-\begin{code}
-#include "HsVersions.h"
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1998
+%
+\section[Type]{Type - public interface}
+\begin{code}
module Type (
- GenType(..), SYN_IE(Type), SYN_IE(TauType),
- mkTyVarTy, mkTyVarTys,
- getTyVar, getTyVar_maybe, isTyVarTy,
- mkAppTy, mkAppTys, splitAppTy, splitAppTys,
- mkFunTy, mkFunTys,
- splitFunTy, splitFunTyExpandingDicts, splitFunTyExpandingDictsAndPeeking,
- getFunTy_maybe, getFunTyExpandingDicts_maybe,
- mkTyConTy, getTyCon_maybe, applyTyCon,
- mkSynTy,
- mkForAllTy, mkForAllTys, getForAllTy_maybe, getForAllTyExpandingDicts_maybe,
- splitForAllTy, splitForAllTyExpandingDicts,
- mkForAllUsageTy, getForAllUsageTy,
- applyTy, specialiseTy,
-#ifdef DEBUG
- expandTy, -- only let out for debugging (ToDo: rm?)
-#endif
- isPrimType, isUnboxedType, typePrimRep,
-
- SYN_IE(RhoType), SYN_IE(SigmaType), SYN_IE(ThetaType),
- mkDictTy,
- mkRhoTy, splitRhoTy, mkTheta, isDictTy,
- mkSigmaTy, splitSigmaTy,
-
- maybeAppTyCon, getAppTyCon,
- maybeAppDataTyCon, getAppDataTyCon, getAppSpecDataTyCon,
- maybeAppDataTyConExpandingDicts, maybeAppSpecDataTyConExpandingDicts,
- getAppDataTyConExpandingDicts, getAppSpecDataTyConExpandingDicts,
- maybeBoxedPrimType,
-
- matchTy, matchTys, eqTy, eqSimpleTy, eqSimpleTheta,
-
- instantiateTy, instantiateTauTy, instantiateUsage,
- applyTypeEnvToTy,
-
- isTauTy,
-
- tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
- showTypeCategory
- ) where
+ -- re-exports from TypeRep
+ TyThing(..), Type, PredType(..), ThetaType, TyVarSubst,
+ funTyCon,
-IMP_Ubiq()
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
-IMPORT_DELOOPER(IdLoop) -- for paranoia checking
-IMPORT_DELOOPER(TyLoop)
---IMPORT_DELOOPER(PrelLoop) -- for paranoia checking
-#else
-import {-# SOURCE #-} Id ( Id, dataConArgTys )
-import {-# SOURCE #-} TysPrim ( voidTy )
-import {-# SOURCE #-} TysWiredIn ( tupleTyCon )
-#endif
+ -- Re-exports from Kind
+ module Kind,
--- friends:
-import Class ( classDictArgTys, GenClass{-instances-}, SYN_IE(Class) )
-import Kind ( mkBoxedTypeKind, resultKind, notArrowKind, Kind )
-import TyCon ( mkFunTyCon, isFunTyCon, isEnumerationTyCon, isTupleTyCon, maybeTyConSingleCon,
- isPrimTyCon, isAlgTyCon, isDataTyCon, isSynTyCon, maybeNewTyCon, isNewTyCon,
- tyConKind, tyConDataCons, getSynTyConDefn, TyCon )
-import TyVar ( tyVarKind, GenTyVar{-instances-}, SYN_IE(GenTyVarSet),
- emptyTyVarSet, unionTyVarSets, minusTyVarSet,
- unitTyVarSet, nullTyVarEnv, lookupTyVarEnv, delFromTyVarEnv,
- addOneToTyVarEnv, SYN_IE(TyVarEnv), SYN_IE(TyVar) )
-import Usage ( usageOmega, GenUsage, SYN_IE(Usage), SYN_IE(UVar), SYN_IE(UVarEnv),
- nullUVarEnv, addOneToUVarEnv, lookupUVarEnv, eqUVar,
- eqUsage )
-
-import Name ( NamedThing(..),
- NameSet(..), unionNameSets, emptyNameSet, unitNameSet, minusNameSet
- )
+ -- Re-exports from TyCon
+ PrimRep(..),
--- others
-import Maybes ( maybeToBool, assocMaybe )
-import PrimRep ( PrimRep(..) )
-import Unique -- quite a few *Keys
-import Util ( thenCmp, zipEqual, assoc,
- panic, panic#, assertPanic, pprPanic,
- Ord3(..){-instances-}
- )
--- ToDo:rm all these
---import {-mumble-}
--- Pretty
---import {-mumble-}
--- PprStyle
---import {-mumble-}
--- PprType --(pprType )
---import PprEnv
-\end{code}
+ mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
-Data types
-~~~~~~~~~~
+ mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
-\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 -- Must *not* be a SynTyCon
- (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}
+ mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys,
+ funResultTy, funArgTy, zipFunTys, isFunTy,
-\begin{code}
-type RhoType = Type
-type TauType = Type
-type ThetaType = [(Class, Type)]
-type SigmaType = Type
-\end{code}
+ mkGenTyConApp, mkTyConApp, mkTyConTy,
+ tyConAppTyCon, tyConAppArgs,
+ splitTyConApp_maybe, splitTyConApp,
+ mkSynTy,
-Notes on type synonyms
-~~~~~~~~~~~~~~~~~~~~~~
-The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
-to return type synonyms whereever possible. Thus
+ repType, typePrimRep,
- type Foo a = a -> a
+ mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
+ applyTy, applyTys, isForAllTy, dropForAlls,
-we want
- splitFunTys (a -> Foo a) = ([a], Foo a)
-not ([a], a -> a)
+ -- Source types
+ predTypeRep, mkPredTy, mkPredTys,
-The reason is that we then get better (shorter) type signatures in
-interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
+ -- Newtypes
+ splitRecNewType_maybe,
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedTupleType, isAlgType, isPrimitiveType,
+ isStrictType, isStrictPred,
-Expand abbreviations
-~~~~~~~~~~~~~~~~~~~~
-Removes just the top level of any abbreviations.
+ -- Free variables
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
+ typeKind, addFreeTyVars,
-\begin{code}
-expandTy :: Type -> Type -- Restricted to Type due to Dict expansion
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVarBndr, tidyFreeTyVars,
+ tidyOpenTyVar, tidyOpenTyVars,
+ tidyTopType, tidyPred,
+
+ -- Comparison
+ eqType,
+
+ -- 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
+ -- Pretty-printing
+ pprType, pprParendType,
+ pprPred, pprTheta, pprThetaArrow, pprClassPred
+ ) where
- [] -> voidTy -- Empty dictionary represented by Void
+#include "HsVersions.h"
- [arg_ty] -> expandTy arg_ty -- just the <whatever> itself
+-- We import the representation and primitive functions from TypeRep.
+-- Many things are reexported, but not the representation!
- -- 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!
+import TypeRep
- other -> ASSERT(not (null all_arg_tys))
- foldl AppTy (TyConTy (tupleTyCon (length all_arg_tys)) u) all_arg_tys
+-- Other imports:
- -- 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
- all_arg_tys = classDictArgTys clas ty
+import {-# SOURCE #-} Subst ( substTyWith )
+
+-- friends:
+import Kind
+import Var ( TyVar, tyVarKind, tyVarName, setTyVarName )
+import VarEnv
+import VarSet
+
+import Name ( NamedThing(..), mkInternalName, tidyOccName )
+import Class ( Class, classTyCon )
+import TyCon ( TyCon, isRecursiveTyCon, isPrimTyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
+ isFunTyCon, isNewTyCon, newTyConRep, newTyConRhs,
+ isAlgTyCon, isSynTyCon, tyConArity,
+ tyConKind, getSynTyConDefn, PrimRep(..), tyConPrimRep,
+ )
-expandTy ty = ty
+-- others
+import CmdLineOpts ( opt_DictsStrict )
+import SrcLoc ( noSrcLoc )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList, lengthIs, snocView )
+import Outputable
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
+import Maybe ( isJust )
\end{code}
-Simple construction and analysis functions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+%************************************************************************
+%* *
+\subsection{Constructor-specific functions}
+%* *
+%************************************************************************
+
+
+---------------------------------------------------------------------
+ TyVarTy
+ ~~~~~~~
\begin{code}
-mkTyVarTy :: t -> GenType t u
-mkTyVarTys :: [t] -> [GenType t y]
+mkTyVarTy :: TyVar -> Type
mkTyVarTy = TyVarTy
+
+mkTyVarTys :: [TyVar] -> [Type]
mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
-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 :: String -> Type -> TyVar
+getTyVar msg ty = case getTyVar_maybe ty of
+ Just tv -> tv
+ Nothing -> 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
+isTyVarTy :: Type -> Bool
+isTyVarTy ty = isJust (getTyVar_maybe ty)
-isTyVarTy :: GenType t u -> Bool
-isTyVarTy (TyVarTy tv) = True
-isTyVarTy (SynTy _ _ t) = isTyVarTy t
-isTyVarTy other = False
+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}
-\begin{code}
-mkAppTy = AppTy
-
-mkAppTys :: GenType t u -> [GenType t u] -> GenType t u
-mkAppTys t ts = foldl AppTy t ts
-splitAppTy :: GenType t u -> (GenType t u, GenType t u)
-splitAppTy (AppTy t arg) = (t,arg)
-splitAppTy (SynTy _ _ t) = splitAppTy t
-splitAppTy other = panic "splitAppTy"
+---------------------------------------------------------------------
+ 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.
-splitAppTys :: GenType t u -> (GenType t u, [GenType t u])
-splitAppTys t = go t []
+\begin{code}
+mkAppTy orig_ty1 orig_ty2
+ = mk_app orig_ty1
+ where
+ mk_app (NoteTy _ ty1) = mk_app ty1
+ 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
+ -- 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
+ = 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)
+ -- 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 [ty1], ty2)
+splitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2)
+splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
+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 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
- 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)
+ 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 (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 [], [ty1,ty2])
+ split orig_ty ty args = (orig_ty, args)
\end{code}
+
+---------------------------------------------------------------------
+ FunTy
+ ~~~~~
+
\begin{code}
--- NB mkFunTy, mkFunTys puts in Omega usages, for now at least
-mkFunTy arg res = FunTy arg res usageOmega
-
-mkFunTys :: [GenType t u] -> GenType t u -> GenType t u
-mkFunTys ts t = foldr (\ f a -> FunTy f a usageOmega) t ts
-
- -- getFunTy_maybe and splitFunTy *must* have the general type given, which
- -- means they *can't* do the DictTy jiggery-pokery that
- -- *is* sometimes required. Hence we also have the ExpandingDicts variants
- -- The relationship between these
- -- two functions is like that between eqTy and eqSimpleTy.
- -- ToDo: NUKE when we do dicts via newtype
-
-getFunTy_maybe :: GenType t u -> Maybe (GenType t u, GenType t u)
-getFunTy_maybe t
- = go t t
- where
- -- See notes on type synonyms above
- go syn_t (FunTy arg result _) = Just (arg,result)
- go syn_t (AppTy (AppTy (TyConTy tycon _) arg) res)
- | isFunTyCon tycon = Just (arg, res)
- go syn_t (SynTy _ _ t) = go syn_t t
- go syn_t other = Nothing
-
-getFunTyExpandingDicts_maybe :: Bool -- True <=> peek inside newtype applicatons
- -> Type
- -> Maybe (Type, Type)
-
-getFunTyExpandingDicts_maybe peek (FunTy arg result _) = Just (arg,result)
-getFunTyExpandingDicts_maybe peek
- (AppTy (AppTy (TyConTy tycon _) arg) res) | isFunTyCon tycon = Just (arg, res)
-getFunTyExpandingDicts_maybe peek (SynTy _ _ t) = getFunTyExpandingDicts_maybe peek t
-getFunTyExpandingDicts_maybe peek ty@(DictTy _ _ _) = getFunTyExpandingDicts_maybe peek (expandTy ty)
-
-getFunTyExpandingDicts_maybe True (ForAllTy _ ty) = getFunTyExpandingDicts_maybe True ty
- -- Ignore for-alls when peeking. See note with defn of getFunTyExpandingDictsAndPeeking
-
-
-{- This is a truly disgusting bit of code.
- It's used by the code generator to look at the rep of a newtype.
- The code gen will have thrown away coercions involving that newtype, so
- this is the other side of the coin.
- Gruesome in the extreme.
--}
-
-getFunTyExpandingDicts_maybe peek other
- | not peek = Nothing -- that was easy
- | otherwise
- = case (maybeAppTyCon other) of
- Just (tc, arg_tys)
- | isNewTyCon tc && not (null data_cons)
- -> getFunTyExpandingDicts_maybe peek inside_ty
- where
- data_cons = tyConDataCons tc
- [the_con] = data_cons
- [inside_ty] = dataConArgTys the_con arg_tys
-
- other -> Nothing
-
-
-splitFunTy :: GenType t u -> ([GenType t u], GenType t u)
-splitFunTyExpandingDicts :: Type -> ([Type], Type)
-splitFunTyExpandingDictsAndPeeking :: Type -> ([Type], Type)
-
-splitFunTy t = split_fun_ty getFunTy_maybe t
-splitFunTyExpandingDicts t = split_fun_ty (getFunTyExpandingDicts_maybe False) t
-splitFunTyExpandingDictsAndPeeking t = split_fun_ty (getFunTyExpandingDicts_maybe True) t
- -- This "peeking" stuff is used only by the code generator.
- -- It's interested in the representation type of things, ignoring:
- -- newtype Why??? Nuked SLPJ May 97. We may not know the
- -- rep of an abstractly imported newtype
- -- foralls
- -- expanding dictionary reps
- -- synonyms, of course
-
-split_fun_ty get t = go t []
+mkFunTy :: Type -> Type -> Type
+mkFunTy arg res = FunTy arg res
+
+mkFunTys :: [Type] -> Type -> Type
+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 (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 (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
- go t ts = case (get t) of
- Just (arg,res) -> go res (arg:ts)
- Nothing -> (reverse ts, t)
+ 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 (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 (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 (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 PredTy,
+as apppropriate.
+
\begin{code}
--- NB applyTyCon puts in usageOmega, for now at least
-mkTyConTy tycon
+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 ty1 ty2
+
+ | isNewTyCon tycon
+ = NewTcApp tycon tys
+
+ | otherwise
= ASSERT(not (isSynTyCon tycon))
- TyConTy tycon usageOmega
+ TyConApp tycon tys
-applyTyCon :: TyCon -> [GenType t u] -> GenType t u
-applyTyCon tycon tys
- = ASSERT (not (isSynTyCon tycon))
- --(if (not (isSynTyCon tycon)) then \x->x else pprTrace "applyTyCon:" (pprTyCon PprDebug tycon)) $
- foldl AppTy (TyConTy tycon usageOmega) tys
+mkTyConTy :: TyCon -> Type
+mkTyConTy tycon = mkTyConApp tycon []
-getTyCon_maybe :: GenType t u -> Maybe 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 ..
-getTyCon_maybe (TyConTy tycon _) = Just tycon
-getTyCon_maybe (SynTy _ _ t) = getTyCon_maybe t
-getTyCon_maybe other_ty = Nothing
-\end{code}
+tyConAppTyCon :: Type -> TyCon
+tyConAppTyCon ty = fst (splitTyConApp ty)
-\begin{code}
-specialiseTy :: Type -- The type of the Id of which the SpecId
- -- is a specialised version
- -> [Maybe Type] -- The types at which it is specialised
- -> Int -- Number of leading dictionary args to ignore
- -> Type
-
-specialiseTy main_ty maybe_tys dicts_to_ignore
- = --false:ASSERT(isTauTy tau) TauType??
- mkSigmaTy remaining_tyvars
- (instantiateThetaTy inst_env remaining_theta)
- (instantiateTauTy inst_env tau)
- where
- (tyvars, theta, tau) = splitSigmaTy main_ty -- A prefix of, but usually all,
- -- the theta is discarded!
- remaining_theta = drop dicts_to_ignore theta
- tyvars_and_maybe_tys = tyvars `zip` maybe_tys
- remaining_tyvars = [tyvar | (tyvar, Nothing) <- tyvars_and_maybe_tys]
- inst_env = [(tyvar,ty) | (tyvar, Just ty) <- tyvars_and_maybe_tys]
+tyConAppArgs :: Type -> [Type]
+tyConAppArgs ty = snd (splitTyConApp ty)
+
+splitTyConApp :: Type -> (TyCon, [Type])
+splitTyConApp ty = case splitTyConApp_maybe ty of
+ Just stuff -> stuff
+ 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, [arg,res])
+splitTyConApp_maybe (NoteTy _ 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}
+
+---------------------------------------------------------------------
+ SynTy
+ ~~~~~
+
\begin{code}
-mkSynTy syn_tycon tys
- = ASSERT(isSynTyCon syn_tycon)
- SynTy syn_tycon tys (instantiateTauTy (zipEqual "mkSynTy" 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
-\end{code}
+ mk_syn tys = NoteTy (SynNote (TyConApp tycon tys))
+ (substTyWith tyvars tys body)
-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
+ (tyvars, body) = ASSERT( isSynTyCon tycon ) getSynTyConDefn tycon
+ arity = tyConArity tycon
+ n_args = length tys
\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
+
+ type Foo a = a -> a
+
+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.
-\begin{code}
-mkDictTy :: Class -> GenType t u -> GenType t u
-mkDictTy clas ty = DictTy clas ty usageOmega
-
-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
-
-splitRhoTy :: GenType t u -> ([(Class,GenType t u)], GenType t u)
-splitRhoTy t =
- go t t []
- where
- -- See notes on type synonyms above
- go syn_t (FunTy (DictTy c t _) r _) ts = go r r ((c,t):ts)
- go syn_t (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
- | isFunTyCon tycon
- = go r r ((c,t):ts)
- go syn_t (SynTy _ _ t) ts = go syn_t t ts
- go syn_t t ts = (reverse ts, syn_t)
-
-
-mkTheta :: [Type] -> ThetaType
- -- recover a ThetaType from the types of some dictionaries
-mkTheta dict_tys
- = map cvt dict_tys
- where
- cvt (DictTy clas ty _) = (clas, ty)
- cvt other = panic "Type.mkTheta" -- pprPanic "mkTheta:" (pprType PprDebug other)
-isDictTy (DictTy _ _ _) = True
-isDictTy (SynTy _ _ t) = isDictTy t
-isDictTy _ = False
+ 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
+-- 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
+
+
+-- ToDo: this could be moved to the code generator, using splitTyConApp instead
+-- of inspecting the type directly.
+typePrimRep :: Type -> PrimRep
+typePrimRep ty = case repType ty of
+ TyConApp tc _ -> tyConPrimRep tc
+ FunTy _ _ -> PtrRep
+ AppTy _ _ -> PtrRep -- See note below
+ TyVarTy _ -> PtrRep
+ other -> pprPanic "typePrimRep" (ppr ty)
+ -- Types of the form 'f a' must be of kind *, not *#, so
+ -- we are guaranteed that they are represented by pointers.
+ -- The reason is that f must have kind *->*, not *->*#, because
+ -- (we claim) there is no way to constrain f's kind any other
+ -- way.
+
+-- 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}
-Forall stuff
-~~~~~~~~~~~~
+---------------------------------------------------------------------
+ ForAllTy
+ ~~~~~~~~
+
\begin{code}
-mkForAllTy = ForAllTy
+mkForAllTy :: TyVar -> Type -> Type
+mkForAllTy tyvar ty
+ = mkForAllTys [tyvar] ty
-mkForAllTys :: [t] -> GenType t u -> GenType t u
+mkForAllTys :: [TyVar] -> Type -> Type
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
-
-getForAllTyExpandingDicts_maybe :: Type -> Maybe (TyVar, Type)
-getForAllTyExpandingDicts_maybe (SynTy _ _ t) = getForAllTyExpandingDicts_maybe t
-getForAllTyExpandingDicts_maybe (ForAllTy tyvar t) = Just(tyvar,t)
-getForAllTyExpandingDicts_maybe ty@(DictTy _ _ _) = getForAllTyExpandingDicts_maybe (expandTy ty)
-getForAllTyExpandingDicts_maybe _ = Nothing
-
-splitForAllTy :: GenType t u -> ([t], GenType t u)
-splitForAllTy t = go t t []
- where
- -- See notes on type synonyms above
- go syn_t (ForAllTy tv t) tvs = go t t (tv:tvs)
- go syn_t (SynTy _ _ t) tvs = go syn_t t tvs
- go syn_t t tvs = (reverse tvs, syn_t)
-
-splitForAllTyExpandingDicts :: Type -> ([TyVar], Type)
-splitForAllTyExpandingDicts ty
- = go [] ty
+isForAllTy :: Type -> Bool
+isForAllTy (NoteTy _ ty) = isForAllTy ty
+isForAllTy (ForAllTy _ _) = True
+isForAllTy other_ty = False
+
+splitForAllTy_maybe :: Type -> Maybe (TyVar, Type)
+splitForAllTy_maybe ty = splitFAT_m ty
where
- go tvs ty = case getForAllTyExpandingDicts_maybe ty of
- Just (tv, ty') -> go (tv:tvs) ty'
- Nothing -> (reverse tvs, ty)
+ splitFAT_m (NoteTy _ ty) = splitFAT_m ty
+ 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 _ = 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 (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}
-\begin{code}
-mkForAllUsageTy :: u -> [u] -> GenType t u -> GenType t u
-mkForAllUsageTy = ForAllUsageTy
+-- (mkPiType now in CoreUtils)
-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}
+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.
-Applied tycons (includes FunTyCons)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\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)
+applyTy :: Type -> Type -> Type
+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
+-- 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
- (app_ty, arg_tys) = splitAppTys ty
+ (tvs, rho_ty) = splitForAllTys orig_fun_ty
+ n_tvs = length tvs
+ n_args = length arg_tys
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Source types}
+%* *
+%************************************************************************
-getAppTyCon
- :: GenType tyvar uvar
- -> (TyCon, -- the type constructor
- [GenType tyvar uvar]) -- types to which it is applied
+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.
-getAppTyCon ty
- = case maybeAppTyCon ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppTyCon" -- (ppr PprShowAll ty)
-#endif
-\end{code}
+Source types are always lifted.
-Applied data tycons (give back constrs)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Nota Bene: all these functions suceed for @newtype@ applications too!
+The key function is predTypeRep which gives the representation of a source type:
\begin{code}
-maybeAppDataTyCon
- :: GenType (GenTyVar any) uvar
- -> Maybe (TyCon, -- the type constructor
- [GenType (GenTyVar any) uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
-maybeAppDataTyConExpandingDicts, maybeAppSpecDataTyConExpandingDicts
- :: Type -> Maybe (TyCon, [Type], [Id])
-
-maybeAppDataTyCon ty = maybe_app_data_tycon (\x->x) ty
-maybeAppDataTyConExpandingDicts ty = maybe_app_data_tycon expandTy ty
-maybeAppSpecDataTyConExpandingDicts ty = maybe_app_data_tycon expandTy ty
-
-
-maybe_app_data_tycon expand ty
- = let
- expanded_ty = expand ty
- (app_ty, arg_tys) = splitAppTys expanded_ty
- in
- case (getTyCon_maybe app_ty) of
- Just tycon | isAlgTyCon tycon && -- NB "Alg"; succeeds for newtype too
- notArrowKind (typeKind expanded_ty)
- -- Must be saturated for ty to be a data type
- -> Just (tycon, arg_tys, tyConDataCons tycon)
-
- other -> Nothing
-
-getAppDataTyCon, getAppSpecDataTyCon
- :: GenType (GenTyVar any) uvar
- -> (TyCon, -- the type constructor
- [GenType (GenTyVar any) uvar], -- types to which it is applied
- [Id]) -- its family of data-constructors
-getAppDataTyConExpandingDicts, getAppSpecDataTyConExpandingDicts
- :: Type -> (TyCon, [Type], [Id])
-
-getAppDataTyCon ty = get_app_data_tycon maybeAppDataTyCon ty
-getAppDataTyConExpandingDicts ty = --pprTrace "getAppDataTyConEx...:" (pprType PprDebug ty) $
- get_app_data_tycon maybeAppDataTyConExpandingDicts ty
-
--- these should work like the UniTyFuns.getUniDataSpecTyCon* things of old (ToDo)
-getAppSpecDataTyCon = getAppDataTyCon
-getAppSpecDataTyConExpandingDicts = getAppDataTyConExpandingDicts
-
-get_app_data_tycon maybe ty
- = case maybe ty of
- Just stuff -> stuff
-#ifdef DEBUG
- Nothing -> panic "Type.getAppDataTyCon"-- (pprGenType PprShowAll ty)
-#endif
-
-
-maybeBoxedPrimType :: Type -> Maybe (Id, Type)
-
-maybeBoxedPrimType ty
- = case (maybeAppDataTyCon ty) of -- Data type,
- Just (tycon, tys_applied, [data_con]) | isDataTyCon tycon -- with exactly one constructor
- -> case (dataConArgTys 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
+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.
+-- Unwraps only the outermost level; for example, the result might
+-- be a NewTcApp; c.f. newTypeRep
+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}
-\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
-
-mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
-\end{code}
+%************************************************************************
+%* *
+ NewTypes
+%* *
+%************************************************************************
-Finding the kind of a type
-~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-typeKind :: GenType (GenTyVar any) u -> Kind
-
-typeKind (TyVarTy tyvar) = tyVarKind tyvar
-typeKind (TyConTy tycon usage) = tyConKind tycon
-typeKind (SynTy _ _ ty) = typeKind ty
-typeKind (FunTy fun arg _) = mkBoxedTypeKind
-typeKind (DictTy clas arg _) = mkBoxedTypeKind
-typeKind (AppTy fun arg) = resultKind (typeKind fun)
-typeKind (ForAllTy _ _) = mkBoxedTypeKind
-typeKind (ForAllUsageTy _ _ _) = mkBoxedTypeKind
+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
+-- It only strips *one layer* off, so the caller will usually call itself recursively
+-- Only applied to types of kind *, hence the newtype is always saturated
+splitRecNewType_maybe (NoteTy _ ty) = splitRecNewType_maybe ty
+splitRecNewType_maybe (PredTy p) = splitRecNewType_maybe (predTypeRep p)
+splitRecNewType_maybe (NewTcApp tc tys)
+ | isRecursiveTyCon tc
+ = ASSERT( tys `lengthIs` tyConArity tc && isNewTyCon tc )
+ -- The assert should hold because splitRecNewType_maybe
+ -- should only be applied to *types* (of kind *)
+ Just (new_type_rhs tc tys)
+splitRecNewType_maybe other = Nothing
+
+-----------------------------
+newTypeRep :: TyCon -> [Type] -> Type
+-- A local helper function (not exported)
+-- Expands *the outermoset level of* a newtype application to
+-- *either* a vanilla TyConApp (recursive newtype, or non-saturated)
+-- *or* the newtype representation (otherwise), meaning the
+-- type written in the RHS of the newtype decl,
+-- which may itself be a newtype
+--
+-- Example: newtype R = MkR S
+-- newtype S = MkS T
+-- newtype T = MkT (T -> T)
+-- newTypeRep on R gives NewTcApp S
+-- on S gives NewTcApp T
+-- on T gives TyConApp T
+--
+-- 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_rhs tc tys
+ | otherwise
+ = TyConApp tc tys
+ -- ToDo: Consider caching this substitution in a NType
+
+-- new_type_rhs doesn't ask any questions:
+-- it just expands newtype one level, whether recursive or not
+new_type_rhs tc tys
+ = case newTyConRhs tc of
+ (tvs, rep_ty) -> substTyWith tvs tys rep_ty
\end{code}
-Free variables of a type
-~~~~~~~~~~~~~~~~~~~~~~~~
+%************************************************************************
+%* *
+\subsection{Kinds and free variables}
+%* *
+%************************************************************************
+
+---------------------------------------------------------------------
+ Finding the kind 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
-
--- Find the free names of a type, including the type constructors and classes it mentions
-namesOfType :: GenType (GenTyVar flexi) uvar -> NameSet
-namesOfType (TyVarTy tv) = unitNameSet (getName tv)
-namesOfType (TyConTy tycon usage) = unitNameSet (getName tycon)
-namesOfType (SynTy tycon tys ty) = unitNameSet (getName tycon) `unionNameSets`
- namesOfType ty
-namesOfType (FunTy arg res _) = namesOfType arg `unionNameSets` namesOfType res
-namesOfType (AppTy fun arg) = namesOfType fun `unionNameSets` namesOfType arg
-namesOfType (DictTy clas ty _) = unitNameSet (getName clas) `unionNameSets`
- namesOfType ty
-namesOfType (ForAllTy tyvar ty) = namesOfType ty `minusNameSet` unitNameSet (getName tyvar)
-namesOfType (ForAllUsageTy _ _ ty) = panic "forall usage"
+typeKind :: Type -> Kind
+
+typeKind (TyVarTy tyvar) = tyVarKind tyvar
+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 (PredTy _) = liftedTypeKind -- Predicates are always
+ -- represented by lifted types
+typeKind (AppTy fun arg) = kindFunResult (typeKind fun)
+typeKind (FunTy arg res) = liftedTypeKind
+typeKind (ForAllTy tv ty) = typeKind ty
\end{code}
-Instantiating a type
-~~~~~~~~~~~~~~~~~~~~
+---------------------------------------------------------------------
+ Free variables of a type
+ ~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
--- applyTy :: GenType (GenTyVar flexi) uvar
--- -> GenType (GenTyVar flexi) uvar
--- -> GenType (GenTyVar flexi) uvar
+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 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
+
+-- 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.
-applyTy :: Type -> Type -> Type
-applyTy (SynTy _ _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = instantiateTy [(tv,arg)] ty
-applyTy ty@(DictTy _ _ _) arg = applyTy (expandTy ty) arg
-applyTy other arg = panic "applyTy"
+tyVarsOfTypes :: [Type] -> TyVarSet
+tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
+
+tyVarsOfPred :: PredType -> TyVarSet
+tyVarsOfPred (IParam _ ty) = tyVarsOfType ty
+tyVarsOfPred (ClassP _ tys) = tyVarsOfTypes tys
+
+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
\end{code}
+%************************************************************************
+%* *
+\subsection{TidyType}
+%* *
+%************************************************************************
+
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
+
+It doesn't change the uniques at all, just the print names.
+
\begin{code}
-instantiateTy :: [(GenTyVar flexi, GenType (GenTyVar flexi) uvar)]
- -> GenType (GenTyVar flexi) uvar
- -> GenType (GenTyVar flexi) uvar
+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
-instantiateTauTy :: Eq tv =>
- [(tv, GenType tv' u)]
- -> GenType tv u
- -> GenType tv' u
+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 = fst (tidyOpenTyVars env (varSetElems tyvars))
-applyTypeEnvToTy :: TyVarEnv Type -> SigmaType -> SigmaType
+tidyOpenTyVars :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar])
+tidyOpenTyVars env tyvars = mapAccumL tidyOpenTyVar env tyvars
--- 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
+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
-instant_help ty lookup_tv deflt_tv choose_tycon
- if_usage if_forall bound_forall_tv_BAD deflt_forall_tv
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(tidy_env, subst) ty
= go ty
where
- go (TyVarTy tv) = case (lookup_tv tv) of
- Nothing -> deflt_tv tv
- Just ty -> ty
- go ty@(TyConTy tycon usage) = choose_tycon ty 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
- go (ForAllUsageTy uvar bds ty) = if_usage $
- ForAllUsageTy uvar bds (go ty)
- go (ForAllTy tv ty) = if_forall $
- (if (bound_forall_tv_BAD && maybeToBool (lookup_tv tv)) then
- trace "instantiateTy: unexpected forall hit"
- else
- \x->x) ForAllTy (deflt_forall_tv tv) (go ty)
-
-instantiateTy [] ty = ty
-
-instantiateTy tenv ty
- = instant_help ty lookup_tv deflt_tv choose_tycon
- if_usage if_forall bound_forall_tv_BAD deflt_forall_tv
- where
- lookup_tv tv = case [ty | (tv',ty) <- tenv, tv == tv'] of
- [] -> Nothing
- [ty] -> Just ty
- _ -> panic "instantiateTy:lookup_tv"
-
- deflt_tv tv = TyVarTy tv
- choose_tycon ty _ _ = ty
- if_usage ty = ty
- if_forall ty = ty
- bound_forall_tv_BAD = True
- deflt_forall_tv tv = tv
-
-instantiateTauTy tenv ty
- = instant_help ty lookup_tv deflt_tv choose_tycon
- if_usage if_forall bound_forall_tv_BAD deflt_forall_tv
- where
- lookup_tv tv = case [ty | (tv',ty) <- tenv, tv == tv'] of
- [] -> Nothing
- [ty] -> Just ty
- _ -> panic "instantiateTauTy:lookup_tv"
-
- deflt_tv tv = panic "instantiateTauTy"
- choose_tycon _ tycon usage = TyConTy tycon usage
- if_usage ty = panic "instantiateTauTy:ForAllUsageTy"
- if_forall ty = panic "instantiateTauTy:ForAllTy"
- bound_forall_tv_BAD = panic "instantiateTauTy:bound_forall_tv"
- deflt_forall_tv tv = panic "instantiateTauTy:deflt_forall_tv"
-
-instantiateThetaTy tenv theta
- = [(clas,instantiateTauTy tenv ty) | (clas,ty) <- theta]
-
--- applyTypeEnv applies a type environment to a type.
--- It can handle shadowing; for example:
--- f = /\ t1 t2 -> \ d ->
--- letrec f' = /\ t1 -> \x -> ...(f' t1 x')...
--- in f' t1
--- Here, when we clone t1 to t1', say, we'll come across shadowing
--- when applying the clone environment to the type of f'.
---
--- As a sanity check, we should also check that name capture
--- doesn't occur, but that means keeping track of the free variables of the
--- range of the TyVarEnv, which I don't do just yet.
---
--- We don't use instant_help because we need to carry in the environment
-
-applyTypeEnvToTy tenv ty
- = go tenv ty
- where
- go tenv ty@(TyVarTy tv) = case (lookupTyVarEnv tenv tv) of
- Nothing -> ty
- Just ty -> ty
- go tenv ty@(TyConTy tycon usage) = ty
- go tenv (SynTy tycon tys ty) = SynTy tycon (map (go tenv) tys) (go tenv ty)
- go tenv (FunTy arg res usage) = FunTy (go tenv arg) (go tenv res) usage
- go tenv (AppTy fun arg) = AppTy (go tenv fun) (go tenv arg)
- go tenv (DictTy clas ty usage) = DictTy clas (go tenv ty) usage
- go tenv (ForAllUsageTy uvar bds ty) = ForAllUsageTy uvar bds (go tenv ty)
- go tenv (ForAllTy tv ty) = ForAllTy tv (go tenv' ty)
- where
- tenv' = case lookupTyVarEnv tenv tv of
- Nothing -> tenv
- Just _ -> delFromTyVarEnv tenv tv
+ 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 (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) = tidyTyVarBndr env tv
+
+ 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 -> PredType -> PredType
+tidyPred env (IParam n ty) = IParam n (tidyType env ty)
+tidyPred env (ClassP clas tys) = ClassP clas (tidyTypes env tys)
\end{code}
+
+@tidyOpenType@ grabs the free type variables, tidies them
+and then uses @tidyType@ to work over the type itself
+
\begin{code}
-instantiateUsage
- :: Ord3 u => [(u, GenType t u')] -> GenType t u -> GenType t u'
+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
-instantiateUsage = panic "instantiateUsage: not implemented"
+tidyTopType :: Type -> Type
+tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
-At present there are no unboxed non-primitive types, so
-isUnboxedType is the same as isPrimType.
-We're a bit cavalier about finding out whether something is
-primitive/unboxed or not. Rather than deal with the type
-arguemnts we just zoom into the function part of the type.
-That is, given (T a) we just recurse into the "T" part,
-ignoring "a".
+%************************************************************************
+%* *
+\subsection{Liftedness}
+%* *
+%************************************************************************
\begin{code}
-isPrimType, isUnboxedType :: Type -> Bool
-
-isPrimType (AppTy ty _) = isPrimType ty
-isPrimType (SynTy _ _ ty) = isPrimType ty
-isPrimType (TyConTy tycon _) = case maybeNewTyCon tycon of
- Just (tyvars, ty) -> isPrimType ty
- Nothing -> isPrimTyCon tycon
+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 (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
+ 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( ty_args `lengthIs` tyConArity tc )
+ isAlgTyCon tc
+ other -> False
+\end{code}
-isPrimType _ = False
+@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.
-isUnboxedType = isPrimType
+\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}
-This is *not* right: it is a placeholder (ToDo 96/03 WDP):
\begin{code}
-typePrimRep :: Type -> PrimRep
-
-typePrimRep (SynTy _ _ ty) = typePrimRep ty
-typePrimRep (AppTy ty _) = typePrimRep ty
-typePrimRep (TyConTy tc _)
- | isPrimTyCon tc = case (assocMaybe tc_primrep_list (uniqueOf tc)) of
- Just xx -> xx
- Nothing -> panic "Type.typePrimRep" -- pprPanic "typePrimRep:" (pprTyCon PprDebug tc)
-
- | otherwise = case maybeNewTyCon tc of
- Just (tyvars, ty) | isPrimType ty -> typePrimRep ty
- _ -> PtrRep -- Default
-
-typePrimRep _ = PtrRep -- the "default"
-
-tc_primrep_list
- = [(addrPrimTyConKey, AddrRep)
- ,(arrayPrimTyConKey, ArrayRep)
- ,(byteArrayPrimTyConKey, ByteArrayRep)
- ,(charPrimTyConKey, CharRep)
- ,(doublePrimTyConKey, DoubleRep)
- ,(floatPrimTyConKey, FloatRep)
- ,(foreignObjPrimTyConKey, ForeignObjRep)
- ,(intPrimTyConKey, IntRep)
- ,(mutableArrayPrimTyConKey, ArrayRep)
- ,(mutableByteArrayPrimTyConKey, ByteArrayRep)
- ,(stablePtrPrimTyConKey, StablePtrRep)
- ,(statePrimTyConKey, VoidRep)
- ,(synchVarPrimTyConKey, PtrRep)
- ,(voidTyConKey, PtrRep) -- Not VoidRep! That's just for Void#
- -- The type Void is represented by a pointer to
- -- a bottom closure.
- ,(wordPrimTyConKey, WordRep)
- ]
+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}
+
%************************************************************************
%* *
-\subsection{Matching on types}
+\subsection{Sequencing on types
%* *
%************************************************************************
-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.
-
-@matchTys@ matches corresponding elements of a list of templates and
-types.
-
\begin{code}
-matchTy :: GenType t1 u1 -- Template
- -> GenType t2 u2 -- Proposed instance of template
- -> Maybe [(t1,GenType t2 u2)] -- Matching substitution
-
-
-matchTys :: [GenType t1 u1] -- Templates
- -> [GenType t2 u2] -- Proposed instance of template
- -> Maybe ([(t1,GenType t2 u2)],-- Matching substitution
- [GenType t2 u2]) -- Left over instance types
-
-matchTy ty1 ty2 = match ty1 ty2 (\s -> Just s) []
-matchTys tys1 tys2 = go [] tys1 tys2
- where
- go s [] tys2 = Just (s,tys2)
- go s (ty1:tys1) [] = trace "matchTys" Nothing
- go s (ty1:tys1) (ty2:tys2) = match ty1 ty2 (\s' -> go s' tys1 tys2) s
+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 (NewTcApp tc tys) = tc `seq` seqTypes tys
+seqType (ForAllTy tv ty) = tv `seq` seqType ty
+
+seqTypes :: [Type] -> ()
+seqTypes [] = ()
+seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
+
+seqNote :: TyNote -> ()
+seqNote (SynNote ty) = seqType ty
+seqNote (FTVNote set) = sizeUniqSet set `seq` ()
+
+seqPred :: PredType -> ()
+seqPred (ClassP c tys) = c `seq` seqTypes tys
+seqPred (IParam n ty) = n `seq` seqType ty
\end{code}
-@match@ is the main function.
-
-\begin{code}
-match :: GenType t1 u1 -> GenType t2 u2 -- Current match pair
- -> ([(t1, GenType t2 u2)] -> Maybe result) -- Continuation
- -> [(t1, GenType t2 u2)] -- Current substitution
- -> Maybe result
-
-match (TyVarTy v) ty k = \s -> k ((v,ty) : s)
-match (FunTy fun1 arg1 _) (FunTy fun2 arg2 _) k = match fun1 fun2 (match arg1 arg2 k)
-match (AppTy fun1 arg1) (AppTy fun2 arg2) k = match fun1 fun2 (match arg1 arg2 k)
-match (TyConTy con1 _) (TyConTy con2 _) k | con1 == con2 = k
-match (DictTy clas1 ty1 _) (DictTy clas2 ty2 _) k | clas1 == clas2 = match ty1 ty2 k
-match (SynTy _ _ ty1) ty2 k = match ty1 ty2 k
-match ty1 (SynTy _ _ ty2) k = match ty1 ty2 k
-
- -- 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 _ _ _ = \s -> Nothing
-\end{code}
%************************************************************************
%* *
%* *
%************************************************************************
-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.
+Comparison; don't use instances so that we know where it happens.
+Look through newtypes but not usage types.
-\begin{code}
-eqSimpleTheta :: (Eq t,Eq u) =>
- [(Class,GenType t u)] -> [(Class,GenType t u)] -> Bool
+Note that eqType can respond 'False' for partial applications of newtypes.
+Consider
+ newtype Parser m a = MkParser (Foogle m a)
-eqSimpleTheta [] [] = True
-eqSimpleTheta ((c1,t1):th1) ((c2,t2):th2) =
- c1==c2 && t1 `eqSimpleTy` t2 && th1 `eqSimpleTheta` th2
-eqSimpleTheta other1 other2 = False
-\end{code}
+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}
-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 --ToDo: later: && 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
-\end{code}
+eqType t1 t2 = eq_ty emptyVarEnv t1 t2
-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).
+-- 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
-\begin{code}
-eqTy :: Type -> Type -> Bool
-
-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 -- ToDo: LATER: && 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
- -- NB we use a guard for c1==c2 so that if they aren't equal we
- -- fall through into expanding the type. Why? Because brain-dead
- -- people might write
- -- class Foo a => Baz a where {}
- -- and that means that a Foo dictionary and a Baz dictionary are identical
- -- Sigh. Let's hope we don't spend too much time in here!
-
- 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
-\end{code}
+-- 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)
-\begin{code}
-showTypeCategory :: Type -> Char
- {-
- {C,I,F,D} char, int, float, double
- T tuple
- S other single-constructor type
- {c,i,f,d} unboxed ditto
- t *unpacked* tuple
- s *unpacked" single-cons...
-
- v void#
- a primitive array
-
- E enumeration type
- + dictionary, unless it's a ...
- L List
- > function
- M other (multi-constructor) data-con type
- . other type
- - reserved for others to mark as "uninteresting"
- -}
-showTypeCategory ty
- = if isDictTy ty
- then '+'
- else
- case getTyCon_maybe ty of
- Nothing -> if maybeToBool (getFunTy_maybe ty)
- then '>'
- else '.'
-
- Just tycon ->
- let utc = uniqueOf tycon in
- if utc == charDataConKey then 'C'
- else if utc == intDataConKey then 'I'
- else if utc == floatDataConKey then 'F'
- else if utc == doubleDataConKey then 'D'
- else if utc == integerDataConKey then 'J'
- else if utc == charPrimTyConKey then 'c'
- else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
- || utc == addrPrimTyConKey) then 'i'
- else if utc == floatPrimTyConKey then 'f'
- else if utc == doublePrimTyConKey then 'd'
- else if isPrimTyCon tycon {- array, we hope -} then 'A'
- else if isEnumerationTyCon tycon then 'E'
- else if isTupleTyCon tycon then 'T'
- else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
- else if utc == listTyConKey then 'L'
- else 'M' -- oh, well...
+-- 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 (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 (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 tys1 tys2)
+eq_tys env tys1 tys2 = False
\end{code}
+
projects / ghc-hetmet.git / blobdiff