\begin{code}
module Type (
-- re-exports from TypeRep:
- Type, PredType, TauType, ThetaType,
- Kind, TyVarSubst,
+ Type, PredType, ThetaType,
+ Kind, TyVarSubst,
superKind, superBoxity, -- KX and BX respectively
liftedBoxity, unliftedBoxity, -- :: BX
typeCon, -- :: BX -> KX
liftedTypeKind, unliftedTypeKind, openTypeKind, -- :: KX
mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX
-
+ isTypeKind, isAnyTypeKind,
funTyCon,
usageKindCon, -- :: KX
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,
+ SourceType(..), sourceTypeRep, mkPredTy, mkPredTys,
-- Newtypes
- mkNewTyConApp,
+ splitNewType_maybe,
-- Lifting and boxity
- isUnLiftedType, isUnboxedTupleType, isAlgType,
+ isUnLiftedType, isUnboxedTupleType, isAlgType, isStrictType, isPrimitiveType,
-- 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,
-- 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 Var ( TyVar, tyVarKind, tyVarName, setTyVarName )
import VarEnv
import VarSet
-import Name ( NamedThing(..), mkLocalName, tidyOccName )
+import Name ( NamedThing(..), mkInternalName, tidyOccName )
import Class ( classTyCon )
-import TyCon ( TyCon, isRecursiveTyCon,
+import TyCon ( TyCon, isRecursiveTyCon, isPrimTyCon,
isUnboxedTupleTyCon, isUnLiftedTyCon,
isFunTyCon, isNewTyCon, newTyConRep,
isAlgTyCon, isSynTyCon, tyConArity,
)
-- 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 )
import Outputable
import UniqSet ( sizeUniqSet ) -- Should come via VarSet
+import Maybe ( isJust )
\end{code}
\begin{code}
hasMoreBoxityInfo :: Kind -> Kind -> Bool
+-- (k1 `hasMoreBoxityInfo` k2) checks that k1 <: k2
hasMoreBoxityInfo k1 k2
- | k2 `eqKind` openTypeKind = True
- | otherwise = k1 `eqType` k2
+ | k2 `eqKind` openTypeKind = isAnyTypeKind k1
+ | otherwise = k1 `eqKind` k2
+ where
+
+isAnyTypeKind :: Kind -> Bool
+-- True of kind * and *# and ?
+isAnyTypeKind (TyConApp tc _) = tc == typeCon || tc == openKindCon
+isAnyTypeKind (NoteTy _ k) = isAnyTypeKind k
+isAnyTypeKind other = False
+
+isTypeKind :: Kind -> Bool
+-- True of kind * and *#
+isTypeKind (TyConApp tc _) = tc == typeCon
+isTypeKind (NoteTy _ k) = isTypeKind k
+isTypeKind other = False
defaultKind :: Kind -> Kind
-- Used when generalising: default kind '?' to '*'
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
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
\end{code}
\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
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 (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
-- 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
where
mk_app (NoteTy _ ty1) = mk_app ty1
mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ orig_tys2)
- mk_app ty@(UsageTy _ _) = pprPanic "mkAppTys: UTy:" (pprType ty)
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)
split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
split (ty:tys) acc = split tys (ty:acc)
-splitAppTy_maybe ty@(UsageTy _ _) = pprPanic "splitAppTy_maybe: UTy:" (pprType ty)
splitAppTy_maybe other = Nothing
splitAppTy :: Type -> (Type, Type)
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 (FunTy ty1 ty2) args = ASSERT( null args )
- (TyConApp funTyCon [], [unUTy ty1,unUTy ty2])
+ (TyConApp funTyCon [], [ty1,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)
split orig_ty ty args = (orig_ty, args)
\end{code}
\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 (SourceTy p) = splitFunTy (sourceTypeRep p)
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 (SourceTy p) = splitFunTy_maybe (sourceTypeRep p)
splitFunTy_maybe other = Nothing
splitFunTys :: Type -> ([Type], Type)
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 (SourceTy p) = split args orig_ty (sourceTypeRep p)
split args orig_ty ty = (reverse args, orig_ty)
zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
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 xs nty (SourceTy p) = split acc xs nty (sourceTypeRep p)
split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty)
funResultTy :: Type -> Type
funResultTy (FunTy arg res) = res
funResultTy (NoteTy _ ty) = funResultTy ty
-funResultTy (SourceTy p) = funResultTy (sourceTypeRep p)
-funResultTy (UsageTy _ ty) = funResultTy ty
+funResultTy (SourceTy p) = funResultTy (sourceTypeRep p)
funResultTy ty = pprPanic "funResultTy" (pprType 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 (SourceTy p) = funArgTy (sourceTypeRep p)
funArgTy ty = pprPanic "funArgTy" (pprType ty)
\end{code}
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
+ tys `lengthIs` tyConArity tycon -- use the SourceType form
= SourceTy (NType tycon tys)
| otherwise
= ASSERT(not (isSynTyCon tycon))
- UASSERT2( not (any isUTy tys), ppr tycon <+> fsep (map pprType tys) )
TyConApp tycon tys
mkTyConTy :: TyCon -> Type
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 other = Nothing
\end{code}
~~~~~
\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
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.
+Remember, non-recursive newtypes get expanded as part of the SourceTy case,
+but recursive ones are represented by TyConApps and have to be expanded
+by steam.
+
\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)
+repType (ForAllTy _ ty) = repType ty
+repType (NoteTy _ ty) = repType ty
+repType (SourceTy p) = repType (sourceTypeRep p)
+repType (TyConApp tc tys) | isNewTyCon tc && tys `lengthIs` tyConArity tc
+ = repType (newTypeRep tc tys)
+repType ty = ty
+
typePrimRep :: Type -> PrimRep
typePrimRep ty = case repType ty of
= 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)
splitFAT_m (NoteTy _ ty) = splitFAT_m ty
splitFAT_m (SourceTy p) = splitFAT_m (sourceTypeRep p)
splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
- splitFAT_m (UsageTy _ ty) = splitFAT_m ty
splitFAT_m _ = Nothing
splitForAllTys :: Type -> ([TyVar], Type)
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)
+
+dropForAlls :: Type -> Type
+dropForAlls ty = snd (splitForAllTys ty)
\end{code}
-- (mkPiType now in CoreUtils)
\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 (SourceTy p) arg = applyTy (sourceTypeRep p) 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
+ = substTyWith tvs arg_tys ty
where
(mu, tvs, ty) = split fun_ty arg_tys
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"
\end{code}
----------------------------------------------------------------------
- UsageTy
- ~~~~~~~
-
-Constructing and taking apart usage 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}
-
-\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}
-
-\begin{code}
-mkUTyM :: Type -> Type
- -- put TOP (no info) annotation on unannotated type
-mkUTyM ty = mkUTy usMany ty
-\end{code}
-
-\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)
-\end{code}
-
-
%************************************************************************
%* *
\subsection{Source types}
The key function is sourceTypeRep which gives the representation of a source type:
\begin{code}
+mkPredTy :: PredType -> Type
+mkPredTy pred = SourceTy pred
+
+mkPredTys :: ThetaType -> [Type]
+mkPredTys preds = map SourceTy preds
+
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 (IParam _ 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
+sourceTypeRep (NType tc tys) = newTypeRep 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
+
+
+splitNewType_maybe :: Type -> Maybe Type
+-- Newtypes that are recursive are reprsented by TyConApp, just
+-- as they always were. Occasionally we want to find their representation type.
+-- NB: remember that in this module, non-recursive newtypes are transparent
+
+splitNewType_maybe ty
+ = case splitTyConApp_maybe ty of
+ Just (tc,tys) | isNewTyCon tc -> ASSERT( tys `lengthIs` tyConArity tc )
+ -- The assert should hold because repType should
+ -- only be applied to *types* (of kind *)
+ Just (newTypeRep tc tys)
+ other -> Nothing
+
+-- A local helper function (not exported)
+newTypeRep new_tycon tys = case newTyConRep new_tycon of
+ (tvs, rep_ty) -> substTyWith tvs tys rep_ty
\end{code}
-- a strange kind like (*->*).
typeKind (ForAllTy tv ty) = typeKind ty
-typeKind (UsageTy _ ty) = typeKind ty -- we don't have separate kinds for ann/unann
\end{code}
Free variables of a type
~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-
tyVarsOfType :: Type -> TyVarSet
tyVarsOfType (TyVarTy tv) = unitVarSet tv
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
-tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
+tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty2 -- See note [Syn] below
tyVarsOfType (SourceTy sty) = tyVarsOfSourceType 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 = 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
+tyVarsOfSourceType (IParam _ ty) = tyVarsOfType ty
+tyVarsOfSourceType (ClassP _ tys) = tyVarsOfTypes tys
+tyVarsOfSourceType (NType _ tys) = tyVarsOfTypes tys
tyVarsOfTheta :: ThetaType -> TyVarSet
tyVarsOfTheta = foldr (unionVarSet . tyVarsOfSourceType) emptyVarSet
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}
%************************************************************************
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') -> -- New occname reqd
+ ((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
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 (NoteTy note ty) = (NoteTy $! (go_note note)) $! (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 (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
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
-- 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 (SourceTy (ClassP clas _)) = opt_DictsStrict && not (isNewTyCon (classTyCon clas))
+ -- 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.]
+isStrictType other = False
+\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}
+
%************************************************************************
%* *
seqType (SourceTy p) = seqPred p
seqType (TyConApp 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 [] = ()
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
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
eq_tys env [] [] = True
-eq_tys env (t1:tys1) (t2:tys2) = (eq_ty env t1 t2) && (eq_tys env tys2 tys2)
+eq_tys env (t1:tys1) (t2:tys2) = (eq_ty env t1 t2) && (eq_tys env tys1 tys2)
eq_tys env tys1 tys2 = False
\end{code}