X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcType.lhs;h=8286f64b868f1a444301b113f3da440d519398a4;hb=72c2f581702ca162f56012dd0c8cafcbac284b5c;hp=c7af9ee146c7083d79e578c59022fd4f65f84f3c;hpb=317a1fd9a021218f7ef4fbd35783186ab7329901;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcType.lhs b/ghc/compiler/typecheck/TcType.lhs index c7af9ee..8286f64 100644 --- a/ghc/compiler/typecheck/TcType.lhs +++ b/ghc/compiler/typecheck/TcType.lhs @@ -17,12 +17,13 @@ is the principal client. module TcType ( -------------------------------- -- Types - TcType, TcTauType, TcPredType, TcThetaType, TcRhoType, - TcTyVar, TcTyVarSet, TcKind, + TcType, TcSigmaType, TcPhiType, TcTauType, TcPredType, TcThetaType, + TcTyVar, TcTyVarSet, TcKind, -------------------------------- -- TyVarDetails - TyVarDetails(..), isUserTyVar, isSkolemTyVar, + TyVarDetails(..), isUserTyVar, isSkolemTyVar, isHoleTyVar, + tyVarBindingInfo, -------------------------------- -- Builders @@ -40,11 +41,12 @@ module TcType ( --------------------------------- -- Predicates. -- Again, newtypes are opaque - tcEqType, tcEqPred, tcCmpType, tcCmpTypes, tcCmpPred, - isQualifiedTy, isOverloadedTy, + tcEqType, tcEqTypes, tcEqPred, tcCmpType, tcCmpTypes, tcCmpPred, + isSigmaTy, isOverloadedTy, isDoubleTy, isFloatTy, isIntTy, isIntegerTy, isAddrTy, isBoolTy, isUnitTy, isForeignPtrTy, isTauTy, tcIsTyVarTy, tcIsForAllTy, + allDistinctTyVars, --------------------------------- -- Misc type manipulators @@ -58,7 +60,7 @@ module TcType ( isPredTy, isClassPred, isTyVarClassPred, predHasFDs, mkDictTy, tcSplitPredTy_maybe, predTyUnique, isDictTy, tcSplitDFunTy, predTyUnique, - mkClassPred, inheritablePred, isIPPred, mkPredName, + mkClassPred, isInheritablePred, isLinearPred, isIPPred, mkPredName, --------------------------------- -- Foreign import and export @@ -73,7 +75,6 @@ module TcType ( --------------------------------- -- Unifier and matcher unifyTysX, unifyTyListsX, unifyExtendTysX, - allDistinctTyVars, matchTy, matchTys, match, -------------------------------- @@ -81,12 +82,12 @@ module TcType ( Kind, -- Stuff to do with kinds is insensitive to pre/post Tc unliftedTypeKind, liftedTypeKind, openTypeKind, mkArrowKind, mkArrowKinds, superBoxity, liftedBoxity, hasMoreBoxityInfo, defaultKind, superKind, - isTypeKind, + isTypeKind, isAnyTypeKind, Type, SourceType(..), PredType, ThetaType, mkForAllTy, mkForAllTys, mkFunTy, mkFunTys, zipFunTys, - mkTyConApp, mkAppTy, mkAppTys, mkSynTy, applyTy, applyTys, + mkTyConApp, mkGenTyConApp, mkAppTy, mkAppTys, mkSynTy, applyTy, applyTys, mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy, mkPredTys, isUnLiftedType, -- Source types are always lifted @@ -107,15 +108,14 @@ import {-# SOURCE #-} PprType( pprType ) -- friends: import TypeRep ( Type(..), TyNote(..), funTyCon ) -- friend -import Type ( mkUTyM, unUTy ) -- Used locally import Type ( -- Re-exports tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta, - Kind, Type, TauType, SourceType(..), PredType, ThetaType, + Kind, Type, SourceType(..), PredType, ThetaType, unliftedTypeKind, liftedTypeKind, openTypeKind, mkArrowKind, mkArrowKinds, - mkForAllTy, mkForAllTys, defaultKind, isTypeKind, + mkForAllTy, mkForAllTys, defaultKind, isTypeKind, isAnyTypeKind, mkFunTy, mkFunTys, zipFunTys, - mkTyConApp, mkAppTy, mkAppTys, mkSynTy, applyTy, applyTys, + mkTyConApp, mkGenTyConApp, mkAppTy, mkAppTys, mkSynTy, applyTy, applyTys, mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy, mkPredTys, isUnLiftedType, isUnboxedTupleType, isPrimitiveType, splitNewType_maybe, splitTyConApp_maybe, @@ -125,18 +125,19 @@ import Type ( -- Re-exports ) import TyCon ( TyCon, isUnLiftedTyCon ) import Class ( classHasFDs, Class ) -import Var ( TyVar, tyVarKind ) +import Var ( TyVar, tyVarKind, isMutTyVar, mutTyVarDetails ) import ForeignCall ( Safety, playSafe ) import VarEnv import VarSet -- others: import CmdLineOpts ( DynFlags, DynFlag( Opt_GlasgowExts ), dopt ) -import Name ( Name, NamedThing(..), mkLocalName ) +import Name ( Name, NamedThing(..), mkLocalName, getSrcLoc ) import OccName ( OccName, mkDictOcc ) import NameSet import PrelNames -- Lots (e.g. in isFFIArgumentTy) import TysWiredIn ( ptrTyCon, funPtrTyCon, addrTyCon, unitTyCon ) +import BasicTypes ( IPName(..), ipNameName ) import Unique ( Unique, Uniquable(..) ) import SrcLoc ( SrcLoc ) import Util ( cmpList, thenCmp, equalLength ) @@ -151,6 +152,40 @@ import Outputable %* * %************************************************************************ +The type checker divides the generic Type world into the +following more structured beasts: + +sigma ::= forall tyvars. theta => phi + -- A sigma type is a qualified type + -- + -- Note that even if 'tyvars' is empty, theta + -- may not be: e.g. (?x::Int) => Int + + -- Note that 'sigma' is in prenex form: + -- all the foralls are at the front. + -- A 'phi' type has no foralls to the right of + -- an arrow + +phi ::= sigma -> phi + | tau + +-- A 'tau' type has no quantification anywhere +-- Note that the args of a type constructor must be taus +tau ::= tyvar + | tycon tau_1 .. tau_n + | tau_1 tau_2 + | tau_1 -> tau_2 + +-- In all cases, a (saturated) type synonym application is legal, +-- provided it expands to the required form. + + +\begin{code} +type SigmaType = Type +type PhiType = Type +type TauType = Type +\end{code} + \begin{code} type TcTyVar = TyVar -- Might be a mutable tyvar type TcTyVarSet = TyVarSet @@ -163,8 +198,9 @@ type TcType = Type -- A TcType can have mutable type variables type TcPredType = PredType type TcThetaType = ThetaType -type TcRhoType = Type -type TcTauType = TauType +type TcSigmaType = TcType +type TcPhiType = TcType +type TcTauType = TcType type TcKind = TcType \end{code} @@ -182,7 +218,12 @@ why Var.lhs shouldn't actually have the definition, but it "belongs" here. \begin{code} data TyVarDetails - = SigTv -- Introduced when instantiating a type signature, + = HoleTv -- Used *only* by the type checker when passing in a type + -- variable that should be side-effected to the result type. + -- Always has kind openTypeKind. + -- Never appears in types + + | SigTv -- Introduced when instantiating a type signature, -- prior to checking that the defn of a fn does -- have the expected type. Should not be instantiated. -- @@ -202,20 +243,40 @@ data TyVarDetails | VanillaTv -- Everything else -isUserTyVar :: TyVarDetails -> Bool -- Avoid unifying these if possible -isUserTyVar VanillaTv = False -isUserTyVar other = True - -isSkolemTyVar :: TyVarDetails -> Bool -isSkolemTyVar SigTv = True -isSkolemTyVar other = False - -instance Outputable TyVarDetails where - ppr SigTv = ptext SLIT("type signature") - ppr ClsTv = ptext SLIT("class declaration") - ppr InstTv = ptext SLIT("instance declaration") - ppr PatSigTv = ptext SLIT("pattern type signature") - ppr VanillaTv = ptext SLIT("???") +isUserTyVar :: TcTyVar -> Bool -- Avoid unifying these if possible +isUserTyVar tv = case mutTyVarDetails tv of + VanillaTv -> False + other -> True + +isSkolemTyVar :: TcTyVar -> Bool +isSkolemTyVar tv = case mutTyVarDetails tv of + SigTv -> True + ClsTv -> True + InstTv -> True + oteher -> False + +isHoleTyVar :: TcTyVar -> Bool +-- NB: the hole might be filled in by now, and this +-- function does not check for that +isHoleTyVar tv = ASSERT( isMutTyVar tv ) + case mutTyVarDetails tv of + HoleTv -> True + other -> False + +tyVarBindingInfo :: TyVar -> SDoc -- Used in checkSigTyVars +tyVarBindingInfo tv + | isMutTyVar tv + = sep [ptext SLIT("is bound by the") <+> details (mutTyVarDetails tv), + ptext SLIT("at") <+> ppr (getSrcLoc tv)] + | otherwise + = empty + where + details SigTv = ptext SLIT("type signature") + details ClsTv = ptext SLIT("class declaration") + details InstTv = ptext SLIT("instance declaration") + details PatSigTv = ptext SLIT("pattern type signature") + details HoleTv = ptext SLIT("//hole//") -- Should not happen + details VanillaTv = ptext SLIT("//vanilla//") -- Ditto \end{code} @@ -229,9 +290,7 @@ instance Outputable TyVarDetails where mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau) mkRhoTy :: [SourceType] -> Type -> Type -mkRhoTy theta ty = UASSERT2( not (isUTy ty), pprType ty ) - foldr (\p r -> FunTy (mkUTyM (mkPredTy p)) (mkUTyM r)) ty theta - +mkRhoTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta \end{code} @@ -245,7 +304,6 @@ isTauTy (AppTy a b) = isTauTy a && isTauTy b isTauTy (FunTy a b) = isTauTy a && isTauTy b isTauTy (SourceTy p) = True -- Don't look through source types isTauTy (NoteTy _ ty) = isTauTy ty -isTauTy (UsageTy _ ty) = isTauTy ty isTauTy other = False \end{code} @@ -258,7 +316,6 @@ 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 getDFunTyKey (SourceTy (NType tc _)) = getOccName tc -- Newtypes are quite reasonable getDFunTyKey ty = pprPanic "getDFunTyKey" (pprType ty) -- SourceTy shouldn't happen @@ -285,12 +342,10 @@ tcSplitForAllTys ty = split ty ty [] where split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs) split orig_ty (NoteTy n ty) tvs = split orig_ty ty tvs - split orig_ty (UsageTy _ ty) tvs = split orig_ty ty tvs split orig_ty t tvs = (reverse tvs, orig_ty) tcIsForAllTy (ForAllTy tv ty) = True tcIsForAllTy (NoteTy n ty) = tcIsForAllTy ty -tcIsForAllTy (UsageTy n ty) = tcIsForAllTy ty tcIsForAllTy t = False tcSplitRhoTy :: Type -> ([PredType], Type) @@ -300,7 +355,6 @@ tcSplitRhoTy ty = split ty ty [] Just p -> split res res (p:ts) Nothing -> (reverse ts, orig_ty) split orig_ty (NoteTy n 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) tcSplitSigmaTy ty = case tcSplitForAllTys ty of @@ -319,12 +373,11 @@ tcSplitTyConApp ty = case tcSplitTyConApp_maybe ty of Nothing -> pprPanic "tcSplitTyConApp" (pprType ty) tcSplitTyConApp_maybe :: Type -> Maybe (TyCon, [Type]) --- Newtypes are opaque, so they may be split tcSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys) -tcSplitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [unUTy arg,unUTy res]) +tcSplitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res]) tcSplitTyConApp_maybe (NoteTy n ty) = tcSplitTyConApp_maybe ty -tcSplitTyConApp_maybe (UsageTy _ ty) = tcSplitTyConApp_maybe ty tcSplitTyConApp_maybe (SourceTy (NType tc tys)) = Just (tc,tys) + -- Newtypes are opaque, so they may be split -- However, predicates are not treated -- as tycon applications by the type checker tcSplitTyConApp_maybe other = Nothing @@ -339,7 +392,6 @@ tcSplitFunTys ty = case tcSplitFunTy_maybe ty of tcSplitFunTy_maybe :: Type -> Maybe (Type, Type) tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res) tcSplitFunTy_maybe (NoteTy n ty) = tcSplitFunTy_maybe ty -tcSplitFunTy_maybe (UsageTy _ ty) = tcSplitFunTy_maybe ty tcSplitFunTy_maybe other = Nothing tcFunArgTy ty = case tcSplitFunTy_maybe ty of { Just (arg,res) -> arg } @@ -347,10 +399,9 @@ tcFunResultTy ty = case tcSplitFunTy_maybe ty of { Just (arg,res) -> res } tcSplitAppTy_maybe :: Type -> Maybe (Type, Type) -tcSplitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [unUTy ty1], unUTy ty2) +tcSplitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2) tcSplitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2) tcSplitAppTy_maybe (NoteTy n ty) = tcSplitAppTy_maybe ty -tcSplitAppTy_maybe (UsageTy _ ty) = tcSplitAppTy_maybe ty tcSplitAppTy_maybe (SourceTy (NType tc tys)) = tc_split_app tc tys --- Don't forget that newtype! tcSplitAppTy_maybe (TyConApp tc tys) = tc_split_app tc tys @@ -369,7 +420,6 @@ tcSplitAppTy ty = case tcSplitAppTy_maybe ty of tcGetTyVar_maybe :: Type -> Maybe TyVar tcGetTyVar_maybe (TyVarTy tv) = Just tv tcGetTyVar_maybe (NoteTy _ t) = tcGetTyVar_maybe t -tcGetTyVar_maybe ty@(UsageTy _ _) = pprPanic "tcGetTyVar_maybe: UTy:" (pprType ty) tcGetTyVar_maybe other = Nothing tcGetTyVar :: String -> Type -> TyVar @@ -395,7 +445,6 @@ tcSplitMethodTy ty = split ty Just p -> (p, res) Nothing -> panic "splitMethodTy" split (NoteTy n ty) = split ty - split (UsageTy _ ty) = split ty split _ = panic "splitMethodTy" tcSplitDFunTy :: Type -> ([TyVar], [SourceType], Class, [Type]) @@ -406,6 +455,31 @@ tcSplitDFunTy ty (tvs, theta, clas, tys) }} \end{code} +(allDistinctTyVars tys tvs) = True + iff +all the types tys are type variables, +distinct from each other and from tvs. + +This is useful when checking that unification hasn't unified signature +type variables. For example, if the type sig is + f :: forall a b. a -> b -> b +we want to check that 'a' and 'b' havn't + (a) been unified with a non-tyvar type + (b) been unified with each other (all distinct) + (c) been unified with a variable free in the environment + +\begin{code} +allDistinctTyVars :: [Type] -> TyVarSet -> Bool + +allDistinctTyVars [] acc + = True +allDistinctTyVars (ty:tys) acc + = case tcGetTyVar_maybe ty of + Nothing -> False -- (a) + Just tv | tv `elemVarSet` acc -> False -- (b) or (c) + | otherwise -> allDistinctTyVars tys (acc `extendVarSet` tv) +\end{code} + %************************************************************************ %* * @@ -419,23 +493,21 @@ tcSplitDFunTy ty isPred :: SourceType -> Bool isPred (ClassP _ _) = True isPred (IParam _ _) = True -isPred (NType _ __) = False +isPred (NType _ _) = False isPredTy :: Type -> Bool isPredTy (NoteTy _ ty) = isPredTy ty -isPredTy (UsageTy _ ty) = isPredTy ty isPredTy (SourceTy sty) = isPred sty isPredTy _ = False tcSplitPredTy_maybe :: Type -> Maybe PredType -- Returns Just for predicates only tcSplitPredTy_maybe (NoteTy _ ty) = tcSplitPredTy_maybe ty -tcSplitPredTy_maybe (UsageTy _ ty) = tcSplitPredTy_maybe ty tcSplitPredTy_maybe (SourceTy p) | isPred p = Just p tcSplitPredTy_maybe other = Nothing predTyUnique :: PredType -> Unique -predTyUnique (IParam n _) = getUnique n +predTyUnique (IParam n _) = getUnique (ipNameName n) predTyUnique (ClassP clas tys) = getUnique clas predHasFDs :: PredType -> Bool @@ -446,15 +518,14 @@ predHasFDs (ClassP cls _) = classHasFDs cls mkPredName :: Unique -> SrcLoc -> SourceType -> Name mkPredName uniq loc (ClassP cls tys) = mkLocalName uniq (mkDictOcc (getOccName cls)) loc -mkPredName uniq loc (IParam name ty) = name +mkPredName uniq loc (IParam ip ty) = mkLocalName uniq (getOccName (ipNameName ip)) loc \end{code} --------------------- Dictionary types --------------------------------- \begin{code} -mkClassPred clas tys = UASSERT2( not (any isUTy tys), ppr clas <+> fsep (map pprType tys) ) - ClassP clas tys +mkClassPred clas tys = ClassP clas tys isClassPred :: SourceType -> Bool isClassPred (ClassP clas tys) = True @@ -471,13 +542,11 @@ getClassPredTys :: PredType -> (Class, [Type]) getClassPredTys (ClassP clas tys) = (clas, tys) mkDictTy :: Class -> [Type] -> Type -mkDictTy clas tys = UASSERT2( not (any isUTy tys), ppr clas <+> fsep (map pprType tys) ) - mkPredTy (ClassP clas tys) +mkDictTy clas tys = mkPredTy (ClassP clas tys) isDictTy :: Type -> Bool isDictTy (SourceTy p) = isClassPred p isDictTy (NoteTy _ ty) = isDictTy ty -isDictTy (UsageTy _ ty) = isDictTy ty isDictTy other = False \end{code} @@ -488,7 +557,7 @@ isIPPred :: SourceType -> Bool isIPPred (IParam _ _) = True isIPPred other = False -inheritablePred :: PredType -> Bool +isInheritablePred :: 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, @@ -497,8 +566,12 @@ inheritablePred :: PredType -> Bool -- 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 +isInheritablePred (ClassP _ _) = True +isInheritablePred other = False + +isLinearPred :: TcPredType -> Bool +isLinearPred (IParam (Linear n) _) = True +isLinearPred other = False \end{code} @@ -515,6 +588,9 @@ But ignoring usage types tcEqType :: Type -> Type -> Bool tcEqType ty1 ty2 = case ty1 `tcCmpType` ty2 of { EQ -> True; other -> False } +tcEqTypes :: [Type] -> [Type] -> Bool +tcEqTypes ty1 ty2 = case ty1 `tcCmpTypes` ty2 of { EQ -> True; other -> False } + tcEqPred :: PredType -> PredType -> Bool tcEqPred p1 p2 = case p1 `tcCmpPred` p2 of { EQ -> True; other -> False } @@ -534,11 +610,9 @@ cmpTy :: TyVarEnv TyVar -> Type -> Type -> Ordering -- So when comparing for-alls.. (forall tv1 . t1) (forall tv2 . t2) -- we in effect substitute tv2 for tv1 in t1 before continuing - -- Look through NoteTy and UsageTy + -- Look through NoteTy cmpTy env (NoteTy _ ty1) ty2 = cmpTy env ty1 ty2 cmpTy env ty1 (NoteTy _ ty2) = cmpTy env ty1 ty2 -cmpTy env (UsageTy _ ty1) ty2 = cmpTy env ty1 ty2 -cmpTy env ty1 (UsageTy _ ty2) = cmpTy env ty1 ty2 -- Deal with equal constructors cmpTy env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of @@ -573,7 +647,7 @@ cmpTy env _ _ = LT \begin{code} cmpSourceTy :: TyVarEnv TyVar -> SourceType -> SourceType -> Ordering -cmpSourceTy env (IParam n1 ty1) (IParam n2 ty2) = (n1 `compare` n2) `thenCmp` (cmpTy env ty1 ty2) +cmpSourceTy 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 @@ -602,23 +676,21 @@ instance Ord SourceType where { compare = tcCmpPred } %* * %************************************************************************ -isQualifiedTy returns true of any qualified type. It doesn't *necessarily* have +isSigmaTy returns true of any qualified type. It doesn't *necessarily* have any foralls. E.g. f :: (?x::Int) => Int -> Int \begin{code} -isQualifiedTy :: Type -> Bool -isQualifiedTy (ForAllTy tyvar ty) = True -isQualifiedTy (FunTy a b) = isPredTy a -isQualifiedTy (NoteTy n ty) = isQualifiedTy ty -isQualifiedTy (UsageTy _ ty) = isQualifiedTy ty -isQualifiedTy _ = False +isSigmaTy :: Type -> Bool +isSigmaTy (ForAllTy tyvar ty) = True +isSigmaTy (FunTy a b) = isPredTy a +isSigmaTy (NoteTy n ty) = isSigmaTy ty +isSigmaTy _ = False isOverloadedTy :: Type -> Bool isOverloadedTy (ForAllTy tyvar ty) = isOverloadedTy ty isOverloadedTy (FunTy a b) = isPredTy a isOverloadedTy (NoteTy n ty) = isOverloadedTy ty -isOverloadedTy (UsageTy _ ty) = isOverloadedTy ty isOverloadedTy _ = False \end{code} @@ -648,19 +720,28 @@ is_tc uniq ty = case tcSplitTyConApp_maybe ty of \begin{code} hoistForAllTys :: Type -> Type - -- Move all the foralls to the top - -- e.g. T -> forall a. a ==> forall a. T -> a - -- Careful: LOSES USAGE ANNOTATIONS! +-- Used for user-written type signatures only +-- Move all the foralls and constraints to the top +-- e.g. T -> forall a. a ==> forall a. T -> a +-- T -> (?x::Int) -> Int ==> (?x::Int) -> T -> Int +-- +-- We want to 'look through' type synonyms when doing this +-- so it's better done on the Type than the HsType + hoistForAllTys ty - = case hoist ty of { (tvs, body) -> mkForAllTys tvs body } + = case hoist ty ty of + (tvs, theta, body) -> mkForAllTys tvs (mkFunTys theta body) where - hoist :: Type -> ([TyVar], Type) - hoist ty = case tcSplitFunTys ty of { (args, res) -> - case tcSplitForAllTys res of { - ([], body) -> ([], ty) ; - (tvs1, body1) -> case hoist body1 of { (tvs2,body2) -> - (tvs1 ++ tvs2, mkFunTys args body2) - }}} + hoist orig_ty (ForAllTy tv ty) = case hoist ty ty of + (tvs,theta,tau) -> (tv:tvs,theta,tau) + hoist orig_ty (FunTy arg res) + | isPredTy arg = case hoist res res of + (tvs,theta,tau) -> (tvs,arg:theta,tau) + | otherwise = case hoist res res of + (tvs,theta,tau) -> (tvs,theta,mkFunTy arg tau) + + hoist orig_ty (NoteTy _ ty) = hoist orig_ty ty + hoist orig_ty ty = ([], [], orig_ty) \end{code} @@ -674,12 +755,11 @@ 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) deNoteSourceType :: SourceType -> SourceType -deNoteSourceType (ClassP c tys) = ClassP c (map deNoteType tys) -deNoteSourceType (IParam n ty) = IParam n (deNoteType ty) -deNoteSourceType (NType tc tys) = NType tc (map deNoteType tys) +deNoteSourceType (ClassP c tys) = ClassP c (map deNoteType tys) +deNoteSourceType (IParam n ty) = IParam n (deNoteType ty) +deNoteSourceType (NType tc tys) = NType tc (map deNoteType tys) \end{code} Find the free names of a type, including the type constructors and classes it mentions @@ -697,7 +777,6 @@ namesOfType (SourceTy (NType tc tys)) = unitNameSet (getName tc) `unionNameSets` 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 @@ -834,38 +913,6 @@ boxedMarshalableTyCon tc %* * %************************************************************************ -(allDistinctTyVars tys tvs) = True - iff -all the types tys are type variables, -distinct from each other and from tvs. - -This is useful when checking that unification hasn't unified signature -type variables. For example, if the type sig is - f :: forall a b. a -> b -> b -we want to check that 'a' and 'b' havn't - (a) been unified with a non-tyvar type - (b) been unified with each other (all distinct) - (c) been unified with a variable free in the environment - -\begin{code} -allDistinctTyVars :: [Type] -> TyVarSet -> Bool - -allDistinctTyVars [] acc - = True -allDistinctTyVars (ty:tys) acc - = case tcGetTyVar_maybe ty of - Nothing -> False -- (a) - Just tv | tv `elemVarSet` acc -> False -- (b) or (c) - | otherwise -> allDistinctTyVars tys (acc `extendVarSet` tv) -\end{code} - - -%************************************************************************ -%* * -\subsection{Unification with an explicit substitution} -%* * -%************************************************************************ - Unify types with an explicit substitution and no monad. Ignore usage annotations. @@ -952,10 +999,6 @@ uTysX (ForAllTy _ _) ty2 k subst = panic "Unify.uTysX subst:ForAllTy (1st arg)" uTysX ty1 (ForAllTy _ _) k subst = panic "Unify.uTysX subst:ForAllTy (2nd arg)" #endif - -- Ignore usages -uTysX (UsageTy _ t1) t2 k subst = uTysX t1 t2 k subst -uTysX t1 (UsageTy _ t2) k subst = uTysX t1 t2 k subst - -- Anything else fails uTysX ty1 ty2 k subst = Nothing @@ -976,7 +1019,6 @@ uVarX tv1 ty2 k subst@(tmpls, env) | typeKind ty2 `eqKind` tyVarKind tv1 && occur_check_ok ty2 -> -- No kind mismatch nor occur check - UASSERT( not (isUTy ty2) ) k (tmpls, extendSubstEnv env tv1 (DoneTy ty2)) | otherwise -> Nothing -- Fail if kind mis-match or occur check @@ -1044,8 +1086,15 @@ match (TyVarTy v) ty tmpls k senv | v `elemVarSet` tmpls = -- v is a template variable case lookupSubstEnv senv v of - Nothing -> UASSERT( not (isUTy ty) ) - k (extendSubstEnv senv v (DoneTy ty)) + Nothing | typeKind ty `eqKind` tyVarKind v + -- We do a kind check, just as in the uVarX above + -- The kind check is needed to avoid bogus matches + -- of (a b) with (c d), where the kinds don't match + -- An occur check isn't needed when matching. + -> k (extendSubstEnv senv v (DoneTy ty)) + + | otherwise -> Nothing -- Fails + Just (DoneTy ty') | ty' `tcEqType` ty -> k senv -- Succeeds | otherwise -> Nothing -- Fails @@ -1086,9 +1135,6 @@ match (TyConApp tc1 tys1) (TyConApp tc2 tys2) tmpls k senv match (SourceTy (NType tc1 tys1)) (SourceTy (NType tc2 tys2)) tmpls k senv | tc1 == tc2 = match_list_exactly tys1 tys2 tmpls k senv -match (UsageTy _ ty1) ty2 tmpls k senv = match ty1 ty2 tmpls k senv -match ty1 (UsageTy _ ty2) tmpls k senv = match ty1 ty2 tmpls k senv - -- 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