+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+
\begin{code}
module Type (
- Type(..), TyNote(..), -- Representation visible to friends
+ -- re-exports from TypeRep:
+ Type,
Kind, TyVarSubst,
superKind, superBoxity, -- :: SuperKind
boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
- mkArrowKind, mkArrowKinds, hasMoreBoxityInfo,
+ mkArrowKind, mkArrowKinds, -- mentioned below: hasMoreBoxityInfo,
funTyCon,
+ -- exports from this module:
+ hasMoreBoxityInfo,
+
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
- mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys, funResultTy,
- zipFunTys,
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
+ funResultTy, funArgTy, zipFunTys,
mkTyConApp, mkTyConTy, splitTyConApp_maybe,
- splitAlgTyConApp_maybe, splitAlgTyConApp,
- mkDictTy, splitDictTy_maybe, isDictTy,
+ splitAlgTyConApp_maybe, splitAlgTyConApp,
+ mkDictTy, mkPredTy, splitPredTy_maybe, splitDictTy_maybe, isDictTy,
+
+ mkSynTy, isSynTy, deNoteType,
- 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,
+ isForAllTy, applyTy, applyTys, mkPiType, hoistForAllTys,
- TauType, RhoType, SigmaType, ThetaType,
- isTauTy,
- mkRhoTy, splitRhoTy,
+ TauType, RhoType, SigmaType, PredType(..), ThetaType,
+ ClassPred, ClassContext, mkClassPred,
+ getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
+ isTauTy, mkRhoTy, splitRhoTy,
mkSigmaTy, splitSigmaTy,
-- Lifting and boxity
- isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType,
- typePrimRep,
+ isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
-- Free variables
- tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
- addFreeTyVars,
-
- -- Substitution
- substTy, substTheta, fullSubstTy, substTyVar,
- substTopTy, substTopTheta,
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
+ namesOfType, typeKind, addFreeTyVars,
-- Tidying up for printing
tidyType, tidyTypes,
tidyOpenType, tidyOpenTypes,
tidyTyVar, tidyTyVars,
- tidyTopType
+ tidyTopType,
+
+ -- Seq
+ seqType, seqTypes
+
) where
#include "HsVersions.h"
-import {-# SOURCE #-} DataCon( DataCon )
-import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
+-- 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, pprPred ) -- Only called in debug messages
+import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
-- friends:
-import Var ( Id, TyVar, IdOrTyVar,
- tyVarKind, tyVarName, isId, idType, setTyVarName
+import Var ( TyVar, Var, UVar,
+ tyVarKind, tyVarName, setTyVarName, isId, idType,
)
import VarEnv
import VarSet
-import Name ( NamedThing(..), Provenance(..), ExportFlag(..),
- mkWiredInTyConName, mkGlobalName, mkLocalName, mkKindOccFS, tcName,
- tidyOccName, TidyOccEnv
+import Name ( Name, NamedThing(..), mkLocalName, tidyOccName
)
import NameSet
import Class ( classTyCon, Class )
-import TyCon ( TyCon, KindCon,
- mkFunTyCon, mkKindCon, mkSuperKindCon,
- matchesTyCon, isUnboxedTupleTyCon, isUnLiftedTyCon,
- isFunTyCon, isDataTyCon,
+import TyCon ( TyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
+ isFunTyCon, isDataTyCon, isNewTyCon, newTyConRep,
isAlgTyCon, isSynTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn,
+ tyConKind, tyConDataCons, getSynTyConDefn,
tyConPrimRep, tyConClass_maybe
)
-- others
-import BasicTypes ( Unused )
-import SrcLoc ( mkBuiltinSrcLoc, noSrcLoc )
-import PrelMods ( pREL_GHC )
+import SrcLoc ( noSrcLoc )
import Maybes ( maybeToBool )
import PrimRep ( PrimRep(..), isFollowableRep )
-import Unique -- quite a few *Keys
-import Util ( thenCmp, mapAccumL, seqList, ($!) )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList )
import Outputable
-
-\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, whether declared
- with "data" or "newtype".
- 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.
-
- *data* A type declared with "data". Also boxed tuples.
-
- *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}
-%* *
-%************************************************************************
-
-
-\begin{code}
-type SuperKind = Type
-type Kind = Type
-
-type TyVarSubst = TyVarEnv Type
-
-data Type
- = TyVarTy TyVar
-
- | AppTy
- Type -- Function is *not* a TyConApp
- Type
-
- | TyConApp -- Application of a TyCon
- TyCon -- *Invariant* saturated appliations of FunTyCon and
- -- synonyms have their own constructors, below.
- [Type] -- Might not be saturated.
-
- | FunTy -- Special case of TyConApp: TyConApp FunTyCon [t1,t2]
- Type
- Type
-
- | NoteTy -- Saturated application of a type synonym
- TyNote
- Type -- The expanded version
-
- | ForAllTy
- TyVar
- Type -- TypeKind
-
-data TyNote
- = SynNote Type -- The unexpanded version of the type synonym; always a TyConApp
- | FTVNote TyVarSet -- The free type variables of the noted expression
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
\end{code}
%************************************************************************
%* *
-\subsection{Kinds}
+\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
-Kinds
-~~~~~
-k::K = Type bx
- | k -> k
- | kv
-
-kv :: KX is a kind variable
-
-Type :: BX -> KX
-
-bx::BX = Boxed
- | Unboxed
- | AnyBox -- Used *only* for special built-in things
- -- like error :: forall (a::*?). String -> a
- -- Here, the 'a' can be instantiated to a boxed or
- -- unboxed type.
- | bv
-
-bxv :: BX is a boxity variable
-
-sk = KX -- A kind
- | BX -- A boxity
- | sk -> sk -- In ptic (BX -> KX)
-
-\begin{code}
-mk_kind_name key str = mkGlobalName key pREL_GHC (mkKindOccFS tcName 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.
- -- It's used for both Kinds and Boxities
-\end{code}
-
-Define KX, BX.
-
-\begin{code}
-superKind :: SuperKind -- KX, the type of all kinds
-superKindName = mk_kind_name kindConKey SLIT("KX")
-superKind = TyConApp (mkSuperKindCon superKindName) []
-
-superBoxity :: SuperKind -- BX, the type of all boxities
-superBoxityName = mk_kind_name boxityConKey SLIT("BX")
-superBoxity = TyConApp (mkSuperKindCon superBoxityName) []
-\end{code}
-
-Define Boxed, Unboxed, AnyBox
-
-\begin{code}
-boxedKind, unboxedKind, anyBoxKind :: Kind -- Of superkind superBoxity
-
-boxedConName = mk_kind_name boxedConKey SLIT("*")
-boxedKind = TyConApp (mkKindCon boxedConName superBoxity) []
-
-unboxedConName = mk_kind_name unboxedConKey SLIT("#")
-unboxedKind = TyConApp (mkKindCon unboxedConName superBoxity) []
-
-anyBoxConName = mk_kind_name anyBoxConKey SLIT("?")
-anyBoxCon = mkKindCon anyBoxConName superBoxity -- A kind of wild card
-anyBoxKind = TyConApp anyBoxCon []
-\end{code}
-
-Define Type
-
-\begin{code}
-typeCon :: KindCon
-typeConName = mk_kind_name typeConKey SLIT("Type")
-typeCon = mkKindCon typeConName (superBoxity `FunTy` superKind)
-\end{code}
-
-Define (Type Boxed), (Type Unboxed), (Type AnyBox)
-
-\begin{code}
-boxedTypeKind, unboxedTypeKind, openTypeKind :: Kind
-boxedTypeKind = TyConApp typeCon [boxedKind]
-unboxedTypeKind = TyConApp typeCon [unboxedKind]
-openTypeKind = TyConApp typeCon [anyBoxKind]
-
-mkArrowKind :: Kind -> Kind -> Kind
-mkArrowKind k1 k2 = k1 `FunTy` k2
-
-mkArrowKinds :: [Kind] -> Kind -> Kind
-mkArrowKinds arg_kinds result_kind = foldr mkArrowKind result_kind arg_kinds
-\end{code}
-
\begin{code}
hasMoreBoxityInfo :: Kind -> Kind -> Bool
hasMoreBoxityInfo k1 k2
%************************************************************************
%* *
-\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}
-
-
-
-%************************************************************************
-%* *
\subsection{Constructor-specific functions}
%* *
%************************************************************************
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 )
+ mk_app orig_ty1
where
mk_app (NoteTy _ ty1) = mk_app ty1
mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
-- 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 )
+ 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 :: Type -> Maybe (Type, Type)
splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2)
mkFunTys :: [Type] -> Type -> Type
mkFunTys tys ty = foldr FunTy ty tys
+splitFunTy :: Type -> (Type, Type)
+splitFunTy (FunTy arg res) = (arg, res)
+splitFunTy (NoteTy _ ty) = splitFunTy ty
+
splitFunTy_maybe :: Type -> Maybe (Type, Type)
splitFunTy_maybe (FunTy arg res) = Just (arg, res)
splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
splitFunTy_maybe other = Nothing
-
splitFunTys :: Type -> ([Type], Type)
splitFunTys ty = split [] ty ty
where
split args orig_ty (NoteTy _ ty) = split args orig_ty ty
split args orig_ty ty = (reverse args, orig_ty)
+splitFunTysN :: String -> Int -> Type -> ([Type], Type)
+splitFunTysN msg orig_n orig_ty = split orig_n [] orig_ty orig_ty
+ where
+ split 0 args syn_ty ty = (reverse args, syn_ty)
+ split n args syn_ty (FunTy arg res) = split (n-1) (arg:args) res res
+ split n args syn_ty (NoteTy _ ty) = split n args syn_ty ty
+ split n args syn_ty ty = pprPanic ("splitFunTysN: " ++ msg) (int orig_n <+> pprType orig_ty)
+
zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
zipFunTys orig_xs orig_ty = split [] orig_xs orig_ty orig_ty
where
funResultTy (FunTy arg res) = res
funResultTy (NoteTy _ ty) = funResultTy ty
funResultTy ty = pprPanic "funResultTy" (pprType ty)
-\end{code}
+funArgTy :: Type -> Type
+funArgTy (FunTy arg res) = arg
+funArgTy (NoteTy _ ty) = funArgTy ty
+funArgTy ty = pprPanic "funArgTy" (pprType ty)
+\end{code}
---------------------------------------------------------------------
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 other = Nothing
mkDictTy :: Class -> [Type] -> Type
mkDictTy clas tys = TyConApp (classTyCon clas) tys
+mkPredTy :: PredType -> Type
+mkPredTy (Class clas tys) = TyConApp (classTyCon clas) tys
+mkPredTy (IParam n ty) = NoteTy (IPNote n) ty
+
+{-
splitDictTy_maybe :: Type -> Maybe (Class, [Type])
splitDictTy_maybe (TyConApp tc tys)
| maybeToBool maybe_class
splitDictTy_maybe (NoteTy _ ty) = splitDictTy_maybe ty
splitDictTy_maybe other = Nothing
+-}
+
+splitPredTy_maybe :: Type -> Maybe PredType
+splitPredTy_maybe (TyConApp tc tys)
+ | maybeToBool maybe_class
+ && tyConArity tc == length tys = Just (Class clas tys)
+ where
+ maybe_class = tyConClass_maybe tc
+ Just clas = maybe_class
+
+splitPredTy_maybe (NoteTy (IPNote n) ty)
+ = Just (IParam n ty)
+splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
+splitPredTy_maybe other = Nothing
+
+splitDictTy_maybe :: Type -> Maybe (Class, [Type])
+splitDictTy_maybe ty
+ = case splitPredTy_maybe ty of
+ Just p -> getClassTys_maybe p
+ Nothing -> Nothing
isDictTy :: Type -> Bool
-- This version is slightly more efficient than (maybeToBool . splitDictTy)
isDictTy other = False
\end{code}
-
---------------------------------------------------------------------
SynTy
~~~~~
\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))
- (substTopTy (zipVarEnv tyvars tys) body)
+ (substTy (mkTyVarSubst tyvars tys) body)
where
(tyvars, body) = getSynTyConDefn syn_tycon
interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
+ Representation types
+ ~~~~~~~~~~~~~~~~~~~~
+
+repType looks through
+ (a) for-alls, and
+ (b) newtypes
+ (c) synonyms
+It's useful in the back end where we're not
+interested in newtypes anymore.
+
+\begin{code}
+repType :: Type -> Type
+repType (ForAllTy _ ty) = repType ty
+repType (NoteTy _ ty) = repType ty
+repType ty = case splitNewType_maybe ty of
+ Just ty' -> repType ty' -- Still re-apply repType in case of for-all
+ Nothing -> ty
+
+splitRepFunTys :: Type -> ([Type], Type)
+-- Like splitFunTys, but looks through newtypes and for-alls
+splitRepFunTys ty = split [] (repType ty)
+ where
+ split args (FunTy arg res) = split (arg:args) (repType res)
+ split args ty = (reverse args, ty)
+
+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 (TyConApp tc tys) = case newTyConRep tc of
+ Just rep_ty -> ASSERT( length tys == tyConArity tc )
+ -- The assert should hold because repType should
+ -- only be applied to *types* (of kind *)
+ Just (applyTys rep_ty tys)
+ Nothing -> Nothing
+splitNewType_maybe other = Nothing
+\end{code}
+
+
+
+---------------------------------------------------------------------
+ UsgNote
+ ~~~~~~~
+
+NB: Invariant: if present, usage note is at the very top of the type.
+This should be carefully preserved.
+
+In some parts of the compiler, comments use the _Once Upon a
+Polymorphic Type_ (POPL'99) usage of "rho = generalised
+usage-annotated type; sigma = usage-annotated type; tau =
+usage-annotated type except on top"; unfortunately this conflicts with
+the rho/tau/theta/sigma usage in the rest of the compiler. (KSW
+1999-07)
+
+\begin{code}
+mkUsgTy :: UsageAnn -> Type -> Type
+#ifndef USMANY
+mkUsgTy UsMany ty = ASSERT2( isNotUsgTy ty, pprType ty )
+ ty
+#endif
+mkUsgTy usg ty = ASSERT2( isNotUsgTy ty, pprType ty )
+ NoteTy (UsgNote usg) ty
+
+-- The isUsgTy function is utterly useless if UsManys are omitted.
+-- Be warned! KSW 1999-04.
+isUsgTy :: Type -> Bool
+#ifndef USMANY
+isUsgTy _ = True
+#else
+isUsgTy (NoteTy (UsgForAll _) ty) = isUsgTy ty
+isUsgTy (NoteTy (UsgNote _) _ ) = True
+isUsgTy other = False
+#endif
+
+-- The isNotUsgTy function may return a false True if UsManys are omitted;
+-- in other words, A SSERT( isNotUsgTy ty ) may be useful but
+-- A SSERT( not (isNotUsg ty) ) is asking for trouble. KSW 1999-04.
+isNotUsgTy :: Type -> Bool
+isNotUsgTy (NoteTy (UsgForAll _) _) = False
+isNotUsgTy (NoteTy (UsgNote _) _) = False
+isNotUsgTy other = True
+
+-- splitUsgTy_maybe is not exported, since it is meaningless if
+-- UsManys are omitted. It is used in several places in this module,
+-- however. KSW 1999-04.
+splitUsgTy_maybe :: Type -> Maybe (UsageAnn,Type)
+splitUsgTy_maybe (NoteTy (UsgNote usg) ty2) = ASSERT( isNotUsgTy ty2 )
+ Just (usg,ty2)
+splitUsgTy_maybe ty@(NoteTy (UsgForAll _) _) = pprPanic "splitUsgTy_maybe:" $ pprType ty
+splitUsgTy_maybe ty = Nothing
+
+splitUsgTy :: Type -> (UsageAnn,Type)
+splitUsgTy ty = case splitUsgTy_maybe ty of
+ Just ans -> ans
+ Nothing ->
+#ifndef USMANY
+ (UsMany,ty)
+#else
+ pprPanic "splitUsgTy: no usage annot:" $ pprType ty
+#endif
+
+tyUsg :: Type -> UsageAnn
+tyUsg = fst . splitUsgTy
+
+unUsgTy :: Type -> Type
+-- strip outer usage annotation if present
+unUsgTy ty = case splitUsgTy_maybe ty of
+ Just (_,ty1) -> ASSERT2( isNotUsgTy ty1, pprType ty )
+ ty1
+ Nothing -> ty
+
+mkUsForAllTy :: UVar -> Type -> Type
+mkUsForAllTy uv ty = NoteTy (UsgForAll uv) ty
+
+mkUsForAllTys :: [UVar] -> Type -> Type
+mkUsForAllTys uvs ty = foldr (NoteTy . UsgForAll) ty uvs
+
+splitUsForAllTys :: Type -> ([UVar],Type)
+splitUsForAllTys ty = split ty []
+ where split (NoteTy (UsgForAll u) ty) uvs = split ty (u:uvs)
+ split other_ty uvs = (reverse uvs, other_ty)
+
+substUsTy :: VarEnv UsageAnn -> Type -> Type
+-- assumes range is fresh uvars, so no conflicts
+substUsTy ve (NoteTy note@(UsgNote (UsVar u))
+ ty ) = NoteTy (case lookupVarEnv ve u of
+ Just ua -> UsgNote ua
+ Nothing -> note)
+ (substUsTy ve ty)
+substUsTy ve (NoteTy note@(UsgNote _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve (NoteTy note@(UsgForAll _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1))
+ (substUsTy ve ty2)
+substUsTy ve (NoteTy note@(FTVNote _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve ty@(TyVarTy _ ) = ty
+substUsTy ve (AppTy ty1 ty2) = AppTy (substUsTy ve ty1)
+ (substUsTy ve ty2)
+substUsTy ve (FunTy ty1 ty2) = FunTy (substUsTy ve ty1)
+ (substUsTy ve ty2)
+substUsTy ve (TyConApp tyc tys) = TyConApp tyc (map (substUsTy ve) tys)
+substUsTy ve (ForAllTy yv ty ) = ForAllTy yv (substUsTy ve ty)
+\end{code}
---------------------------------------------------------------------
ForAllTy
~~~~~~~~
+We need to be clever here with usage annotations; they need to be
+lifted or lowered through the forall as appropriate.
+
\begin{code}
-mkForAllTy = ForAllTy
+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 = foldr ForAllTy ty tyvars
+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 (NoteTy _ ty) = splitForAllTy_maybe ty
-splitForAllTy_maybe (ForAllTy tyvar ty) = Just(tyvar, ty)
-splitForAllTy_maybe _ = Nothing
+splitForAllTy_maybe ty = case splitUsgTy_maybe ty of
+ Just (usg,ty') -> do (tyvar,ty'') <- splitFAT_m ty'
+ return (tyvar, NoteTy (UsgNote usg) ty'')
+ Nothing -> splitFAT_m ty
+ where
+ splitFAT_m (NoteTy _ ty) = splitFAT_m ty
+ splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
+ splitFAT_m _ = Nothing
isForAllTy :: Type -> Bool
isForAllTy (NoteTy _ ty) = isForAllTy ty
isForAllTy _ = False
splitForAllTys :: Type -> ([TyVar], Type)
-splitForAllTys ty = split ty ty []
+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
it is given a type variable or a term variable.
\begin{code}
-mkPiType :: IdOrTyVar -> Type -> Type -- The more polymorphic version doesn't work...
+mkPiType :: Var -> Type -> Type -- The more polymorphic version doesn't work...
mkPiType v ty | isId v = mkFunTy (idType v) ty
- | otherwise = ForAllTy v ty
+ | otherwise = mkForAllTy v ty
\end{code}
+Applying a for-all to its arguments
+
\begin{code}
applyTy :: Type -> Type -> Type
-applyTy (NoteTy _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = substTy (mkVarEnv [(tv,arg)]) ty
-applyTy other arg = panic "applyTy"
+applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (NoteTy note@(UsgForAll _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (NoteTy _ fun) arg = applyTy fun arg
+applyTy (ForAllTy tv ty) arg = ASSERT( isNotUsgTy arg )
+ substTy (mkTyVarSubst [tv] [arg]) ty
+applyTy other arg = panic "applyTy"
applyTys :: Type -> [Type] -> Type
applyTys fun_ty arg_tys
- = 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 (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.
%* *
%************************************************************************
\begin{code}
type RhoType = Type
type TauType = Type
-type ThetaType = [(Class, [Type])]
+data PredType = Class Class [Type]
+ | IParam Name Type
+type ThetaType = [PredType]
+type ClassPred = (Class, [Type])
+type ClassContext = [ClassPred]
type SigmaType = Type
\end{code}
+\begin{code}
+instance Outputable PredType where
+ ppr = pprPred
+\end{code}
+
+\begin{code}
+mkClassPred clas tys = Class clas tys
+
+getClassTys_maybe :: PredType -> Maybe ClassPred
+getClassTys_maybe (Class clas tys) = Just (clas, tys)
+getClassTys_maybe _ = Nothing
+
+ipName_maybe :: PredType -> Maybe Name
+ipName_maybe (IParam n _) = Just n
+ipName_maybe _ = Nothing
+
+classesToPreds cts = map (uncurry Class) cts
+
+classesOfPreds theta = concatMap cvt theta
+ where cvt (Class clas tys) = [(clas, tys)]
+ cvt (IParam _ _ ) = []
+\end{code}
+
@isTauTy@ tests for nested for-alls.
\begin{code}
\end{code}
\begin{code}
-mkRhoTy :: [(Class, [Type])] -> Type -> Type
-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 :: Type -> ([(Class, [Type])], Type)
+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)
+ 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)
\begin{code}
mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
-splitSigmaTy :: Type -> ([TyVar], [(Class, [Type])], Type)
+splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
splitSigmaTy ty =
(tyvars, theta, tau)
where
typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
typeKind (NoteTy _ ty) = typeKind ty
typeKind (AppTy fun arg) = funResultTy (typeKind fun)
-typeKind (FunTy fun arg) = typeKindF arg
-typeKind (ForAllTy _ ty) = typeKindF ty -- We could make this a new kind polyTypeKind
- -- to prevent a forall type unifying with a
- -- boxed type variable, but I didn't think it
- -- was worth it yet.
-
--- The complication is that a *function* is boxed even if
--- its *result* type is unboxed. Seems wierd.
-
-typeKindF :: Type -> Kind
-typeKindF (NoteTy _ ty) = typeKindF ty
-typeKindF (FunTy _ ty) = typeKindF ty
-typeKindF (ForAllTy _ ty) = typeKindF ty
-typeKindF other = fix_up (typeKind other)
- where
- fix_up (TyConApp kc _) | kc == typeCon = boxedTypeKind
- -- Functions at the type level are always boxed
- fix_up (NoteTy _ kind) = fix_up kind
- fix_up kind = kind
+
+typeKind (FunTy arg res) = boxedTypeKind -- A function is boxed regardless of its result type
+ -- No functions at the type level, hence we don't need
+ -- to say (typeKind res).
+
+typeKind (ForAllTy tv ty) = typeKind ty
\end{code}
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
+tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty
+tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty
+tyVarsOfType (NoteTy (IPNote _) ty) = tyVarsOfType ty
tyVarsOfType (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 ty@(NoteTy (FTVNote _) _) = ty
-addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
+addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
+addFreeTyVars (NoteTy note@(UsgForAll _) ty) = NoteTy note (addFreeTyVars ty)
+addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
+addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
-- Find the free names of a type, including the type constructors and classes it mentions
namesOfType :: Type -> NameSet
%************************************************************************
%* *
-\subsection{Instantiating a type}
-%* *
-%************************************************************************
-
-@substTy@ applies a substitution to a type. It deals correctly with name capture.
-
-\begin{code}
-substTy :: TyVarSubst -> Type -> Type
-substTy tenv ty
- | isEmptyVarEnv tenv = ty
- | otherwise = 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
-
-substTheta :: TyVarSubst -> ThetaType -> ThetaType
-substTheta tenv theta
- | isEmptyVarEnv tenv = theta
- | otherwise = [(clas, map (subst_ty tenv tset) tys) | (clas, tys) <- theta]
- where
- tset = foldVarEnv (unionVarSet . tyVarsOfType) emptyVarSet tenv
- -- If ty doesn't have any for-alls, then this thunk
- -- will never be evaluated
-
-substTopTy :: TyVarSubst -> Type -> Type
-substTopTy = substTy -- Called when doing top-level substitutions.
- -- Here we expect that the free vars of the range of the
- -- substitution will be empty; but during typechecking I'm
- -- a bit dubious about that (mutable tyvars bouund to Int, say)
- -- So I've left it as substTy for the moment. SLPJ Nov 98
-substTopTheta = substTheta
-\end{code}
-
-@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.
-
-\begin{code}
-fullSubstTy :: TyVarSubst -- Substitution to apply
- -> TyVarSet -- Superset of the free tyvars of
- -- the range of the tyvar env
- -> Type -> Type
--- 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
- where
- go (TyConApp tc tys) = let args = map go tys
- in args `seqList` TyConApp tc args
- 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 :: TyVarSubst -> TyVarSet -> TyVar
- -> (TyVarSubst, TyVarSet, TyVar)
-
-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}
-
-
-%************************************************************************
-%* *
\subsection{TidyType}
%* *
%************************************************************************
Just tv' -> TyVarTy tv'
go (TyConApp tycon tys) = let args = map go tys
in args `seqList` TyConApp tycon args
- go (NoteTy note ty) = (NoteTy $! (go_note note)) $! (go ty)
- go (AppTy fun arg) = (AppTy $! (go fun)) $! (go arg)
- go (FunTy fun arg) = (FunTy $! (go fun)) $! (go arg)
- go (ForAllTy tv ty) = ForAllTy tv' $! (tidyType env' ty)
- where
- (env', tv') = tidyTyVar env tv
+ go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
+ go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
+ where
+ (envp, tvp) = tidyTyVar env tv
- go_note (SynNote ty) = SynNote $! (go ty)
+ 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_note (IPNote n) = IPNote (tidyIPName n)
tidyTypes env tys = map (tidyType env) tys
\end{code}
-@tidyOpenType@ grabs the free type varibles, tidies them
+@tidyOpenType@ grabs the free type variables, tidies them
and then uses @tidyType@ to work over the type itself
\begin{code}
tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
+\begin{code}
+tidyIPName :: Name -> Name
+tidyIPName name
+ = mkLocalName (getUnique name) (getOccName name) noSrcLoc
+\end{code}
+
%************************************************************************
%* *
isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
isUnLiftedType :: Type -> Bool
-isUnLiftedType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isUnLiftedTyCon tc
- other -> False
+ -- 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
isDataTyCon tc
other -> False
-typePrimRep :: Type -> 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{Equality on types}
+\subsection{Sequencing on types
%* *
%************************************************************************
-For the moment at least, type comparisons don't work if
-there are embedded for-alls.
-
\begin{code}
-instance Eq Type where
- ty1 == ty2 = case ty1 `cmpTy` ty2 of { EQ -> True; other -> False }
-
-instance Ord Type where
- compare ty1 ty2 = cmpTy ty1 ty2
-
-cmpTy :: Type -> Type -> Ordering
-cmpTy ty1 ty2
- = cmp emptyVarEnv ty1 ty2
- where
- -- 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
-
- -- 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
-
- -- Deal with the rest: TyVarTy < AppTy < FunTy < TyConApp < ForAllTy
- cmp env (AppTy _ _) (TyVarTy _) = GT
-
- cmp env (FunTy _ _) (TyVarTy _) = GT
- cmp env (FunTy _ _) (AppTy _ _) = GT
-
- cmp env (TyConApp _ _) (TyVarTy _) = GT
- cmp env (TyConApp _ _) (AppTy _ _) = GT
- cmp env (TyConApp _ _) (FunTy _ _) = GT
-
- cmp 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
+seqType :: Type -> ()
+seqType (TyVarTy tv) = tv `seq` ()
+seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (NoteTy note t2) = seqNote note `seq` seqType t2
+seqType (TyConApp tc tys) = tc `seq` seqTypes tys
+seqType (ForAllTy tv ty) = tv `seq` seqType ty
+
+seqTypes :: [Type] -> ()
+seqTypes [] = ()
+seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
+
+seqNote :: TyNote -> ()
+seqNote (SynNote ty) = seqType ty
+seqNote (FTVNote set) = sizeUniqSet set `seq` ()
+seqNote (UsgNote usg) = usg `seq` ()
+seqNote (IPNote nm) = nm `seq` ()
\end{code}
-
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