _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = ASSERT( isNotUsgTy arg )
- substTy (mkTyVarSubst [tv] [arg]) ty
-applyTy other arg = panic "applyTy"
+applyTy (SourceTy p) arg = applyTy (sourceTypeRep p) arg
+applyTy (NoteTy _ fun) arg = applyTy fun arg
+applyTy (ForAllTy tv ty) arg = substTyWith [tv] [arg] ty
+applyTy other arg = panic "applyTy"
applyTys :: Type -> [Type] -> Type
-applyTys fun_ty arg_tys
- = substTy (mkTyVarSubst tvs arg_tys) ty
+applyTys orig_fun_ty arg_tys
+ = substTyWith tvs arg_tys ty
where
- (tvs, ty) = split fun_ty arg_tys
+ (tvs, ty) = split orig_fun_ty arg_tys
split fun_ty [] = ([], fun_ty)
- split (NoteTy note@(UsgNote _) fun_ty)
- args = case split fun_ty args of
- (tvs, ty) -> (tvs, NoteTy note ty)
- split (NoteTy note@(UsgForAll _) fun_ty)
- args = case split fun_ty args of
- (tvs, ty) -> (tvs, NoteTy note ty)
split (NoteTy _ fun_ty) args = split fun_ty args
- split (ForAllTy tv fun_ty) (arg:args) = ASSERT2( isNotUsgTy arg, vcat (map pprType arg_tys) $$
- text "in application of" <+> pprType fun_ty)
- case split fun_ty args of
+ split (SourceTy p) args = split (sourceTypeRep p) args
+ split (ForAllTy tv fun_ty) (arg:args) = case split fun_ty args of
(tvs, ty) -> (tv:tvs, ty)
split other_ty args = panic "applyTys"
-\end{code}
-
-Note that we allow applications to be of usage-annotated- types, as an
-extension: we handle them by lifting the annotation outside. The
-argument, however, must still be unannotated.
-
-\begin{code}
-hoistForAllTys :: Type -> Type
- -- Move all the foralls to the top
- -- e.g. T -> forall a. a ==> forall a. T -> a
-hoistForAllTys ty
- = case hoist ty of { (tvs, body) -> mkForAllTys tvs body }
- where
- hoist :: Type -> ([TyVar], Type)
- hoist ty = case splitFunTys ty of { (args, res) ->
- case splitForAllTys res of {
- ([], body) -> ([], ty) ;
- (tvs1, body1) -> case hoist body1 of { (tvs2,body2) ->
- (tvs1 ++ tvs2, mkFunTys args body2)
- }}}
+ -- No show instance for Type yet
\end{code}
%************************************************************************
%* *
-\subsection{Stuff to do with the source-language types}
-
-PredType and ThetaType are used in types for expressions and bindings.
-ClassPred and ClassContext are used in class and instance declarations.
+\subsection{Source types}
%* *
%************************************************************************
-\begin{code}
-data PredType = Class Class [Type]
- | IParam Name Type
- deriving( Eq, Ord )
-
-type ThetaType = [PredType]
-type RhoType = Type
-type TauType = Type
-type SigmaType = Type
-\end{code}
-
-\begin{code}
-instance Outputable PredType where
- ppr = pprPred
-\end{code}
-
-\begin{code}
-mkClassPred clas tys = Class clas tys
-
-getClassTys_maybe :: PredType -> Maybe ClassPred
-getClassTys_maybe (Class clas tys) = Just (clas, tys)
-getClassTys_maybe _ = Nothing
+A "source type" is a type that is a separate type as far as the type checker is
+concerned, but which has low-level representation as far as the back end is concerned.
-ipName_maybe :: PredType -> Maybe Name
-ipName_maybe (IParam n _) = Just n
-ipName_maybe _ = Nothing
+Source types are always lifted.
-classesToPreds cts = map (uncurry Class) cts
-
-classesOfPreds theta = concatMap cvt theta
- where cvt (Class clas tys) = [(clas, tys)]
- cvt (IParam _ _ ) = []
-\end{code}
-
-@isTauTy@ tests for nested for-alls.
+The key function is sourceTypeRep which gives the representation of a source type:
\begin{code}
-isTauTy :: Type -> Bool
-isTauTy (TyVarTy v) = True
-isTauTy (TyConApp _ tys) = all isTauTy tys
-isTauTy (AppTy a b) = isTauTy a && isTauTy b
-isTauTy (FunTy a b) = isTauTy a && isTauTy b
-isTauTy (NoteTy (IPNote _) ty) = False
-isTauTy (NoteTy _ ty) = isTauTy ty
-isTauTy other = False
-\end{code}
+mkPredTy :: PredType -> Type
+mkPredTy pred = SourceTy pred
-\begin{code}
-mkRhoTy :: [PredType] -> Type -> Type
-mkRhoTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
+mkPredTys :: ThetaType -> [Type]
+mkPredTys preds = map SourceTy preds
-splitRhoTy :: Type -> ([PredType], Type)
-splitRhoTy ty = split ty ty []
- where
- split orig_ty (FunTy arg res) ts = case splitPredTy_maybe arg of
- Just p -> split res res (p:ts)
- Nothing -> (reverse ts, orig_ty)
- split orig_ty (NoteTy (IPNote _) ty) ts = (reverse ts, orig_ty)
- split orig_ty (NoteTy _ ty) ts = split orig_ty ty ts
- split orig_ty ty ts = (reverse ts, orig_ty)
-\end{code}
+sourceTypeRep :: SourceType -> Type
+-- Convert a predicate to its "representation type";
+-- the type of evidence for that predicate, which is actually passed at runtime
+sourceTypeRep (IParam _ ty) = ty
+sourceTypeRep (ClassP clas tys) = mkTyConApp (classTyCon clas) tys
+ -- Note the mkTyConApp; the classTyCon might be a newtype!
+sourceTypeRep (NType tc tys) = newTypeRep tc tys
+ -- ToDo: Consider caching this substitution in a NType
+isSourceTy :: Type -> Bool
+isSourceTy (NoteTy _ ty) = isSourceTy ty
+isSourceTy (SourceTy sty) = True
+isSourceTy _ = False
-\begin{code}
-mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
-
-isSigmaTy :: Type -> Bool
-isSigmaTy (FunTy a b) = isPredTy a
- where isPredTy (NoteTy (IPNote _) _) = True
- -- JRL could be a dict ty, but that would be polymorphic,
- -- and thus there would have been an outer ForAllTy
- isPredTy _ = False
-isSigmaTy (NoteTy (IPNote _) _) = False
-isSigmaTy (NoteTy _ ty) = isSigmaTy ty
-isSigmaTy (ForAllTy tyvar ty) = True
-isSigmaTy _ = False
-
-splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
-splitSigmaTy ty =
- (tyvars, theta, tau)
- where
- (tyvars,rho) = splitForAllTys ty
- (theta,tau) = splitRhoTy rho
+splitNewType_maybe :: Type -> Maybe Type
+-- Newtypes that are recursive are reprsented by TyConApp, just
+-- as they always were. Occasionally we want to find their representation type.
+-- NB: remember that in this module, non-recursive newtypes are transparent
+
+splitNewType_maybe ty
+ = case splitTyConApp_maybe ty of
+ Just (tc,tys) | isNewTyCon tc -> ASSERT( tys `lengthIs` tyConArity tc )
+ -- The assert should hold because repType should
+ -- only be applied to *types* (of kind *)
+ Just (newTypeRep tc tys)
+ other -> Nothing
+
+-- A local helper function (not exported)
+newTypeRep new_tycon tys = case newTyConRep new_tycon of
+ (tvs, rep_ty) -> substTyWith tvs tys rep_ty
\end{code}
typeKind (TyVarTy tyvar) = tyVarKind tyvar
typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
typeKind (NoteTy _ ty) = typeKind ty
+typeKind (SourceTy _) = liftedTypeKind -- Predicates are always
+ -- represented by lifted types
typeKind (AppTy fun arg) = funResultTy (typeKind fun)
-typeKind (FunTy arg res) = boxedTypeKind -- A function is boxed regardless of its result type
- -- No functions at the type level, hence we don't need
- -- to say (typeKind res).
+typeKind (FunTy arg res) = fix_up (typeKind res)
+ where
+ fix_up (TyConApp tycon _) | tycon == typeCon
+ || tycon == openKindCon = liftedTypeKind
+ fix_up (NoteTy _ kind) = fix_up kind
+ fix_up kind = kind
+ -- The basic story is
+ -- typeKind (FunTy arg res) = typeKind res
+ -- But a function is lifted regardless of its result type
+ -- Hence the strange fix-up.
+ -- Note that 'res', being the result of a FunTy, can't have
+ -- a strange kind like (*->*).
typeKind (ForAllTy tv ty) = typeKind ty
\end{code}
~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
tyVarsOfType :: Type -> TyVarSet
-
tyVarsOfType (TyVarTy tv) = unitVarSet tv
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
-tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
-tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty
-tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty
-tyVarsOfType (NoteTy (IPNote _) ty) = tyVarsOfType ty
+tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty2 -- See note [Syn] below
+tyVarsOfType (SourceTy sty) = tyVarsOfSourceType sty
tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
+-- Note [Syn]
+-- Consider
+-- type T a = Int
+-- What are the free tyvars of (T x)? Empty, of course!
+-- Here's the example that Ralf Laemmel showed me:
+-- foo :: (forall a. C u a -> C u a) -> u
+-- mappend :: Monoid u => u -> u -> u
+--
+-- bar :: Monoid u => u
+-- bar = foo (\t -> t `mappend` t)
+-- We have to generalise at the arg to f, and we don't
+-- want to capture the constraint (Monad (C u a)) because
+-- it appears to mention a. Pretty silly, but it was useful to him.
+
+
tyVarsOfTypes :: [Type] -> TyVarSet
tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
tyVarsOfPred :: PredType -> TyVarSet
-tyVarsOfPred (Class clas tys) = tyVarsOfTypes tys
-tyVarsOfPred (IParam n ty) = tyVarsOfType ty
+tyVarsOfPred = tyVarsOfSourceType -- Just a subtype
+
+tyVarsOfSourceType :: SourceType -> TyVarSet
+tyVarsOfSourceType (IParam _ ty) = tyVarsOfType ty
+tyVarsOfSourceType (ClassP _ tys) = tyVarsOfTypes tys
+tyVarsOfSourceType (NType _ tys) = tyVarsOfTypes tys
tyVarsOfTheta :: ThetaType -> TyVarSet
-tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet
+tyVarsOfTheta = foldr (unionVarSet . tyVarsOfSourceType) emptyVarSet
-- Add a Note with the free tyvars to the top of the type
--- (but under a usage if there is one)
addFreeTyVars :: Type -> Type
-addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
-addFreeTyVars (NoteTy note@(UsgForAll _) ty) = NoteTy note (addFreeTyVars ty)
addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
-
--- Find the free names of a type, including the type constructors and classes it mentions
-namesOfType :: Type -> NameSet
-namesOfType (TyVarTy tv) = unitNameSet (getName tv)
-namesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets`
- namesOfTypes tys
-namesOfType (NoteTy (SynNote ty1) ty2) = namesOfType ty1
-namesOfType (NoteTy other_note ty2) = namesOfType ty2
-namesOfType (FunTy arg res) = namesOfType arg `unionNameSets` namesOfType res
-namesOfType (AppTy fun arg) = namesOfType fun `unionNameSets` namesOfType arg
-namesOfType (ForAllTy tyvar ty) = namesOfType ty `minusNameSet` unitNameSet (getName tyvar)
-
-namesOfTypes tys = foldr (unionNameSets . namesOfType) emptyNameSet tys
\end{code}
-
%************************************************************************
%* *
\subsection{TidyType}
It doesn't change the uniques at all, just the print names.
\begin{code}
-tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
-tidyTyVar env@(tidy_env, subst) tyvar
- = case lookupVarEnv subst tyvar of
-
- Just tyvar' -> -- Already substituted
- (env, tyvar')
-
- Nothing -> -- Make a new nice name for it
-
- case tidyOccName tidy_env (getOccName name) of
- (tidy', occ') -> -- New occname reqd
- ((tidy', subst'), tyvar')
- where
- subst' = extendVarEnv subst tyvar tyvar'
- tyvar' = setTyVarName tyvar name'
- name' = mkLocalName (getUnique name) occ' noSrcLoc
- -- Note: make a *user* tyvar, so it printes nicely
- -- Could extract src loc, but no need.
+tidyTyVarBndr :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+tidyTyVarBndr (tidy_env, subst) tyvar
+ = case tidyOccName tidy_env (getOccName name) of
+ (tidy', occ') -> -- New occname reqd
+ ((tidy', subst'), tyvar')
+ where
+ subst' = extendVarEnv subst tyvar tyvar'
+ tyvar' = setTyVarName tyvar name'
+ name' = mkInternalName (getUnique name) occ' noSrcLoc
+ -- Note: make a *user* tyvar, so it printes nicely
+ -- Could extract src loc, but no need.
where
name = tyVarName tyvar
-tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
+tidyFreeTyVars :: TidyEnv -> TyVarSet -> TidyEnv
+-- Add the free tyvars to the env in tidy form,
+-- so that we can tidy the type they are free in
+tidyFreeTyVars env tyvars = fst (tidyOpenTyVars env (varSetElems tyvars))
+
+tidyOpenTyVars :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar])
+tidyOpenTyVars env tyvars = mapAccumL tidyOpenTyVar env tyvars
+
+tidyOpenTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+-- Treat a new tyvar as a binder, and give it a fresh tidy name
+tidyOpenTyVar env@(tidy_env, subst) tyvar
+ = case lookupVarEnv subst tyvar of
+ Just tyvar' -> (env, tyvar') -- Already substituted
+ Nothing -> tidyTyVarBndr env tyvar -- Treat it as a binder
tidyType :: TidyEnv -> Type -> Type
tidyType env@(tidy_env, subst) ty
Just tv' -> TyVarTy tv'
go (TyConApp tycon tys) = let args = map go tys
in args `seqList` TyConApp tycon args
- go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
- go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
- go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
- go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
+ go (NoteTy note ty) = (NoteTy $! (go_note note)) $! (go ty)
+ go (SourceTy sty) = SourceTy (tidySourceType env sty)
+ go (AppTy fun arg) = (AppTy $! (go fun)) $! (go arg)
+ go (FunTy fun arg) = (FunTy $! (go fun)) $! (go arg)
+ go (ForAllTy tv ty) = ForAllTy tvp $! (tidyType envp ty)
where
- (envp, tvp) = tidyTyVar env tv
+ (envp, tvp) = tidyTyVarBndr env tv
- go_note (SynNote ty) = SynNote SAPPLY (go ty)
+ go_note (SynNote ty) = SynNote $! (go ty)
go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
- go_note note@(UsgNote _) = note -- Usage annotation is already tidy
- go_note note@(UsgForAll _) = note -- Uvar binder is already tidy
- go_note (IPNote n) = IPNote (tidyIPName n)
-tidyTypes env tys = map (tidyType env) tys
+tidyTypes env tys = map (tidyType env) tys
+
+tidyPred :: TidyEnv -> SourceType -> SourceType
+tidyPred = tidySourceType
+
+tidySourceType :: TidyEnv -> SourceType -> SourceType
+tidySourceType env (IParam n ty) = IParam n (tidyType env ty)
+tidySourceType env (ClassP clas tys) = ClassP clas (tidyTypes env tys)
+tidySourceType env (NType tc tys) = NType tc (tidyTypes env tys)
\end{code}
tidyOpenType env ty
= (env', tidyType env' ty)
where
- env' = foldl go env (varSetElems (tyVarsOfType ty))
- go env tyvar = fst (tidyTyVar env tyvar)
+ env' = tidyFreeTyVars env (tyVarsOfType ty)
tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
-\begin{code}
-tidyIPName :: Name -> Name
-tidyIPName name
- = mkLocalName (getUnique name) (getOccName name) noSrcLoc
-\end{code}
%************************************************************************
%* *
-\subsection{Boxedness and liftedness}
+\subsection{Liftedness}
%* *
%************************************************************************
\begin{code}
-isUnboxedType :: Type -> Bool
-isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
-
isUnLiftedType :: Type -> Bool
-- isUnLiftedType returns True for forall'd unlifted types:
-- x :: forall a. Int#
isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
-isUnLiftedType other = False
+isUnLiftedType (SourceTy _) = False -- All source types are lifted
+isUnLiftedType other = False
isUnboxedTupleType :: Type -> Bool
isUnboxedTupleType ty = case splitTyConApp_maybe ty of
-- Should only be applied to *types*; hence the assert
isAlgType :: Type -> Bool
isAlgType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc )
isAlgTyCon tc
other -> False
+\end{code}
--- Should only be applied to *types*; hence the assert
-isDataType :: Type -> Bool
-isDataType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
- isDataTyCon tc
- other -> False
+@isStrictType@ computes whether an argument (or let RHS) should
+be computed strictly or lazily, based only on its type.
+Works just like isUnLiftedType, except that it has a special case
+for dictionaries. Since it takes account of ClassP, you might think
+this function should be in TcType, but isStrictType is used by DataCon,
+which is below TcType in the hierarchy, so it's convenient to put it here.
-isNewType :: Type -> Bool
-isNewType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
- isNewTyCon tc
+\begin{code}
+isStrictType (ForAllTy tv ty) = isStrictType ty
+isStrictType (NoteTy _ ty) = isStrictType ty
+isStrictType (TyConApp tc _) = isUnLiftedTyCon tc
+isStrictType (SourceTy (ClassP clas _)) = opt_DictsStrict && not (isNewTyCon (classTyCon clas))
+ -- We may be strict in dictionary types, but only if it
+ -- has more than one component.
+ -- [Being strict in a single-component dictionary risks
+ -- poking the dictionary component, which is wrong.]
+isStrictType other = False
+\end{code}
+
+\begin{code}
+isPrimitiveType :: Type -> Bool
+-- Returns types that are opaque to Haskell.
+-- Most of these are unlifted, but now that we interact with .NET, we
+-- may have primtive (foreign-imported) types that are lifted
+isPrimitiveType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc )
+ isPrimTyCon tc
other -> False
\end{code}
seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
seqType (NoteTy note t2) = seqNote note `seq` seqType t2
+seqType (SourceTy p) = seqPred p
seqType (TyConApp tc tys) = tc `seq` seqTypes tys
seqType (ForAllTy tv ty) = tv `seq` seqType ty
seqNote :: TyNote -> ()
seqNote (SynNote ty) = seqType ty
seqNote (FTVNote set) = sizeUniqSet set `seq` ()
-seqNote (UsgNote usg) = usg `seq` ()
-seqNote (IPNote nm) = nm `seq` ()
+
+seqPred :: SourceType -> ()
+seqPred (ClassP c tys) = c `seq` seqTypes tys
+seqPred (NType tc tys) = tc `seq` seqTypes tys
+seqPred (IParam n ty) = n `seq` seqType ty
\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Equality on types}
+%* *
+%************************************************************************
+
+Comparison; don't use instances so that we know where it happens.
+Look through newtypes but not usage types.
+
+Note that eqType can respond 'False' for partial applications of newtypes.
+Consider
+ newtype Parser m a = MkParser (Foogle m a)
+
+Does
+ Monad (Parser m) `eqType` Monad (Foogle m)
+
+Well, yes, but eqType won't see that they are the same.
+I don't think this is harmful, but it's soemthing to watch out for.
+
+\begin{code}
+eqType t1 t2 = eq_ty emptyVarEnv t1 t2
+eqKind = eqType -- No worries about looking
+
+-- Look through Notes
+eq_ty env (NoteTy _ t1) t2 = eq_ty env t1 t2
+eq_ty env t1 (NoteTy _ t2) = eq_ty env t1 t2
+
+-- Look through SourceTy. This is where the looping danger comes from
+eq_ty env (SourceTy sty1) t2 = eq_ty env (sourceTypeRep sty1) t2
+eq_ty env t1 (SourceTy sty2) = eq_ty env t1 (sourceTypeRep sty2)
+
+-- The rest is plain sailing
+eq_ty env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of
+ Just tv1a -> tv1a == tv2
+ Nothing -> tv1 == tv2
+eq_ty env (ForAllTy tv1 t1) (ForAllTy tv2 t2)
+ | tv1 == tv2 = eq_ty (delVarEnv env tv1) t1 t2
+ | otherwise = eq_ty (extendVarEnv env tv1 tv2) t1 t2
+eq_ty env (AppTy s1 t1) (AppTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2)
+eq_ty env (FunTy s1 t1) (FunTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2)
+eq_ty env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 == tc2) && (eq_tys env tys1 tys2)
+eq_ty env t1 t2 = False
+
+eq_tys env [] [] = True
+eq_tys env (t1:tys1) (t2:tys2) = (eq_ty env t1 t2) && (eq_tys env tys1 tys2)
+eq_tys env tys1 tys2 = False
+\end{code}
+
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