+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+
\begin{code}
module Type (
- GenType(..), TyNote(..), -- Representation visible to friends
- Type, GenKind, Kind,
- TyVarSubst, GenTyVarSubst,
+ -- re-exports from TypeRep:
+ Type,
+ Kind, TyVarSubst,
+
+ superKind, superBoxity, -- KX and BX respectively
+ boxedBoxity, unboxedBoxity, -- :: BX
+ openKindCon, -- :: KX
+ typeCon, -- :: BX -> KX
+ boxedTypeKind, unboxedTypeKind, openTypeKind, -- :: KX
+ mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX
- funTyCon, boxedKindCon, unboxedKindCon, openKindCon,
+ funTyCon,
- boxedTypeKind, unboxedTypeKind, openTypeKind, mkArrowKind, mkArrowKinds,
- hasMoreBoxityInfo, superKind,
+ -- exports from this module:
+ hasMoreBoxityInfo, defaultKind,
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
- mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys, funResultTy,
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
+ funResultTy, funArgTy, zipFunTys,
mkTyConApp, mkTyConTy, splitTyConApp_maybe,
- splitAlgTyConApp_maybe, splitAlgTyConApp,
- mkDictTy, splitDictTy_maybe, isDictTy,
+ splitAlgTyConApp_maybe, splitAlgTyConApp,
+
+ -- Predicates and the like
+ mkDictTy, mkDictTys, mkPredTy, splitPredTy_maybe,
+ splitDictTy_maybe, isDictTy, predRepTy,
- mkSynTy, isSynTy,
+ mkSynTy, isSynTy, deNoteType,
+
+ repType, splitRepFunTys, splitNewType_maybe, typePrimRep,
+
+ UsageAnn(..), mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
+ mkUsForAllTy, mkUsForAllTys, splitUsForAllTys, substUsTy,
mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
- applyTy, applyTys, isForAllTy,
- mkPiType,
+ applyTy, applyTys, hoistForAllTys,
+
+ TauType, RhoType, SigmaType, PredType(..), ThetaType,
+ ClassPred, ClassContext, mkClassPred,
+ getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
+ isTauTy, mkRhoTy, splitRhoTy,
+ mkSigmaTy, isSigmaTy, splitSigmaTy,
+ getDFunTyKey,
- TauType, RhoType, SigmaType, ThetaType,
- isTauTy,
- mkRhoTy, splitRhoTy,
- mkSigmaTy, splitSigmaTy,
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
- isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType,
- typePrimRep,
+ -- Free variables
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
+ namesOfType, typeKind, addFreeTyVars,
- tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
- addFreeTyVars,
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVar, tidyTyVars,
+ tidyTopType,
- substTy, fullSubstTy, substTyVar,
- substFlexiTy, substFlexiTheta,
+ -- Seq
+ seqType, seqTypes
- showTypeCategory
) where
#include "HsVersions.h"
-import {-# SOURCE #-} DataCon( DataCon )
+-- We import the representation and primitive functions from TypeRep.
+-- Many things are reexported, but not the representation!
+
+import TypeRep
+
+-- Other imports:
+
+import {-# SOURCE #-} DataCon( DataCon, dataConRepType )
+import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
+import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
-- friends:
-import Var ( Id, TyVar, GenTyVar, IdOrTyVar,
- removeTyVarFlexi,
- tyVarKind, isId, idType
+import Var ( TyVar, Var, UVar,
+ tyVarKind, tyVarName, setTyVarName, isId, idType,
)
import VarEnv
import VarSet
-import Name ( NamedThing(..), Provenance(..), ExportFlag(..),
- mkWiredInTyConName, mkGlobalName, varOcc
- )
+import Name ( Name, NamedThing(..), OccName, mkLocalName, tidyOccName )
import NameSet
-import Class ( classTyCon, Class )
-import TyCon ( TyCon, Boxity(..),
- mkFunTyCon, mkKindCon, superKindCon,
- matchesTyCon, isUnboxedTupleTyCon, isUnLiftedTyCon,
- isFunTyCon, isEnumerationTyCon,
- isTupleTyCon, maybeTyConSingleCon,
- isPrimTyCon, isAlgTyCon, isSynTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn,
- tyConPrimRep, tyConClass_maybe
+import Class ( classTyCon, Class, ClassPred, ClassContext )
+import TyCon ( TyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
+ isFunTyCon, isDataTyCon, isNewTyCon, newTyConRep,
+ isAlgTyCon, isSynTyCon, tyConArity,
+ tyConKind, tyConDataCons, getSynTyConDefn,
+ tyConPrimRep
)
-- others
-import BasicTypes ( Unused )
-import SrcLoc ( mkBuiltinSrcLoc )
-import PrelMods ( pREL_GHC )
-import Maybes ( maybeToBool )
+import SrcLoc ( noSrcLoc )
import PrimRep ( PrimRep(..), isFollowableRep )
-import Unique -- quite a few *Keys
-import Util ( thenCmp )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList, thenCmp )
import Outputable
-
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
\end{code}
-%************************************************************************
-%* *
-\subsection{Type Classifications}
-%* *
-%************************************************************************
-
-A type is
-
- *unboxed* iff its representation is other than a pointer
- Unboxed types cannot instantiate a type variable
- Unboxed types are always unlifted.
-
- *lifted* A type is lifted iff it has bottom as an element.
- Closures always have lifted types: i.e. any
- let-bound identifier in Core must have a lifted
- type. Operationally, a lifted object is one that
- can be entered.
- (NOTE: previously "pointed").
-
- *algebraic* A type with one or more constructors. An algebraic
- type is one that can be deconstructed with a case
- expression. *NOT* the same as lifted types,
- because we also include unboxed tuples in this
- classification.
-
- *primitive* iff it is a built-in type that can't be expressed
- in Haskell.
-
-Currently, all primitive types are unlifted, but that's not necessarily
-the case. (E.g. Int could be primitive.)
-
-Some primitive types are unboxed, such as Int#, whereas some are boxed
-but unlifted (such as ByteArray#). The only primitive types that we
-classify as algebraic are the unboxed tuples.
-
-examples of type classifications:
-
-Type primitive boxed lifted algebraic
------------------------------------------------------------------------------
-Int#, Yes No No No
-ByteArray# Yes Yes No No
-(# a, b #) Yes No No Yes
-( a, b ) No Yes Yes Yes
-[a] No Yes Yes Yes
%************************************************************************
%* *
-\subsection{The data type}
+\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
-
\begin{code}
-type Type = GenType Unused -- Used after typechecker
-
-type GenKind flexi = GenType flexi
-type Kind = Type
-
-type TyVarSubst = TyVarEnv Type
-type GenTyVarSubst flexi = TyVarEnv (GenType flexi)
-
-data GenType flexi -- Parameterised over the "flexi" part of a type variable
- = TyVarTy (GenTyVar flexi)
-
- | AppTy
- (GenType flexi) -- Function is *not* a TyConApp
- (GenType flexi)
-
- | TyConApp -- Application of a TyCon
- TyCon -- *Invariant* saturated appliations of FunTyCon and
- -- synonyms have their own constructors, below.
- [GenType flexi] -- Might not be saturated.
-
- | FunTy -- Special case of TyConApp: TyConApp FunTyCon [t1,t2]
- (GenType flexi)
- (GenType flexi)
-
- | NoteTy -- Saturated application of a type synonym
- (TyNote flexi)
- (GenType flexi) -- The expanded version
-
- | ForAllTy
- (GenTyVar flexi)
- (GenType flexi) -- TypeKind
-
-data TyNote flexi
- = SynNote (GenType flexi) -- The unexpanded version of the type synonym; always a TyConApp
- | FTVNote (GenTyVarSet flexi) -- The free type variables of the noted expression
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Wired-in type constructors
-%* *
-%************************************************************************
-
-We define a few wired-in type constructors here to avoid module knots
-
-\begin{code}
-funTyConName = mkWiredInTyConName funTyConKey pREL_GHC SLIT("->") funTyCon
-funTyCon = mkFunTyCon funTyConName (mkArrowKinds [boxedTypeKind, boxedTypeKind] boxedTypeKind)
-\end{code}
-
-\begin{code}
-mk_kind_name key str = mkGlobalName key pREL_GHC (varOcc str)
- (LocalDef mkBuiltinSrcLoc NotExported)
- -- mk_kind_name is a bit of a hack
- -- The LocalDef means that we print the name without
- -- a qualifier, which is what we want for these kinds.
-
-boxedKindConName = mk_kind_name boxedKindConKey SLIT("*")
-boxedKindCon = mkKindCon boxedKindConName superKind Boxed
-
-unboxedKindConName = mk_kind_name unboxedKindConKey SLIT("*#")
-unboxedKindCon = mkKindCon unboxedKindConName superKind Unboxed
-
-openKindConName = mk_kind_name openKindConKey SLIT("*?")
-openKindCon = mkKindCon openKindConName superKind Open
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Kinds}
-%* *
-%************************************************************************
-
-\begin{code}
-superKind :: GenKind flexi -- Box, the type of all kinds
-superKind = TyConApp superKindCon []
-
-boxedTypeKind, unboxedTypeKind, openTypeKind :: GenKind flexi
-boxedTypeKind = TyConApp boxedKindCon []
-unboxedTypeKind = TyConApp unboxedKindCon []
-openTypeKind = TyConApp openKindCon []
-
-mkArrowKind :: GenKind flexi -> GenKind flexi -> GenKind flexi
-mkArrowKind = FunTy
-
-mkArrowKinds :: [GenKind flexi] -> GenKind flexi -> GenKind flexi
-mkArrowKinds arg_kinds result_kind = foldr FunTy result_kind arg_kinds
-\end{code}
-
-\begin{code}
-hasMoreBoxityInfo :: GenKind flexi -> GenKind flexi -> Bool
-
-(NoteTy _ k1) `hasMoreBoxityInfo` k2 = k1 `hasMoreBoxityInfo` k2
-k1 `hasMoreBoxityInfo` (NoteTy _ k2) = k1 `hasMoreBoxityInfo` k2
-
-(TyConApp kc1 ts1) `hasMoreBoxityInfo` (TyConApp kc2 ts2)
- = ASSERT( null ts1 && null ts2 )
- kc2 `matchesTyCon` kc1 -- NB the reversal of arguments
-
-kind1@(FunTy _ _) `hasMoreBoxityInfo` kind2@(FunTy _ _)
- = ASSERT( kind1 == kind2 )
- True
- -- The two kinds can be arrow kinds; for example when unifying
- -- (m1 Int) and (m2 Int) we end up unifying m1 and m2, which should
- -- have the same kind.
-
--- Other cases are impossible
+hasMoreBoxityInfo :: Kind -> Kind -> Bool
+hasMoreBoxityInfo k1 k2
+ | k2 == openTypeKind = True
+ | otherwise = k1 == k2
+
+defaultKind :: Kind -> Kind
+-- Used when generalising: default kind '?' to '*'
+defaultKind kind | kind == openTypeKind = boxedTypeKind
+ | otherwise = kind
\end{code}
TyVarTy
~~~~~~~
\begin{code}
-mkTyVarTy :: GenTyVar flexi -> GenType flexi
+mkTyVarTy :: TyVar -> Type
mkTyVarTy = TyVarTy
-mkTyVarTys :: [GenTyVar flexi] -> [GenType flexi]
+mkTyVarTys :: [TyVar] -> [Type]
mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
-getTyVar :: String -> GenType flexi -> GenTyVar flexi
+getTyVar :: String -> Type -> TyVar
getTyVar msg (TyVarTy tv) = tv
+getTyVar msg (PredTy p) = getTyVar msg (predRepTy p)
getTyVar msg (NoteTy _ t) = getTyVar msg t
getTyVar msg other = panic ("getTyVar: " ++ msg)
-getTyVar_maybe :: GenType flexi -> Maybe (GenTyVar flexi)
+getTyVar_maybe :: Type -> Maybe TyVar
getTyVar_maybe (TyVarTy tv) = Just tv
getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
+getTyVar_maybe (PredTy p) = getTyVar_maybe (predRepTy p)
getTyVar_maybe other = Nothing
-isTyVarTy :: GenType flexi -> Bool
+isTyVarTy :: Type -> Bool
isTyVarTy (TyVarTy tv) = True
isTyVarTy (NoteTy _ ty) = isTyVarTy ty
+isTyVarTy (PredTy p) = isTyVarTy (predRepTy p)
isTyVarTy other = False
\end{code}
invariant: use it.
\begin{code}
-mkAppTy orig_ty1 orig_ty2 = mk_app orig_ty1
+mkAppTy orig_ty1 orig_ty2
+ = ASSERT2( isNotUsgTy orig_ty1 && isNotUsgTy orig_ty2, pprType orig_ty1 <+> text "to" <+> pprType orig_ty2 )
+ ASSERT( not (isPredTy orig_ty1) ) -- Predicates 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 ty1 = AppTy orig_ty1 orig_ty2
-mkAppTys :: GenType flexi -> [GenType flexi] -> GenType flexi
+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 = mk_app orig_ty1
+mkAppTys orig_ty1 orig_tys2
+ = ASSERT2( isNotUsgTy orig_ty1, pprType orig_ty1 )
+ ASSERT( not (isPredTy orig_ty1) ) -- Predicates 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 = foldl AppTy orig_ty1 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 :: GenType flexi -> Maybe (GenType flexi, GenType flexi)
+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 (PredTy p) = splitAppTy_maybe (predRepTy p)
splitAppTy_maybe (TyConApp tc []) = Nothing
splitAppTy_maybe (TyConApp tc tys) = split tys []
where
splitAppTy_maybe other = Nothing
-splitAppTy :: GenType flexi -> (GenType flexi, GenType flexi)
+splitAppTy :: Type -> (Type, Type)
splitAppTy ty = case splitAppTy_maybe ty of
Just pr -> pr
Nothing -> panic "splitAppTy"
-splitAppTys :: GenType flexi -> (GenType flexi, [GenType flexi])
+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 (PredTy p) args = split orig_ty (predRepTy 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)
~~~~~
\begin{code}
-mkFunTy :: GenType flexi -> GenType flexi -> GenType flexi
+mkFunTy :: Type -> Type -> Type
mkFunTy arg res = FunTy arg res
-mkFunTys :: [GenType flexi] -> GenType flexi -> GenType flexi
+mkFunTys :: [Type] -> Type -> Type
mkFunTys tys ty = foldr FunTy ty tys
-splitFunTy_maybe :: GenType flexi -> Maybe (GenType flexi, GenType flexi)
+splitFunTy :: Type -> (Type, Type)
+splitFunTy (FunTy arg res) = (arg, res)
+splitFunTy (NoteTy _ ty) = splitFunTy ty
+splitFunTy (PredTy p) = splitFunTy (predRepTy p)
+
+splitFunTy_maybe :: Type -> Maybe (Type, Type)
splitFunTy_maybe (FunTy arg res) = Just (arg, res)
splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
+splitFunTy_maybe (PredTy p) = splitFunTy_maybe (predRepTy p)
splitFunTy_maybe other = Nothing
-
-splitFunTys :: GenType flexi -> ([GenType flexi], GenType flexi)
+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 _ ty) = split args orig_ty ty
+ split args orig_ty (PredTy p) = split args orig_ty (predRepTy p)
split args orig_ty ty = (reverse args, orig_ty)
-funResultTy :: GenType flexi -> GenType flexi
+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 (PredTy p) = split n args syn_ty (predRepTy p)
+ 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 (PredTy p) = split acc xs nty (predRepTy 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 ty = ty
+funResultTy (PredTy p) = funResultTy (predRepTy p)
+funResultTy ty = pprPanic "funResultTy" (pprType ty)
+
+funArgTy :: Type -> Type
+funArgTy (FunTy arg res) = arg
+funArgTy (NoteTy _ ty) = funArgTy ty
+funArgTy (PredTy p) = funArgTy (predRepTy p)
+funArgTy ty = pprPanic "funArgTy" (pprType ty)
\end{code}
-
---------------------------------------------------------------------
TyConApp
~~~~~~~~
\begin{code}
-mkTyConApp :: TyCon -> [GenType flexi] -> GenType flexi
+mkTyConApp :: TyCon -> [Type] -> Type
mkTyConApp tycon tys
| isFunTyCon tycon && length tys == 2
= case tys of
= ASSERT(not (isSynTyCon tycon))
TyConApp tycon tys
-mkTyConTy :: TyCon -> GenType flexi
+mkTyConTy :: TyCon -> Type
mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) )
TyConApp tycon []
-- mean a distinct type, but all other type-constructor applications
-- including functions are returned as Just ..
-splitTyConApp_maybe :: GenType flexi -> Maybe (TyCon, [GenType flexi])
+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 (PredTy p) = splitTyConApp_maybe (predRepTy p)
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.
+-- We return the constructors too, so there had better be some.
-splitAlgTyConApp_maybe :: GenType flexi -> Maybe (TyCon, [GenType flexi], [DataCon])
+splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
splitAlgTyConApp_maybe (TyConApp tc tys)
- | isAlgTyCon tc &&
+ | isAlgTyCon tc &&
tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
+splitAlgTyConApp_maybe (PredTy p) = splitAlgTyConApp_maybe (predRepTy p)
splitAlgTyConApp_maybe other = Nothing
-splitAlgTyConApp :: GenType flexi -> (TyCon, [GenType flexi], [DataCon])
+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.
-
-\begin{code}
-mkDictTy :: Class -> [GenType flexi] -> GenType flexi
-mkDictTy clas tys = TyConApp (classTyCon clas) tys
-
-splitDictTy_maybe :: GenType flexi -> Maybe (Class, [GenType flexi])
-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 :: GenType flexi -> 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
+splitAlgTyConApp (PredTy p) = splitAlgTyConApp (predRepTy p)
+#ifdef DEBUG
+splitAlgTyConApp ty = pprPanic "splitAlgTyConApp" (pprType ty)
+#endif
\end{code}
\begin{code}
mkSynTy syn_tycon tys
- = ASSERT(isSynTyCon syn_tycon)
+ = ASSERT( isSynTyCon syn_tycon )
+ ASSERT( isNotUsgTy body )
+ ASSERT( length tyvars == length tys )
NoteTy (SynNote (TyConApp syn_tycon tys))
- (substFlexiTy (zipVarEnv tyvars tys) body)
- -- The "flexi" is needed so we can get a TcType from a synonym
+ (substTy (mkTyVarSubst tyvars tys) body)
where
(tyvars, body) = getSynTyConDefn syn_tycon
isSynTy (NoteTy (SynNote _) _) = True
isSynTy other = False
+
+deNoteType :: Type -> Type
+ -- Remove synonyms, but not Preds
+deNoteType ty@(TyVarTy tyvar) = ty
+deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
+deNoteType (PredTy p) = PredTy p
+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}
Notes on type synonyms
interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
+ Representation types
+ ~~~~~~~~~~~~~~~~~~~~
+
+repType looks through
+ (a) for-alls, and
+ (b) newtypes
+ (c) synonyms
+ (d) predicates
+It's useful in the back end where we're not
+interested in newtypes anymore.
+
+\begin{code}
+repType :: Type -> Type
+repType (ForAllTy _ ty) = repType ty
+repType (NoteTy _ ty) = repType ty
+repType (PredTy p) = repType (predRepTy p)
+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)
+
+typePrimRep :: Type -> PrimRep
+typePrimRep ty = case repType ty of
+ TyConApp tc _ -> tyConPrimRep tc
+ 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 _ ty) = splitNewType_maybe ty
+splitNewType_maybe (PredTy p) = splitNewType_maybe (predRepTy p)
+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}
+
---------------------------------------------------------------------
- ForAllTy
- ~~~~~~~~
+ 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}
-mkForAllTy = ForAllTy
+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 (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1)) (substUsTy ve ty2)
+substUsTy ve (NoteTy note ty) = NoteTy note (substUsTy ve ty)
+
+substUsTy ve (PredTy (Class c tys)) = PredTy (Class c (map (substUsTy ve) tys))
+substUsTy ve (PredTy (IParam n ty)) = PredTy (IParam n (substUsTy ve ty))
+substUsTy ve (TyVarTy tv) = TyVarTy tv
+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}
-mkForAllTys :: [GenTyVar flexi] -> GenType flexi -> GenType flexi
-mkForAllTys tyvars ty = foldr ForAllTy ty tyvars
-splitForAllTy_maybe :: GenType flexi -> Maybe (GenTyVar flexi, GenType flexi)
-splitForAllTy_maybe (NoteTy _ ty) = splitForAllTy_maybe ty
-splitForAllTy_maybe (ForAllTy tyvar ty) = Just(tyvar, ty)
-splitForAllTy_maybe _ = Nothing
+---------------------------------------------------------------------
+ ForAllTy
+ ~~~~~~~~
-isForAllTy :: GenType flexi -> Bool
-isForAllTy (NoteTy _ ty) = isForAllTy ty
-isForAllTy (ForAllTy tyvar ty) = True
-isForAllTy _ = False
+We need to be clever here with usage annotations; they need to be
+lifted or lowered through the forall as appropriate.
-splitForAllTys :: GenType flexi -> ([GenTyVar flexi], GenType flexi)
-splitForAllTys ty = split ty ty []
+\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 (PredTy p) = splitFAT_m (predRepTy 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 []
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)
+ 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 (PredTy p) tvs = split orig_ty (predRepTy p) tvs
+ split orig_ty t tvs = (reverse tvs, orig_ty)
\end{code}
-@mkPiType@ makes a (->) type or a forall type, depending on whether
-it is given a type variable or a term variable.
+-- (mkPiType now in CoreUtils)
-\begin{code}
-mkPiType :: IdOrTyVar -> Type -> Type -- The more polymorphic version doesn't work...
-mkPiType v ty | isId v = mkFunTy (idType v) ty
- | otherwise = ForAllTy v ty
-\end{code}
+Applying a for-all to its arguments
\begin{code}
-applyTy :: GenType flexi -> GenType flexi -> GenType flexi
-applyTy (NoteTy _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = substTy (mkVarEnv [(tv,arg)]) ty
-applyTy other arg = panic "applyTy"
-
-applyTys :: GenType flexi -> [GenType flexi] -> GenType flexi
+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 (PredTy p) arg = applyTy (predRepTy p) 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
- = go [] fun_ty arg_tys
+ = substTy (mkTyVarSubst tvs arg_tys) ty
where
- go env ty [] = substTy (mkVarEnv env) ty
- go env (NoteTy _ fun) args = go env fun args
- go env (ForAllTy tv ty) (arg:args) = go ((tv,arg):env) ty args
- go env other args = panic "applyTys"
+ (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 (PredTy p) args = split (predRepTy p) 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.
+
+\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)
+ }}}
\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.
%* *
%************************************************************************
+"Dictionary" types are just ordinary data types, but you can
+tell from the type constructor whether it's a dictionary or not.
+
\begin{code}
-type RhoType = Type
-type TauType = Type
-type ThetaType = [(Class, [Type])]
-type SigmaType = Type
+mkClassPred clas tys = Class clas tys
+
+mkDictTy :: Class -> [Type] -> Type
+mkDictTy clas tys = mkPredTy (Class clas tys)
+
+mkDictTys :: ClassContext -> [Type]
+mkDictTys cxt = [mkDictTy cls tys | (cls,tys) <- cxt]
+
+mkPredTy :: PredType -> Type
+mkPredTy pred = PredTy pred
+
+predRepTy :: PredType -> Type
+-- Convert a predicate to its "representation type";
+-- the type of evidence for that predicate, which is actually passed at runtime
+predRepTy (Class clas tys) = TyConApp (classTyCon clas) tys
+predRepTy (IParam n ty) = ty
+
+isPredTy :: Type -> Bool
+isPredTy (NoteTy _ ty) = isPredTy ty
+isPredTy (PredTy _) = True
+isPredTy _ = False
+
+isDictTy :: Type -> Bool
+isDictTy (NoteTy _ ty) = isDictTy ty
+isDictTy (PredTy (Class _ _)) = True
+isDictTy other = False
+
+splitPredTy_maybe :: Type -> Maybe PredType
+splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
+splitPredTy_maybe (PredTy p) = Just p
+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
+
+getClassTys_maybe :: PredType -> Maybe ClassPred
+getClassTys_maybe (Class clas tys) = Just (clas, tys)
+getClassTys_maybe _ = Nothing
+
+ipName_maybe :: PredType -> Maybe Name
+ipName_maybe (IParam n _) = Just n
+ipName_maybe _ = Nothing
+
+classesToPreds :: ClassContext -> ThetaType
+classesToPreds cts = map (uncurry Class) cts
+
+classesOfPreds :: ThetaType -> ClassContext
+classesOfPreds theta = [(clas,tys) | Class clas tys <- theta]
\end{code}
@isTauTy@ tests for nested for-alls.
\begin{code}
-isTauTy :: GenType flexi -> Bool
-isTauTy (TyVarTy v) = True
+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
+isTauTy (AppTy a b) = isTauTy a && isTauTy b
+isTauTy (FunTy a b) = isTauTy a && isTauTy b
+isTauTy (PredTy p) = isTauTy (predRepTy p)
+isTauTy (NoteTy _ ty) = isTauTy ty
+isTauTy other = False
\end{code}
\begin{code}
-mkRhoTy :: [(Class, [GenType flexi])] -> GenType flexi -> GenType flexi
-mkRhoTy theta ty = foldr (\(c,t) r -> FunTy (mkDictTy c t) r) ty theta
+mkRhoTy :: [PredType] -> Type -> Type
+mkRhoTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
-splitRhoTy :: GenType flexi -> ([(Class, [GenType flexi])], GenType flexi)
+splitRhoTy :: Type -> ([PredType], 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)
+ 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 _ ty) ts = split orig_ty ty ts
+ split orig_ty ty ts = (reverse ts, orig_ty)
\end{code}
+isSigmaType returns true of any qualified type. It doesn't *necessarily* have
+any foralls. E.g.
+ f :: (?x::Int) => Int -> Int
\begin{code}
mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
-splitSigmaTy :: GenType flexi -> ([GenTyVar flexi], [(Class, [GenType flexi])], GenType flexi)
+isSigmaTy :: Type -> Bool
+isSigmaTy (ForAllTy tyvar ty) = True
+isSigmaTy (FunTy a b) = isPredTy a
+isSigmaTy (NoteTy _ ty) = isSigmaTy ty
+isSigmaTy _ = False
+
+splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
splitSigmaTy ty =
(tyvars, theta, tau)
where
(theta,tau) = splitRhoTy rho
\end{code}
+\begin{code}
+getDFunTyKey :: Type -> OccName -- Get some string from a type, to be used to
+ -- construct a dictionary function name
+getDFunTyKey (TyVarTy tv) = getOccName tv
+getDFunTyKey (TyConApp tc _) = getOccName tc
+getDFunTyKey (AppTy fun _) = getDFunTyKey fun
+getDFunTyKey (NoteTy _ t) = getDFunTyKey t
+getDFunTyKey (FunTy arg _) = getOccName funTyCon
+getDFunTyKey (ForAllTy _ t) = getDFunTyKey t
+-- PredTy shouldn't happen
+\end{code}
+
%************************************************************************
%* *
Finding the kind of a type
~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
--- typeKind is only ever used on Types, never Kinds
--- If it were used on Kinds, the typeKind of FunTy would not be boxedTypeKind;
--- yet at the type level functions are boxed even if neither argument nor
--- result are boxed. This seems pretty fishy to me.
-
-typeKind :: GenType flexi -> Kind
+typeKind :: Type -> Kind
-typeKind (TyVarTy tyvar) = tyVarKind tyvar
+typeKind (TyVarTy tyvar) = tyVarKind tyvar
typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
typeKind (NoteTy _ ty) = typeKind ty
-typeKind (FunTy fun arg) = boxedTypeKind
+typeKind (PredTy _) = boxedTypeKind -- Predicates are always
+ -- represented by boxed types
typeKind (AppTy fun arg) = funResultTy (typeKind fun)
-typeKind (ForAllTy _ _) = boxedTypeKind
+
+typeKind (FunTy arg res) = fix_up (typeKind res)
+ where
+ fix_up (TyConApp tycon _) | tycon == typeCon
+ || tycon == openKindCon = boxedTypeKind
+ 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 boxed 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}
Free variables of a type
~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tyVarsOfType :: GenType flexi -> GenTyVarSet flexi
+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 (PredTy p) = tyVarsOfPred p
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 :: [GenType flexi] -> GenTyVarSet flexi
+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
+
+tyVarsOfTheta :: ThetaType -> TyVarSet
+tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet
+
-- Add a Note with the free tyvars to the top of the type
-addFreeTyVars :: GenType flexi -> GenType flexi
-addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
-addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
+-- (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 :: GenType flexi -> NameSet
+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 (PredTy p) = namesOfType (predRepTy p)
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)
%************************************************************************
%* *
-\subsection{Instantiating a type}
+\subsection{TidyType}
%* *
%************************************************************************
-@substTy@ applies a substitution to a type. It deals correctly with name capture.
-
-\begin{code}
-substTy :: GenTyVarSubst flexi -> GenType flexi -> GenType flexi
-substTy tenv ty = subst_ty tenv tset ty
- where
- tset = foldVarEnv (unionVarSet . tyVarsOfType) emptyVarSet tenv
- -- If ty doesn't have any for-alls, then this thunk
- -- will never be evaluated
-\end{code}
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
-@fullSubstTy@ is like @substTy@ except that it needs to be given a set
-of in-scope type variables. In exchange it's a bit more efficient, at least
-if you happen to have that set lying around.
+It doesn't change the uniques at all, just the print names.
\begin{code}
-fullSubstTy :: GenTyVarSubst flexi -- Substitution to apply
- -> GenTyVarSet flexi -- Superset of the free tyvars of
- -- the range of the tyvar env
- -> GenType flexi -> GenType flexi
--- ASSUMPTION: The substitution is idempotent.
--- Equivalently: No tyvar is both in scope, and in the domain of the substitution.
-fullSubstTy tenv tset ty | isEmptyVarEnv tenv = ty
- | otherwise = subst_ty tenv tset ty
-
--- subst_ty does the business
-subst_ty tenv tset ty
- = go ty
+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
- go (TyConApp tc tys) = TyConApp tc (map go tys)
- go (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (go ty1)) (go ty2)
- go (NoteTy (FTVNote _) ty2) = go ty2 -- Discard the free tyvar note
- go (FunTy arg res) = FunTy (go arg) (go res)
- go (AppTy fun arg) = mkAppTy (go fun) (go arg)
- go ty@(TyVarTy tv) = case (lookupVarEnv tenv tv) of
- Nothing -> ty
- Just ty' -> ty'
- go (ForAllTy tv ty) = case substTyVar tenv tset tv of
- (tenv', tset', tv') -> ForAllTy tv' (subst_ty tenv' tset' ty)
-
-substTyVar :: GenTyVarSubst flexi -> GenTyVarSet flexi -> GenTyVar flexi
- -> (GenTyVarSubst flexi, GenTyVarSet flexi, GenTyVar flexi)
-
-substTyVar tenv tset tv
- | not (tv `elemVarSet` tset) -- No need to clone
- -- But must delete from substitution
- = (tenv `delVarEnv` tv, tset `extendVarSet` tv, tv)
-
- | otherwise -- The forall's variable is in scope so
- -- we'd better rename it away from the in-scope variables
- -- Extending the substitution to do this renaming also
- -- has the (correct) effect of discarding any existing
- -- substitution for that variable
- = (extendVarEnv tenv tv (TyVarTy tv'), tset `extendVarSet` tv', tv')
- where
- tv' = uniqAway tset tv
-\end{code}
+ name = tyVarName tyvar
+tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
-@substFlexiTy@ applies a substitution to a (GenType flexi1) returning
-a (GenType flexi2). Note that we convert from one flexi status to another.
+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 (PredTy p) = PredTy (go_pred p)
+ 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
+
+ go_pred (Class c tys) = Class c (tidyTypes env tys)
+ go_pred (IParam n ty) = IParam n (go ty)
+
+tidyTypes env tys = map (tidyType env) tys
+\end{code}
-Two assumptions, for (substFlexiTy env ty)
- (a) the substitution, env, must cover all free tyvars of the type, ty
- (b) the free vars of the range of the substitution must be
- different than any of the forall'd variables in the type, ty
-The latter assumption is reasonable because, after all, ty has a different
-type to the range of the substitution.
+@tidyOpenType@ grabs the free type variables, tidies them
+and then uses @tidyType@ to work over the type itself
\begin{code}
-substFlexiTy :: GenTyVarSubst flexi2 -> GenType flexi1 -> GenType flexi2
-substFlexiTy env ty = go ty
+tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
+tidyOpenType env ty
+ = (env', tidyType env' ty)
where
- go (TyVarTy tv) = case lookupVarEnv env tv of
- Just ty -> ty
- Nothing -> pprPanic "substFlexiTy" (ppr tv)
- go (TyConApp tc tys) = TyConApp tc (map go tys)
- go (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (go ty1)) (go ty2)
- go (NoteTy (FTVNote _) ty2) = go ty2 -- Discard free tyvar note
- go (FunTy arg res) = FunTy (go arg) (go res)
- go (AppTy fun arg) = mkAppTy (go fun) (go arg)
- go (ForAllTy tv ty) = ForAllTy tv' (substFlexiTy env' ty)
- where
- tv' = removeTyVarFlexi tv
- env' = extendVarEnv env tv (TyVarTy tv')
-
-substFlexiTheta :: GenTyVarSubst flexi2 -> [(Class, [GenType flexi1])]
- -> [(Class, [GenType flexi2])]
-substFlexiTheta env theta = [(clas, map (substFlexiTy env) tys) | (clas,tys) <- theta]
+ 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{Boxedness and liftedness}
%************************************************************************
\begin{code}
-isUnboxedType :: GenType flexi -> Bool
+isUnboxedType :: Type -> Bool
isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
-isUnLiftedType :: GenType flexi -> Bool
-isUnLiftedType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isUnLiftedTyCon tc
- other -> False
+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
-isUnboxedTupleType :: GenType flexi -> Bool
+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
-isAlgType :: GenType flexi -> Bool
+-- Should only be applied to *types*; hence the assert
+isAlgType :: Type -> Bool
isAlgType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isAlgTyCon tc
+ 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
-typePrimRep :: GenType flexi -> PrimRep
-typePrimRep ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> tyConPrimRep tc
- other -> PtrRep
+isNewType :: Type -> Bool
+isNewType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isNewTyCon tc
+ other -> False
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Sequencing on types
+%* *
+%************************************************************************
+
+\begin{code}
+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 (PredTy p) = seqPred p
+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` ()
+
+seqPred :: PredType -> ()
+seqPred (Class c tys) = c `seq` seqTypes tys
+seqPred (IParam n ty) = n `seq` seqType ty
+\end{code}
+
+
%************************************************************************
%* *
\subsection{Equality on types}
%* *
%************************************************************************
+
For the moment at least, type comparisons don't work if
there are embedded for-alls.
\begin{code}
-instance Eq (GenType flexi) where
- ty1 == ty2 = case ty1 `cmpTy` ty2 of { EQ -> True; other -> False }
+instance Eq Type where
+ ty1 == ty2 = case ty1 `compare` ty2 of { EQ -> True; other -> False }
-instance Ord (GenType flexi) where
- compare ty1 ty2 = cmpTy ty1 ty2
+instance Ord Type where
+ compare ty1 ty2 = cmpTy emptyVarEnv ty1 ty2
-cmpTy :: GenType flexi -> GenType flexi -> Ordering
-cmpTy ty1 ty2
- = cmp emptyVarEnv ty1 ty2
- where
+cmpTy :: TyVarEnv TyVar -> Type -> Type -> Ordering
-- The "env" maps type variables in ty1 to type variables in ty2
-- So when comparing for-alls.. (forall tv1 . t1) (forall tv2 . t2)
-- we in effect substitute tv2 for tv1 in t1 before continuing
- lookup env tv1 = case lookupVarEnv env tv1 of
- Just tv2 -> tv2
- Nothing -> tv1
-- Get rid of NoteTy
- cmp env (NoteTy _ ty1) ty2 = cmp env ty1 ty2
- cmp env ty1 (NoteTy _ ty2) = cmp env ty1 ty2
-
+cmpTy env (NoteTy _ ty1) ty2 = cmpTy env ty1 ty2
+cmpTy env ty1 (NoteTy _ ty2) = cmpTy env ty1 ty2
+
+ -- Get rid of PredTy
+cmpTy env (PredTy p1) (PredTy p2) = cmpPred env p1 p2
+cmpTy env (PredTy p1) ty2 = cmpTy env (predRepTy p1) ty2
+cmpTy env ty1 (PredTy p2) = cmpTy env ty1 (predRepTy p2)
+
-- Deal with equal constructors
- cmp env (TyVarTy tv1) (TyVarTy tv2) = lookup env tv1 `compare` tv2
- cmp env (AppTy f1 a1) (AppTy f2 a2) = cmp env f1 f2 `thenCmp` cmp env a1 a2
- cmp env (FunTy f1 a1) (FunTy f2 a2) = cmp env f1 f2 `thenCmp` cmp env a1 a2
- cmp env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 `compare` tc2) `thenCmp` (cmps env tys1 tys2)
- cmp env (ForAllTy tv1 t1) (ForAllTy tv2 t2) = cmp (extendVarEnv env tv1 tv2) t1 t2
+cmpTy env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of
+ Just tv1a -> tv1a `compare` tv2
+ Nothing -> tv1 `compare` tv2
+
+cmpTy env (AppTy f1 a1) (AppTy f2 a2) = cmpTy env f1 f2 `thenCmp` cmpTy env a1 a2
+cmpTy env (FunTy f1 a1) (FunTy f2 a2) = cmpTy env f1 f2 `thenCmp` cmpTy env a1 a2
+cmpTy env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 `compare` tc2) `thenCmp` (cmpTys env tys1 tys2)
+cmpTy env (ForAllTy tv1 t1) (ForAllTy tv2 t2) = cmpTy (extendVarEnv env tv1 tv2) t1 t2
-- Deal with the rest: TyVarTy < AppTy < FunTy < TyConApp < ForAllTy
- cmp env (AppTy _ _) (TyVarTy _) = GT
+cmpTy env (AppTy _ _) (TyVarTy _) = GT
- cmp env (FunTy _ _) (TyVarTy _) = GT
- cmp env (FunTy _ _) (AppTy _ _) = GT
+cmpTy env (FunTy _ _) (TyVarTy _) = GT
+cmpTy env (FunTy _ _) (AppTy _ _) = GT
- cmp env (TyConApp _ _) (TyVarTy _) = GT
- cmp env (TyConApp _ _) (AppTy _ _) = GT
- cmp env (TyConApp _ _) (FunTy _ _) = GT
+cmpTy env (TyConApp _ _) (TyVarTy _) = GT
+cmpTy env (TyConApp _ _) (AppTy _ _) = GT
+cmpTy env (TyConApp _ _) (FunTy _ _) = GT
- cmp env (ForAllTy _ _) other = GT
+cmpTy env (ForAllTy _ _) other = GT
- cmp env _ _ = LT
-
- cmps env [] [] = EQ
- cmps env (t:ts) [] = GT
- cmps env [] (t:ts) = LT
- cmps env (t1:t1s) (t2:t2s) = cmp env t1 t2 `thenCmp` cmps env t1s t2s
-\end{code}
-
-
-
-%************************************************************************
-%* *
-\subsection{Grime}
-%* *
-%************************************************************************
+cmpTy env _ _ = LT
+cmpTys env [] [] = EQ
+cmpTys env (t:ts) [] = GT
+cmpTys env [] (t:ts) = LT
+cmpTys env (t1:t1s) (t2:t2s) = cmpTy env t1 t2 `thenCmp` cmpTys env t1s t2s
+\end{code}
\begin{code}
-showTypeCategory :: Type -> Char
- {-
- {C,I,F,D} char, int, float, double
- T tuple
- S other single-constructor type
- {c,i,f,d} unboxed ditto
- t *unpacked* tuple
- s *unpacked" single-cons...
-
- v void#
- a primitive array
-
- E enumeration type
- + dictionary, unless it's a ...
- L List
- > function
- M other (multi-constructor) data-con type
- . other type
- - reserved for others to mark as "uninteresting"
- -}
-showTypeCategory ty
- = if isDictTy ty
- then '+'
- else
- case splitTyConApp_maybe ty of
- Nothing -> if maybeToBool (splitFunTy_maybe ty)
- then '>'
- else '.'
-
- Just (tycon, _) ->
- let utc = getUnique tycon in
- if utc == charDataConKey then 'C'
- else if utc == intDataConKey then 'I'
- else if utc == floatDataConKey then 'F'
- else if utc == doubleDataConKey then 'D'
- else if utc == integerDataConKey then 'J'
- else if utc == charPrimTyConKey then 'c'
- else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
- || utc == addrPrimTyConKey) then 'i'
- else if utc == floatPrimTyConKey then 'f'
- else if utc == doublePrimTyConKey then 'd'
- else if isPrimTyCon tycon {- array, we hope -} then 'A'
- else if isEnumerationTyCon tycon then 'E'
- else if isTupleTyCon tycon then 'T'
- else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
- else if utc == listTyConKey then 'L'
- else 'M' -- oh, well...
+instance Eq PredType where
+ p1 == p2 = case p1 `compare` p2 of { EQ -> True; other -> False }
+
+instance Ord PredType where
+ compare p1 p2 = cmpPred emptyVarEnv p1 p2
+
+cmpPred :: TyVarEnv TyVar -> PredType -> PredType -> Ordering
+cmpPred env (IParam n1 t) (IParam n2 t2) = n1 `compare` n2
+ -- Just compare the names!
+cmpPred env (Class c1 tys1) (Class c2 tys2) = (c1 `compare` c2) `thenCmp` (cmpTys env tys1 tys2)
+cmpPred env (IParam _ _) (Class _ _) = LT
+cmpPred env (Class _ _) (IParam _ _) = GT
\end{code}
projects / ghc-hetmet.git / blobdiff