X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypes%2FType.lhs;h=8271ce32f389168eac64f3219f2002b90aef3ae9;hb=938f825c4c3aac524459a801816db10718dff9de;hp=3078d8d5299198fed974303cc12db6f58e795a34;hpb=8295d9ca0f3e72e545b35c43a4a2e1e4ec582fb6;p=ghc-hetmet.git diff --git a/ghc/compiler/types/Type.lhs b/ghc/compiler/types/Type.lhs index 3078d8d..8271ce3 100644 --- a/ghc/compiler/types/Type.lhs +++ b/ghc/compiler/types/Type.lhs @@ -1,6 +1,12 @@ +% +% (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 @@ -12,26 +18,31 @@ module Type ( 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_maybe, splitFunTys, splitFunTysN, + funResultTy, funArgTy, zipFunTys, mkTyConApp, mkTyConTy, splitTyConApp_maybe, - splitAlgTyConApp_maybe, splitAlgTyConApp, + splitAlgTyConApp_maybe, splitAlgTyConApp, mkDictTy, splitDictTy_maybe, isDictTy, - mkSynTy, isSynTy, deNoteType, + mkSynTy, isSynTy, deNoteType, repType, splitNewType_maybe, + + 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, TauType, RhoType, SigmaType, ThetaType, isTauTy, @@ -39,245 +50,73 @@ module Type ( mkSigmaTy, splitSigmaTy, -- Lifting and boxity - isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, + isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType, typePrimRep, -- Free variables tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind, addFreeTyVars, - -- Substitution - substTy, substTheta, fullSubstTy, substTyVar, - substTopTy, substTopTheta, - -- Tidying up for printing tidyType, tidyTypes, tidyOpenType, tidyOpenTypes, tidyTyVar, tidyTyVars, - tidyTopType + tidyTopType, + + -- Seq + seqType, seqTypes + ) 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, dataConType ) import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages +import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy ) -- friends: -import Var ( Id, TyVar, IdOrTyVar, - tyVarKind, isId, idType, setVarOcc +import Var ( TyVar, IdOrTyVar, UVar, + tyVarKind, tyVarName, setTyVarName, isId, idType, ) import VarEnv import VarSet -import Name ( NamedThing(..), Provenance(..), ExportFlag(..), - mkWiredInTyConName, mkGlobalName, tcOcc, - tidyOccName, TidyOccEnv +import 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, isAlgTyCon, isSynTyCon, tyConArity, - tyConKind, tyConDataCons, getSynTyConDefn, + tyConKind, tyConDataCons, getSynTyConDefn, tyConPrimRep, tyConClass_maybe ) -- others -import BasicTypes ( Unused ) -import SrcLoc ( mkBuiltinSrcLoc ) -import PrelMods ( pREL_GHC ) +import SrcLoc ( noSrcLoc ) import Maybes ( maybeToBool ) import PrimRep ( PrimRep(..), isFollowableRep ) -import Unique -- quite a few *Keys -import Util ( thenCmp, mapAccumL ) +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 (tcOcc 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 @@ -293,21 +132,6 @@ 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} %* * %************************************************************************ @@ -348,7 +172,8 @@ invariant that a TyConApp is always visibly so. mkAppTy maintains the 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]) @@ -361,11 +186,13 @@ mkAppTys orig_ty1 [] = orig_ty1 -- 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) @@ -412,7 +239,6 @@ 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 @@ -420,6 +246,14 @@ splitFunTys ty = split [] ty ty 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 @@ -432,8 +266,12 @@ funResultTy :: Type -> Type 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} --------------------------------------------------------------------- @@ -512,16 +350,17 @@ isDictTy (NoteTy _ ty) = isDictTy ty 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 @@ -554,21 +393,175 @@ interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs. +repType looks through + (a) for-alls, and + (b) newtypes +in addition to synonyms. It's useful in the back end where we're not +interested in newtypes anymore. + +\begin{code} +repType :: Type -> Type +repType (NoteTy _ ty) = repType ty +repType (ForAllTy _ ty) = repType ty +repType (TyConApp tc tys) | isNewTyCon tc = repType (new_type_rep tc tys) +repType other_ty = other_ty + +splitNewType_maybe :: Type -> Maybe Type +-- Find the representation of a newtype, if it is one +-- Looks through multiple levels of newtype +splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty +splitNewType_maybe (TyConApp tc tys) | isNewTyCon tc = case splitNewType_maybe rep_ty of + Just rep_ty' -> Just rep_ty' + Nothing -> Just rep_ty + where + rep_ty = new_type_rep tc tys + +splitNewType_maybe other = Nothing + +new_type_rep :: TyCon -> [Type] -> Type +-- The representation type for (T t1 .. tn), where T is a newtype +-- Looks through one layer only +new_type_rep tc tys + = ASSERT( isNewTyCon tc ) + case splitFunTy_maybe (applyTys (dataConType (head (tyConDataCons tc))) tys) of + Just (rep_ty, _) -> rep_ty +\end{code} + + + +--------------------------------------------------------------------- + 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 @@ -576,7 +569,10 @@ isForAllTy (ForAllTy tyvar ty) = True 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 @@ -589,25 +585,45 @@ it is given a type variable or a term variable. \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 + | 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. + %************************************************************************ %* * @@ -678,25 +694,12 @@ typeKind (TyVarTy tyvar) = tyVarKind tyvar typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys typeKind (NoteTy _ ty) = typeKind ty typeKind (AppTy fun arg) = funResultTy (typeKind fun) -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} @@ -710,6 +713,8 @@ tyVarsOfType (TyVarTy tv) = unitVarSet tv tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1 +tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty +tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar @@ -718,9 +723,12 @@ tyVarsOfTypes :: [Type] -> TyVarSet tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys -- Add a Note with the free tyvars to the top of the type +-- (but under a usage if there is one) addFreeTyVars :: Type -> Type -addFreeTyVars 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 @@ -739,90 +747,6 @@ namesOfTypes tys = foldr (unionNameSets . namesOfType) emptyNameSet tys %************************************************************************ %* * -\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) = 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 :: 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} %* * %************************************************************************ @@ -842,12 +766,17 @@ tidyTyVar env@(tidy_env, subst) tyvar Nothing -> -- Make a new nice name for it - case tidyOccName tidy_env (getOccName tyvar) of + case tidyOccName tidy_env (getOccName name) of (tidy', occ') -> -- New occname reqd ((tidy', subst'), tyvar') where subst' = extendVarEnv subst tyvar tyvar' - tyvar' = setVarOcc tyvar occ' + 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 @@ -858,22 +787,25 @@ tidyType env@(tidy_env, subst) ty go (TyVarTy tv) = case lookupVarEnv subst tv of Nothing -> TyVarTy tv Just tv' -> TyVarTy tv' - go (TyConApp tycon tys) = TyConApp tycon (map go tys) - 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 (TyConApp tycon tys) = let args = map go tys + in args `seqList` TyConApp tycon args + go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty) + go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg) + go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg) + go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty) + where + (envp, tvp) = tidyTyVar env tv - go_note (SynNote ty) = SynNote (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 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} @@ -903,9 +835,16 @@ isUnboxedType :: Type -> Bool 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 @@ -926,68 +865,41 @@ isDataType ty = case splitTyConApp_maybe ty of isDataTyCon tc other -> False +isNewType :: Type -> Bool +isNewType ty = case splitTyConApp_maybe ty of + Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc ) + isNewTyCon tc + other -> False + typePrimRep :: Type -> PrimRep typePrimRep ty = case splitTyConApp_maybe ty of Just (tc, ty_args) -> tyConPrimRep tc other -> PtrRep \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` () \end{code} -