+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+
\begin{code}
module Type (
- GenType(..), Type,
+ -- 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,
+
+ -- exports from this module:
+ hasMoreBoxityInfo, defaultKind,
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
- mkAppTy, mkAppTys, splitAppTy, splitAppTys,
+ mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
- mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys,
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
+ funResultTy, funArgTy, zipFunTys,
mkTyConApp, mkTyConTy, splitTyConApp_maybe,
- splitAlgTyConApp_maybe, splitAlgTyConApp,
- mkDictTy, splitDictTy_maybe, isDictTy,
+ splitAlgTyConApp_maybe, splitAlgTyConApp,
- mkSynTy, isSynTy,
+ -- Predicates and the like
+ mkDictTy, mkDictTys, mkPredTy, splitPredTy_maybe,
+ splitDictTy_maybe, isDictTy, predRepTy,
+
+ 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,
+ applyTy, applyTys, hoistForAllTys,
- TauType, RhoType, SigmaType, ThetaType,
- isTauTy,
- mkRhoTy, splitRhoTy,
- mkSigmaTy, splitSigmaTy,
+ TauType, RhoType, SigmaType, PredType(..), ThetaType,
+ ClassPred, ClassContext, mkClassPred,
+ getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
+ isTauTy, mkRhoTy, splitRhoTy,
+ mkSigmaTy, isSigmaTy, splitSigmaTy,
+ getDFunTyKey,
- isUnpointedType, isUnboxedType, typePrimRep,
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
- matchTy, matchTys,
+ -- Free variables
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
+ namesOfType, typeKind, addFreeTyVars,
- tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVar, tidyTyVars,
+ tidyTopType,
- instantiateTy, instantiateTauTy, instantiateThetaTy, applyToTyVars,
+ -- Seq
+ seqType, seqTypes
- showTypeCategory
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Id ( Id )
+-- 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 Class ( classTyCon, Class )
-import Kind ( mkBoxedTypeKind, resultKind, Kind )
-import TyCon ( mkFunTyCon, isFunTyCon, isEnumerationTyCon, isTupleTyCon, maybeTyConSingleCon,
- isPrimTyCon, isAlgTyCon, isSynTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn,
- tyConPrimRep, tyConClass_maybe, TyCon )
-import TyVar ( GenTyVarSet, TyVarEnv, GenTyVar, TyVar,
- tyVarKind, tyVarFlexi, emptyTyVarSet, unionTyVarSets, minusTyVarSet,
- unitTyVarSet, lookupTyVarEnv, delFromTyVarEnv, zipTyVarEnv, mkTyVarEnv,
- emptyTyVarEnv, isEmptyTyVarEnv, addToTyVarEnv )
-import Name ( NamedThing(..),
- NameSet(..), unionNameSets, emptyNameSet, unitNameSet, minusNameSet
+import Var ( TyVar, Var, UVar,
+ tyVarKind, tyVarName, setTyVarName, isId, idType,
+ )
+import VarEnv
+import VarSet
+
+import Name ( Name, NamedThing(..), OccName, mkLocalName, tidyOccName )
+import NameSet
+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 Maybes ( maybeToBool, assocMaybe )
-import PrimRep ( PrimRep(..) )
-import Unique -- quite a few *Keys
-import Util ( thenCmp, panic, assertPanic )
+import SrcLoc ( noSrcLoc )
+import PrimRep ( PrimRep(..), isFollowableRep )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList, thenCmp )
+import Outputable
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
\end{code}
-
%************************************************************************
%* *
-\subsection{The data type}
+\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
-
\begin{code}
-type Type = GenType Unused -- Used after typechecker
-
-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)
-
- | SynTy -- Saturated application of a type synonym
- (GenType flexi) -- The unexpanded version; always a TyConTy
- (GenType flexi) -- The expanded version
-
- | ForAllTy
- (GenTyVar flexi)
- (GenType flexi) -- TypeKind
+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 (SynTy _ t) = getTyVar msg t
+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 (SynTy _ t) = getTyVar_maybe t
+getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
+getTyVar_maybe (PredTy p) = getTyVar_maybe (predRepTy p)
getTyVar_maybe other = Nothing
-isTyVarTy :: GenType flexi -> Bool
-isTyVarTy (TyVarTy tv) = True
-isTyVarTy (SynTy _ ty) = isTyVarTy ty
-isTyVarTy other = False
+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 (SynTy _ ty1) = mk_app ty1
+ 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 (SynTy _ ty1) = mk_app ty1
+ 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
-
-splitAppTy :: GenType flexi -> (GenType flexi, GenType flexi)
-splitAppTy (FunTy ty1 ty2) = (TyConApp mkFunTyCon [ty1], ty2)
-splitAppTy (AppTy ty1 ty2) = (ty1, ty2)
-splitAppTy (SynTy _ ty) = splitAppTy ty
-splitAppTy (TyConApp tc tys) = split tys []
+ 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 (PredTy p) = splitAppTy_maybe (predRepTy p)
+splitAppTy_maybe (TyConApp tc []) = Nothing
+splitAppTy_maybe (TyConApp tc tys) = split tys []
where
- split [ty2] acc = (TyConApp tc (reverse acc), ty2)
+ split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
split (ty:tys) acc = split tys (ty:acc)
-splitAppTy other = panic "splitAppTy"
-splitAppTys :: GenType flexi -> (GenType flexi, [GenType flexi])
+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 (SynTy _ ty) args = split orig_ty ty 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 mkFunTyCon [], [ty1,ty2])
+ (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}
~~~~~
\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 (SynTy _ ty) = splitFunTy_maybe ty
+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 (SynTy _ ty) = split args orig_ty ty
+ 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)
-\end{code}
+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 (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}
---------------------------------------------------------------------
~~~~~~~~
\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 (mkFunTyCon, [arg,res])
-splitTyConApp_maybe (SynTy _ ty) = splitTyConApp_maybe ty
+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], [Id])
+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 (SynTy _ ty) = splitAlgTyConApp_maybe ty
-splitAlgTyConApp_maybe other = Nothing
+ | 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], [Id])
+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 (SynTy _ 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 (SynTy _ 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 (SynTy _ ty) = isDictTy ty
-isDictTy other = False
+splitAlgTyConApp (NoteTy _ ty) = splitAlgTyConApp ty
+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)
- SynTy (TyConApp syn_tycon tys)
- (instantiateTauTy (zipTyVarEnv 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
-isSynTy (SynTy _ _) = True
-isSynTy other = False
+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 (SynTy _ ty) = splitForAllTy_maybe ty
-splitForAllTy_maybe (ForAllTy tyvar ty) = Just(tyvar, ty)
-splitForAllTy_maybe _ = Nothing
+---------------------------------------------------------------------
+ ForAllTy
+ ~~~~~~~~
-isForAllTy :: GenType flexi -> Bool
-isForAllTy (SynTy _ 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 (SynTy _ 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 now in CoreUtils)
-\begin{code}
-applyTy :: GenType flexi -> GenType flexi -> GenType flexi
-applyTy (SynTy _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = instantiateTy (mkTyVarEnv [(tv,arg)]) ty
-applyTy other arg = panic "applyTy"
+Applying a for-all to its arguments
-applyTys :: GenType flexi -> [GenType flexi] -> GenType flexi
+\begin{code}
+applyTy :: Type -> Type -> Type
+applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (NoteTy note@(UsgForAll _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (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 [] = instantiateTy (mkTyVarEnv env) ty
- go env (SynTy _ 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 (SynTy _ 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 (SynTy _ 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 :: GenType flexi -> Kind
-
-typeKind (TyVarTy tyvar) = tyVarKind tyvar
-typeKind (TyConApp tycon tys) = foldr (\_ k -> resultKind k) (tyConKind tycon) tys
-typeKind (SynTy _ ty) = typeKind ty
-typeKind (FunTy fun arg) = mkBoxedTypeKind
-typeKind (AppTy fun arg) = resultKind (typeKind fun)
-typeKind (ForAllTy _ _) = mkBoxedTypeKind
+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 (PredTy _) = boxedTypeKind -- Predicates are always
+ -- represented by boxed types
+typeKind (AppTy fun arg) = funResultTy (typeKind fun)
+
+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 (TyVarTy tv) = unitTyVarSet tv
+tyVarsOfType :: Type -> TyVarSet
+tyVarsOfType (TyVarTy tv) = unitVarSet tv
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
-tyVarsOfType (SynTy ty1 ty2) = tyVarsOfType ty1
-tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionTyVarSets` tyVarsOfType res
-tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionTyVarSets` tyVarsOfType arg
-tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusTyVarSet` unitTyVarSet tyvar
-
-tyVarsOfTypes :: [GenType flexi] -> GenTyVarSet flexi
-tyVarsOfTypes tys = foldr (unionTyVarSets.tyVarsOfType) emptyTyVarSet 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 :: [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
+-- (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 (SynTy ty1 ty2) = namesOfType ty1
+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}
%* *
%************************************************************************
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
+
+It doesn't change the uniques at all, just the print names.
+
\begin{code}
-instantiateTy :: TyVarEnv (GenType flexi) -> GenType flexi -> GenType flexi
-instantiateTauTy :: TyVarEnv (GenType flexi2) -> GenType flexi1 -> GenType flexi2
-
-
--- instantiateTy applies a type environment to a type.
--- It can handle shadowing; for example:
--- f = /\ t1 t2 -> \ d ->
--- letrec f' = /\ t1 -> \x -> ...(f' t1 x')...
--- in f' t1
--- Here, when we clone t1 to t1', say, we'll come across shadowing
--- when applying the clone environment to the type of f'.
---
--- As a sanity check, we should also check that name capture
--- doesn't occur, but that means keeping track of the free variables of the
--- range of the TyVarEnv, which I don't do just yet.
-
-instantiateTy tenv ty
- | isEmptyTyVarEnv tenv
- = ty
+tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+tidyTyVar env@(tidy_env, subst) tyvar
+ = case lookupVarEnv subst tyvar of
- | otherwise
- = go tenv ty
+ 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
+
+tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
+
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(tidy_env, subst) ty
+ = go ty
where
- go tenv ty@(TyVarTy tv) = case (lookupTyVarEnv tenv tv) of
- Nothing -> ty
- Just ty -> ty
- go tenv (TyConApp tc tys) = TyConApp tc (map (go tenv) tys)
- go tenv (SynTy ty1 ty2) = SynTy (go tenv ty1) (go tenv ty2)
- go tenv (FunTy arg res) = FunTy (go tenv arg) (go tenv res)
- go tenv (AppTy fun arg) = mkAppTy (go tenv fun) (go tenv arg)
- go tenv (ForAllTy tv ty) = ForAllTy tv (go tenv' ty)
+ 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
- tenv' = case lookupTyVarEnv tenv tv of
- Nothing -> tenv
- Just _ -> delFromTyVarEnv tenv tv
+ (envp, tvp) = tidyTyVar env tv
--- 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
+ 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
-instantiateTauTy tenv ty = applyToTyVars lookup ty
- where
- lookup tv = case lookupTyVarEnv tenv tv of
- Just ty -> ty -- Must succeed
+ 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}
-instantiateThetaTy :: TyVarEnv Type -> ThetaType -> ThetaType
-instantiateThetaTy tenv theta
- = [(clas, map (instantiateTauTy tenv) tys) | (clas, tys) <- theta]
+@tidyOpenType@ grabs the free type variables, tidies them
+and then uses @tidyType@ to work over the type itself
-applyToTyVars :: (GenTyVar flexi1 -> GenType flexi2)
- -> GenType flexi1
- -> GenType flexi2
-applyToTyVars f ty = go ty
+\begin{code}
+tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
+tidyOpenType env ty
+ = (env', tidyType env' ty)
where
- go (TyVarTy tv) = f tv
- go (TyConApp tc tys) = TyConApp tc (map go tys)
- go (SynTy ty1 ty2) = SynTy (go ty1) (go ty2)
- go (FunTy arg res) = FunTy (go arg) (go res)
- go (AppTy fun arg) = mkAppTy (go fun) (go arg)
- go (ForAllTy tv ty) = panic "instantiateTauTy"
+ 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 pointedness}
+\subsection{Boxedness and liftedness}
%* *
%************************************************************************
-A type is
- *unboxed* iff its representation is other than a pointer
- Unboxed types cannot instantiate a type variable
- Unboxed types are always unpointed.
-
- *unpointed* iff it can't be a thunk, and cannot have value bottom
- An unpointed type may or may not be unboxed.
- (E.g. Array# is unpointed, but boxed.)
- An unpointed type *can* instantiate a type variable,
- provided it is boxed.
-
- *primitive* iff it is a built-in type that can't be expressed
- in Haskell
-
-Currently, all primitive types are unpointed, but that's not necessarily
-the case. (E.g. Int could be primitive.)
-
\begin{code}
isUnboxedType :: Type -> Bool
-isUnboxedType ty = case typePrimRep ty of
- PtrRep -> False
- other -> True
-
--- Danger! Currently the unpointed types are precisely
--- the primitive ones, but that might not always be the case
-isUnpointedType :: Type -> Bool
-isUnpointedType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isPrimTyCon tc
+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
-typePrimRep :: Type -> PrimRep
-typePrimRep ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> tyConPrimRep tc
- other -> PtrRep
+-- 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
\end{code}
%************************************************************************
%* *
-\subsection{Matching on types}
+\subsection{Sequencing on types
%* *
%************************************************************************
-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.
-
-@matchTys@ matches corresponding elements of a list of templates and
-types.
-
\begin{code}
-matchTy :: GenType Bool -- Template
- -> GenType flexi -- Proposed instance of template
- -> Maybe (TyVarEnv (GenType flexi)) -- Matching substitution
-
-
-matchTys :: [GenType Bool] -- Templates
- -> [GenType flexi] -- Proposed instance of template
- -> Maybe (TyVarEnv (GenType flexi), -- Matching substitution
- [GenType flexi]) -- Left over instance types
-
-matchTy ty1 ty2 = match ty1 ty2 (\s -> Just s) emptyTyVarEnv
-matchTys tys1 tys2 = match_list tys1 tys2 (\pr -> Just pr) emptyTyVarEnv
+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}
-@match@ is the main function.
-
-\begin{code}
-match :: GenType Bool -> GenType flexi -- Current match pair
- -> (TyVarEnv (GenType flexi) -> Maybe result) -- Continuation
- -> TyVarEnv (GenType flexi) -- Current substitution
- -> Maybe result
-
--- When matching against a type variable, see if the variable
--- has already been bound. If so, check that what it's bound to
--- is the same as ty; if not, bind it and carry on.
-
-match (TyVarTy v) ty k = \s -> if tyVarFlexi v then
- -- v is a template variable
- case lookupTyVarEnv s v of
- Nothing -> k (addToTyVarEnv s v ty)
- Just ty' | ty' == ty -> k s -- Succeeds
- | otherwise -> Nothing -- Fails
- else
- -- v is not a template variable; ty had better match
- -- Can't use (==) because types differ
- case ty of
- TyVarTy v' | uniqueOf v == uniqueOf v'
- -> k s -- Success
- other -> Nothing -- Failure
-
-match (FunTy arg1 res1) (FunTy arg2 res2) k = match arg1 arg2 (match res1 res2 k)
-match (AppTy fun1 arg1) (AppTy fun2 arg2) k = match fun1 fun2 (match arg1 arg2 k)
-match (TyConApp tc1 tys1) (TyConApp tc2 tys2) k | tc1 == tc2
- = match_list tys1 tys2 ( \(s,tys2') ->
- if null tys2' then
- k s -- Succeed
- else
- Nothing -- Fail
- )
-
- -- 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)
-match (SynTy _ ty1) ty2 k = match ty1 ty2 k
-match ty1 (SynTy _ ty2) k = match ty1 ty2 k
-
--- Catch-all fails
-match _ _ _ = \s -> Nothing
-
-match_list [] tys2 k = \s -> k (s, tys2)
-match_list (ty1:tys1) [] k = panic "match_list"
-match_list (ty1:tys1) (ty2:tys2) k = match ty1 ty2 (match_list tys1 tys2 k)
-\end{code}
%************************************************************************
%* *
%* *
%************************************************************************
+
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 emptyTyVarEnv 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 lookupTyVarEnv env tv1 of
- Just tv2 -> tv2
- Nothing -> tv1
- -- Get rid of SynTy
- cmp env (SynTy _ ty1) ty2 = cmp env ty1 ty2
- cmp env ty1 (SynTy _ ty2) = cmp env ty1 ty2
-
+ -- Get rid of NoteTy
+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 (addToTyVarEnv 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 = uniqueOf 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