X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypes%2FType.lhs;h=5cf242c4050c0321ca23a50afcc732ad6e277ce6;hb=f714e6b642fd614a9971717045ae47c3d871275e;hp=973074d87560a5b407b49233f28c4bd580e05010;hpb=574b218dcfab79ec277beca2f729cc8ea8c078dc;p=ghc-hetmet.git diff --git a/ghc/compiler/types/Type.lhs b/ghc/compiler/types/Type.lhs index 973074d..5cf242c 100644 --- a/ghc/compiler/types/Type.lhs +++ b/ghc/compiler/types/Type.lhs @@ -5,74 +5,62 @@ \begin{code} module Type ( - -- re-exports from TypeRep: - Type, PredType, TauType, ThetaType, - Kind, TyVarSubst, - - superKind, superBoxity, -- KX and BX respectively - liftedBoxity, unliftedBoxity, -- :: BX - openKindCon, -- :: KX - typeCon, -- :: BX -> KX - liftedTypeKind, unliftedTypeKind, openTypeKind, -- :: KX - mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX - + -- re-exports from TypeRep + TyThing(..), Type, PredType(..), ThetaType, TyVarSubst, funTyCon, - usageKindCon, -- :: KX - usageTypeKind, -- :: KX - usOnceTyCon, usManyTyCon, -- :: $ - usOnce, usMany, -- :: $ + -- Re-exports from Kind + module Kind, - -- exports from this module: - hasMoreBoxityInfo, defaultKind, mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy, mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe, mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, - funResultTy, funArgTy, zipFunTys, + funResultTy, funArgTy, zipFunTys, isFunTy, - mkTyConApp, mkTyConTy, + mkGenTyConApp, mkTyConApp, mkTyConTy, tyConAppTyCon, tyConAppArgs, splitTyConApp_maybe, splitTyConApp, - mkUTy, splitUTy, splitUTy_maybe, - isUTy, uaUTy, unUTy, liftUTy, mkUTyM, - isUsageKind, isUsage, isUTyVar, - mkSynTy, - repType, splitRepFunTys, typePrimRep, + repType, typePrimRep, mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys, - applyTy, applyTys, isForAllTy, + applyTy, applyTys, isForAllTy, dropForAlls, -- Source types - SourceType(..), sourceTypeRep, + predTypeRep, mkPredTy, mkPredTys, -- Newtypes - mkNewTyConApp, + splitRecNewType_maybe, -- Lifting and boxity - isUnLiftedType, isUnboxedTupleType, isAlgType, + isUnLiftedType, isUnboxedTupleType, isAlgType, isPrimitiveType, + isStrictType, isStrictPred, -- Free variables tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta, - usageAnnOfType, typeKind, addFreeTyVars, + typeKind, addFreeTyVars, -- Tidying up for printing - tidyType, tidyTypes, - tidyOpenType, tidyOpenTypes, - tidyTyVar, tidyTyVars, tidyFreeTyVars, - tidyTopType, tidyPred, + tidyType, tidyTypes, + tidyOpenType, tidyOpenTypes, + tidyTyVarBndr, tidyFreeTyVars, + tidyOpenTyVar, tidyOpenTyVars, + tidyTopType, tidyPred, -- Comparison - eqType, eqKind, eqUsage, + eqType, -- Seq - seqType, seqTypes + seqType, seqTypes, + -- Pretty-printing + pprType, pprParendType, + pprPred, pprTheta, pprThetaArrow, pprClassPred ) where #include "HsVersions.h" @@ -84,17 +72,17 @@ import TypeRep -- Other imports: -import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages -import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy ) +import {-# SOURCE #-} Subst ( substTyWith ) -- friends: -import Var ( Var, TyVar, tyVarKind, tyVarName, setTyVarName ) +import Kind +import Var ( TyVar, tyVarKind, tyVarName, setTyVarName ) import VarEnv import VarSet -import Name ( NamedThing(..), mkLocalName, tidyOccName ) -import Class ( classTyCon ) -import TyCon ( TyCon, isRecursiveTyCon, +import Name ( NamedThing(..), mkInternalName, tidyOccName ) +import Class ( Class, classTyCon ) +import TyCon ( TyCon, isRecursiveTyCon, isPrimTyCon, isUnboxedTupleTyCon, isUnLiftedTyCon, isFunTyCon, isNewTyCon, newTyConRep, isAlgTyCon, isSynTyCon, tyConArity, @@ -103,32 +91,14 @@ import TyCon ( TyCon, isRecursiveTyCon, ) -- others -import Maybes ( maybeToBool ) +import CmdLineOpts ( opt_DictsStrict ) import SrcLoc ( noSrcLoc ) import PrimRep ( PrimRep(..) ) import Unique ( Uniquable(..) ) -import Util ( mapAccumL, seqList ) +import Util ( mapAccumL, seqList, lengthIs, snocView ) import Outputable import UniqSet ( sizeUniqSet ) -- Should come via VarSet -\end{code} - - -%************************************************************************ -%* * -\subsection{Stuff to do with kinds.} -%* * -%************************************************************************ - -\begin{code} -hasMoreBoxityInfo :: Kind -> Kind -> Bool -hasMoreBoxityInfo k1 k2 - | k2 `eqKind` openTypeKind = True - | otherwise = k1 `eqType` k2 - -defaultKind :: Kind -> Kind --- Used when generalising: default kind '?' to '*' -defaultKind kind | kind `eqKind` openTypeKind = liftedTypeKind - | otherwise = kind +import Maybe ( isJust ) \end{code} @@ -150,25 +120,19 @@ mkTyVarTys :: [TyVar] -> [Type] mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy getTyVar :: String -> Type -> TyVar -getTyVar msg (TyVarTy tv) = tv -getTyVar msg (SourceTy p) = getTyVar msg (sourceTypeRep p) -getTyVar msg (NoteTy _ t) = getTyVar msg t -getTyVar msg ty@(UsageTy _ _) = pprPanic "getTyVar: UTy:" (text msg $$ pprType ty) -getTyVar msg other = panic ("getTyVar: " ++ msg) - -getTyVar_maybe :: Type -> Maybe TyVar -getTyVar_maybe (TyVarTy tv) = Just tv -getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t -getTyVar_maybe (SourceTy p) = getTyVar_maybe (sourceTypeRep p) -getTyVar_maybe ty@(UsageTy _ _) = pprPanic "getTyVar_maybe: UTy:" (pprType ty) -getTyVar_maybe other = Nothing +getTyVar msg ty = case getTyVar_maybe ty of + Just tv -> tv + Nothing -> panic ("getTyVar: " ++ msg) isTyVarTy :: Type -> Bool -isTyVarTy (TyVarTy tv) = True -isTyVarTy (NoteTy _ ty) = isTyVarTy ty -isTyVarTy (SourceTy p) = isTyVarTy (sourceTypeRep p) -isTyVarTy ty@(UsageTy _ _) = pprPanic "isTyVarTy: UTy:" (pprType ty) -isTyVarTy other = False +isTyVarTy ty = isJust (getTyVar_maybe ty) + +getTyVar_maybe :: Type -> Maybe TyVar +getTyVar_maybe (TyVarTy tv) = Just tv +getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t +getTyVar_maybe (PredTy p) = getTyVar_maybe (predTypeRep p) +getTyVar_maybe (NewTcApp tc tys) = getTyVar_maybe (newTypeRep tc tys) +getTyVar_maybe other = Nothing \end{code} @@ -181,15 +145,20 @@ invariant: use it. \begin{code} mkAppTy orig_ty1 orig_ty2 - = ASSERT( not (isSourceTy orig_ty1) ) -- Source types are of kind * - UASSERT2( not (isUTy orig_ty2), pprType orig_ty1 <+> pprType orig_ty2 ) - -- argument must be unannotated - mk_app orig_ty1 + = mk_app orig_ty1 where mk_app (NoteTy _ ty1) = mk_app ty1 - mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2]) - mk_app ty@(UsageTy _ _) = pprPanic "mkAppTy: UTy:" (pprType ty) + mk_app (NewTcApp tc tys) = NewTcApp tc (tys ++ [orig_ty2]) + mk_app (TyConApp tc tys) = mkGenTyConApp tc (tys ++ [orig_ty2]) mk_app ty1 = AppTy orig_ty1 orig_ty2 + -- We call mkGenTyConApp because the TyConApp could be an + -- under-saturated type synonym. GHC allows that; e.g. + -- type Foo k = k a -> k a + -- type Id x = x + -- foo :: Foo Id -> Foo Id + -- + -- Here Id is partially applied in the type sig for Foo, + -- but once the type synonyms are expanded all is well mkAppTys :: Type -> [Type] -> Type mkAppTys orig_ty1 [] = orig_ty1 @@ -199,29 +168,26 @@ mkAppTys orig_ty1 [] = orig_ty1 -- returns to (Ratio Integer), which has needlessly lost -- the Rational part. mkAppTys orig_ty1 orig_tys2 - = ASSERT( not (isSourceTy orig_ty1) ) -- Source types are of kind * - UASSERT2( not (any isUTy orig_tys2), pprType orig_ty1 <+> fsep (map pprType orig_tys2) ) - -- arguments must be unannotated - mk_app orig_ty1 + = mk_app orig_ty1 where mk_app (NoteTy _ ty1) = mk_app ty1 + mk_app (NewTcApp tc tys) = NewTcApp tc (tys ++ orig_tys2) mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ orig_tys2) - mk_app ty@(UsageTy _ _) = pprPanic "mkAppTys: UTy:" (pprType ty) + -- Use mkTyConApp in case tc is (->) mk_app ty1 = foldl AppTy orig_ty1 orig_tys2 splitAppTy_maybe :: Type -> Maybe (Type, Type) -splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [unUTy ty1], unUTy ty2) +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 (SourceTy p) = splitAppTy_maybe (sourceTypeRep p) -splitAppTy_maybe (TyConApp tc []) = Nothing -splitAppTy_maybe (TyConApp tc tys) = split tys [] - where - split [ty2] acc = Just (TyConApp tc (reverse acc), ty2) - split (ty:tys) acc = split tys (ty:acc) +splitAppTy_maybe (PredTy p) = splitAppTy_maybe (predTypeRep p) +splitAppTy_maybe (NewTcApp tc tys) = splitAppTy_maybe (newTypeRep tc tys) +splitAppTy_maybe (TyConApp tc tys) = case snocView tys of + Nothing -> Nothing + Just (tys',ty') -> Just (mkGenTyConApp tc tys', ty') + -- mkGenTyConApp just in case the tc is a newtype -splitAppTy_maybe ty@(UsageTy _ _) = pprPanic "splitAppTy_maybe: UTy:" (pprType ty) -splitAppTy_maybe other = Nothing +splitAppTy_maybe other = Nothing splitAppTy :: Type -> (Type, Type) splitAppTy ty = case splitAppTy_maybe ty of @@ -233,11 +199,12 @@ splitAppTys ty = split ty ty [] where split orig_ty (AppTy ty arg) args = split ty ty (arg:args) split orig_ty (NoteTy _ ty) args = split orig_ty ty args - split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args + split orig_ty (PredTy p) args = split orig_ty (predTypeRep p) args + split orig_ty (NewTcApp tc tc_args) args = split orig_ty (newTypeRep tc tc_args) args + split orig_ty (TyConApp tc tc_args) args = (mkGenTyConApp tc [], tc_args ++ args) + -- mkGenTyConApp just in case the tc is a newtype split orig_ty (FunTy ty1 ty2) args = ASSERT( null args ) - (TyConApp funTyCon [], [unUTy ty1,unUTy ty2]) - split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args) - split orig_ty (UsageTy _ _) args = pprPanic "splitAppTys: UTy:" (pprType orig_ty) + (TyConApp funTyCon [], [ty1,ty2]) split orig_ty ty args = (orig_ty, args) \end{code} @@ -248,86 +215,90 @@ splitAppTys ty = split ty ty [] \begin{code} mkFunTy :: Type -> Type -> Type -mkFunTy arg res = UASSERT2( isUTy arg && isUTy res, pprType arg <+> pprType res ) - FunTy arg res +mkFunTy arg res = FunTy arg res mkFunTys :: [Type] -> Type -> Type -mkFunTys tys ty = UASSERT2( all isUTy (ty:tys), fsep (map pprType (tys++[ty])) ) - foldr FunTy ty tys +mkFunTys tys ty = foldr FunTy ty tys + +isFunTy :: Type -> Bool +isFunTy ty = isJust (splitFunTy_maybe ty) splitFunTy :: Type -> (Type, Type) -splitFunTy (FunTy arg res) = (arg, res) -splitFunTy (NoteTy _ ty) = splitFunTy ty -splitFunTy (SourceTy p) = splitFunTy (sourceTypeRep p) -splitFunTy ty@(UsageTy _ _) = pprPanic "splitFunTy: UTy:" (pprType ty) +splitFunTy (FunTy arg res) = (arg, res) +splitFunTy (NoteTy _ ty) = splitFunTy ty +splitFunTy (PredTy p) = splitFunTy (predTypeRep p) +splitFunTy (NewTcApp tc tys) = splitFunTy (newTypeRep tc tys) +splitFunTy other = pprPanic "splitFunTy" (ppr other) splitFunTy_maybe :: Type -> Maybe (Type, Type) -splitFunTy_maybe (FunTy arg res) = Just (arg, res) -splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty -splitFunTy_maybe (SourceTy p) = splitFunTy_maybe (sourceTypeRep p) -splitFunTy_maybe ty@(UsageTy _ _) = pprPanic "splitFunTy_maybe: UTy:" (pprType ty) -splitFunTy_maybe other = Nothing +splitFunTy_maybe (FunTy arg res) = Just (arg, res) +splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty +splitFunTy_maybe (PredTy p) = splitFunTy_maybe (predTypeRep p) +splitFunTy_maybe (NewTcApp tc tys) = splitFunTy_maybe (newTypeRep tc tys) +splitFunTy_maybe other = Nothing splitFunTys :: Type -> ([Type], Type) splitFunTys ty = split [] ty ty where - split args orig_ty (FunTy arg res) = split (arg:args) res res - split args orig_ty (NoteTy _ ty) = split args orig_ty ty - split args orig_ty (SourceTy p) = split args orig_ty (sourceTypeRep p) - split args orig_ty (UsageTy _ _) = pprPanic "splitFunTys: UTy:" (pprType orig_ty) - split args orig_ty ty = (reverse args, orig_ty) + split args orig_ty (FunTy arg res) = split (arg:args) res res + split args orig_ty (NoteTy _ ty) = split args orig_ty ty + split args orig_ty (PredTy p) = split args orig_ty (predTypeRep p) + split args orig_ty (NewTcApp tc tys) = split args orig_ty (newTypeRep tc tys) + split args orig_ty ty = (reverse args, 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 (SourceTy p) = split acc xs nty (sourceTypeRep p) - split acc xs nty (UsageTy _ _) = pprPanic "zipFunTys: UTy:" (ppr orig_xs <+> pprType orig_ty) - split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty) + 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 (predTypeRep p) + split acc xs nty (NewTcApp tc tys) = split acc xs nty (newTypeRep tc tys) + split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> ppr orig_ty) funResultTy :: Type -> Type -funResultTy (FunTy arg res) = res -funResultTy (NoteTy _ ty) = funResultTy ty -funResultTy (SourceTy p) = funResultTy (sourceTypeRep p) -funResultTy (UsageTy _ ty) = funResultTy ty -funResultTy ty = pprPanic "funResultTy" (pprType ty) +funResultTy (FunTy arg res) = res +funResultTy (NoteTy _ ty) = funResultTy ty +funResultTy (PredTy p) = funResultTy (predTypeRep p) +funResultTy (NewTcApp tc tys) = funResultTy (newTypeRep tc tys) +funResultTy ty = pprPanic "funResultTy" (ppr ty) funArgTy :: Type -> Type -funArgTy (FunTy arg res) = arg -funArgTy (NoteTy _ ty) = funArgTy ty -funArgTy (SourceTy p) = funArgTy (sourceTypeRep p) -funArgTy (UsageTy _ ty) = funArgTy ty -funArgTy ty = pprPanic "funArgTy" (pprType ty) +funArgTy (FunTy arg res) = arg +funArgTy (NoteTy _ ty) = funArgTy ty +funArgTy (PredTy p) = funArgTy (predTypeRep p) +funArgTy (NewTcApp tc tys) = funArgTy (newTypeRep tc tys) +funArgTy ty = pprPanic "funArgTy" (ppr ty) \end{code} --------------------------------------------------------------------- TyConApp ~~~~~~~~ -@mkTyConApp@ is a key function, because it builds a TyConApp, FunTy or SourceTy, +@mkTyConApp@ is a key function, because it builds a TyConApp, FunTy or PredTy, as apppropriate. \begin{code} +mkGenTyConApp :: TyCon -> [Type] -> Type +mkGenTyConApp tc tys + | isSynTyCon tc = mkSynTy tc tys + | otherwise = mkTyConApp tc tys + mkTyConApp :: TyCon -> [Type] -> Type +-- Assumes TyCon is not a SynTyCon; use mkSynTy instead for those mkTyConApp tycon tys | isFunTyCon tycon, [ty1,ty2] <- tys - = FunTy (mkUTyM ty1) (mkUTyM ty2) + = FunTy ty1 ty2 - | isNewTyCon tycon, -- A saturated newtype application; - not (isRecursiveTyCon tycon), -- Not recursive (we don't use SourceTypes for them) - length tys == tyConArity tycon -- use the SourceType form - = SourceTy (NType tycon tys) + | isNewTyCon tycon + = NewTcApp tycon tys | otherwise = ASSERT(not (isSynTyCon tycon)) - UASSERT2( not (any isUTy tys), ppr tycon <+> fsep (map pprType tys) ) TyConApp tycon tys mkTyConTy :: TyCon -> Type -mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) ) - TyConApp tycon [] +mkTyConTy tycon = mkTyConApp tycon [] -- splitTyConApp "looks through" synonyms, because they don't -- mean a distinct type, but all other type-constructor applications @@ -342,14 +313,14 @@ tyConAppArgs ty = snd (splitTyConApp ty) splitTyConApp :: Type -> (TyCon, [Type]) splitTyConApp ty = case splitTyConApp_maybe ty of Just stuff -> stuff - Nothing -> pprPanic "splitTyConApp" (pprType ty) + Nothing -> pprPanic "splitTyConApp" (ppr ty) splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type]) splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys) -splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [unUTy arg,unUTy res]) +splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res]) splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty -splitTyConApp_maybe (SourceTy p) = splitTyConApp_maybe (sourceTypeRep p) -splitTyConApp_maybe (UsageTy _ ty) = splitTyConApp_maybe ty +splitTyConApp_maybe (PredTy p) = splitTyConApp_maybe (predTypeRep p) +splitTyConApp_maybe (NewTcApp tc tys) = splitTyConApp_maybe (newTypeRep tc tys) splitTyConApp_maybe other = Nothing \end{code} @@ -359,13 +330,29 @@ splitTyConApp_maybe other = Nothing ~~~~~ \begin{code} -mkSynTy syn_tycon tys - = ASSERT( isSynTyCon syn_tycon ) - ASSERT( length tyvars == length tys ) - NoteTy (SynNote (TyConApp syn_tycon tys)) - (substTy (mkTyVarSubst tyvars tys) body) +mkSynTy tycon tys + | n_args == arity -- Exactly saturated + = mk_syn tys + | n_args > arity -- Over-saturated + = case splitAt arity tys of { (as,bs) -> mkAppTys (mk_syn as) bs } + -- Its important to use mkAppTys, rather than (foldl AppTy), + -- because (mk_syn as) might well return a partially-applied + -- type constructor; indeed, usually will! + | otherwise -- Un-saturated + = TyConApp tycon tys + -- For the un-saturated case we build TyConApp directly + -- (mkTyConApp ASSERTs that the tc isn't a SynTyCon). + -- Here we are relying on checkValidType to find + -- the error. What we can't do is use mkSynTy with + -- too few arg tys, because that is utterly bogus. + where - (tyvars, body) = getSynTyConDefn syn_tycon + mk_syn tys = NoteTy (SynNote (TyConApp tycon tys)) + (substTyWith tyvars tys body) + + (tyvars, body) = ASSERT( isSynTyCon tycon ) getSynTyConDefn tycon + arity = tyConArity tycon + n_args = length tys \end{code} Notes on type synonyms @@ -385,28 +372,24 @@ interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs. Representation types ~~~~~~~~~~~~~~~~~~~~ - repType looks through (a) for-alls, and (b) synonyms (c) predicates (d) usage annotations + (e) [recursive] newtypes It's useful in the back end. \begin{code} repType :: Type -> Type -repType (ForAllTy _ ty) = repType ty -repType (NoteTy _ ty) = repType ty -repType (SourceTy p) = repType (sourceTypeRep p) -repType (UsageTy _ ty) = repType ty -repType ty = 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) +-- Only applied to types of kind *; hence tycons are saturated +repType (ForAllTy _ ty) = repType ty +repType (NoteTy _ ty) = repType ty +repType (PredTy p) = repType (predTypeRep p) +repType (NewTcApp tc tys) = ASSERT( tys `lengthIs` tyConArity tc ) + repType (new_type_rep tc tys) +repType ty = ty + typePrimRep :: Type -> PrimRep typePrimRep ty = case repType ty of @@ -414,6 +397,7 @@ typePrimRep ty = case repType ty of FunTy _ _ -> PtrRep AppTy _ _ -> PtrRep -- ?? TyVarTy _ -> PtrRep + other -> pprPanic "typePrimRep" (ppr ty) \end{code} @@ -428,188 +412,158 @@ mkForAllTy tyvar ty = mkForAllTys [tyvar] ty mkForAllTys :: [TyVar] -> Type -> Type -mkForAllTys tyvars ty - = case splitUTy_maybe ty of - Just (u,ty1) -> UASSERT2( not (mkVarSet tyvars `intersectsVarSet` tyVarsOfType u), - ptext SLIT("mkForAllTys: usage scope") - <+> ppr tyvars <+> pprType ty ) - mkUTy u (foldr ForAllTy ty1 tyvars) -- we lift usage annotations over foralls - Nothing -> foldr ForAllTy ty tyvars +mkForAllTys tyvars ty = foldr ForAllTy ty tyvars isForAllTy :: Type -> Bool isForAllTy (NoteTy _ ty) = isForAllTy ty isForAllTy (ForAllTy _ _) = True -isForAllTy (UsageTy _ ty) = isForAllTy ty isForAllTy other_ty = False splitForAllTy_maybe :: Type -> Maybe (TyVar, Type) splitForAllTy_maybe ty = splitFAT_m ty where splitFAT_m (NoteTy _ ty) = splitFAT_m ty - splitFAT_m (SourceTy p) = splitFAT_m (sourceTypeRep p) + splitFAT_m (PredTy p) = splitFAT_m (predTypeRep p) + splitFAT_m (NewTcApp tc tys) = splitFAT_m (newTypeRep tc tys) splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty) - splitFAT_m (UsageTy _ ty) = splitFAT_m ty splitFAT_m _ = Nothing splitForAllTys :: Type -> ([TyVar], Type) splitForAllTys ty = split ty ty [] where - split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs) - split orig_ty (NoteTy _ ty) tvs = split orig_ty ty tvs - split orig_ty (SourceTy p) tvs = split orig_ty (sourceTypeRep p) tvs - split orig_ty (UsageTy _ 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 (predTypeRep p) tvs + split orig_ty (NewTcApp tc tys) tvs = split orig_ty (newTypeRep tc tys) tvs + split orig_ty t tvs = (reverse tvs, orig_ty) + +dropForAlls :: Type -> Type +dropForAlls ty = snd (splitForAllTys ty) \end{code} -- (mkPiType now in CoreUtils) -Applying a for-all to its arguments. Lift usage annotation as required. +applyTy, applyTys +~~~~~~~~~~~~~~~~~ +Instantiate a for-all type with one or more type arguments. +Used when we have a polymorphic function applied to type args: + f t1 t2 +Then we use (applyTys type-of-f [t1,t2]) to compute the type of +the expression. \begin{code} applyTy :: Type -> Type -> Type -applyTy (SourceTy p) arg = applyTy (sourceTypeRep p) arg -applyTy (NoteTy _ fun) arg = applyTy fun arg -applyTy (ForAllTy tv ty) arg = UASSERT2( not (isUTy arg), - ptext SLIT("applyTy") - <+> pprType ty <+> pprType arg ) - substTy (mkTyVarSubst [tv] [arg]) ty -applyTy (UsageTy u ty) arg = UsageTy u (applyTy ty arg) -applyTy other arg = panic "applyTy" +applyTy (PredTy p) arg = applyTy (predTypeRep p) arg +applyTy (NewTcApp tc tys) arg = applyTy (newTypeRep tc tys) arg +applyTy (NoteTy _ fun) arg = applyTy fun arg +applyTy (ForAllTy tv ty) arg = substTyWith [tv] [arg] ty +applyTy other arg = panic "applyTy" applyTys :: Type -> [Type] -> Type -applyTys fun_ty arg_tys - = UASSERT2( not (any isUTy arg_tys), ptext SLIT("applyTys") <+> pprType fun_ty ) - (case mu of - Just u -> UsageTy u - Nothing -> id) $ - substTy (mkTyVarSubst tvs arg_tys) ty - where - (mu, tvs, ty) = split fun_ty arg_tys - - split fun_ty [] = (Nothing, [], fun_ty) - split (NoteTy _ fun_ty) args = split fun_ty args - split (SourceTy p) args = split (sourceTypeRep p) args - split (ForAllTy tv fun_ty) (arg:args) = case split fun_ty args of - (mu, tvs, ty) -> (mu, tv:tvs, ty) - split (UsageTy u ty) args = case split ty args of - (Nothing, tvs, ty) -> (Just u, tvs, ty) - (Just _ , _ , _ ) -> pprPanic "applyTys:" - (pprType fun_ty) - split other_ty args = panic "applyTys" +-- This function is interesting because +-- a) the function may have more for-alls than there are args +-- b) less obviously, it may have fewer for-alls +-- For case (b) think of +-- applyTys (forall a.a) [forall b.b, Int] +-- This really can happen, via dressing up polymorphic types with newtype +-- clothing. Here's an example: +-- newtype R = R (forall a. a->a) +-- foo = case undefined :: R of +-- R f -> f () + +applyTys orig_fun_ty [] = orig_fun_ty +applyTys orig_fun_ty arg_tys + | n_tvs == n_args -- The vastly common case + = substTyWith tvs arg_tys rho_ty + | n_tvs > n_args -- Too many for-alls + = substTyWith (take n_args tvs) arg_tys + (mkForAllTys (drop n_args tvs) rho_ty) + | otherwise -- Too many type args + = ASSERT2( n_tvs > 0, ppr orig_fun_ty ) -- Zero case gives infnite loop! + applyTys (substTyWith tvs (take n_tvs arg_tys) rho_ty) + (drop n_tvs arg_tys) + where + (tvs, rho_ty) = splitForAllTys orig_fun_ty + n_tvs = length tvs + n_args = length arg_tys \end{code} ---------------------------------------------------------------------- - UsageTy - ~~~~~~~ - -Constructing and taking apart usage types. +%************************************************************************ +%* * +\subsection{Source types} +%* * +%************************************************************************ -\begin{code} -mkUTy :: Type -> Type -> Type -mkUTy u ty - = ASSERT2( typeKind u `eqKind` usageTypeKind, - ptext SLIT("mkUTy:") <+> pprType u <+> pprType ty ) - UASSERT2( not (isUTy ty), ptext SLIT("mkUTy:") <+> pprType u <+> pprType ty ) - -- if u == usMany then ty else : ToDo? KSW 2000-10 -#ifdef DO_USAGES - UsageTy u ty -#else - ty -#endif - -splitUTy :: Type -> (Type {- :: $ -}, Type) -splitUTy orig_ty - = case splitUTy_maybe orig_ty of - Just (u,ty) -> (u,ty) -#ifdef DO_USAGES - Nothing -> pprPanic "splitUTy:" (pprType orig_ty) -#else - Nothing -> (usMany,orig_ty) -- default annotation ToDo KSW 2000-10 -#endif - -splitUTy_maybe :: Type -> Maybe (Type {- :: $ -}, Type) -splitUTy_maybe (UsageTy u ty) = Just (u,ty) -splitUTy_maybe (NoteTy _ ty) = splitUTy_maybe ty -splitUTy_maybe other_ty = Nothing - -isUTy :: Type -> Bool - -- has usage annotation -isUTy = maybeToBool . splitUTy_maybe - -uaUTy :: Type -> Type - -- extract annotation -uaUTy = fst . splitUTy - -unUTy :: Type -> Type - -- extract unannotated type -unUTy = snd . splitUTy -\end{code} +A "source type" is a type that is a separate type as far as the type checker is +concerned, but which has low-level representation as far as the back end is concerned. -\begin{code} -liftUTy :: (Type -> Type) -> Type -> Type - -- lift outer usage annot over operation on unannotated types -liftUTy f ty - = let - (u,ty') = splitUTy ty - in - mkUTy u (f ty') -\end{code} +Source types are always lifted. -\begin{code} -mkUTyM :: Type -> Type - -- put TOP (no info) annotation on unannotated type -mkUTyM ty = mkUTy usMany ty -\end{code} +The key function is predTypeRep which gives the representation of a source type: \begin{code} -isUsageKind :: Kind -> Bool -isUsageKind k - = ASSERT( typeKind k `eqKind` superKind ) - k `eqKind` usageTypeKind - -isUsage :: Type -> Bool -isUsage ty - = isUsageKind (typeKind ty) - -isUTyVar :: Var -> Bool -isUTyVar v - = isUsageKind (tyVarKind v) +mkPredTy :: PredType -> Type +mkPredTy pred = PredTy pred + +mkPredTys :: ThetaType -> [Type] +mkPredTys preds = map PredTy preds + +predTypeRep :: PredType -> Type +-- Convert a PredType to its "representation type"; +-- the post-type-checking type used by all the Core passes of GHC. +predTypeRep (IParam _ ty) = ty +predTypeRep (ClassP clas tys) = mkTyConApp (classTyCon clas) tys + -- Result might be a NewTcApp, but the consumer will + -- look through that too if necessary \end{code} %************************************************************************ %* * -\subsection{Source types} + NewTypes %* * %************************************************************************ -A "source type" is a type that is a separate type as far as the type checker is -concerned, but which has low-level representation as far as the back end is concerned. - -Source types are always lifted. - -The key function is sourceTypeRep which gives the representation of a source type: - \begin{code} -sourceTypeRep :: SourceType -> Type --- Convert a predicate to its "representation type"; --- the type of evidence for that predicate, which is actually passed at runtime -sourceTypeRep (IParam n ty) = ty -sourceTypeRep (ClassP clas tys) = mkTyConApp (classTyCon clas) tys - -- Note the mkTyConApp; the classTyCon might be a newtype! -sourceTypeRep (NType tc tys) = case newTyConRep tc of - (tvs, rep_ty) -> substTy (mkTyVarSubst tvs tys) rep_ty +splitRecNewType_maybe :: Type -> Maybe Type +-- Newtypes are always represented by a NewTcApp +-- Sometimes we want to look through a recursive newtype, and that's what happens here +-- Only applied to types of kind *, hence the newtype is always saturated +splitRecNewType_maybe (NoteTy _ ty) = splitRecNewType_maybe ty +splitRecNewType_maybe (NewTcApp tc tys) + | isRecursiveTyCon tc + = ASSERT( tys `lengthIs` tyConArity tc && isNewTyCon tc ) + -- The assert should hold because repType should + -- only be applied to *types* (of kind *) + Just (new_type_rep tc tys) +splitRecNewType_maybe other = Nothing + +----------------------------- +newTypeRep :: TyCon -> [Type] -> Type +-- A local helper function (not exported) +-- Expands a newtype application to +-- *either* a vanilla TyConApp (recursive newtype, or non-saturated) +-- *or* the newtype representation (otherwise) +-- Either way, the result is not a NewTcApp +-- +-- NB: the returned TyConApp is always deconstructed immediately by the +-- caller... a TyConApp with a newtype type constructor never lives +-- in an ordinary type +newTypeRep tc tys + | not (isRecursiveTyCon tc), -- Not recursive and saturated + tys `lengthIs` tyConArity tc -- treat as equivalent to expansion + = new_type_rep tc tys + | otherwise + = TyConApp tc tys -- ToDo: Consider caching this substitution in a NType -mkNewTyConApp :: TyCon -> [Type] -> SourceType -mkNewTyConApp tc tys = NType tc tys -- Here is where we might cache the substitution - -isSourceTy :: Type -> Bool -isSourceTy (NoteTy _ ty) = isSourceTy ty -isSourceTy (UsageTy _ ty) = isSourceTy ty -isSourceTy (SourceTy sty) = True -isSourceTy _ = False +---------------------------- +-- new_type_rep doesn't ask any questions: +-- it just expands newtype, whether recursive or not +new_type_rep new_tycon tys = ASSERT( tys `lengthIs` tyConArity new_tycon ) + case newTyConRep new_tycon of + (tvs, rep_ty) -> substTyWith tvs tys rep_ty \end{code} @@ -626,27 +580,14 @@ isSourceTy _ = False typeKind :: Type -> Kind typeKind (TyVarTy tyvar) = tyVarKind tyvar -typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys +typeKind (TyConApp tycon tys) = foldr (\_ k -> kindFunResult k) (tyConKind tycon) tys +typeKind (NewTcApp tycon tys) = foldr (\_ k -> kindFunResult k) (tyConKind tycon) tys typeKind (NoteTy _ ty) = typeKind ty -typeKind (SourceTy _) = liftedTypeKind -- Predicates are always +typeKind (PredTy _) = liftedTypeKind -- Predicates are always -- represented by lifted 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 = liftedTypeKind - 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 lifted 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 (AppTy fun arg) = kindFunResult (typeKind fun) +typeKind (FunTy arg res) = liftedTypeKind typeKind (ForAllTy tv ty) = typeKind ty -typeKind (UsageTy _ ty) = typeKind ty -- we don't have separate kinds for ann/unann \end{code} @@ -654,31 +595,41 @@ typeKind (UsageTy _ ty) = typeKind ty -- we don't have separate kinds f Free variables of a type ~~~~~~~~~~~~~~~~~~~~~~~~ \begin{code} - tyVarsOfType :: Type -> TyVarSet tyVarsOfType (TyVarTy tv) = unitVarSet tv tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys +tyVarsOfType (NewTcApp tycon tys) = tyVarsOfTypes tys tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs -tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1 -tyVarsOfType (SourceTy sty) = tyVarsOfSourceType sty +tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty2 -- See note [Syn] below +tyVarsOfType (PredTy sty) = tyVarsOfPred sty 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 -tyVarsOfType (UsageTy u ty) = tyVarsOfType u `unionVarSet` tyVarsOfType ty + +-- Note [Syn] +-- Consider +-- type T a = Int +-- What are the free tyvars of (T x)? Empty, of course! +-- Here's the example that Ralf Laemmel showed me: +-- foo :: (forall a. C u a -> C u a) -> u +-- mappend :: Monoid u => u -> u -> u +-- +-- bar :: Monoid u => u +-- bar = foo (\t -> t `mappend` t) +-- We have to generalise at the arg to f, and we don't +-- want to capture the constraint (Monad (C u a)) because +-- it appears to mention a. Pretty silly, but it was useful to him. + tyVarsOfTypes :: [Type] -> TyVarSet tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys tyVarsOfPred :: PredType -> TyVarSet -tyVarsOfPred = tyVarsOfSourceType -- Just a subtype - -tyVarsOfSourceType :: SourceType -> TyVarSet -tyVarsOfSourceType (IParam n ty) = tyVarsOfType ty -tyVarsOfSourceType (ClassP clas tys) = tyVarsOfTypes tys -tyVarsOfSourceType (NType tc tys) = tyVarsOfTypes tys +tyVarsOfPred (IParam _ ty) = tyVarsOfType ty +tyVarsOfPred (ClassP _ tys) = tyVarsOfTypes tys tyVarsOfTheta :: ThetaType -> TyVarSet -tyVarsOfTheta = foldr (unionVarSet . tyVarsOfSourceType) emptyVarSet +tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet -- Add a Note with the free tyvars to the top of the type addFreeTyVars :: Type -> Type @@ -686,30 +637,6 @@ addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty \end{code} -Usage annotations of a type -~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Get a list of usage annotations of a type, *in left-to-right pre-order*. - -\begin{code} -usageAnnOfType :: Type -> [Type] -usageAnnOfType ty - = goS ty - where - goT (TyVarTy _) = [] - goT (AppTy ty1 ty2) = goT ty1 ++ goT ty2 - goT (TyConApp tc tys) = concatMap goT tys - goT (FunTy sty1 sty2) = goS sty1 ++ goS sty2 - goT (ForAllTy mv ty) = goT ty - goT (SourceTy p) = goT (sourceTypeRep p) - goT ty@(UsageTy _ _) = pprPanic "usageAnnOfType: unexpected usage:" (pprType ty) - goT (NoteTy note ty) = goT ty - - goS sty = case splitUTy sty of - (u,tty) -> u : goT tty -\end{code} - - %************************************************************************ %* * \subsection{TidyType} @@ -722,36 +649,33 @@ an interface file. It doesn't change the uniques at all, just the print names. \begin{code} -tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar) -tidyTyVar env@(tidy_env, subst) tyvar - = case lookupVarEnv subst tyvar of - - Just tyvar' -> -- Already substituted - (env, tyvar') - - Nothing -> -- Make a new nice name for it - - case tidyOccName tidy_env (getOccName name) of - (tidy', occ') -> -- New occname reqd - ((tidy', subst'), tyvar') - where - subst' = extendVarEnv subst tyvar tyvar' - tyvar' = setTyVarName tyvar name' - name' = mkLocalName (getUnique name) occ' noSrcLoc - -- Note: make a *user* tyvar, so it printes nicely - -- Could extract src loc, but no need. +tidyTyVarBndr :: TidyEnv -> TyVar -> (TidyEnv, TyVar) +tidyTyVarBndr (tidy_env, subst) tyvar + = case tidyOccName tidy_env (getOccName name) of + (tidy', occ') -> ((tidy', subst'), tyvar') + where + subst' = extendVarEnv subst tyvar tyvar' + tyvar' = setTyVarName tyvar name' + name' = mkInternalName (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 :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar]) -tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars - tidyFreeTyVars :: TidyEnv -> TyVarSet -> TidyEnv -- Add the free tyvars to the env in tidy form, -- so that we can tidy the type they are free in -tidyFreeTyVars env tyvars = foldl add env (varSetElems tyvars) - where - add env tv = fst (tidyTyVar env tv) +tidyFreeTyVars env tyvars = fst (tidyOpenTyVars env (varSetElems tyvars)) + +tidyOpenTyVars :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar]) +tidyOpenTyVars env tyvars = mapAccumL tidyOpenTyVar env tyvars + +tidyOpenTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar) +-- Treat a new tyvar as a binder, and give it a fresh tidy name +tidyOpenTyVar env@(tidy_env, subst) tyvar + = case lookupVarEnv subst tyvar of + Just tyvar' -> (env, tyvar') -- Already substituted + Nothing -> tidyTyVarBndr env tyvar -- Treat it as a binder tidyType :: TidyEnv -> Type -> Type tidyType env@(tidy_env, subst) ty @@ -762,27 +686,24 @@ tidyType env@(tidy_env, subst) ty 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 (SourceTy sty) = SourceTy (tidySourceType env sty) - 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) + go (NewTcApp tycon tys) = let args = map go tys + in args `seqList` NewTcApp tycon args + go (NoteTy note ty) = (NoteTy $! (go_note note)) $! (go ty) + go (PredTy sty) = PredTy (tidyPred env sty) + go (AppTy fun arg) = (AppTy $! (go fun)) $! (go arg) + go (FunTy fun arg) = (FunTy $! (go fun)) $! (go arg) + go (ForAllTy tv ty) = ForAllTy tvp $! (tidyType envp ty) where - (envp, tvp) = tidyTyVar env tv - go (UsageTy u ty) = (UsageTy SAPPLY (go u)) SAPPLY (go ty) + (envp, tvp) = tidyTyVarBndr env tv - go_note (SynNote ty) = SynNote SAPPLY (go ty) + go_note (SynNote ty) = SynNote $! (go ty) go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars tidyTypes env tys = map (tidyType env) tys -tidyPred :: TidyEnv -> SourceType -> SourceType -tidyPred = tidySourceType - -tidySourceType :: TidyEnv -> SourceType -> SourceType -tidySourceType env (IParam n ty) = IParam n (tidyType env ty) -tidySourceType env (ClassP clas tys) = ClassP clas (tidyTypes env tys) -tidySourceType env (NType tc tys) = NType tc (tidyTypes env tys) +tidyPred :: TidyEnv -> PredType -> PredType +tidyPred env (IParam n ty) = IParam n (tidyType env ty) +tidyPred env (ClassP clas tys) = ClassP clas (tidyTypes env tys) \end{code} @@ -819,12 +740,12 @@ isUnLiftedType :: Type -> Bool -- 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 (UsageTy _ ty) = isUnLiftedType ty -isUnLiftedType (SourceTy _) = False -- All source types are lifted -isUnLiftedType other = False +isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty +isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty +isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc +isUnLiftedType (PredTy _) = False -- All source types are lifted +isUnLiftedType (NewTcApp tc tys) = isUnLiftedType (newTypeRep tc tys) +isUnLiftedType other = False isUnboxedTupleType :: Type -> Bool isUnboxedTupleType ty = case splitTyConApp_maybe ty of @@ -834,11 +755,45 @@ isUnboxedTupleType ty = case splitTyConApp_maybe ty of -- 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 ) + Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc ) isAlgTyCon tc other -> False \end{code} +@isStrictType@ computes whether an argument (or let RHS) should +be computed strictly or lazily, based only on its type. +Works just like isUnLiftedType, except that it has a special case +for dictionaries. Since it takes account of ClassP, you might think +this function should be in TcType, but isStrictType is used by DataCon, +which is below TcType in the hierarchy, so it's convenient to put it here. + +\begin{code} +isStrictType (ForAllTy tv ty) = isStrictType ty +isStrictType (NoteTy _ ty) = isStrictType ty +isStrictType (TyConApp tc _) = isUnLiftedTyCon tc +isStrictType (NewTcApp tc tys) = isStrictType (newTypeRep tc tys) +isStrictType (PredTy pred) = isStrictPred pred +isStrictType other = False + +isStrictPred (ClassP clas _) = opt_DictsStrict && not (isNewTyCon (classTyCon clas)) +isStrictPred other = False + -- We may be strict in dictionary types, but only if it + -- has more than one component. + -- [Being strict in a single-component dictionary risks + -- poking the dictionary component, which is wrong.] +\end{code} + +\begin{code} +isPrimitiveType :: Type -> Bool +-- Returns types that are opaque to Haskell. +-- Most of these are unlifted, but now that we interact with .NET, we +-- may have primtive (foreign-imported) types that are lifted +isPrimitiveType ty = case splitTyConApp_maybe ty of + Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc ) + isPrimTyCon tc + other -> False +\end{code} + %************************************************************************ %* * @@ -852,10 +807,10 @@ 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 (SourceTy p) = seqPred p +seqType (PredTy p) = seqPred p seqType (TyConApp tc tys) = tc `seq` seqTypes tys +seqType (NewTcApp tc tys) = tc `seq` seqTypes tys seqType (ForAllTy tv ty) = tv `seq` seqType ty -seqType (UsageTy u ty) = seqType u `seq` seqType ty seqTypes :: [Type] -> () seqTypes [] = () @@ -865,9 +820,8 @@ seqNote :: TyNote -> () seqNote (SynNote ty) = seqType ty seqNote (FTVNote set) = sizeUniqSet set `seq` () -seqPred :: SourceType -> () +seqPred :: PredType -> () seqPred (ClassP c tys) = c `seq` seqTypes tys -seqPred (NType tc tys) = tc `seq` seqTypes tys seqPred (IParam n ty) = n `seq` seqType ty \end{code} @@ -881,29 +835,58 @@ seqPred (IParam n ty) = n `seq` seqType ty Comparison; don't use instances so that we know where it happens. Look through newtypes but not usage types. +Note that eqType can respond 'False' for partial applications of newtypes. +Consider + newtype Parser m a = MkParser (Foogle m a) + +Does + Monad (Parser m) `eqType` Monad (Foogle m) + +Well, yes, but eqType won't see that they are the same. +I don't think this is harmful, but it's soemthing to watch out for. + \begin{code} eqType t1 t2 = eq_ty emptyVarEnv t1 t2 -eqKind = eqType -- No worries about looking -eqUsage = eqType -- through source types for these two -- Look through Notes eq_ty env (NoteTy _ t1) t2 = eq_ty env t1 t2 eq_ty env t1 (NoteTy _ t2) = eq_ty env t1 t2 --- Look through SourceTy. This is where the looping danger comes from -eq_ty env (SourceTy sty1) t2 = eq_ty env (sourceTypeRep sty1) t2 -eq_ty env t1 (SourceTy sty2) = eq_ty env t1 (sourceTypeRep sty2) +-- Look through PredTy and NewTcApp. This is where the looping danger comes from. +-- We don't bother to check for the PredType/PredType case, no good reason +-- Hmm: maybe there is a good reason: see the notes below about newtypes +eq_ty env (PredTy sty1) t2 = eq_ty env (predTypeRep sty1) t2 +eq_ty env t1 (PredTy sty2) = eq_ty env t1 (predTypeRep sty2) + +-- NB: we *cannot* short-cut the newtype comparison thus: +-- eq_ty env (NewTcApp tc1 tys1) (NewTcApp tc2 tys2) +-- | (tc1 == tc2) = (eq_tys env tys1 tys2) +-- +-- Consider: +-- newtype T a = MkT [a] +-- newtype Foo m = MkFoo (forall a. m a -> Int) +-- w1 :: Foo [] +-- w1 = ... +-- +-- w2 :: Foo T +-- w2 = MkFoo (\(MkT x) -> case w1 of MkFoo f -> f x) +-- +-- We end up with w2 = w1; so we need that Foo T = Foo [] +-- but we can only expand saturated newtypes, so just comparing +-- T with [] won't do. + +eq_ty env (NewTcApp tc1 tys1) t2 = eq_ty env (newTypeRep tc1 tys1) t2 +eq_ty env t1 (NewTcApp tc2 tys2) = eq_ty env t1 (newTypeRep tc2 tys2) -- The rest is plain sailing eq_ty env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of Just tv1a -> tv1a == tv2 Nothing -> tv1 == tv2 eq_ty env (ForAllTy tv1 t1) (ForAllTy tv2 t2) - | tv1 == tv2 = eq_ty env t1 t2 + | tv1 == tv2 = eq_ty (delVarEnv env tv1) t1 t2 | otherwise = eq_ty (extendVarEnv env tv1 tv2) t1 t2 eq_ty env (AppTy s1 t1) (AppTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2) eq_ty env (FunTy s1 t1) (FunTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2) -eq_ty env (UsageTy _ t1) (UsageTy _ t2) = eq_ty env t1 t2 eq_ty env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 == tc2) && (eq_tys env tys1 tys2) eq_ty env t1 t2 = False