-\begin{code}
-#include "HsVersions.h"
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+\begin{code}
module Type (
- GenType(..), Type(..), TauType(..),
- mkTyVarTy, mkTyVarTys,
- getTyVar, getTyVar_maybe, isTyVarTy,
- mkAppTy, mkAppTys, splitAppTy,
- mkFunTy, mkFunTys, splitFunTy, getFunTy_maybe,
- mkTyConTy, getTyCon_maybe, applyTyCon,
- mkSynTy,
- mkForAllTy, mkForAllTys, getForAllTy_maybe, splitForAllTy,
- mkForAllUsageTy, getForAllUsageTy,
- applyTy,
+ -- re-exports from TypeRep:
+ Type,
+ Kind, TyVarSubst,
- isPrimType, isUnboxedType, typePrimRep,
+ superKind, superBoxity, -- KX and BX respectively
+ liftedBoxity, unliftedBoxity, -- :: BX
+ openKindCon, -- :: KX
+ typeCon, -- :: BX -> KX
+ liftedTypeKind, unliftedTypeKind, openTypeKind, -- :: KX
+ mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX
- RhoType(..), SigmaType(..), ThetaType(..),
- mkDictTy,
- mkRhoTy, splitRhoTy,
- mkSigmaTy, splitSigmaTy,
+ funTyCon,
- maybeAppTyCon, getAppTyCon,
- maybeAppDataTyCon, getAppDataTyCon,
- maybeBoxedPrimType,
+ usageKindCon, -- :: KX
+ usageTypeKind, -- :: KX
+ usOnceTyCon, usManyTyCon, -- :: $
+ usOnce, usMany, -- :: $
- matchTy, matchTys, eqTy, eqSimpleTy, eqSimpleTheta,
+ -- exports from this module:
+ hasMoreBoxityInfo, defaultKind,
- instantiateTy, instantiateTauTy, instantiateUsage,
- applyTypeEnvToTy,
+ mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
- isTauTy,
+ mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
- tyVarsOfType, tyVarsOfTypes, getTypeKind
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
+ funResultTy, funArgTy, zipFunTys,
+ mkTyConApp, mkTyConTy,
+ tyConAppTyCon, tyConAppArgs,
+ splitTyConApp_maybe, splitTyConApp,
+ splitAlgTyConApp_maybe, splitAlgTyConApp,
-) where
+ mkUTy, splitUTy, splitUTy_maybe,
+ isUTy, uaUTy, unUTy, liftUTy, mkUTyM,
+ isUsageKind, isUsage, isUTyVar,
-import Ubiq
-import IdLoop -- for paranoia checking
-import TyLoop -- for paranoia checking
-import PrelLoop -- for paranoia checking
+ mkSynTy, deNoteType,
--- friends:
-import Class ( getClassSig, getClassOpLocalType, GenClass{-instances-} )
-import Kind ( mkBoxedTypeKind, resultKind )
-import TyCon ( mkFunTyCon, mkTupleTyCon, isFunTyCon, isPrimTyCon, isDataTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn, TyCon )
-import TyVar ( getTyVarKind, GenTyVar{-instances-}, GenTyVarSet(..),
- emptyTyVarSet, unionTyVarSets, minusTyVarSet,
- unitTyVarSet, nullTyVarEnv, lookupTyVarEnv,
- addOneToTyVarEnv, TyVarEnv(..) )
-import Usage ( usageOmega, GenUsage, Usage(..), UVar(..), UVarEnv(..),
- nullUVarEnv, addOneToUVarEnv, lookupUVarEnv, eqUVar,
- eqUsage )
+ repType, splitRepFunTys, splitNewType_maybe, typePrimRep,
--- others
-import PrimRep ( PrimRep(..) )
-import Util ( thenCmp, zipEqual, panic, panic#, assertPanic,
- Ord3(..){-instances-}
- )
-\end{code}
+ mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
+ applyTy, applyTys, hoistForAllTys, isForAllTy,
-Data types
-~~~~~~~~~~
+ -- Predicates and the like
+ PredType(..), getClassPredTys_maybe, getClassPredTys,
+ isPredTy, isClassPred, isTyVarClassPred, predHasFDs,
+ mkDictTy, mkPredTy, mkPredTys, splitPredTy_maybe, predTyUnique,
+ splitDictTy, splitDictTy_maybe, isDictTy, predRepTy, splitDFunTy,
+ mkClassPred, predMentionsIPs, inheritablePred, isIPPred, mkPredName,
-\begin{code}
-type Type = GenType TyVar UVar -- Used after typechecker
-
-data GenType tyvar uvar -- Parameterised over type and usage variables
- = TyVarTy tyvar
-
- | AppTy
- (GenType tyvar uvar)
- (GenType tyvar uvar)
-
- | TyConTy -- Constants of a specified kind
- TyCon
- (GenUsage uvar) -- Usage gives uvar of the full application,
- -- iff the full application is of kind Type
- -- c.f. the Usage field in TyVars
-
- | SynTy -- Synonyms must be saturated, and contain their expansion
- TyCon -- Must be a SynTyCon
- [GenType tyvar uvar]
- (GenType tyvar uvar) -- Expansion!
-
- | ForAllTy
- tyvar
- (GenType tyvar uvar) -- TypeKind
-
- | ForAllUsageTy
- uvar -- Quantify over this
- [uvar] -- Bounds; the quantified var must be
- -- less than or equal to all these
- (GenType tyvar uvar)
-
- -- Two special cases that save a *lot* of administrative
- -- overhead:
-
- | FunTy -- BoxedTypeKind
- (GenType tyvar uvar) -- Both args are of TypeKind
- (GenType tyvar uvar)
- (GenUsage uvar)
-
- | DictTy -- TypeKind
- Class -- Class
- (GenType tyvar uvar) -- Arg has kind TypeKind
- (GenUsage uvar)
-\end{code}
+ -- Tau, Rho, Sigma
+ TauType, RhoType, SigmaType, ThetaType,
+ isTauTy, mkRhoTy, splitRhoTy, splitMethodTy,
+ mkSigmaTy, isSigmaTy, splitSigmaTy,
+ getDFunTyKey,
-\begin{code}
-type RhoType = Type
-type TauType = Type
-type ThetaType = [(Class, Type)]
-type SigmaType = Type
-\end{code}
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
+ -- Free variables
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
+ namesOfType, usageAnnOfType, typeKind, addFreeTyVars,
+ namesOfDFunHead,
-Expand abbreviations
-~~~~~~~~~~~~~~~~~~~~
-Removes just the top level of any abbreviations.
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVar, tidyTyVars, tidyFreeTyVars,
+ tidyTopType, tidyPred,
-\begin{code}
-expandTy :: Type -> Type -- Restricted to Type due to Dict expansion
+ -- Seq
+ seqType, seqTypes
-expandTy (FunTy t1 t2 u) = AppTy (AppTy (TyConTy mkFunTyCon u) t1) t2
-expandTy (SynTy _ _ t) = expandTy t
-expandTy (DictTy clas ty u)
- = case all_arg_tys of
+ ) where
- [arg_ty] -> expandTy arg_ty -- just the <whatever> itself
+#include "HsVersions.h"
- -- The extra expandTy is to make sure that
- -- the result isn't still a dict, which it might be
- -- if the original guy was a dict with one superdict and
- -- no methods!
+-- We import the representation and primitive functions from TypeRep.
+-- Many things are reexported, but not the representation!
- other -> ASSERT(not (null all_arg_tys))
- foldl AppTy (TyConTy (mkTupleTyCon (length all_arg_tys)) u) all_arg_tys
+import TypeRep
- -- A tuple of 'em
- -- Note: length of all_arg_tys can be 0 if the class is
- -- _CCallable, _CReturnable (and anything else
- -- *really weird* that the user writes).
- where
- (tyvar, super_classes, ops) = getClassSig clas
- super_dict_tys = map mk_super_ty super_classes
- class_op_tys = map mk_op_ty ops
- all_arg_tys = super_dict_tys ++ class_op_tys
- mk_super_ty sc = DictTy sc ty usageOmega
- mk_op_ty op = instantiateTy [(tyvar,ty)] (getClassOpLocalType op)
-
-expandTy ty = ty
+-- Other imports:
+
+import {-# SOURCE #-} DataCon( DataCon )
+import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
+import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
+
+-- friends:
+import Var ( Var, TyVar, tyVarKind, tyVarName, setTyVarName )
+import VarEnv
+import VarSet
+
+import OccName ( mkDictOcc )
+import Name ( Name, NamedThing(..), OccName, mkLocalName, tidyOccName )
+import NameSet
+import Class ( classTyCon, classHasFDs, Class )
+import TyCon ( TyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
+ isFunTyCon, isDataTyCon, isNewTyCon, newTyConRep,
+ isAlgTyCon, isSynTyCon, tyConArity,
+ tyConKind, tyConDataCons, getSynTyConDefn,
+ tyConPrimRep
+ )
+
+-- others
+import Maybes ( maybeToBool )
+import SrcLoc ( SrcLoc, noSrcLoc )
+import PrimRep ( PrimRep(..) )
+import Unique ( Unique, Uniquable(..) )
+import Util ( mapAccumL, seqList, thenCmp )
+import Outputable
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
\end{code}
-Simple construction and analysis functions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+%************************************************************************
+%* *
+\subsection{Stuff to do with kinds.}
+%* *
+%************************************************************************
+
\begin{code}
-mkTyVarTy :: t -> GenType t u
-mkTyVarTys :: [t] -> [GenType t y]
-mkTyVarTy = TyVarTy
-mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
+hasMoreBoxityInfo :: Kind -> Kind -> Bool
+hasMoreBoxityInfo k1 k2
+ | k2 == openTypeKind = True
+ | otherwise = k1 == k2
+
+defaultKind :: Kind -> Kind
+-- Used when generalising: default kind '?' to '*'
+defaultKind kind | kind == openTypeKind = liftedTypeKind
+ | otherwise = kind
+\end{code}
-getTyVar :: String -> GenType t u -> t
-getTyVar msg (TyVarTy tv) = tv
-getTyVar msg (SynTy _ _ t) = getTyVar msg t
-getTyVar msg other = panic ("getTyVar: " ++ msg)
-getTyVar_maybe :: GenType t u -> Maybe t
-getTyVar_maybe (TyVarTy tv) = Just tv
-getTyVar_maybe (SynTy _ _ t) = getTyVar_maybe t
-getTyVar_maybe other = Nothing
+%************************************************************************
+%* *
+\subsection{Constructor-specific functions}
+%* *
+%************************************************************************
-isTyVarTy :: GenType t u -> Bool
-isTyVarTy (TyVarTy tv) = True
-isTyVarTy (SynTy _ _ t) = isTyVarTy t
-isTyVarTy other = False
-\end{code}
+---------------------------------------------------------------------
+ TyVarTy
+ ~~~~~~~
\begin{code}
-mkAppTy = AppTy
+mkTyVarTy :: TyVar -> Type
+mkTyVarTy = TyVarTy
-mkAppTys :: GenType t u -> [GenType t u] -> GenType t u
-mkAppTys t ts = foldl AppTy t ts
+mkTyVarTys :: [TyVar] -> [Type]
+mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
-splitAppTy :: GenType t u -> (GenType t u, [GenType t u])
-splitAppTy t = go t []
- where
- go (AppTy t arg) ts = go t (arg:ts)
- go (FunTy fun arg u) ts = (TyConTy mkFunTyCon u, fun:arg:ts)
- go (SynTy _ _ t) ts = go t ts
- go t ts = (t,ts)
+getTyVar :: String -> Type -> TyVar
+getTyVar msg (TyVarTy tv) = tv
+getTyVar msg (PredTy p) = getTyVar msg (predRepTy 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 (PredTy p) = getTyVar_maybe (predRepTy 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 (PredTy p) = isTyVarTy (predRepTy p)
+isTyVarTy ty@(UsageTy _ _) = pprPanic "isTyVarTy: UTy:" (pprType ty)
+isTyVarTy other = False
\end{code}
+
+---------------------------------------------------------------------
+ AppTy
+ ~~~~~
+We need to be pretty careful with AppTy to make sure we obey the
+invariant that a TyConApp is always visibly so. mkAppTy maintains the
+invariant: use it.
+
\begin{code}
--- NB mkFunTy, mkFunTys puts in Omega usages, for now at least
-mkFunTy arg res = FunTy arg res usageOmega
+mkAppTy orig_ty1 orig_ty2
+ = ASSERT( not (isPredTy orig_ty1) ) -- Predicates 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 ty1 = AppTy orig_ty1 orig_ty2
+
+mkAppTys :: Type -> [Type] -> Type
+mkAppTys orig_ty1 [] = orig_ty1
+ -- This check for an empty list of type arguments
+ -- avoids the needless loss of a type synonym constructor.
+ -- For example: mkAppTys Rational []
+ -- returns to (Ratio Integer), which has needlessly lost
+ -- the Rational part.
+mkAppTys orig_ty1 orig_tys2
+ = ASSERT( not (isPredTy orig_ty1) ) -- Predicates 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 (AppTy ty1 ty2) = Just (ty1, ty2)
+splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
+splitAppTy_maybe (PredTy p) = splitAppTy_maybe (predRepTy p)
+splitAppTy_maybe (TyConApp tc []) = Nothing
+splitAppTy_maybe (TyConApp tc tys) = split tys []
+ where
+ split [ty2] acc = 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)
+splitAppTy ty = case splitAppTy_maybe ty of
+ Just pr -> pr
+ Nothing -> panic "splitAppTy"
+
+splitAppTys :: Type -> (Type, [Type])
+splitAppTys ty = split ty ty []
+ where
+ split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
+ split orig_ty (NoteTy _ ty) args = split orig_ty ty args
+ split orig_ty (PredTy p) args = split orig_ty (predRepTy p) args
+ split orig_ty (FunTy ty1 ty2) args = ASSERT( null args )
+ (TyConApp 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)
+ split orig_ty ty args = (orig_ty, args)
+\end{code}
-mkFunTys :: [GenType t u] -> GenType t u -> GenType t u
-mkFunTys ts t = foldr (\ f a -> FunTy f a usageOmega) t ts
-getFunTy_maybe :: GenType t u -> Maybe (GenType t u, GenType t u)
-getFunTy_maybe (FunTy arg result _) = Just (arg,result)
-getFunTy_maybe (AppTy (AppTy (TyConTy tycon _) arg) res)
- | isFunTyCon tycon = Just (arg, res)
-getFunTy_maybe (SynTy _ _ t) = getFunTy_maybe t
-getFunTy_maybe other = Nothing
+---------------------------------------------------------------------
+ FunTy
+ ~~~~~
-splitFunTy :: GenType t u -> ([GenType t u], GenType t u)
-splitFunTy t = go t []
+\begin{code}
+mkFunTy :: Type -> Type -> Type
+mkFunTy arg res = UASSERT2( isUTy arg && isUTy res, pprType arg <+> pprType 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
+
+splitFunTy :: Type -> (Type, Type)
+splitFunTy (FunTy arg res) = (arg, res)
+splitFunTy (NoteTy _ ty) = splitFunTy ty
+splitFunTy (PredTy p) = splitFunTy (predRepTy p)
+splitFunTy ty@(UsageTy _ _) = pprPanic "splitFunTy: UTy:" (pprType ty)
+
+splitFunTy_maybe :: Type -> Maybe (Type, Type)
+splitFunTy_maybe (FunTy arg res) = Just (arg, res)
+splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
+splitFunTy_maybe (PredTy p) = splitFunTy_maybe (predRepTy p)
+splitFunTy_maybe ty@(UsageTy _ _) = pprPanic "splitFunTy_maybe: UTy:" (pprType ty)
+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 (PredTy p) = split args orig_ty (predRepTy p)
+ split args orig_ty (UsageTy _ _) = pprPanic "splitFunTys: UTy:" (pprType orig_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
- go (FunTy arg res _) ts = go res (arg:ts)
- go (AppTy (AppTy (TyConTy tycon _) arg) res) ts
- | isFunTyCon tycon
- = go res (arg:ts)
- go (SynTy _ _ t) ts
- = go t ts
- go t ts
- = (reverse ts, t)
+ split 0 args syn_ty ty = (reverse args, syn_ty)
+ split n args syn_ty (FunTy arg res) = split (n-1) (arg:args) res res
+ split n args syn_ty (NoteTy _ ty) = split n args syn_ty ty
+ split n args syn_ty (PredTy p) = split n args syn_ty (predRepTy p)
+ split n args syn_ty (UsageTy _ _) = pprPanic "splitFunTysN: UTy:" (pprType orig_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
+ split acc [] nty ty = (reverse acc, nty)
+ split acc (x:xs) nty (FunTy arg res) = split ((x,arg):acc) xs res res
+ split acc xs nty (NoteTy _ ty) = split acc xs nty ty
+ split acc xs nty (PredTy p) = split acc xs nty (predRepTy p)
+ split acc 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)
+
+funResultTy :: Type -> Type
+funResultTy (FunTy arg res) = res
+funResultTy (NoteTy _ ty) = funResultTy ty
+funResultTy (PredTy p) = funResultTy (predRepTy p)
+funResultTy (UsageTy _ ty) = funResultTy ty
+funResultTy ty = pprPanic "funResultTy" (pprType ty)
+
+funArgTy :: Type -> Type
+funArgTy (FunTy arg res) = arg
+funArgTy (NoteTy _ ty) = funArgTy ty
+funArgTy (PredTy p) = funArgTy (predRepTy p)
+funArgTy (UsageTy _ ty) = funArgTy ty
+funArgTy ty = pprPanic "funArgTy" (pprType ty)
\end{code}
-\begin{code}
--- NB applyTyCon puts in usageOmega, for now at least
-mkTyConTy tycon = TyConTy tycon usageOmega
-applyTyCon :: TyCon -> [GenType t u] -> GenType t u
-applyTyCon tycon tys = foldl AppTy (TyConTy tycon usageOmega) tys
+---------------------------------------------------------------------
+ TyConApp
+ ~~~~~~~~
-getTyCon_maybe :: GenType t u -> Maybe TyCon
-getTyCon_maybe (TyConTy tycon _) = Just tycon
-getTyCon_maybe (SynTy _ _ t) = getTyCon_maybe t
-getTyCon_maybe other_ty = Nothing
+\begin{code}
+mkTyConApp :: TyCon -> [Type] -> Type
+mkTyConApp tycon tys
+ | isFunTyCon tycon && length tys == 2
+ = case tys of
+ (ty1:ty2:_) -> FunTy (mkUTyM ty1) (mkUTyM ty2)
+
+ | 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 []
+
+-- splitTyConApp "looks through" synonyms, because they don't
+-- mean a distinct type, but all other type-constructor applications
+-- including functions are returned as Just ..
+
+tyConAppTyCon :: Type -> TyCon
+tyConAppTyCon ty = case splitTyConApp_maybe ty of
+ Just (tc,_) -> tc
+ Nothing -> pprPanic "tyConAppTyCon" (pprType ty)
+
+tyConAppArgs :: Type -> [Type]
+tyConAppArgs ty = case splitTyConApp_maybe ty of
+ Just (_,args) -> args
+ Nothing -> pprPanic "tyConAppArgs" (pprType ty)
+
+splitTyConApp :: Type -> (TyCon, [Type])
+splitTyConApp ty = case splitTyConApp_maybe ty of
+ Just stuff -> stuff
+ Nothing -> pprPanic "splitTyConApp" (pprType 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 (NoteTy _ ty) = splitTyConApp_maybe ty
+splitTyConApp_maybe (PredTy p) = splitTyConApp_maybe (predRepTy p)
+splitTyConApp_maybe (UsageTy _ ty) = splitTyConApp_maybe ty
+splitTyConApp_maybe other = Nothing
+
+-- splitAlgTyConApp_maybe looks for
+-- *saturated* applications of *algebraic* data types
+-- "Algebraic" => newtype, data type, or dictionary (not function types)
+-- We return the constructors too, so there had better be some.
+
+splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
+splitAlgTyConApp_maybe (TyConApp tc tys)
+ | isAlgTyCon tc &&
+ tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
+splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
+splitAlgTyConApp_maybe (PredTy p) = splitAlgTyConApp_maybe (predRepTy p)
+splitAlgTyConApp_maybe (UsageTy _ ty)= splitAlgTyConApp_maybe ty
+splitAlgTyConApp_maybe other = Nothing
+
+splitAlgTyConApp :: Type -> (TyCon, [Type], [DataCon])
+ -- Here the "algebraic" property is an *assertion*
+splitAlgTyConApp (TyConApp tc tys) = ASSERT( isAlgTyCon tc && tyConArity tc == length tys )
+ (tc, tys, tyConDataCons tc)
+splitAlgTyConApp (NoteTy _ ty) = splitAlgTyConApp ty
+splitAlgTyConApp (PredTy p) = splitAlgTyConApp (predRepTy p)
+splitAlgTyConApp (UsageTy _ ty) = splitAlgTyConApp ty
+#ifdef DEBUG
+splitAlgTyConApp ty = pprPanic "splitAlgTyConApp" (pprType ty)
+#endif
\end{code}
+
+---------------------------------------------------------------------
+ SynTy
+ ~~~~~
+
\begin{code}
mkSynTy syn_tycon tys
- = SynTy syn_tycon tys (instantiateTauTy (zipEqual tyvars tys) body)
+ = ASSERT( isSynTyCon syn_tycon )
+ ASSERT( length tyvars == length tys )
+ NoteTy (SynNote (TyConApp syn_tycon tys))
+ (substTy (mkTyVarSubst tyvars tys) body)
where
(tyvars, body) = getSynTyConDefn syn_tycon
-\end{code}
-Tau stuff
-~~~~~~~~~
-\begin{code}
-isTauTy :: GenType t u -> Bool
-isTauTy (TyVarTy v) = True
-isTauTy (TyConTy _ _) = True
-isTauTy (AppTy a b) = isTauTy a && isTauTy b
-isTauTy (FunTy a b _) = isTauTy a && isTauTy b
-isTauTy (SynTy _ _ ty) = isTauTy ty
-isTauTy other = False
+deNoteType :: Type -> Type
+ -- Remove synonyms, but not Preds
+deNoteType ty@(TyVarTy tyvar) = ty
+deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
+deNoteType (PredTy p) = PredTy (deNotePred p)
+deNoteType (NoteTy _ ty) = deNoteType ty
+deNoteType (AppTy fun arg) = AppTy (deNoteType fun) (deNoteType arg)
+deNoteType (FunTy fun arg) = FunTy (deNoteType fun) (deNoteType arg)
+deNoteType (ForAllTy tv ty) = ForAllTy tv (deNoteType ty)
+deNoteType (UsageTy u ty) = UsageTy u (deNoteType ty)
+
+deNotePred :: PredType -> PredType
+deNotePred (ClassP c tys) = ClassP c (map deNoteType tys)
+deNotePred (IParam n ty) = IParam n (deNoteType ty)
\end{code}
-Rho stuff
-~~~~~~~~~
-NB mkRhoTy and mkDictTy put in usageOmega, for now at least
+Notes on type synonyms
+~~~~~~~~~~~~~~~~~~~~~~
+The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
+to return type synonyms whereever possible. Thus
-\begin{code}
-mkDictTy :: Class -> GenType t u -> GenType t u
-mkDictTy clas ty = DictTy clas ty usageOmega
+ type Foo a = a -> a
-mkRhoTy :: [(Class, GenType t u)] -> GenType t u -> GenType t u
-mkRhoTy theta ty =
- foldr (\(c,t) r -> FunTy (DictTy c t usageOmega) r usageOmega) ty theta
+we want
+ splitFunTys (a -> Foo a) = ([a], Foo a)
+not ([a], a -> a)
+
+The reason is that we then get better (shorter) type signatures in
+interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
-splitRhoTy :: GenType t u -> ([(Class,GenType t u)], GenType t u)
-splitRhoTy t =
- go t []
- where
- go (FunTy (DictTy c t _) r _) ts = go r ((c,t):ts)
- go (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
- | isFunTyCon tycon
- = go r ((c,t):ts)
- go (SynTy _ _ t) ts = go t ts
- go t ts = (reverse ts, t)
-\end{code}
+ Representation types
+ ~~~~~~~~~~~~~~~~~~~~
+
+repType looks through
+ (a) for-alls, and
+ (b) newtypes
+ (c) synonyms
+ (d) predicates
+ (e) usage annotations
+It's useful in the back end where we're not
+interested in newtypes anymore.
-Forall stuff
-~~~~~~~~~~~~
\begin{code}
-mkForAllTy = ForAllTy
-
-mkForAllTys :: [t] -> GenType t u -> GenType t u
-mkForAllTys tyvars ty = foldr ForAllTy ty tyvars
-
-getForAllTy_maybe :: GenType t u -> Maybe (t,GenType t u)
-getForAllTy_maybe (SynTy _ _ t) = getForAllTy_maybe t
-getForAllTy_maybe (ForAllTy tyvar t) = Just(tyvar,t)
-getForAllTy_maybe _ = Nothing
-
-splitForAllTy :: GenType t u-> ([t], GenType t u)
-splitForAllTy t = go t []
- where
- go (ForAllTy tv t) tvs = go t (tv:tvs)
- go (SynTy _ _ t) tvs = go t tvs
- go t tvs = (reverse tvs, t)
+repType :: Type -> Type
+repType (ForAllTy _ ty) = repType ty
+repType (NoteTy _ ty) = repType ty
+repType (PredTy p) = repType (predRepTy p)
+repType (UsageTy _ ty) = repType ty
+repType ty = case splitNewType_maybe ty of
+ Just ty' -> repType ty' -- Still re-apply repType in case of for-all
+ Nothing -> ty
+
+splitRepFunTys :: Type -> ([Type], Type)
+-- Like splitFunTys, but looks through newtypes and for-alls
+splitRepFunTys ty = split [] (repType ty)
+ where
+ split args (FunTy arg res) = split (arg:args) (repType res)
+ split args ty = (reverse args, ty)
+
+typePrimRep :: Type -> PrimRep
+typePrimRep ty = case repType ty of
+ TyConApp tc _ -> tyConPrimRep tc
+ FunTy _ _ -> PtrRep
+ AppTy _ _ -> PtrRep -- ??
+ TyVarTy _ -> PtrRep
+
+splitNewType_maybe :: Type -> Maybe Type
+-- Find the representation of a newtype, if it is one
+-- Looks through multiple levels of newtype, but does not look through for-alls
+splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
+splitNewType_maybe (PredTy p) = splitNewType_maybe (predRepTy p)
+splitNewType_maybe (UsageTy _ ty) = splitNewType_maybe ty
+splitNewType_maybe (TyConApp tc tys) = case newTyConRep tc of
+ Just rep_ty -> ASSERT( length tys == tyConArity tc )
+ -- The assert should hold because repType should
+ -- only be applied to *types* (of kind *)
+ Just (applyTys rep_ty tys)
+ Nothing -> Nothing
+splitNewType_maybe other = Nothing
\end{code}
-\begin{code}
-mkForAllUsageTy :: u -> [u] -> GenType t u -> GenType t u
-mkForAllUsageTy = ForAllUsageTy
-getForAllUsageTy :: GenType t u -> Maybe (u,[u],GenType t u)
-getForAllUsageTy (ForAllUsageTy uvar bounds t) = Just(uvar,bounds,t)
-getForAllUsageTy (SynTy _ _ t) = getForAllUsageTy t
-getForAllUsageTy _ = Nothing
-\end{code}
-Applied tycons (includes FunTyCons)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+---------------------------------------------------------------------
+ ForAllTy
+ ~~~~~~~~
+
\begin{code}
-maybeAppTyCon
- :: GenType tyvar uvar
- -> Maybe (TyCon, -- the type constructor
- [GenType tyvar uvar]) -- types to which it is applied
-
-maybeAppTyCon ty
- = case (getTyCon_maybe app_ty) of
- Nothing -> Nothing
- Just tycon -> Just (tycon, arg_tys)
+mkForAllTy :: TyVar -> Type -> Type
+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
+
+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
- (app_ty, arg_tys) = splitAppTy ty
+ splitFAT_m (NoteTy _ ty) = splitFAT_m ty
+ splitFAT_m (PredTy p) = splitFAT_m (predRepTy p)
+ splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
+ splitFAT_m (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 (PredTy p) tvs = split orig_ty (predRepTy p) tvs
+ split orig_ty (UsageTy _ ty) tvs = split orig_ty ty tvs
+ split orig_ty t tvs = (reverse tvs, orig_ty)
+\end{code}
+-- (mkPiType now in CoreUtils)
-getAppTyCon
- :: GenType tyvar uvar
- -> (TyCon, -- the type constructor
- [GenType tyvar uvar]) -- types to which it is applied
+Applying a for-all to its arguments. Lift usage annotation as required.
-getAppTyCon ty
- = case maybeAppTyCon ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppTyCon" -- (ppr PprShowAll ty)
-#endif
+\begin{code}
+applyTy :: Type -> Type -> Type
+applyTy (PredTy p) arg = applyTy (predRepTy 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"
+
+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 (PredTy p) args = split (predRepTy 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}
-Applied data tycons (give back constrs)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-maybeAppDataTyCon
- :: GenType tyvar uvar
- -> Maybe (TyCon, -- the type constructor
- [GenType tyvar uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
-
-maybeAppDataTyCon ty
- = case (getTyCon_maybe app_ty) of
- Just tycon | isDataTyCon tycon &&
- tyConArity tycon == length arg_tys
- -- Must be saturated for ty to be a data type
- -> Just (tycon, arg_tys, tyConDataCons tycon)
-
- other -> Nothing
+hoistForAllTys :: Type -> Type
+ -- Move all the foralls to the top
+ -- e.g. T -> forall a. a ==> forall a. T -> a
+ -- Careful: LOSES USAGE ANNOTATIONS!
+hoistForAllTys ty
+ = case hoist ty of { (tvs, body) -> mkForAllTys tvs body }
where
- (app_ty, arg_tys) = splitAppTy ty
+ hoist :: Type -> ([TyVar], Type)
+ hoist ty = case splitFunTys ty of { (args, res) ->
+ case splitForAllTys res of {
+ ([], body) -> ([], ty) ;
+ (tvs1, body1) -> case hoist body1 of { (tvs2,body2) ->
+ (tvs1 ++ tvs2, mkFunTys args body2)
+ }}}
+\end{code}
-getAppDataTyCon
- :: GenType tyvar uvar
- -> (TyCon, -- the type constructor
- [GenType tyvar uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
+---------------------------------------------------------------------
+ UsageTy
+ ~~~~~~~
-getAppDataTyCon ty
- = case maybeAppDataTyCon ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppDataTyCon" -- (ppr PprShowAll ty)
+Constructing and taking apart usage types.
+
+\begin{code}
+mkUTy :: Type -> Type -> Type
+mkUTy u ty
+ = ASSERT2( typeKind u == 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
-maybeBoxedPrimType :: Type -> Maybe (Id, Type)
+uaUTy :: Type -> Type
+ -- extract annotation
+uaUTy = fst . splitUTy
-maybeBoxedPrimType ty
- = case (maybeAppDataTyCon ty) of -- Data type,
- Just (tycon, tys_applied, [data_con]) -- with exactly one constructor
- -> case (getInstantiatedDataConSig data_con tys_applied) of
- (_, [data_con_arg_ty], _) -- Applied to exactly one type,
- | isPrimType data_con_arg_ty -- which is primitive
- -> Just (data_con, data_con_arg_ty)
- other_cases -> Nothing
- other_cases -> Nothing
+unUTy :: Type -> Type
+ -- extract unannotated type
+unUTy = snd . splitUTy
\end{code}
\begin{code}
-splitSigmaTy :: GenType t u -> ([t], [(Class,GenType t u)], GenType t u)
-splitSigmaTy ty =
- (tyvars, theta, tau)
- where
- (tyvars,rho) = splitForAllTy ty
- (theta,tau) = splitRhoTy rho
+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}
-mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
+\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 == superKind )
+ k == usageTypeKind
+
+isUsage :: Type -> Bool
+isUsage ty
+ = isUsageKind (typeKind ty)
+
+isUTyVar :: Var -> Bool
+isUTyVar v
+ = isUsageKind (tyVarKind v)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Predicates}
+%* *
+%************************************************************************
+
+"Dictionary" types are just ordinary data types, but you can
+tell from the type constructor whether it's a dictionary or not.
-Finding the kind of a type
-~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-getTypeKind :: GenType (GenTyVar any) u -> Kind
-getTypeKind (TyVarTy tyvar) = getTyVarKind tyvar
-getTypeKind (TyConTy tycon usage) = tyConKind tycon
-getTypeKind (SynTy _ _ ty) = getTypeKind ty
-getTypeKind (FunTy fun arg _) = mkBoxedTypeKind
-getTypeKind (DictTy clas arg _) = mkBoxedTypeKind
-getTypeKind (AppTy fun arg) = resultKind (getTypeKind fun)
-getTypeKind (ForAllTy _ _) = mkBoxedTypeKind
-getTypeKind (ForAllUsageTy _ _ _) = mkBoxedTypeKind
+mkClassPred clas tys = UASSERT2( not (any isUTy tys), ppr clas <+> fsep (map pprType tys) )
+ ClassP clas tys
+
+isClassPred (ClassP clas tys) = True
+isClassPred other = False
+
+isIPPred (IParam _ _) = True
+isIPPred other = False
+
+isTyVarClassPred (ClassP clas tys) = all isTyVarTy tys
+isTyVarClassPred other = False
+
+getClassPredTys_maybe :: PredType -> Maybe (Class, [Type])
+getClassPredTys_maybe (ClassP clas tys) = Just (clas, tys)
+getClassPredTys_maybe _ = Nothing
+
+getClassPredTys :: PredType -> (Class, [Type])
+getClassPredTys (ClassP clas tys) = (clas, tys)
+
+inheritablePred :: PredType -> Bool
+-- Can be inherited by a context. For example, consider
+-- f x = let g y = (?v, y+x)
+-- in (g 3 with ?v = 8,
+-- g 4 with ?v = 9)
+-- The point is that g's type must be quantifed over ?v:
+-- g :: (?v :: a) => a -> a
+-- but it doesn't need to be quantified over the Num a dictionary
+-- which can be free in g's rhs, and shared by both calls to g
+inheritablePred (ClassP _ _) = True
+inheritablePred other = False
+
+predMentionsIPs :: PredType -> NameSet -> Bool
+predMentionsIPs (IParam n _) ns = n `elemNameSet` ns
+predMentionsIPs other ns = False
+
+predHasFDs :: PredType -> Bool
+-- True if the predicate has functional depenencies;
+-- I.e. should participate in improvement
+predHasFDs (IParam _ _) = True
+predHasFDs (ClassP cls _) = classHasFDs cls
+
+mkDictTy :: Class -> [Type] -> Type
+mkDictTy clas tys = UASSERT2( not (any isUTy tys), ppr clas <+> fsep (map pprType tys) )
+ mkPredTy (ClassP clas tys)
+
+mkPredTy :: PredType -> Type
+mkPredTy pred = PredTy pred
+
+mkPredTys :: ThetaType -> [Type]
+mkPredTys preds = map PredTy preds
+
+predTyUnique :: PredType -> Unique
+predTyUnique (IParam n _) = getUnique n
+predTyUnique (ClassP clas tys) = getUnique clas
+
+predRepTy :: PredType -> Type
+-- Convert a predicate to its "representation type";
+-- the type of evidence for that predicate, which is actually passed at runtime
+predRepTy (ClassP clas tys) = TyConApp (classTyCon clas) tys
+predRepTy (IParam n ty) = ty
+
+isPredTy :: Type -> Bool
+isPredTy (NoteTy _ ty) = isPredTy ty
+isPredTy (PredTy _) = True
+isPredTy (UsageTy _ ty)= isPredTy ty
+isPredTy _ = False
+
+isDictTy :: Type -> Bool
+isDictTy (NoteTy _ ty) = isDictTy ty
+isDictTy (PredTy (ClassP _ _)) = True
+isDictTy (UsageTy _ ty) = isDictTy ty
+isDictTy other = False
+
+splitPredTy_maybe :: Type -> Maybe PredType
+splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
+splitPredTy_maybe (PredTy p) = Just p
+splitPredTy_maybe (UsageTy _ ty)= splitPredTy_maybe ty
+splitPredTy_maybe other = Nothing
+
+splitDictTy :: Type -> (Class, [Type])
+splitDictTy (NoteTy _ ty) = splitDictTy ty
+splitDictTy (PredTy (ClassP clas tys)) = (clas, tys)
+
+splitDictTy_maybe :: Type -> Maybe (Class, [Type])
+splitDictTy_maybe (NoteTy _ ty) = splitDictTy_maybe ty
+splitDictTy_maybe (PredTy (ClassP clas tys)) = Just (clas, tys)
+splitDictTy_maybe other = Nothing
+
+splitDFunTy :: Type -> ([TyVar], [PredType], Class, [Type])
+-- Split the type of a dictionary function
+splitDFunTy ty
+ = case splitSigmaTy ty of { (tvs, theta, tau) ->
+ case splitDictTy tau of { (clas, tys) ->
+ (tvs, theta, clas, tys) }}
+
+namesOfDFunHead :: Type -> NameSet
+-- Find the free type constructors and classes
+-- of the head of the dfun instance type
+-- The 'dfun_head_type' is because of
+-- instance Foo a => Baz T where ...
+-- The decl is an orphan if Baz and T are both not locally defined,
+-- even if Foo *is* locally defined
+namesOfDFunHead dfun_ty = case splitSigmaTy dfun_ty of
+ (tvs,_,head_ty) -> delListFromNameSet (namesOfType head_ty)
+ (map getName tvs)
+
+mkPredName :: Unique -> SrcLoc -> PredType -> Name
+mkPredName uniq loc (ClassP cls tys) = mkLocalName uniq (mkDictOcc (getOccName cls)) loc
+mkPredName uniq loc (IParam name ty) = name
\end{code}
+%************************************************************************
+%* *
+\subsection{Tau, sigma and rho}
+%* *
+%************************************************************************
+
+@isTauTy@ tests for nested for-alls.
-Free variables of a type
-~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tyVarsOfType :: GenType (GenTyVar flexi) uvar -> GenTyVarSet flexi
-
-tyVarsOfType (TyVarTy tv) = unitTyVarSet tv
-tyVarsOfType (TyConTy tycon usage) = emptyTyVarSet
-tyVarsOfType (SynTy _ tys ty) = tyVarsOfTypes tys
-tyVarsOfType (FunTy arg res _) = tyVarsOfType arg `unionTyVarSets` tyVarsOfType res
-tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionTyVarSets` tyVarsOfType arg
-tyVarsOfType (DictTy clas ty _) = tyVarsOfType ty
-tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusTyVarSet` unitTyVarSet tyvar
-tyVarsOfType (ForAllUsageTy _ _ ty) = tyVarsOfType ty
-
-tyVarsOfTypes :: [GenType (GenTyVar flexi) uvar] -> GenTyVarSet flexi
-tyVarsOfTypes tys = foldr (unionTyVarSets.tyVarsOfType) emptyTyVarSet tys
+isTauTy :: Type -> Bool
+isTauTy (TyVarTy v) = True
+isTauTy (TyConApp _ tys) = all isTauTy tys
+isTauTy (AppTy a b) = isTauTy a && isTauTy b
+isTauTy (FunTy a b) = isTauTy a && isTauTy b
+isTauTy (PredTy p) = isTauTy (predRepTy p)
+isTauTy (NoteTy _ ty) = isTauTy ty
+isTauTy (UsageTy _ ty) = isTauTy ty
+isTauTy other = False
\end{code}
+\begin{code}
+mkRhoTy :: [PredType] -> Type -> Type
+mkRhoTy theta ty = UASSERT2( not (isUTy ty), pprType ty )
+ foldr (\p r -> FunTy (mkUTyM (mkPredTy p)) (mkUTyM r)) ty theta
+
+splitRhoTy :: Type -> ([PredType], Type)
+splitRhoTy ty = split ty ty []
+ where
+ split orig_ty (FunTy arg res) ts = case splitPredTy_maybe arg of
+ Just p -> split res res (p:ts)
+ Nothing -> (reverse ts, orig_ty)
+ split orig_ty (NoteTy _ ty) ts = split orig_ty ty ts
+ split orig_ty (UsageTy _ ty) ts = split orig_ty ty ts
+ split orig_ty ty ts = (reverse ts, orig_ty)
+\end{code}
+
+The type of a method for class C is always of the form:
+ Forall a1..an. C a1..an => sig_ty
+where sig_ty is the type given by the method's signature, and thus in general
+is a ForallTy. At the point that splitMethodTy is called, it is expected
+that the outer Forall has already been stripped off. splitMethodTy then
+returns (C a1..an, sig_ty') where sig_ty' is sig_ty with any Notes or
+Usages stripped off.
-Instantiating a type
-~~~~~~~~~~~~~~~~~~~~
\begin{code}
-applyTy :: Eq t => GenType t u -> GenType t u -> GenType t u
-applyTy (SynTy _ _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = instantiateTy [(tv,arg)] ty
-applyTy other arg = panic "applyTy"
+splitMethodTy :: Type -> (PredType, Type)
+splitMethodTy ty = split ty
+ where
+ split (FunTy arg res) = case splitPredTy_maybe arg of
+ Just p -> (p, res)
+ Nothing -> panic "splitMethodTy"
+ split (NoteTy _ ty) = split ty
+ split (UsageTy _ ty) = split ty
+ split _ = panic "splitMethodTy"
+\end{code}
-instantiateTy :: Eq t => [(t, GenType t u)] -> GenType t u -> GenType t u
-instantiateTy tenv ty
- = go ty
- where
- go (TyVarTy tv) = case [ty | (tv',ty) <- tenv, tv==tv'] of
- [] -> TyVarTy tv
- (ty:_) -> ty
- go ty@(TyConTy tycon usage) = ty
- go (SynTy tycon tys ty) = SynTy tycon (map go tys) (go ty)
- go (FunTy arg res usage) = FunTy (go arg) (go res) usage
- go (AppTy fun arg) = AppTy (go fun) (go arg)
- go (DictTy clas ty usage) = DictTy clas (go ty) usage
- go (ForAllTy tv ty) = ASSERT(null tv_bound)
- ForAllTy tv (go ty)
- where
- tv_bound = [() | (tv',_) <- tenv, tv==tv']
- go (ForAllUsageTy uvar bds ty) = ForAllUsageTy uvar bds (go ty)
+isSigmaType returns true of any qualified type. It doesn't *necessarily* have
+any foralls. E.g.
+ f :: (?x::Int) => Int -> Int
+\begin{code}
+mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
--- instantiateTauTy works only (a) on types with no ForAlls,
--- and when (b) all the type variables are being instantiated
--- In return it is more polymorphic than instantiateTy
+isSigmaTy :: Type -> Bool
+isSigmaTy (ForAllTy tyvar ty) = True
+isSigmaTy (FunTy a b) = isPredTy a
+isSigmaTy (NoteTy _ ty) = isSigmaTy ty
+isSigmaTy (UsageTy _ ty) = isSigmaTy ty
+isSigmaTy _ = False
-instantiateTauTy :: Eq t => [(t, GenType t' u)] -> GenType t u -> GenType t' u
-instantiateTauTy tenv ty
- = go ty
- where
- go (TyVarTy tv) = case [ty | (tv',ty) <- tenv, tv==tv'] of
- (ty:_) -> ty
- [] -> panic "instantiateTauTy"
- go (TyConTy tycon usage) = TyConTy tycon usage
- go (SynTy tycon tys ty) = SynTy tycon (map go tys) (go ty)
- go (FunTy arg res usage) = FunTy (go arg) (go res) usage
- go (AppTy fun arg) = AppTy (go fun) (go arg)
- go (DictTy clas ty usage) = DictTy clas (go ty) usage
-
-instantiateUsage
- :: Ord3 u => [(u, GenType t u')] -> GenType t u -> GenType t u'
-instantiateUsage = error "instantiateUsage: not implemented"
+splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
+splitSigmaTy ty =
+ (tyvars, theta, tau)
+ where
+ (tyvars,rho) = splitForAllTys ty
+ (theta,tau) = splitRhoTy rho
\end{code}
\begin{code}
-type TypeEnv = TyVarEnv Type
-
-applyTypeEnvToTy :: TypeEnv -> SigmaType -> SigmaType
-applyTypeEnvToTy tenv ty
- = mapOverTyVars v_fn ty
- where
- v_fn v = case (lookupTyVarEnv tenv v) of
- Just ty -> ty
- Nothing -> TyVarTy v
+getDFunTyKey :: Type -> OccName -- Get some string from a type, to be used to
+ -- construct a dictionary function name
+getDFunTyKey (TyVarTy tv) = getOccName tv
+getDFunTyKey (TyConApp tc _) = getOccName tc
+getDFunTyKey (AppTy fun _) = getDFunTyKey fun
+getDFunTyKey (NoteTy _ t) = getDFunTyKey t
+getDFunTyKey (FunTy arg _) = getOccName funTyCon
+getDFunTyKey (ForAllTy _ t) = getDFunTyKey t
+getDFunTyKey (UsageTy _ t) = getDFunTyKey t
+-- PredTy shouldn't happen
\end{code}
-@mapOverTyVars@ is a local function which actually does the work. It
-does no cloning or other checks for shadowing, so be careful when
-calling this on types with Foralls in them.
+%************************************************************************
+%* *
+\subsection{Kinds and free variables}
+%* *
+%************************************************************************
+
+---------------------------------------------------------------------
+ Finding the kind of a type
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-mapOverTyVars :: (TyVar -> Type) -> Type -> Type
+typeKind :: Type -> Kind
-mapOverTyVars v_fn ty
- = let
- mapper = mapOverTyVars v_fn
- in
- case ty of
- TyVarTy v -> v_fn v
- SynTy c as e -> SynTy c (map mapper as) (mapper e)
- FunTy a r u -> FunTy (mapper a) (mapper r) u
- AppTy f a -> AppTy (mapper f) (mapper a)
- DictTy c t u -> DictTy c (mapper t) u
- ForAllTy v t -> ForAllTy v (mapper t)
- tc@(TyConTy _ _) -> tc
+typeKind (TyVarTy tyvar) = tyVarKind tyvar
+typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
+typeKind (NoteTy _ ty) = typeKind ty
+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 (ForAllTy tv ty) = typeKind ty
+typeKind (UsageTy _ ty) = typeKind ty -- we don't have separate kinds for ann/unann
\end{code}
-At present there are no unboxed non-primitive types, so
-isUnboxedType is the same as isPrimType.
+---------------------------------------------------------------------
+ Free variables of a type
+ ~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-isPrimType, isUnboxedType :: GenType tyvar uvar -> Bool
-isPrimType (AppTy ty _) = isPrimType ty
-isPrimType (SynTy _ _ ty) = isPrimType ty
-isPrimType (TyConTy tycon _) = isPrimTyCon tycon
-isPrimType _ = False
-
-isUnboxedType = isPrimType
+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 (PredTy p) = tyVarsOfPred p
+tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
+tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
+tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
+tyVarsOfType (UsageTy u ty) = tyVarsOfType u `unionVarSet` tyVarsOfType ty
+
+tyVarsOfTypes :: [Type] -> TyVarSet
+tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
+
+tyVarsOfPred :: PredType -> TyVarSet
+tyVarsOfPred (ClassP clas tys) = tyVarsOfTypes tys
+tyVarsOfPred (IParam n ty) = tyVarsOfType ty
+
+tyVarsOfTheta :: ThetaType -> TyVarSet
+tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet
+
+-- Add a Note with the free tyvars to the top of the type
+addFreeTyVars :: Type -> Type
+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
+namesOfType (TyVarTy tv) = unitNameSet (getName tv)
+namesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets`
+ namesOfTypes tys
+namesOfType (NoteTy (SynNote ty1) ty2) = namesOfType ty1
+namesOfType (NoteTy other_note ty2) = namesOfType ty2
+namesOfType (PredTy p) = namesOfType (predRepTy p)
+namesOfType (FunTy arg res) = namesOfType arg `unionNameSets` namesOfType res
+namesOfType (AppTy fun arg) = namesOfType fun `unionNameSets` namesOfType arg
+namesOfType (ForAllTy tyvar ty) = namesOfType ty `delFromNameSet` getName tyvar
+namesOfType (UsageTy u ty) = namesOfType u `unionNameSets` namesOfType ty
+
+namesOfTypes tys = foldr (unionNameSets . namesOfType) emptyNameSet tys
\end{code}
-This is *not* right: it is a placeholder (ToDo 96/03 WDP):
-\begin{code}
-typePrimRep :: GenType tyvar uvar -> PrimRep
+Usage annotations of a type
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Get a list of usage annotations of a type, *in left-to-right pre-order*.
-typePrimRep (SynTy _ _ ty) = typePrimRep ty
-typePrimRep (TyConTy tc _) = if isPrimTyCon tc then panic "typePrimRep:PrimTyCon" else PtrRep
-typePrimRep (AppTy ty _) = typePrimRep ty
-typePrimRep _ = PtrRep -- the "default"
+\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 (PredTy p) = goT (predRepTy 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{Matching on types}
+\subsection{TidyType}
%* *
%************************************************************************
-Matching is a {\em unidirectional} process, matching a type against a
-template (which is just a type with type variables in it). The
-matcher assumes that there are no repeated type variables in the
-template, so that it simply returns a mapping of type variables to
-types. It also fails on nested foralls.
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
-@matchTys@ matches corresponding elements of a list of templates and
-types.
+It doesn't change the uniques at all, just the print names.
\begin{code}
-matchTy :: GenType t1 u1 -- Template
- -> GenType t2 u2 -- Proposed instance of template
- -> Maybe [(t1,GenType t2 u2)] -- Matching substitution
+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.
+ where
+ name = tyVarName tyvar
+
+tidyTyVars :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar])
+tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
-matchTys :: [GenType t1 u1] -- Templates
- -> [GenType t2 u2] -- Proposed instance of template
- -> Maybe [(t1,GenType t2 u2)] -- Matching substitution
+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)
-matchTy ty1 ty2 = match [] [] ty1 ty2
-matchTys tys1 tys2 = match' [] (zipEqual tys1 tys2)
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(tidy_env, subst) ty
+ = go ty
+ where
+ go (TyVarTy tv) = case lookupVarEnv subst tv of
+ Nothing -> TyVarTy tv
+ Just tv' -> TyVarTy tv'
+ go (TyConApp tycon tys) = let args = map go tys
+ in args `seqList` TyConApp tycon args
+ go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
+ go (PredTy p) = PredTy (tidyPred env p)
+ go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
+ where
+ (envp, tvp) = tidyTyVar env tv
+ go (UsageTy u ty) = (UsageTy SAPPLY (go u)) SAPPLY (go ty)
+
+ go_note (SynNote ty) = SynNote SAPPLY (go ty)
+ go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
+
+tidyTypes env tys = map (tidyType env) tys
+
+tidyPred :: TidyEnv -> PredType -> PredType
+tidyPred env (ClassP clas tys) = ClassP clas (tidyTypes env tys)
+tidyPred env (IParam n ty) = IParam n (tidyType env ty)
\end{code}
-@match@ is the main function.
+
+@tidyOpenType@ grabs the free type variables, tidies them
+and then uses @tidyType@ to work over the type itself
\begin{code}
-match :: [(t1, GenType t2 u2)] -- r, the accumulating result
- -> [(GenType t1 u1, GenType t2 u2)] -- w, the work list
- -> GenType t1 u1 -> GenType t2 u2 -- Current match pair
- -> Maybe [(t1, GenType t2 u2)]
-
-match r w (TyVarTy v) ty = match' ((v,ty) : r) w
-match r w (FunTy fun1 arg1 _) (FunTy fun2 arg2 _) = match r ((fun1,fun2):w) arg1 arg2
-match r w (AppTy fun1 arg1) (AppTy fun2 arg2) = match r ((fun1,fun2):w) arg1 arg2
-match r w (TyConTy con1 _) (TyConTy con2 _) | con1 == con2 = match' r w
-match r w (DictTy clas1 ty1 _) (DictTy clas2 ty2 _) | clas1 == clas2 = match r w ty1 ty2
-match r w (SynTy _ _ ty1) ty2 = match r w ty1 ty2
-match r w ty1 (SynTy _ _ ty2) = match r w ty1 ty2
-
- -- With type synonyms, we have to be careful for the exact
- -- same reasons as in the unifier. Please see the
- -- considerable commentary there before changing anything
- -- here! (WDP 95/05)
-
--- Catch-all fails
-match _ _ _ _ = Nothing
-
-match' r [] = Just r
-match' r ((ty1,ty2):w) = match r w ty1 ty2
+tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
+tidyOpenType env ty
+ = (env', tidyType env' ty)
+ where
+ env' = tidyFreeTyVars env (tyVarsOfType ty)
+
+tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
+tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
+
+tidyTopType :: Type -> Type
+tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
+
+
%************************************************************************
%* *
-\subsection{Equality on types}
+\subsection{Liftedness}
%* *
%************************************************************************
-The functions eqSimpleTy and eqSimpleTheta are polymorphic in the types t
-and u, but ONLY WORK FOR SIMPLE TYPES (ie. they panic if they see
-dictionaries or polymorphic types). The function eqTy has a more
-specific type, but does the `right thing' for all types.
-
\begin{code}
-eqSimpleTheta :: (Eq t,Eq u) =>
- [(Class,GenType t u)] -> [(Class,GenType t u)] -> Bool
-
-eqSimpleTheta [] [] = True
-eqSimpleTheta ((c1,t1):th1) ((c2,t2):th2) =
- c1==c2 && t1 `eqSimpleTy` t2 && th1 `eqSimpleTheta` th2
-eqSimpleTheta other1 other2 = False
+isUnLiftedType :: Type -> Bool
+ -- isUnLiftedType returns True for forall'd unlifted types:
+ -- x :: forall a. Int#
+ -- I found bindings like these were getting floated to the top level.
+ -- They are pretty bogus types, mind you. It would be better never to
+ -- construct them
+
+isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
+isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
+isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
+isUnLiftedType (UsageTy _ ty) = isUnLiftedType ty
+isUnLiftedType other = False
+
+isUnboxedTupleType :: Type -> Bool
+isUnboxedTupleType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> isUnboxedTupleTyCon tc
+ 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 )
+ isAlgTyCon tc
+ other -> False
+
+-- Should only be applied to *types*; hence the assert
+isDataType :: Type -> Bool
+isDataType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isDataTyCon tc
+ other -> False
+
+isNewType :: Type -> Bool
+isNewType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isNewTyCon tc
+ other -> False
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Sequencing on types
+%* *
+%************************************************************************
+
\begin{code}
-eqSimpleTy :: (Eq t,Eq u) => GenType t u -> GenType t u -> Bool
-
-(TyVarTy tv1) `eqSimpleTy` (TyVarTy tv2) =
- tv1 == tv2
-(AppTy f1 a1) `eqSimpleTy` (AppTy f2 a2) =
- f1 `eqSimpleTy` f2 && a1 `eqSimpleTy` a2
-(TyConTy tc1 u1) `eqSimpleTy` (TyConTy tc2 u2) =
- tc1 == tc2 && u1 == u2
-
-(FunTy f1 a1 u1) `eqSimpleTy` (FunTy f2 a2 u2) =
- f1 `eqSimpleTy` f2 && a1 `eqSimpleTy` a2 && u1 == u2
-(FunTy f1 a1 u1) `eqSimpleTy` t2 =
- -- Expand t1 just in case t2 matches that version
- (AppTy (AppTy (TyConTy mkFunTyCon u1) f1) a1) `eqSimpleTy` t2
-t1 `eqSimpleTy` (FunTy f2 a2 u2) =
- -- Expand t2 just in case t1 matches that version
- t1 `eqSimpleTy` (AppTy (AppTy (TyConTy mkFunTyCon u2) f2) a2)
-
-(SynTy tc1 ts1 t1) `eqSimpleTy` (SynTy tc2 ts2 t2) =
- (tc1 == tc2 && and (zipWith eqSimpleTy ts1 ts2) && length ts1 == length ts2)
- || t1 `eqSimpleTy` t2
-(SynTy _ _ t1) `eqSimpleTy` t2 =
- t1 `eqSimpleTy` t2 -- Expand the abbrevation and try again
-t1 `eqSimpleTy` (SynTy _ _ t2) =
- t1 `eqSimpleTy` t2 -- Expand the abbrevation and try again
-
-(DictTy _ _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got DictTy"
-_ `eqSimpleTy` (DictTy _ _ _) = panic "eqSimpleTy: got DictTy"
-
-(ForAllTy _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got ForAllTy"
-_ `eqSimpleTy` (ForAllTy _ _) = panic "eqSimpleTy: got ForAllTy"
-
-(ForAllUsageTy _ _ _) `eqSimpleTy` _ = panic "eqSimpleTy: got ForAllUsageTy"
-_ `eqSimpleTy` (ForAllUsageTy _ _ _) = panic "eqSimpleTy: got ForAllUsageTy"
-
-_ `eqSimpleTy` _ = False
+seqType :: Type -> ()
+seqType (TyVarTy tv) = tv `seq` ()
+seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (NoteTy note t2) = seqNote note `seq` seqType t2
+seqType (PredTy p) = seqPred p
+seqType (TyConApp tc tys) = tc `seq` seqTypes tys
+seqType (ForAllTy tv ty) = tv `seq` seqType ty
+seqType (UsageTy u ty) = seqType u `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` ()
+
+seqPred :: PredType -> ()
+seqPred (ClassP c tys) = c `seq` seqTypes tys
+seqPred (IParam n ty) = n `seq` seqType ty
\end{code}
-Types are ordered so we can sort on types in the renamer etc. DNT: Since
-this class is also used in CoreLint and other such places, we DO expand out
-Fun/Syn/Dict types (if necessary).
+
+%************************************************************************
+%* *
+\subsection{Equality on types}
+%* *
+%************************************************************************
+
\begin{code}
-eqTy :: Type -> Type -> Bool
+instance Eq Type where
+ ty1 == ty2 = case ty1 `compare` ty2 of { EQ -> True; other -> False }
+
+instance Ord Type where
+ compare ty1 ty2 = cmpTy emptyVarEnv ty1 ty2
+
+cmpTy :: TyVarEnv TyVar -> Type -> Type -> Ordering
+ -- The "env" maps type variables in ty1 to type variables in ty2
+ -- So when comparing for-alls.. (forall tv1 . t1) (forall tv2 . t2)
+ -- we in effect substitute tv2 for tv1 in t1 before continuing
+
+ -- Get rid of NoteTy
+cmpTy env (NoteTy _ ty1) ty2 = cmpTy env ty1 ty2
+cmpTy env ty1 (NoteTy _ ty2) = cmpTy env ty1 ty2
+
+ -- Get rid of PredTy
+cmpTy env (PredTy p1) (PredTy p2) = cmpPred env p1 p2
+cmpTy env (PredTy p1) ty2 = cmpTy env (predRepTy p1) ty2
+cmpTy env ty1 (PredTy p2) = cmpTy env ty1 (predRepTy p2)
+
+ -- Deal with equal constructors
+cmpTy env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of
+ Just tv1a -> tv1a `compare` tv2
+ Nothing -> tv1 `compare` tv2
+
+cmpTy env (AppTy f1 a1) (AppTy f2 a2) = cmpTy env f1 f2 `thenCmp` cmpTy env a1 a2
+cmpTy env (FunTy f1 a1) (FunTy f2 a2) = cmpTy env f1 f2 `thenCmp` cmpTy env a1 a2
+cmpTy env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 `compare` tc2) `thenCmp` (cmpTys env tys1 tys2)
+cmpTy env (ForAllTy tv1 t1) (ForAllTy tv2 t2) = cmpTy (extendVarEnv env tv1 tv2) t1 t2
+cmpTy env (UsageTy u1 t1) (UsageTy u2 t2) = cmpTy env u1 u2 `thenCmp` cmpTy env t1 t2
+
+ -- Deal with the rest: TyVarTy < AppTy < FunTy < TyConApp < ForAllTy < UsageTy
+cmpTy env (AppTy _ _) (TyVarTy _) = GT
+
+cmpTy env (FunTy _ _) (TyVarTy _) = GT
+cmpTy env (FunTy _ _) (AppTy _ _) = GT
+
+cmpTy env (TyConApp _ _) (TyVarTy _) = GT
+cmpTy env (TyConApp _ _) (AppTy _ _) = GT
+cmpTy env (TyConApp _ _) (FunTy _ _) = GT
+
+cmpTy env (ForAllTy _ _) (TyVarTy _) = GT
+cmpTy env (ForAllTy _ _) (AppTy _ _) = GT
+cmpTy env (ForAllTy _ _) (FunTy _ _) = GT
+cmpTy env (ForAllTy _ _) (TyConApp _ _) = GT
+
+cmpTy env (UsageTy _ _) other = GT
+
+cmpTy env _ _ = LT
+
+
+cmpTys env [] [] = EQ
+cmpTys env (t:ts) [] = GT
+cmpTys env [] (t:ts) = LT
+cmpTys env (t1:t1s) (t2:t2s) = cmpTy env t1 t2 `thenCmp` cmpTys env t1s t2s
+\end{code}
-eqTy t1 t2 =
- eq nullTyVarEnv nullUVarEnv t1 t2
- where
- eq tve uve (TyVarTy tv1) (TyVarTy tv2) =
- tv1 == tv2 ||
- case (lookupTyVarEnv tve tv1) of
- Just tv -> tv == tv2
- Nothing -> False
- eq tve uve (AppTy f1 a1) (AppTy f2 a2) =
- eq tve uve f1 f2 && eq tve uve a1 a2
- eq tve uve (TyConTy tc1 u1) (TyConTy tc2 u2) =
- tc1 == tc2 && eqUsage uve u1 u2
-
- eq tve uve (FunTy f1 a1 u1) (FunTy f2 a2 u2) =
- eq tve uve f1 f2 && eq tve uve a1 a2 && eqUsage uve u1 u2
- eq tve uve (FunTy f1 a1 u1) t2 =
- -- Expand t1 just in case t2 matches that version
- eq tve uve (AppTy (AppTy (TyConTy mkFunTyCon u1) f1) a1) t2
- eq tve uve t1 (FunTy f2 a2 u2) =
- -- Expand t2 just in case t1 matches that version
- eq tve uve t1 (AppTy (AppTy (TyConTy mkFunTyCon u2) f2) a2)
-
- eq tve uve (DictTy c1 t1 u1) (DictTy c2 t2 u2) =
- c1 == c2 && eq tve uve t1 t2 && eqUsage uve u1 u2
- eq tve uve t1@(DictTy _ _ _) t2 =
- eq tve uve (expandTy t1) t2 -- Expand the dictionary and try again
- eq tve uve t1 t2@(DictTy _ _ _) =
- eq tve uve t1 (expandTy t2) -- Expand the dictionary and try again
-
- eq tve uve (SynTy tc1 ts1 t1) (SynTy tc2 ts2 t2) =
- (tc1 == tc2 && and (zipWith (eq tve uve) ts1 ts2) && length ts1 == length ts2)
- || eq tve uve t1 t2
- eq tve uve (SynTy _ _ t1) t2 =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
- eq tve uve t1 (SynTy _ _ t2) =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
-
- eq tve uve (ForAllTy tv1 t1) (ForAllTy tv2 t2) =
- eq (addOneToTyVarEnv tve tv1 tv2) uve t1 t2
- eq tve uve (ForAllUsageTy u1 b1 t1) (ForAllUsageTy u2 b2 t2) =
- eqBounds uve b1 b2 && eq tve (addOneToUVarEnv uve u1 u2) t1 t2
-
- eq _ _ _ _ = False
-
- eqBounds uve [] [] = True
- eqBounds uve (u1:b1) (u2:b2) = eqUVar uve u1 u2 && eqBounds uve b1 b2
- eqBounds uve _ _ = False
+\begin{code}
+instance Eq PredType where
+ p1 == p2 = case p1 `compare` p2 of { EQ -> True; other -> False }
+
+instance Ord PredType where
+ compare p1 p2 = cmpPred emptyVarEnv p1 p2
+
+cmpPred :: TyVarEnv TyVar -> PredType -> PredType -> Ordering
+cmpPred env (IParam n1 ty1) (IParam n2 ty2) = (n1 `compare` n2) `thenCmp` (cmpTy env ty1 ty2)
+ -- Compare types as well as names for implicit parameters
+ -- This comparison is used exclusively (I think) for the
+ -- finite map built in TcSimplify
+cmpPred env (ClassP c1 tys1) (ClassP c2 tys2) = (c1 `compare` c2) `thenCmp` (cmpTys env tys1 tys2)
+cmpPred env (IParam _ _) (ClassP _ _) = LT
+cmpPred env (ClassP _ _) (IParam _ _) = GT
\end{code}