-\begin{code}
-#include "HsVersions.h"
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+\begin{code}
module Type (
- GenType(..), Type(..), TauType(..),
- mkTyVarTy, mkTyVarTys,
- getTyVar, getTyVar_maybe, isTyVarTy,
- mkAppTy, mkAppTys, splitAppTy,
- mkFunTy, mkFunTys, splitFunTy, getFunTy_maybe,
- mkTyConTy, getTyCon_maybe, applyTyCon,
- mkSynTy,
- mkForAllTy, mkForAllTys, getForAllTy_maybe, splitForAllTy,
- mkForAllUsageTy, getForAllUsageTy,
- applyTy,
-
- isPrimType, isUnboxedType, typePrimRep,
-
- RhoType(..), SigmaType(..), ThetaType(..),
- mkDictTy,
- mkRhoTy, splitRhoTy,
- mkSigmaTy, splitSigmaTy,
+ -- re-exports from TypeRep:
+ Type,
+ Kind, TyVarSubst,
- maybeAppTyCon, getAppTyCon,
- maybeAppDataTyCon, getAppDataTyCon,
- maybeBoxedPrimType,
+ superKind, superBoxity, -- :: SuperKind
- matchTy, matchTys, eqTy, eqSimpleTy, eqSimpleTheta,
+ boxedKind, -- :: Kind :: BX
+ anyBoxKind, -- :: Kind :: BX
+ typeCon, -- :: KindCon :: BX -> KX
+ anyBoxCon, -- :: KindCon :: BX
- instantiateTy, instantiateTauTy, instantiateUsage,
- applyTypeEnvToTy,
+ boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
- isTauTy,
+ mkArrowKind, mkArrowKinds, -- mentioned below: hasMoreBoxityInfo,
- tyVarsOfType, tyVarsOfTypes, getTypeKind
+ funTyCon,
+ -- exports from this module:
+ hasMoreBoxityInfo,
-) where
+ mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
-import Ubiq
-import IdLoop -- for paranoia checking
-import TyLoop -- for paranoia checking
-import PrelLoop -- for paranoia checking
+ mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
--- ToDo:rm
---import PprType ( pprGenType ) -- ToDo: rm
---import PprStyle ( PprStyle(..) )
---import Util ( pprPanic )
+ mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys, splitFunTysN,
+ funResultTy, funArgTy, zipFunTys,
--- friends:
-import Class ( getClassSig, getClassOpLocalType, GenClass{-instances-} )
-import Kind ( mkBoxedTypeKind, resultKind )
-import TyCon ( mkFunTyCon, mkTupleTyCon, isFunTyCon, isPrimTyCon, isDataTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn, TyCon )
-import TyVar ( getTyVarKind, GenTyVar{-instances-}, GenTyVarSet(..),
- emptyTyVarSet, unionTyVarSets, minusTyVarSet,
- unitTyVarSet, nullTyVarEnv, lookupTyVarEnv,
- addOneToTyVarEnv, TyVarEnv(..) )
-import Usage ( usageOmega, GenUsage, Usage(..), UVar(..), UVarEnv(..),
- nullUVarEnv, addOneToUVarEnv, lookupUVarEnv, eqUVar,
- eqUsage )
+ mkTyConApp, mkTyConTy, splitTyConApp_maybe,
+ splitAlgTyConApp_maybe, splitAlgTyConApp,
+ mkDictTy, splitDictTy_maybe, isDictTy,
--- others
-import PrimRep ( PrimRep(..) )
-import Util ( thenCmp, zipEqual, panic, panic#, assertPanic,
- Ord3(..){-instances-}
- )
-\end{code}
+ mkSynTy, isSynTy, deNoteType, repType, splitNewType_maybe,
-Data types
-~~~~~~~~~~
+ UsageAnn(..), mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
+ mkUsForAllTy, mkUsForAllTys, splitUsForAllTys, substUsTy,
-\begin{code}
-type Type = GenType TyVar UVar -- Used after typechecker
-
-data GenType tyvar uvar -- Parameterised over type and usage variables
- = TyVarTy tyvar
-
- | AppTy
- (GenType tyvar uvar)
- (GenType tyvar uvar)
-
- | TyConTy -- Constants of a specified kind
- TyCon
- (GenUsage uvar) -- Usage gives uvar of the full application,
- -- iff the full application is of kind Type
- -- c.f. the Usage field in TyVars
-
- | SynTy -- Synonyms must be saturated, and contain their expansion
- TyCon -- Must be a SynTyCon
- [GenType tyvar uvar]
- (GenType tyvar uvar) -- Expansion!
-
- | ForAllTy
- tyvar
- (GenType tyvar uvar) -- TypeKind
-
- | ForAllUsageTy
- uvar -- Quantify over this
- [uvar] -- Bounds; the quantified var must be
- -- less than or equal to all these
- (GenType tyvar uvar)
-
- -- Two special cases that save a *lot* of administrative
- -- overhead:
-
- | FunTy -- BoxedTypeKind
- (GenType tyvar uvar) -- Both args are of TypeKind
- (GenType tyvar uvar)
- (GenUsage uvar)
-
- | DictTy -- TypeKind
- Class -- Class
- (GenType tyvar uvar) -- Arg has kind TypeKind
- (GenUsage uvar)
-\end{code}
+ mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
+ isForAllTy, applyTy, applyTys, mkPiType,
-\begin{code}
-type RhoType = Type
-type TauType = Type
-type ThetaType = [(Class, Type)]
-type SigmaType = Type
-\end{code}
+ TauType, RhoType, SigmaType, ThetaType,
+ isTauTy,
+ mkRhoTy, splitRhoTy,
+ mkSigmaTy, splitSigmaTy,
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
+ typePrimRep,
-Expand abbreviations
-~~~~~~~~~~~~~~~~~~~~
-Removes just the top level of any abbreviations.
+ -- Free variables
+ tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
+ addFreeTyVars,
-\begin{code}
-expandTy :: Type -> Type -- Restricted to Type due to Dict expansion
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVar, tidyTyVars,
+ tidyTopType,
+
+ -- Seq
+ seqType, seqTypes
+
+ ) where
+
+#include "HsVersions.h"
+
+-- We import the representation and primitive functions from TypeRep.
+-- Many things are reexported, but not the representation!
+
+import TypeRep
+
+-- Other imports:
-expandTy (FunTy t1 t2 u) = AppTy (AppTy (TyConTy mkFunTyCon u) t1) t2
-expandTy (SynTy _ _ t) = expandTy t
-expandTy (DictTy clas ty u)
- = case all_arg_tys of
+import {-# SOURCE #-} DataCon( DataCon, dataConType )
+import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
+import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
- [arg_ty] -> expandTy arg_ty -- just the <whatever> itself
+-- friends:
+import Var ( TyVar, IdOrTyVar, UVar,
+ tyVarKind, tyVarName, setTyVarName, isId, idType,
+ )
+import VarEnv
+import VarSet
- -- The extra expandTy is to make sure that
- -- the result isn't still a dict, which it might be
- -- if the original guy was a dict with one superdict and
- -- no methods!
+import Name ( NamedThing(..), mkLocalName, tidyOccName,
+ )
+import NameSet
+import Class ( classTyCon, Class )
+import TyCon ( TyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
+ isFunTyCon, isDataTyCon, isNewTyCon,
+ isAlgTyCon, isSynTyCon, tyConArity,
+ tyConKind, tyConDataCons, getSynTyConDefn,
+ tyConPrimRep, tyConClass_maybe
+ )
- other -> ASSERT(not (null all_arg_tys))
- foldl AppTy (TyConTy (mkTupleTyCon (length all_arg_tys)) u) all_arg_tys
+-- others
+import SrcLoc ( noSrcLoc )
+import Maybes ( maybeToBool )
+import PrimRep ( PrimRep(..), isFollowableRep )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList )
+import Outputable
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Stuff to do with kinds.}
+%* *
+%************************************************************************
- -- A tuple of 'em
- -- Note: length of all_arg_tys can be 0 if the class is
- -- _CCallable, _CReturnable (and anything else
- -- *really weird* that the user writes).
+\begin{code}
+hasMoreBoxityInfo :: Kind -> Kind -> Bool
+hasMoreBoxityInfo k1 k2
+ | k2 == openTypeKind = ASSERT( is_type_kind k1) True
+ | otherwise = k1 == k2
where
- (tyvar, super_classes, ops) = getClassSig clas
- super_dict_tys = map mk_super_ty super_classes
- class_op_tys = map mk_op_ty ops
- all_arg_tys = super_dict_tys ++ class_op_tys
- mk_super_ty sc = DictTy sc ty usageOmega
- mk_op_ty op = instantiateTy [(tyvar,ty)] (getClassOpLocalType op)
-
-expandTy ty = ty
+ -- Returns true for things of form (Type x)
+ is_type_kind k = case splitTyConApp_maybe k of
+ Just (tc,[_]) -> tc == typeCon
+ Nothing -> False
\end{code}
-Simple construction and analysis functions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+%************************************************************************
+%* *
+\subsection{Constructor-specific functions}
+%* *
+%************************************************************************
+
+
+---------------------------------------------------------------------
+ TyVarTy
+ ~~~~~~~
\begin{code}
-mkTyVarTy :: t -> GenType t u
-mkTyVarTys :: [t] -> [GenType t y]
+mkTyVarTy :: TyVar -> Type
mkTyVarTy = TyVarTy
+
+mkTyVarTys :: [TyVar] -> [Type]
mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
-getTyVar :: String -> GenType t u -> t
-getTyVar msg (TyVarTy tv) = tv
-getTyVar msg (SynTy _ _ t) = getTyVar msg t
-getTyVar msg other = panic ("getTyVar: " ++ msg)
+getTyVar :: String -> Type -> TyVar
+getTyVar msg (TyVarTy tv) = tv
+getTyVar msg (NoteTy _ t) = getTyVar msg t
+getTyVar msg other = panic ("getTyVar: " ++ msg)
-getTyVar_maybe :: GenType t u -> Maybe t
-getTyVar_maybe (TyVarTy tv) = Just tv
-getTyVar_maybe (SynTy _ _ t) = getTyVar_maybe t
-getTyVar_maybe other = Nothing
+getTyVar_maybe :: Type -> Maybe TyVar
+getTyVar_maybe (TyVarTy tv) = Just tv
+getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
+getTyVar_maybe other = Nothing
-isTyVarTy :: GenType t u -> Bool
+isTyVarTy :: Type -> Bool
isTyVarTy (TyVarTy tv) = True
-isTyVarTy (SynTy _ _ t) = isTyVarTy t
-isTyVarTy other = False
+isTyVarTy (NoteTy _ ty) = isTyVarTy ty
+isTyVarTy other = False
\end{code}
-\begin{code}
-mkAppTy = AppTy
-mkAppTys :: GenType t u -> [GenType t u] -> GenType t u
-mkAppTys t ts = foldl AppTy t ts
+---------------------------------------------------------------------
+ AppTy
+ ~~~~~
+We need to be pretty careful with AppTy to make sure we obey the
+invariant that a TyConApp is always visibly so. mkAppTy maintains the
+invariant: use it.
-splitAppTy :: GenType t u -> (GenType t u, [GenType t u])
-splitAppTy t = go t []
+\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
+ where
+ mk_app (NoteTy _ ty1) = mk_app ty1
+ mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
+ mk_app ty1 = AppTy orig_ty1 orig_ty2
+
+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.
+ -- 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
where
- go (AppTy t arg) ts = go t (arg:ts)
- go (FunTy fun arg u) ts = (TyConTy mkFunTyCon u, fun:arg:ts)
- go (SynTy _ _ t) ts = go t ts
- go t ts = (t,ts)
+ 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
+
+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 :: Type -> (Type, Type)
+splitAppTy ty = case splitAppTy_maybe ty of
+ Just pr -> pr
+ Nothing -> panic "splitAppTy"
+
+splitAppTys :: Type -> (Type, [Type])
+splitAppTys ty = split ty ty []
+ 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 (FunTy ty1 ty2) args = ASSERT( null args )
+ (TyConApp funTyCon [], [ty1,ty2])
+ split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
+ split orig_ty ty args = (orig_ty, args)
\end{code}
+
+---------------------------------------------------------------------
+ FunTy
+ ~~~~~
+
\begin{code}
--- NB mkFunTy, mkFunTys puts in Omega usages, for now at least
-mkFunTy arg res = FunTy arg res usageOmega
+mkFunTy :: Type -> Type -> Type
+mkFunTy arg res = FunTy arg res
-mkFunTys :: [GenType t u] -> GenType t u -> GenType t u
-mkFunTys ts t = foldr (\ f a -> FunTy f a usageOmega) t ts
+mkFunTys :: [Type] -> Type -> Type
+mkFunTys tys ty = foldr FunTy ty tys
-getFunTy_maybe :: GenType t u -> Maybe (GenType t u, GenType t u)
-getFunTy_maybe (FunTy arg result _) = Just (arg,result)
-getFunTy_maybe (AppTy (AppTy (TyConTy tycon _) arg) res)
- | isFunTyCon tycon = Just (arg, res)
-getFunTy_maybe (SynTy _ _ t) = getFunTy_maybe t
-getFunTy_maybe other = Nothing
+splitFunTy_maybe :: Type -> Maybe (Type, Type)
+splitFunTy_maybe (FunTy arg res) = Just (arg, res)
+splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
+splitFunTy_maybe other = Nothing
-splitFunTy :: GenType t u -> ([GenType t u], GenType t u)
-splitFunTy t = go t []
+splitFunTys :: Type -> ([Type], Type)
+splitFunTys ty = split [] ty ty
where
- go (FunTy arg res _) ts = go res (arg:ts)
- go (AppTy (AppTy (TyConTy tycon _) arg) res) ts
- | isFunTyCon tycon
- = go res (arg:ts)
- go (SynTy _ _ t) ts
- = go t ts
- go t ts
- = (reverse ts, t)
+ split args orig_ty (FunTy arg res) = split (arg:args) res res
+ split args orig_ty (NoteTy _ ty) = split args orig_ty ty
+ 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 (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 ty = pprPanic "funResultTy" (pprType ty)
+
+funArgTy :: Type -> Type
+funArgTy (FunTy arg res) = arg
+funArgTy (NoteTy _ ty) = funArgTy ty
+funArgTy ty = pprPanic "funArgTy" (pprType ty)
\end{code}
+
+---------------------------------------------------------------------
+ TyConApp
+ ~~~~~~~~
+
\begin{code}
--- NB applyTyCon puts in usageOmega, for now at least
-mkTyConTy tycon = TyConTy tycon usageOmega
+mkTyConApp :: TyCon -> [Type] -> Type
+mkTyConApp tycon tys
+ | isFunTyCon tycon && length tys == 2
+ = case tys of
+ (ty1:ty2:_) -> FunTy ty1 ty2
+
+ | otherwise
+ = ASSERT(not (isSynTyCon tycon))
+ TyConApp tycon tys
+
+mkTyConTy :: TyCon -> Type
+mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) )
+ TyConApp tycon []
+
+-- splitTyConApp "looks through" synonyms, because they don't
+-- 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.
+
+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 _ 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
+\end{code}
+
+"Dictionary" types are just ordinary data types, but you can
+tell from the type constructor whether it's a dictionary or not.
-applyTyCon :: TyCon -> [GenType t u] -> GenType t u
-applyTyCon tycon tys = foldl AppTy (TyConTy tycon usageOmega) tys
+\begin{code}
+mkDictTy :: Class -> [Type] -> Type
+mkDictTy clas tys = TyConApp (classTyCon clas) tys
-getTyCon_maybe :: GenType t u -> Maybe TyCon
-getTyCon_maybe (TyConTy tycon _) = Just tycon
-getTyCon_maybe (SynTy _ _ t) = getTyCon_maybe t
-getTyCon_maybe other_ty = Nothing
+splitDictTy_maybe :: Type -> Maybe (Class, [Type])
+splitDictTy_maybe (TyConApp tc tys)
+ | maybeToBool maybe_class
+ && tyConArity tc == length tys = Just (clas, tys)
+ where
+ maybe_class = tyConClass_maybe tc
+ Just clas = maybe_class
+
+splitDictTy_maybe (NoteTy _ ty) = splitDictTy_maybe ty
+splitDictTy_maybe other = 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
\end{code}
+---------------------------------------------------------------------
+ SynTy
+ ~~~~~
+
\begin{code}
mkSynTy syn_tycon tys
- = SynTy syn_tycon tys (instantiateTauTy (zipEqual tyvars tys) body)
+ = ASSERT( isSynTyCon syn_tycon )
+ ASSERT( isNotUsgTy body )
+ ASSERT( length tyvars == length tys )
+ NoteTy (SynNote (TyConApp syn_tycon tys))
+ (substTy (mkTyVarSubst tyvars tys) body)
where
(tyvars, body) = getSynTyConDefn syn_tycon
-\end{code}
-Tau stuff
-~~~~~~~~~
-\begin{code}
-isTauTy :: GenType t u -> Bool
-isTauTy (TyVarTy v) = True
-isTauTy (TyConTy _ _) = True
-isTauTy (AppTy a b) = isTauTy a && isTauTy b
-isTauTy (FunTy a b _) = isTauTy a && isTauTy b
-isTauTy (SynTy _ _ ty) = isTauTy ty
-isTauTy other = False
+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)
\end{code}
-Rho stuff
-~~~~~~~~~
-NB mkRhoTy and mkDictTy put in usageOmega, for now at least
+Notes on type synonyms
+~~~~~~~~~~~~~~~~~~~~~~
+The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
+to return type synonyms whereever possible. Thus
-\begin{code}
-mkDictTy :: Class -> GenType t u -> GenType t u
-mkDictTy clas ty = DictTy clas ty usageOmega
+ type Foo a = a -> a
-mkRhoTy :: [(Class, GenType t u)] -> GenType t u -> GenType t u
-mkRhoTy theta ty =
- foldr (\(c,t) r -> FunTy (DictTy c t usageOmega) r usageOmega) ty theta
+we want
+ splitFunTys (a -> Foo a) = ([a], Foo a)
+not ([a], a -> a)
-splitRhoTy :: GenType t u -> ([(Class,GenType t u)], GenType t u)
-splitRhoTy t =
- go t []
- where
- go (FunTy (DictTy c t _) r _) ts = go r ((c,t):ts)
- go (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
- | isFunTyCon tycon
- = go r ((c,t):ts)
- go (SynTy _ _ t) ts = go t ts
- go t ts = (reverse ts, t)
-\end{code}
+The reason is that we then get better (shorter) type signatures in
+interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
-Forall stuff
-~~~~~~~~~~~~
-\begin{code}
-mkForAllTy = ForAllTy
-
-mkForAllTys :: [t] -> GenType t u -> GenType t u
-mkForAllTys tyvars ty = foldr ForAllTy ty tyvars
-
-getForAllTy_maybe :: GenType t u -> Maybe (t,GenType t u)
-getForAllTy_maybe (SynTy _ _ t) = getForAllTy_maybe t
-getForAllTy_maybe (ForAllTy tyvar t) = Just(tyvar,t)
-getForAllTy_maybe _ = Nothing
-
-splitForAllTy :: GenType t u-> ([t], GenType t u)
-splitForAllTy t = go t []
- where
- go (ForAllTy tv t) tvs = go t (tv:tvs)
- go (SynTy _ _ t) tvs = go t tvs
- go t tvs = (reverse tvs, t)
-\end{code}
-\begin{code}
-mkForAllUsageTy :: u -> [u] -> GenType t u -> GenType t u
-mkForAllUsageTy = ForAllUsageTy
+repType looks through
+ (a) for-alls, and
+ (b) newtypes
+in addition to synonyms. It's useful in the back end where we're not
+interested in newtypes anymore.
-getForAllUsageTy :: GenType t u -> Maybe (u,[u],GenType t u)
-getForAllUsageTy (ForAllUsageTy uvar bounds t) = Just(uvar,bounds,t)
-getForAllUsageTy (SynTy _ _ t) = getForAllUsageTy t
-getForAllUsageTy _ = Nothing
+\begin{code}
+repType :: Type -> Type
+repType (NoteTy _ ty) = repType ty
+repType (ForAllTy _ ty) = repType ty
+repType (TyConApp tc tys) | isNewTyCon tc = repType (new_type_rep tc tys)
+repType other_ty = other_ty
+
+splitNewType_maybe :: Type -> Maybe Type
+-- Find the representation of a newtype, if it is one
+-- Looks through multiple levels of newtype
+splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
+splitNewType_maybe (TyConApp tc tys) | isNewTyCon tc = case splitNewType_maybe rep_ty of
+ Just rep_ty' -> Just rep_ty'
+ Nothing -> Just rep_ty
+ where
+ rep_ty = new_type_rep tc tys
+
+splitNewType_maybe other = Nothing
+
+new_type_rep :: TyCon -> [Type] -> Type
+-- The representation type for (T t1 .. tn), where T is a newtype
+-- Looks through one layer only
+new_type_rep tc tys
+ = ASSERT( isNewTyCon tc )
+ case splitFunTy_maybe (applyTys (dataConType (head (tyConDataCons tc))) tys) of
+ Just (rep_ty, _) -> rep_ty
\end{code}
-Applied tycons (includes FunTyCons)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-maybeAppTyCon
- :: GenType tyvar uvar
- -> Maybe (TyCon, -- the type constructor
- [GenType tyvar uvar]) -- types to which it is applied
-
-maybeAppTyCon ty
- = case (getTyCon_maybe app_ty) of
- Nothing -> Nothing
- Just tycon -> Just (tycon, arg_tys)
- where
- (app_ty, arg_tys) = splitAppTy ty
-getAppTyCon
- :: GenType tyvar uvar
- -> (TyCon, -- the type constructor
- [GenType tyvar uvar]) -- types to which it is applied
+---------------------------------------------------------------------
+ UsgNote
+ ~~~~~~~
-getAppTyCon ty
- = case maybeAppTyCon ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppTyCon" -- (ppr PprShowAll ty)
-#endif
-\end{code}
+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)
-Applied data tycons (give back constrs)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-maybeAppDataTyCon
- :: GenType tyvar uvar
- -> Maybe (TyCon, -- the type constructor
- [GenType tyvar uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
-
-maybeAppDataTyCon ty
- = case (getTyCon_maybe app_ty) of
- Just tycon | isDataTyCon tycon &&
- tyConArity tycon == length arg_tys
- -- Must be saturated for ty to be a data type
- -> Just (tycon, arg_tys, tyConDataCons tycon)
-
- other -> Nothing
- where
- (app_ty, arg_tys) = splitAppTy ty
+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
-getAppDataTyCon
- :: GenType tyvar uvar
- -> (TyCon, -- the type constructor
- [GenType tyvar uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
+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}
-getAppDataTyCon ty
- = case maybeAppDataTyCon ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppDataTyCon: " -- (pprGenType PprShowAll ty)
-#endif
+---------------------------------------------------------------------
+ ForAllTy
+ ~~~~~~~~
-maybeBoxedPrimType :: Type -> Maybe (Id, Type)
+We need to be clever here with usage annotations; they need to be
+lifted or lowered through the forall as appropriate.
-maybeBoxedPrimType ty
- = case (maybeAppDataTyCon ty) of -- Data type,
- Just (tycon, tys_applied, [data_con]) -- with exactly one constructor
- -> case (dataConArgTys data_con tys_applied) of
- [data_con_arg_ty] -- Applied to exactly one type,
- | isPrimType data_con_arg_ty -- which is primitive
- -> Just (data_con, data_con_arg_ty)
- other_cases -> Nothing
- other_cases -> Nothing
+\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
+
+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
+
+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
+ where
+ splitFAT_m (NoteTy _ ty) = splitFAT_m ty
+ splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
+ splitFAT_m _ = Nothing
+
+isForAllTy :: Type -> Bool
+isForAllTy (NoteTy _ ty) = isForAllTy ty
+isForAllTy (ForAllTy tyvar ty) = True
+isForAllTy _ = False
+
+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 []
+ where
+ split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
+ split orig_ty (NoteTy _ ty) tvs = split orig_ty ty tvs
+ split orig_ty t tvs = (reverse tvs, orig_ty)
\end{code}
-\begin{code}
-splitSigmaTy :: GenType t u -> ([t], [(Class,GenType t u)], GenType t u)
-splitSigmaTy ty =
- (tyvars, theta, tau)
- where
- (tyvars,rho) = splitForAllTy ty
- (theta,tau) = splitRhoTy rho
+@mkPiType@ makes a (->) type or a forall type, depending on whether
+it is given a type variable or a term variable.
-mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
+\begin{code}
+mkPiType :: IdOrTyVar -> Type -> Type -- The more polymorphic version doesn't work...
+mkPiType v ty | isId v = mkFunTy (idType v) ty
+ | otherwise = mkForAllTy v ty
\end{code}
+Applying a for-all to its arguments
-Finding the kind of a type
-~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-getTypeKind :: GenType (GenTyVar any) u -> Kind
-getTypeKind (TyVarTy tyvar) = getTyVarKind tyvar
-getTypeKind (TyConTy tycon usage) = tyConKind tycon
-getTypeKind (SynTy _ _ ty) = getTypeKind ty
-getTypeKind (FunTy fun arg _) = mkBoxedTypeKind
-getTypeKind (DictTy clas arg _) = mkBoxedTypeKind
-getTypeKind (AppTy fun arg) = resultKind (getTypeKind fun)
-getTypeKind (ForAllTy _ _) = mkBoxedTypeKind
-getTypeKind (ForAllUsageTy _ _ _) = mkBoxedTypeKind
+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"
+
+applyTys :: Type -> [Type] -> Type
+applyTys fun_ty arg_tys
+ = substTy (mkTyVarSubst tvs arg_tys) ty
+ where
+ (tvs, ty) = split 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
+ (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.
+
+
+%************************************************************************
+%* *
+\subsection{Stuff to do with the source-language types}
+%* *
+%************************************************************************
-Free variables of a type
-~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tyVarsOfType :: GenType (GenTyVar flexi) uvar -> GenTyVarSet flexi
-
-tyVarsOfType (TyVarTy tv) = unitTyVarSet tv
-tyVarsOfType (TyConTy tycon usage) = emptyTyVarSet
-tyVarsOfType (SynTy _ tys ty) = tyVarsOfTypes tys
-tyVarsOfType (FunTy arg res _) = tyVarsOfType arg `unionTyVarSets` tyVarsOfType res
-tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionTyVarSets` tyVarsOfType arg
-tyVarsOfType (DictTy clas ty _) = tyVarsOfType ty
-tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusTyVarSet` unitTyVarSet tyvar
-tyVarsOfType (ForAllUsageTy _ _ ty) = tyVarsOfType ty
-
-tyVarsOfTypes :: [GenType (GenTyVar flexi) uvar] -> GenTyVarSet flexi
-tyVarsOfTypes tys = foldr (unionTyVarSets.tyVarsOfType) emptyTyVarSet tys
+type RhoType = Type
+type TauType = Type
+type ThetaType = [(Class, [Type])]
+type SigmaType = Type
\end{code}
+@isTauTy@ tests for nested for-alls.
-Instantiating a type
-~~~~~~~~~~~~~~~~~~~~
\begin{code}
-applyTy :: Eq t => GenType t u -> GenType t u -> GenType t u
-applyTy (SynTy _ _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = instantiateTy [(tv,arg)] ty
-applyTy other arg = panic "applyTy"
-
-instantiateTy :: Eq t => [(t, GenType t u)] -> GenType t u -> GenType t u
-instantiateTy tenv ty
- = go ty
- where
- go (TyVarTy tv) = case [ty | (tv',ty) <- tenv, tv==tv'] of
- [] -> TyVarTy tv
- (ty:_) -> ty
- go ty@(TyConTy tycon usage) = ty
- go (SynTy tycon tys ty) = SynTy tycon (map go tys) (go ty)
- go (FunTy arg res usage) = FunTy (go arg) (go res) usage
- go (AppTy fun arg) = AppTy (go fun) (go arg)
- go (DictTy clas ty usage) = DictTy clas (go ty) usage
- go (ForAllTy tv ty) = ASSERT(null tv_bound)
- ForAllTy tv (go ty)
- where
- tv_bound = [() | (tv',_) <- tenv, tv==tv']
-
- go (ForAllUsageTy uvar bds ty) = ForAllUsageTy uvar bds (go ty)
-
-
--- instantiateTauTy works only (a) on types with no ForAlls,
--- and when (b) all the type variables are being instantiated
--- In return it is more polymorphic than instantiateTy
-
-instantiateTauTy :: Eq t => [(t, GenType t' u)] -> GenType t u -> GenType t' u
-instantiateTauTy tenv ty
- = go ty
- where
- go (TyVarTy tv) = case [ty | (tv',ty) <- tenv, tv==tv'] of
- (ty:_) -> ty
- [] -> panic "instantiateTauTy"
- go (TyConTy tycon usage) = TyConTy tycon usage
- go (SynTy tycon tys ty) = SynTy tycon (map go tys) (go ty)
- go (FunTy arg res usage) = FunTy (go arg) (go res) usage
- go (AppTy fun arg) = AppTy (go fun) (go arg)
- go (DictTy clas ty usage) = DictTy clas (go ty) usage
-
-instantiateUsage
- :: Ord3 u => [(u, GenType t u')] -> GenType t u -> GenType t u'
-instantiateUsage = error "instantiateUsage: not implemented"
+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 _ ty) = isTauTy ty
+isTauTy other = False
\end{code}
\begin{code}
-type TypeEnv = TyVarEnv Type
+mkRhoTy :: [(Class, [Type])] -> Type -> Type
+mkRhoTy theta ty = foldr (\(c,t) r -> FunTy (mkDictTy c t) r) ty theta
-applyTypeEnvToTy :: TypeEnv -> SigmaType -> SigmaType
-applyTypeEnvToTy tenv ty
- = mapOverTyVars v_fn ty
- where
- v_fn v = case (lookupTyVarEnv tenv v) of
- Just ty -> ty
- Nothing -> TyVarTy v
+splitRhoTy :: Type -> ([(Class, [Type])], Type)
+splitRhoTy ty = split ty ty []
+ where
+ split orig_ty (FunTy arg res) ts = case splitDictTy_maybe arg of
+ Just pair -> split res res (pair:ts)
+ Nothing -> (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}
-@mapOverTyVars@ is a local function which actually does the work. It
-does no cloning or other checks for shadowing, so be careful when
-calling this on types with Foralls in them.
+
\begin{code}
-mapOverTyVars :: (TyVar -> Type) -> Type -> Type
-
-mapOverTyVars v_fn ty
- = let
- mapper = mapOverTyVars v_fn
- in
- case ty of
- TyVarTy v -> v_fn v
- SynTy c as e -> SynTy c (map mapper as) (mapper e)
- FunTy a r u -> FunTy (mapper a) (mapper r) u
- AppTy f a -> AppTy (mapper f) (mapper a)
- DictTy c t u -> DictTy c (mapper t) u
- ForAllTy v t -> ForAllTy v (mapper t)
- tc@(TyConTy _ _) -> tc
+mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
+
+splitSigmaTy :: Type -> ([TyVar], [(Class, [Type])], Type)
+splitSigmaTy ty =
+ (tyvars, theta, tau)
+ where
+ (tyvars,rho) = splitForAllTys ty
+ (theta,tau) = splitRhoTy rho
\end{code}
-At present there are no unboxed non-primitive types, so
-isUnboxedType is the same as isPrimType.
+%************************************************************************
+%* *
+\subsection{Kinds and free variables}
+%* *
+%************************************************************************
+
+---------------------------------------------------------------------
+ Finding the kind of a type
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-isPrimType, isUnboxedType :: GenType tyvar uvar -> Bool
+typeKind :: Type -> Kind
+
+typeKind (TyVarTy tyvar) = tyVarKind tyvar
+typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
+typeKind (NoteTy _ ty) = typeKind ty
+typeKind (AppTy fun arg) = funResultTy (typeKind fun)
-isPrimType (AppTy ty _) = isPrimType ty
-isPrimType (SynTy _ _ ty) = isPrimType ty
-isPrimType (TyConTy tycon _) = isPrimTyCon tycon
-isPrimType _ = False
+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).
-isUnboxedType = isPrimType
+typeKind (ForAllTy tv ty) = typeKind ty
\end{code}
-This is *not* right: it is a placeholder (ToDo 96/03 WDP):
-\begin{code}
-typePrimRep :: GenType tyvar uvar -> PrimRep
-typePrimRep (SynTy _ _ ty) = typePrimRep ty
-typePrimRep (TyConTy tc _) = if isPrimTyCon tc then panic "typePrimRep:PrimTyCon" else PtrRep
-typePrimRep (AppTy ty _) = typePrimRep ty
-typePrimRep _ = PtrRep -- the "default"
+---------------------------------------------------------------------
+ Free variables of a type
+ ~~~~~~~~~~~~~~~~~~~~~~~~
+\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 (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
+
+tyVarsOfTypes :: [Type] -> TyVarSet
+tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
+
+-- 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{Matching on types}
+\subsection{TidyType}
%* *
%************************************************************************
-Matching is a {\em unidirectional} process, matching a type against a
-template (which is just a type with type variables in it). The
-matcher assumes that there are no repeated type variables in the
-template, so that it simply returns a mapping of type variables to
-types. It also fails on nested foralls.
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
-@matchTys@ matches corresponding elements of a list of templates and
-types.
+It doesn't change the uniques at all, just the print names.
\begin{code}
-matchTy :: GenType t1 u1 -- Template
- -> GenType t2 u2 -- Proposed instance of template
- -> Maybe [(t1,GenType t2 u2)] -- Matching substitution
+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.
+ where
+ name = tyVarName tyvar
-matchTys :: [GenType t1 u1] -- Templates
- -> [GenType t2 u2] -- Proposed instance of template
- -> Maybe [(t1,GenType t2 u2)] -- Matching substitution
+tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
-matchTy ty1 ty2 = match [] [] ty1 ty2
-matchTys tys1 tys2 = match' [] (zipEqual tys1 tys2)
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(tidy_env, subst) ty
+ = go ty
+ where
+ go (TyVarTy tv) = case lookupVarEnv subst tv of
+ Nothing -> TyVarTy tv
+ 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)
+ where
+ (envp, tvp) = tidyTyVar env tv
+
+ go_note (SynNote ty) = SynNote SAPPLY (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
+
+tidyTypes env tys = map (tidyType env) tys
\end{code}
-@match@ is the main function.
+
+@tidyOpenType@ grabs the free type variables, tidies them
+and then uses @tidyType@ to work over the type itself
\begin{code}
-match :: [(t1, GenType t2 u2)] -- r, the accumulating result
- -> [(GenType t1 u1, GenType t2 u2)] -- w, the work list
- -> GenType t1 u1 -> GenType t2 u2 -- Current match pair
- -> Maybe [(t1, GenType t2 u2)]
-
-match r w (TyVarTy v) ty = match' ((v,ty) : r) w
-match r w (FunTy fun1 arg1 _) (FunTy fun2 arg2 _) = match r ((fun1,fun2):w) arg1 arg2
-match r w (AppTy fun1 arg1) (AppTy fun2 arg2) = match r ((fun1,fun2):w) arg1 arg2
-match r w (TyConTy con1 _) (TyConTy con2 _) | con1 == con2 = match' r w
-match r w (DictTy clas1 ty1 _) (DictTy clas2 ty2 _) | clas1 == clas2 = match r w ty1 ty2
-match r w (SynTy _ _ ty1) ty2 = match r w ty1 ty2
-match r w ty1 (SynTy _ _ ty2) = match r w ty1 ty2
-
- -- With type synonyms, we have to be careful for the exact
- -- same reasons as in the unifier. Please see the
- -- considerable commentary there before changing anything
- -- here! (WDP 95/05)
-
--- Catch-all fails
-match _ _ _ _ = Nothing
-
-match' r [] = Just r
-match' r ((ty1,ty2):w) = match r w ty1 ty2
+tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
+tidyOpenType env ty
+ = (env', tidyType env' ty)
+ where
+ env' = foldl go env (varSetElems (tyVarsOfType ty))
+ go env tyvar = fst (tidyTyVar env tyvar)
+
+tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
+tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
+
+tidyTopType :: Type -> Type
+tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
+
%************************************************************************
%* *
-\subsection{Equality on types}
+\subsection{Boxedness and liftedness}
%* *
%************************************************************************
-The functions eqSimpleTy and eqSimpleTheta are polymorphic in the types t
-and u, but ONLY WORK FOR SIMPLE TYPES (ie. they panic if they see
-dictionaries or polymorphic types). The function eqTy has a more
-specific type, but does the `right thing' for all types.
-
\begin{code}
-eqSimpleTheta :: (Eq t,Eq u) =>
- [(Class,GenType t u)] -> [(Class,GenType t u)] -> Bool
-
-eqSimpleTheta [] [] = True
-eqSimpleTheta ((c1,t1):th1) ((c2,t2):th2) =
- c1==c2 && t1 `eqSimpleTy` t2 && th1 `eqSimpleTheta` th2
-eqSimpleTheta other1 other2 = False
+isUnboxedType :: Type -> Bool
+isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
+
+isUnLiftedType :: Type -> Bool
+ -- isUnLiftedType returns True for forall'd unlifted types:
+ -- x :: forall a. Int#
+ -- I found bindings like these were getting floated to the top level.
+ -- They are pretty bogus types, mind you. It would be better never to
+ -- construct them
+
+isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
+isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
+isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
+isUnLiftedType other = False
+
+isUnboxedTupleType :: Type -> Bool
+isUnboxedTupleType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> isUnboxedTupleTyCon tc
+ other -> False
+
+-- 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 )
+ isAlgTyCon tc
+ other -> False
+
+-- 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
+
+isNewType :: Type -> Bool
+isNewType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isNewTyCon tc
+ other -> False
+
+typePrimRep :: Type -> PrimRep
+typePrimRep ty = case splitTyConApp_maybe (repType ty) of
+ Just (tc, ty_args) -> tyConPrimRep tc
+ other -> PtrRep
\end{code}
-\begin{code}
-eqSimpleTy :: (Eq t,Eq u) => GenType t u -> GenType t u -> Bool
-
-(TyVarTy tv1) `eqSimpleTy` (TyVarTy tv2) =
- tv1 == tv2
-(AppTy f1 a1) `eqSimpleTy` (AppTy f2 a2) =
- f1 `eqSimpleTy` f2 && a1 `eqSimpleTy` a2
-(TyConTy tc1 u1) `eqSimpleTy` (TyConTy tc2 u2) =
- tc1 == tc2 && u1 == u2
-
-(FunTy f1 a1 u1) `eqSimpleTy` (FunTy f2 a2 u2) =
- f1 `eqSimpleTy` f2 && a1 `eqSimpleTy` a2 && u1 == u2
-(FunTy f1 a1 u1) `eqSimpleTy` t2 =
- -- Expand t1 just in case t2 matches that version
- (AppTy (AppTy (TyConTy mkFunTyCon u1) f1) a1) `eqSimpleTy` t2
-t1 `eqSimpleTy` (FunTy f2 a2 u2) =
- -- Expand t2 just in case t1 matches that version
- t1 `eqSimpleTy` (AppTy (AppTy (TyConTy mkFunTyCon u2) f2) a2)
-
-(SynTy tc1 ts1 t1) `eqSimpleTy` (SynTy tc2 ts2 t2) =
- (tc1 == tc2 && and (zipWith eqSimpleTy ts1 ts2) && length ts1 == length ts2)
- || t1 `eqSimpleTy` t2
-(SynTy _ _ t1) `eqSimpleTy` t2 =
- t1 `eqSimpleTy` t2 -- Expand the abbrevation and try again
-t1 `eqSimpleTy` (SynTy _ _ t2) =
- t1 `eqSimpleTy` t2 -- Expand the abbrevation and try again
-
-(DictTy _ _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got DictTy"
-_ `eqSimpleTy` (DictTy _ _ _) = panic "eqSimpleTy: got DictTy"
-
-(ForAllTy _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got ForAllTy"
-_ `eqSimpleTy` (ForAllTy _ _) = panic "eqSimpleTy: got ForAllTy"
-
-(ForAllUsageTy _ _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got ForAllUsageTy"
-_ `eqSimpleTy` (ForAllUsageTy _ _ _) = panic "eqSimpleTy: got ForAllUsageTy"
-
-_ `eqSimpleTy` _ = False
-\end{code}
-Types are ordered so we can sort on types in the renamer etc. DNT: Since
-this class is also used in CoreLint and other such places, we DO expand out
-Fun/Syn/Dict types (if necessary).
+%************************************************************************
+%* *
+\subsection{Sequencing on types
+%* *
+%************************************************************************
\begin{code}
-eqTy :: Type -> Type -> Bool
-
-eqTy t1 t2 =
- eq nullTyVarEnv nullUVarEnv t1 t2
- where
- eq tve uve (TyVarTy tv1) (TyVarTy tv2) =
- tv1 == tv2 ||
- case (lookupTyVarEnv tve tv1) of
- Just tv -> tv == tv2
- Nothing -> False
- eq tve uve (AppTy f1 a1) (AppTy f2 a2) =
- eq tve uve f1 f2 && eq tve uve a1 a2
- eq tve uve (TyConTy tc1 u1) (TyConTy tc2 u2) =
- tc1 == tc2 && eqUsage uve u1 u2
-
- eq tve uve (FunTy f1 a1 u1) (FunTy f2 a2 u2) =
- eq tve uve f1 f2 && eq tve uve a1 a2 && eqUsage uve u1 u2
- eq tve uve (FunTy f1 a1 u1) t2 =
- -- Expand t1 just in case t2 matches that version
- eq tve uve (AppTy (AppTy (TyConTy mkFunTyCon u1) f1) a1) t2
- eq tve uve t1 (FunTy f2 a2 u2) =
- -- Expand t2 just in case t1 matches that version
- eq tve uve t1 (AppTy (AppTy (TyConTy mkFunTyCon u2) f2) a2)
-
- eq tve uve (DictTy c1 t1 u1) (DictTy c2 t2 u2) =
- c1 == c2 && eq tve uve t1 t2 && eqUsage uve u1 u2
- eq tve uve t1@(DictTy _ _ _) t2 =
- eq tve uve (expandTy t1) t2 -- Expand the dictionary and try again
- eq tve uve t1 t2@(DictTy _ _ _) =
- eq tve uve t1 (expandTy t2) -- Expand the dictionary and try again
-
- eq tve uve (SynTy tc1 ts1 t1) (SynTy tc2 ts2 t2) =
- (tc1 == tc2 && and (zipWith (eq tve uve) ts1 ts2) && length ts1 == length ts2)
- || eq tve uve t1 t2
- eq tve uve (SynTy _ _ t1) t2 =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
- eq tve uve t1 (SynTy _ _ t2) =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
-
- eq tve uve (ForAllTy tv1 t1) (ForAllTy tv2 t2) =
- eq (addOneToTyVarEnv tve tv1 tv2) uve t1 t2
- eq tve uve (ForAllUsageTy u1 b1 t1) (ForAllUsageTy u2 b2 t2) =
- eqBounds uve b1 b2 && eq tve (addOneToUVarEnv uve u1 u2) t1 t2
-
- eq _ _ _ _ = False
-
- eqBounds uve [] [] = True
- eqBounds uve (u1:b1) (u2:b2) = eqUVar uve u1 u2 && eqBounds uve b1 b2
- eqBounds uve _ _ = False
+seqType :: Type -> ()
+seqType (TyVarTy tv) = tv `seq` ()
+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 (TyConApp tc tys) = tc `seq` seqTypes tys
+seqType (ForAllTy tv ty) = tv `seq` seqType ty
+
+seqTypes :: [Type] -> ()
+seqTypes [] = ()
+seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
+
+seqNote :: TyNote -> ()
+seqNote (SynNote ty) = seqType ty
+seqNote (FTVNote set) = sizeUniqSet set `seq` ()
+seqNote (UsgNote usg) = usg `seq` ()
\end{code}
+
projects / ghc-hetmet.git / blobdiff