X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=3d03c32fa495deb7938942f06fef77e887429385;hb=d5f94cc150c18a060e96795010b30bbcdf7bbc17;hp=a076b026fea586f229ea7fc049d1002d5cb67803;hpb=6e5c95e9102581703b8cb2734b87d7958bce4183;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index a076b02..3d03c32 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -4,79 +4,75 @@ \section[Inst]{The @Inst@ type: dictionaries or method instances} \begin{code} -module Inst ( +module Inst ( LIE, emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, - plusLIEs, mkLIE, isEmptyLIE, + plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE, - Inst, OverloadedLit(..), - pprInst, pprInsts, pprInstsInFull, tidyInst, tidyInsts, + Inst, + pprInst, pprInsts, pprInstsInFull, tidyInsts, tidyMoreInsts, - InstanceMapper, + newDictsFromOld, newDicts, + newMethod, newMethodWithGivenTy, newOverloadedLit, + newIPDict, tcInstId, - newDictFromOld, newDicts, newDictsAtLoc, - newMethod, newMethodWithGivenTy, newOverloadedLit, instOverloadedFun, - - tyVarsOfInst, instLoc, getDictClassTys, + tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, + ipNamesOfInst, ipNamesOfInsts, predsOfInst, predsOfInsts, + instLoc, getDictClassTys, lookupInst, lookupSimpleInst, LookupInstResult(..), - isDict, isTyVarDict, isStdClassTyVarDict, isMethodFor, + isDict, isClassDict, isMethod, + isTyVarDict, isStdClassTyVarDict, isMethodFor, instBindingRequired, instCanBeGeneralised, - zonkInst, instToId, instToIdBndr, + zonkInst, zonkInsts, + instToId, instName, InstOrigin(..), InstLoc, pprInstLoc ) where #include "HsVersions.h" -import HsSyn ( HsLit(..), HsExpr(..) ) -import RnHsSyn ( RenamedArithSeqInfo, RenamedHsExpr, RenamedPat ) +import CmdLineOpts ( opt_NoMethodSharing ) +import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) ) import TcHsSyn ( TcExpr, TcId, - mkHsTyApp, mkHsDictApp, zonkId + mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId ) import TcMonad -import TcEnv ( TcIdSet, tcLookupValueByKey, tcLookupTyConByKey ) -import TcType ( TcThetaType, - TcType, TcTauType, TcTyVarSet, - zonkTcType, zonkTcTypes, - zonkTcThetaType - ) -import Bag -import Class ( classInstEnv, Class ) -import Id ( Id, idFreeTyVars, idType, mkUserLocal, mkSysLocal ) -import VarSet ( elemVarSet ) -import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) -import Name ( OccName, Name, mkDictOcc, mkMethodOcc, getOccName ) -import PprType ( pprConstraint ) -import InstEnv ( InstEnv, lookupInstEnv ) -import SrcLoc ( SrcLoc ) -import Type ( Type, ThetaType, - mkTyVarTy, isTyVarTy, mkDictTy, splitForAllTys, splitSigmaTy, - splitRhoTy, tyVarsOfType, tyVarsOfTypes, - mkSynTy, tidyOpenType, tidyOpenTypes - ) -import InstEnv ( InstEnv ) -import Subst ( emptyInScopeSet, mkSubst, - substTy, substTheta, mkTyVarSubst, mkTopTyVarSubst +import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupId ) +import InstEnv ( InstLookupResult(..), lookupInstEnv ) +import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, + zonkTcThetaType, tcInstTyVar, tcInstType, ) -import TyCon ( TyCon ) -import Subst ( mkTyVarSubst ) -import VarEnv ( lookupVarEnv, TidyEnv, - lookupSubstEnv, SubstResult(..) +import TcType ( Type, + SourceType(..), PredType, ThetaType, + tcSplitForAllTys, tcSplitForAllTys, + tcSplitMethodTy, tcSplitRhoTy, tcFunArgTy, + isIntTy,isFloatTy, isIntegerTy, isDoubleTy, + tcIsTyVarTy, mkPredTy, mkTyVarTy, mkTyVarTys, + tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tidyPred, + isClassPred, isTyVarClassPred, + getClassPredTys, getClassPredTys_maybe, mkPredName, + tidyType, tidyTypes, tidyFreeTyVars, + tcCmpType, tcCmpTypes, tcCmpPred ) -import VarSet ( unionVarSet ) -import TysPrim ( intPrimTy, floatPrimTy, doublePrimTy ) -import TysWiredIn ( intDataCon, isIntTy, inIntRange, - floatDataCon, isFloatTy, - doubleDataCon, isDoubleTy, - integerTy, isIntegerTy - ) -import Unique ( fromRationalClassOpKey, rationalTyConKey, - fromIntClassOpKey, fromIntegerClassOpKey, Unique +import CoreFVs ( idFreeTyVars ) +import Class ( Class ) +import Id ( Id, idName, idType, mkUserLocal, mkSysLocal, mkLocalId ) +import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) +import Name ( Name, mkMethodOcc, getOccName ) +import NameSet ( NameSet ) +import PprType ( pprPred ) +import Subst ( emptyInScopeSet, mkSubst, + substTy, substTyWith, substTheta, mkTyVarSubst, mkTopTyVarSubst ) -import Maybes ( expectJust ) -import Util ( thenCmp, zipWithEqual, mapAccumL ) +import Literal ( inIntRange ) +import VarEnv ( TidyEnv, lookupSubstEnv, SubstResult(..) ) +import VarSet ( elemVarSet, emptyVarSet, unionVarSet ) +import TysWiredIn ( floatDataCon, doubleDataCon ) +import PrelNames( fromIntegerName, fromRationalName ) +import Util ( thenCmp, equalLength ) +import Bag import Outputable \end{code} @@ -96,12 +92,14 @@ mkLIE insts = listToBag insts plusLIE lie1 lie2 = lie1 `unionBags` lie2 consLIE inst lie = inst `consBag` lie plusLIEs lies = unionManyBags lies +lieToList = bagToList +listToLIE = listToBag -zonkLIE :: LIE -> NF_TcM s LIE +zonkLIE :: LIE -> NF_TcM LIE zonkLIE lie = mapBagNF_Tc zonkInst lie pprInsts :: [Inst] -> SDoc -pprInsts insts = parens (sep (punctuate comma (map pprInst insts))) +pprInsts insts = parens (sep (punctuate comma (map pprInst insts))) pprInstsInFull insts @@ -127,13 +125,12 @@ type Int, represented by \begin{code} data Inst = Dict - Unique - Class -- The type of the dict is (c ts), where - [TcType] -- c is the class and ts the types; + Id + TcPredType InstLoc | Method - Unique + Id TcId -- The overloaded function -- This function will be a global, local, or ClassOpId; @@ -157,14 +154,10 @@ data Inst -- type of (f tys dicts(from theta)) = tau | LitInst - Unique - OverloadedLit + Id + HsOverLit -- The literal from the occurrence site TcType -- The type at which the literal is used InstLoc - -data OverloadedLit - = OverloadedIntegral Integer -- The number - | OverloadedFractional Rational -- The number \end{code} Ordering @@ -182,67 +175,95 @@ instance Eq Inst where EQ -> True other -> False -cmpInst (Dict _ clas1 tys1 _) (Dict _ clas2 tys2 _) - = (clas1 `compare` clas2) `thenCmp` (tys1 `compare` tys2) -cmpInst (Dict _ _ _ _) other - = LT - +cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2 +cmpInst (Dict _ _ _) other = LT -cmpInst (Method _ _ _ _ _ _) (Dict _ _ _ _) - = GT -cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) - = (id1 `compare` id2) `thenCmp` (tys1 `compare` tys2) -cmpInst (Method _ _ _ _ _ _) other - = LT +cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT +cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2) +cmpInst (Method _ _ _ _ _ _) other = LT -cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) - = (lit1 `cmpOverLit` lit2) `thenCmp` (ty1 `compare` ty2) -cmpInst (LitInst _ _ _ _) other - = GT +cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2) +cmpInst (LitInst _ _ _ _) other = GT -cmpOverLit (OverloadedIntegral i1) (OverloadedIntegral i2) = i1 `compare` i2 -cmpOverLit (OverloadedFractional f1) (OverloadedFractional f2) = f1 `compare` f2 -cmpOverLit (OverloadedIntegral _) (OverloadedFractional _) = LT -cmpOverLit (OverloadedFractional _) (OverloadedIntegral _) = GT +-- and they can only have HsInt or HsFracs in them. \end{code} Selection ~~~~~~~~~ \begin{code} -instLoc (Dict u clas tys loc) = loc -instLoc (Method u _ _ _ _ loc) = loc -instLoc (LitInst u lit ty loc) = loc +instName :: Inst -> Name +instName inst = idName (instToId inst) + +instToId :: Inst -> TcId +instToId (Dict id _ _) = id +instToId (Method id _ _ _ _ _) = id +instToId (LitInst id _ _ _) = id -getDictClassTys (Dict u clas tys _) = (clas, tys) +instLoc (Dict _ _ loc) = loc +instLoc (Method _ _ _ _ _ loc) = loc +instLoc (LitInst _ _ _ loc) = loc + +getDictClassTys (Dict _ pred _) = getClassPredTys pred + +predsOfInsts :: [Inst] -> [PredType] +predsOfInsts insts = concatMap predsOfInst insts + +predsOfInst (Dict _ pred _) = [pred] +predsOfInst (Method _ _ _ theta _ _) = theta +predsOfInst (LitInst _ _ _ _) = [] + -- The last case is is really a big cheat + -- LitInsts to give rise to a (Num a) or (Fractional a) predicate + -- But Num and Fractional have only one parameter and no functional + -- dependencies, so I think no caller of predsOfInst will care. + +ipNamesOfInsts :: [Inst] -> [Name] +ipNamesOfInst :: Inst -> [Name] +-- Get the implicit parameters mentioned by these Insts + +ipNamesOfInsts insts = [n | inst <- insts, n <- ipNamesOfInst inst] + +ipNamesOfInst (Dict _ (IParam n _) _) = [n] +ipNamesOfInst (Method _ _ _ theta _ _) = [n | IParam n _ <- theta] +ipNamesOfInst other = [] tyVarsOfInst :: Inst -> TcTyVarSet -tyVarsOfInst (Dict _ _ tys _) = tyVarsOfTypes tys +tyVarsOfInst (LitInst _ _ ty _) = tyVarsOfType ty +tyVarsOfInst (Dict _ pred _) = tyVarsOfPred pred tyVarsOfInst (Method _ id tys _ _ _) = tyVarsOfTypes tys `unionVarSet` idFreeTyVars id -- The id might have free type variables; in the case of -- locally-overloaded class methods, for example -tyVarsOfInst (LitInst _ _ ty _) = tyVarsOfType ty + +tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts +tyVarsOfLIE lie = tyVarsOfInsts (lieToList lie) \end{code} Predicates ~~~~~~~~~~ \begin{code} isDict :: Inst -> Bool -isDict (Dict _ _ _ _) = True -isDict other = False +isDict (Dict _ _ _) = True +isDict other = False -isMethodFor :: TcIdSet -> Inst -> Bool -isMethodFor ids (Method uniq id tys _ _ loc) - = id `elemVarSet` ids -isMethodFor ids inst - = False +isClassDict :: Inst -> Bool +isClassDict (Dict _ pred _) = isClassPred pred +isClassDict other = False isTyVarDict :: Inst -> Bool -isTyVarDict (Dict _ _ tys _) = all isTyVarTy tys -isTyVarDict other = False +isTyVarDict (Dict _ pred _) = isTyVarClassPred pred +isTyVarDict other = False + +isMethod :: Inst -> Bool +isMethod (Method _ _ _ _ _ _) = True +isMethod other = False -isStdClassTyVarDict (Dict _ clas [ty] _) = isStandardClass clas && isTyVarTy ty -isStdClassTyVarDict other = False +isMethodFor :: TcIdSet -> Inst -> Bool +isMethodFor ids (Method uniq id tys _ _ loc) = id `elemVarSet` ids +isMethodFor ids inst = False + +isStdClassTyVarDict (Dict _ pred _) = case getClassPredTys_maybe pred of + Just (clas, [ty]) -> isStandardClass clas && tcIsTyVarTy ty + other -> False \end{code} Two predicates which deal with the case where class constraints don't @@ -252,86 +273,152 @@ must be witnessed by an actual binding; the second tells whether an \begin{code} instBindingRequired :: Inst -> Bool -instBindingRequired (Dict _ clas _ _) = not (isNoDictClass clas) -instBindingRequired other = True +instBindingRequired (Dict _ (ClassP clas _) _) = not (isNoDictClass clas) +instBindingRequired (Dict _ (IParam _ _) _) = False +instBindingRequired other = True instCanBeGeneralised :: Inst -> Bool -instCanBeGeneralised (Dict _ clas _ _) = not (isCcallishClass clas) -instCanBeGeneralised other = True +instCanBeGeneralised (Dict _ (ClassP clas _) _) = not (isCcallishClass clas) +instCanBeGeneralised other = True \end{code} -Construction -~~~~~~~~~~~~ +%************************************************************************ +%* * +\subsection{Building dictionaries} +%* * +%************************************************************************ \begin{code} newDicts :: InstOrigin -> TcThetaType - -> NF_TcM s (LIE, [TcId]) + -> NF_TcM [Inst] newDicts orig theta = tcGetInstLoc orig `thenNF_Tc` \ loc -> - newDictsAtLoc loc theta `thenNF_Tc` \ (dicts, ids) -> - returnNF_Tc (listToBag dicts, ids) + newDictsAtLoc loc theta + +newDictsFromOld :: Inst -> TcThetaType -> NF_TcM [Inst] +newDictsFromOld (Dict _ _ loc) theta = newDictsAtLoc loc theta -- Local function, similar to newDicts, -- but with slightly different interface newDictsAtLoc :: InstLoc -> TcThetaType - -> NF_TcM s ([Inst], [TcId]) -newDictsAtLoc loc theta = - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, tys) = Dict u clas tys loc - dicts = zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta - in - returnNF_Tc (dicts, map instToId dicts) + -> NF_TcM [Inst] +newDictsAtLoc inst_loc@(_,loc,_) theta + = tcGetUniques `thenNF_Tc` \ new_uniqs -> + returnNF_Tc (zipWith mk_dict new_uniqs theta) + where + mk_dict uniq pred = Dict (mkLocalId (mkPredName uniq loc pred) (mkPredTy pred)) pred inst_loc + +-- For implicit parameters, since there is only one in scope +-- at any time, we use the name of the implicit parameter itself +newIPDict orig name ty + = tcGetInstLoc orig `thenNF_Tc` \ inst_loc -> + returnNF_Tc (Dict (mkLocalId name (mkPredTy pred)) pred inst_loc) + where pred = IParam name ty +\end{code} -newDictFromOld :: Inst -> Class -> [TcType] -> NF_TcM s Inst -newDictFromOld (Dict _ _ _ loc) clas tys - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (Dict uniq clas tys loc) + +%************************************************************************ +%* * +\subsection{Building methods (calls of overloaded functions)} +%* * +%************************************************************************ + +tcInstId instantiates an occurrence of an Id. +The instantiate_it loop runs round instantiating the Id. +It has to be a loop because we are now prepared to entertain +types like + f:: forall a. Eq a => forall b. Baz b => tau +We want to instantiate this to + f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)} + +The -fno-method-sharing flag controls what happens so far as the LIE +is concerned. The default case is that for an overloaded function we +generate a "method" Id, and add the Method Inst to the LIE. So you get +something like + f :: Num a => a -> a + f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x +If you specify -fno-method-sharing, the dictionary application +isn't shared, so we get + f :: Num a => a -> a + f = /\a (d:Num a) (x:a) -> (+) a d x x +This gets a bit less sharing, but + a) it's better for RULEs involving overloaded functions + b) perhaps fewer separated lambdas + + +\begin{code} +tcInstId :: Id -> NF_TcM (TcExpr, LIE, TcType) +tcInstId fun + | opt_NoMethodSharing = loop_noshare (HsVar fun) (idType fun) + | otherwise = loop_share fun + where + orig = OccurrenceOf fun + loop_noshare fun fun_ty + = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) -> + let + ty_app = mkHsTyApp fun (mkTyVarTys tyvars) + in + if null theta then -- Is it overloaded? + returnNF_Tc (ty_app, emptyLIE, tau) + else + newDicts orig theta `thenNF_Tc` \ dicts -> + loop_noshare (mkHsDictApp ty_app (map instToId dicts)) tau `thenNF_Tc` \ (expr, lie, final_tau) -> + returnNF_Tc (expr, mkLIE dicts `plusLIE` lie, final_tau) + + loop_share fun + = tcInstType (idType fun) `thenNF_Tc` \ (tyvars, theta, tau) -> + let + arg_tys = mkTyVarTys tyvars + in + if null theta then -- Is it overloaded? + returnNF_Tc (mkHsTyApp (HsVar fun) arg_tys, emptyLIE, tau) + else + -- Yes, it's overloaded + newMethodWithGivenTy orig fun arg_tys theta tau `thenNF_Tc` \ meth -> + loop_share (instToId meth) `thenNF_Tc` \ (expr, lie, final_tau) -> + returnNF_Tc (expr, unitLIE meth `plusLIE` lie, final_tau) newMethod :: InstOrigin -> TcId -> [TcType] - -> NF_TcM s (LIE, TcId) + -> NF_TcM Inst newMethod orig id tys = -- Get the Id type and instantiate it at the specified types let - (tyvars, rho) = splitForAllTys (idType id) - rho_ty = substTy (mkTyVarSubst tyvars tys) rho - (theta, tau) = splitRhoTy rho_ty + (tyvars, rho) = tcSplitForAllTys (idType id) + rho_ty = substTyWith tyvars tys rho + (pred, tau) = tcSplitMethodTy rho_ty in - newMethodWithGivenTy orig id tys theta tau `thenNF_Tc` \ meth_inst -> - returnNF_Tc (unitLIE meth_inst, instToId meth_inst) - -instOverloadedFun orig (HsVar v) arg_tys theta tau - = newMethodWithGivenTy orig v arg_tys theta tau `thenNF_Tc` \ inst -> - returnNF_Tc (HsVar (instToId inst), unitLIE inst) + newMethodWithGivenTy orig id tys [pred] tau newMethodWithGivenTy orig id tys theta tau = tcGetInstLoc orig `thenNF_Tc` \ loc -> - tcGetUnique `thenNF_Tc` \ new_uniq -> + newMethodWith loc id tys theta tau + +newMethodWith inst_loc@(_,loc,_) id tys theta tau + = tcGetUnique `thenNF_Tc` \ new_uniq -> let - meth_inst = Method new_uniq id tys theta tau loc + meth_id = mkUserLocal (mkMethodOcc (getOccName id)) new_uniq tau loc in - returnNF_Tc meth_inst + returnNF_Tc (Method meth_id id tys theta tau inst_loc) newMethodAtLoc :: InstLoc -> Id -> [TcType] - -> NF_TcM s (Inst, TcId) -newMethodAtLoc loc real_id tys -- Local function, similar to newMethod but with - -- slightly different interface + -> NF_TcM (Inst, TcId) +newMethodAtLoc inst_loc real_id tys + -- This actually builds the Inst = -- Get the Id type and instantiate it at the specified types - tcGetUnique `thenNF_Tc` \ new_uniq -> let - (tyvars,rho) = splitForAllTys (idType real_id) - rho_ty = ASSERT( length tyvars == length tys ) + (tyvars,rho) = tcSplitForAllTys (idType real_id) + rho_ty = ASSERT( equalLength tyvars tys ) substTy (mkTopTyVarSubst tyvars tys) rho - (theta, tau) = splitRhoTy rho_ty - meth_inst = Method new_uniq real_id tys theta tau loc + (theta, tau) = tcSplitRhoTy rho_ty in + newMethodWith inst_loc real_id tys theta tau `thenNF_Tc` \ meth_inst -> returnNF_Tc (meth_inst, instToId meth_inst) \end{code} @@ -342,60 +429,57 @@ cases (the rest are caught in lookupInst). \begin{code} newOverloadedLit :: InstOrigin - -> OverloadedLit + -> HsOverLit -> TcType - -> NF_TcM s (TcExpr, LIE) -newOverloadedLit orig (OverloadedIntegral i) ty - | isIntTy ty && inIntRange i -- Short cut for Int - = returnNF_Tc (int_lit, emptyLIE) + -> NF_TcM (TcExpr, LIE) +newOverloadedLit orig lit ty + | Just expr <- shortCutLit lit ty + = returnNF_Tc (expr, emptyLIE) - | isIntegerTy ty -- Short cut for Integer - = returnNF_Tc (integer_lit, emptyLIE) - - where - intprim_lit = HsLitOut (HsIntPrim i) intPrimTy - integer_lit = HsLitOut (HsInt i) integerTy - int_lit = HsCon intDataCon [] [intprim_lit] - -newOverloadedLit orig lit ty -- The general case + | otherwise = tcGetInstLoc orig `thenNF_Tc` \ loc -> tcGetUnique `thenNF_Tc` \ new_uniq -> let - lit_inst = LitInst new_uniq lit ty loc + lit_inst = LitInst lit_id lit ty loc + lit_id = mkSysLocal SLIT("lit") new_uniq ty in returnNF_Tc (HsVar (instToId lit_inst), unitLIE lit_inst) -\end{code} - -\begin{code} -instToId :: Inst -> TcId -instToId inst = instToIdBndr inst - -instToIdBndr :: Inst -> TcId -instToIdBndr (Dict u clas ty (_,loc,_)) - = mkUserLocal (mkDictOcc (getOccName clas)) u (mkDictTy clas ty) loc - -instToIdBndr (Method u id tys theta tau (_,loc,_)) - = mkUserLocal (mkMethodOcc (getOccName id)) u tau loc - -instToIdBndr (LitInst u list ty loc) - = mkSysLocal SLIT("lit") u ty +shortCutLit :: HsOverLit -> TcType -> Maybe TcExpr +shortCutLit (HsIntegral i fi) ty + | isIntTy ty && inIntRange i && fi == fromIntegerName -- Short cut for Int + = Just (HsLit (HsInt i)) + | isIntegerTy ty && fi == fromIntegerName -- Short cut for Integer + = Just (HsLit (HsInteger i)) + +shortCutLit (HsFractional f fr) ty + | isFloatTy ty && fr == fromRationalName + = Just (mkHsConApp floatDataCon [] [HsLit (HsFloatPrim f)]) + | isDoubleTy ty && fr == fromRationalName + = Just (mkHsConApp doubleDataCon [] [HsLit (HsDoublePrim f)]) + +shortCutLit lit ty + = Nothing \end{code} -Zonking -~~~~~~~ +%************************************************************************ +%* * +\subsection{Zonking} +%* * +%************************************************************************ + Zonking makes sure that the instance types are fully zonked, -but doesn't do the same for the Id in a Method. There's no +but doesn't do the same for any of the Ids in an Inst. There's no need, and it's a lot of extra work. \begin{code} -zonkInst :: Inst -> NF_TcM s Inst -zonkInst (Dict u clas tys loc) - = zonkTcTypes tys `thenNF_Tc` \ new_tys -> - returnNF_Tc (Dict u clas new_tys loc) +zonkInst :: Inst -> NF_TcM Inst +zonkInst (Dict id pred loc) + = zonkTcPredType pred `thenNF_Tc` \ new_pred -> + returnNF_Tc (Dict id new_pred loc) -zonkInst (Method u id tys theta tau loc) +zonkInst (Method m id tys theta tau loc) = zonkId id `thenNF_Tc` \ new_id -> -- Essential to zonk the id in case it's a local variable -- Can't use zonkIdOcc because the id might itself be @@ -404,16 +488,22 @@ zonkInst (Method u id tys theta tau loc) zonkTcTypes tys `thenNF_Tc` \ new_tys -> zonkTcThetaType theta `thenNF_Tc` \ new_theta -> zonkTcType tau `thenNF_Tc` \ new_tau -> - returnNF_Tc (Method u new_id new_tys new_theta new_tau loc) + returnNF_Tc (Method m new_id new_tys new_theta new_tau loc) -zonkInst (LitInst u lit ty loc) +zonkInst (LitInst id lit ty loc) = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (LitInst u lit new_ty loc) + returnNF_Tc (LitInst id lit new_ty loc) + +zonkInsts insts = mapNF_Tc zonkInst insts \end{code} -Printing -~~~~~~~~ +%************************************************************************ +%* * +\subsection{Printing} +%* * +%************************************************************************ + ToDo: improve these pretty-printing things. The ``origin'' is really only relevant in error messages. @@ -422,162 +512,121 @@ instance Outputable Inst where ppr inst = pprInst inst pprInst (LitInst u lit ty loc) - = hsep [case lit of - OverloadedIntegral i -> integer i - OverloadedFractional f -> rational f, - ptext SLIT("at"), - ppr ty, - show_uniq u] + = hsep [ppr lit, ptext SLIT("at"), ppr ty, show_uniq u] -pprInst (Dict u clas tys loc) = pprConstraint clas tys <+> show_uniq u +pprInst (Dict u pred loc) = pprPred pred <+> show_uniq u -pprInst (Method u id tys _ _ loc) +pprInst m@(Method u id tys theta tau loc) = hsep [ppr id, ptext SLIT("at"), - brackets (interppSP tys), - show_uniq u] + brackets (interppSP tys) {- , + ptext SLIT("theta"), ppr theta, + ptext SLIT("tau"), ppr tau + show_uniq u, + ppr (instToId m) -}] -tidyInst :: TidyEnv -> Inst -> (TidyEnv, Inst) -tidyInst env (LitInst u lit ty loc) - = (env', LitInst u lit ty' loc) - where - (env', ty') = tidyOpenType env ty +show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") -tidyInst env (Dict u clas tys loc) - = (env', Dict u clas tys' loc) - where - (env', tys') = tidyOpenTypes env tys +tidyInst :: TidyEnv -> Inst -> Inst +tidyInst env (LitInst u lit ty loc) = LitInst u lit (tidyType env ty) loc +tidyInst env (Dict u pred loc) = Dict u (tidyPred env pred) loc +tidyInst env (Method u id tys theta tau loc) = Method u id (tidyTypes env tys) theta tau loc -tidyInst env (Method u id tys theta tau loc) - = (env', Method u id tys' theta tau loc) - -- Leave theta, tau alone cos we don't print them +tidyMoreInsts :: TidyEnv -> [Inst] -> (TidyEnv, [Inst]) +-- This function doesn't assume that the tyvars are in scope +-- so it works like tidyOpenType, returning a TidyEnv +tidyMoreInsts env insts + = (env', map (tidyInst env') insts) where - (env', tys') = tidyOpenTypes env tys - -tidyInsts env insts = mapAccumL tidyInst env insts + env' = tidyFreeTyVars env (tyVarsOfInsts insts) -show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") +tidyInsts :: [Inst] -> (TidyEnv, [Inst]) +tidyInsts insts = tidyMoreInsts emptyTidyEnv insts \end{code} %************************************************************************ %* * -\subsection[InstEnv-types]{Type declarations} +\subsection{Looking up Insts} %* * %************************************************************************ \begin{code} -type InstanceMapper = Class -> InstEnv -\end{code} - -A @ClassInstEnv@ lives inside a class, and identifies all the instances -of that class. The @Id@ inside a ClassInstEnv mapping is the dfun for -that instance. - -There is an important consistency constraint between the @MatchEnv@s -in and the dfun @Id@s inside them: the free type variables of the -@Type@ key in the @MatchEnv@ must be a subset of the universally-quantified -type variables of the dfun. Thus, the @ClassInstEnv@ for @Eq@ might -contain the following entry: -@ - [a] ===> dfun_Eq_List :: forall a. Eq a => Eq [a] -@ -The "a" in the pattern must be one of the forall'd variables in -the dfun type. - -\begin{code} data LookupInstResult s = NoInstance | SimpleInst TcExpr -- Just a variable, type application, or literal | GenInst [Inst] TcExpr -- The expression and its needed insts lookupInst :: Inst - -> NF_TcM s (LookupInstResult s) + -> NF_TcM (LookupInstResult s) -- Dictionaries -lookupInst dict@(Dict _ clas tys loc) - = case lookupInstEnv (ppr clas) (classInstEnv clas) tys of +lookupInst dict@(Dict _ (ClassP clas tys) loc) + = tcGetInstEnv `thenNF_Tc` \ inst_env -> + case lookupInstEnv inst_env clas tys of - Just (tenv, dfun_id) + FoundInst tenv dfun_id -> let - subst = mkSubst (tyVarsOfTypes tys) tenv - (tyvars, rho) = splitForAllTys (idType dfun_id) - ty_args = map subst_tv tyvars + (tyvars, rho) = tcSplitForAllTys (idType dfun_id) + mk_ty_arg tv = case lookupSubstEnv tenv tv of + Just (DoneTy ty) -> returnNF_Tc ty + Nothing -> tcInstTyVar tv `thenNF_Tc` \ tc_tv -> + returnTc (mkTyVarTy tc_tv) + in + mapNF_Tc mk_ty_arg tyvars `thenNF_Tc` \ ty_args -> + let + subst = mkTyVarSubst tyvars ty_args dfun_rho = substTy subst rho - (theta, tau) = splitRhoTy dfun_rho + (theta, _) = tcSplitRhoTy dfun_rho ty_app = mkHsTyApp (HsVar dfun_id) ty_args - subst_tv tv = case lookupSubstEnv tenv tv of - Just (DoneTy ty) -> ty - -- tenv should bind all the tyvars in if null theta then returnNF_Tc (SimpleInst ty_app) else - newDictsAtLoc loc theta `thenNF_Tc` \ (dicts, dict_ids) -> + newDictsAtLoc loc theta `thenNF_Tc` \ dicts -> let - rhs = mkHsDictApp ty_app dict_ids + rhs = mkHsDictApp ty_app (map instToId dicts) in returnNF_Tc (GenInst dicts rhs) - - Nothing -> returnNF_Tc NoInstance + + other -> returnNF_Tc NoInstance + +lookupInst dict@(Dict _ _ loc) = returnNF_Tc NoInstance -- Methods lookupInst inst@(Method _ id tys theta _ loc) - = newDictsAtLoc loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids)) + = newDictsAtLoc loc theta `thenNF_Tc` \ dicts -> + returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) (map instToId dicts))) -- Literals -lookupInst inst@(LitInst u (OverloadedIntegral i) ty loc) - | isIntTy ty && in_int_range -- Short cut for Int - = returnNF_Tc (GenInst [] int_lit) - -- GenInst, not SimpleInst, because int_lit is actually a constructor application - - | isIntegerTy ty -- Short cut for Integer - = returnNF_Tc (GenInst [] integer_lit) +-- Look for short cuts first: if the literal is *definitely* a +-- int, integer, float or a double, generate the real thing here. +-- This is essential (see nofib/spectral/nucleic). +-- [Same shortcut as in newOverloadedLit, but we +-- may have done some unification by now] - | in_int_range -- It's overloaded but small enough to fit into an Int - = tcLookupValueByKey fromIntClassOpKey `thenNF_Tc` \ from_int -> - newMethodAtLoc loc from_int [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) int_lit)) +lookupInst inst@(LitInst u lit ty loc) + | Just expr <- shortCutLit lit ty + = returnNF_Tc (GenInst [] expr) -- GenInst, not SimpleInst, because + -- expr may be a constructor application - | otherwise -- Alas, it is overloaded and a big literal! - = tcLookupValueByKey fromIntegerClassOpKey `thenNF_Tc` \ from_integer -> +lookupInst inst@(LitInst u (HsIntegral i from_integer_name) ty loc) + = tcLookupId from_integer_name `thenNF_Tc` \ from_integer -> newMethodAtLoc loc from_integer [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) integer_lit)) - where - in_int_range = inIntRange i - intprim_lit = HsLitOut (HsIntPrim i) intPrimTy - integer_lit = HsLitOut (HsInt i) integerTy - int_lit = HsCon intDataCon [] [intprim_lit] - --- similar idea for overloaded floating point literals: if the literal is --- *definitely* a float or a double, generate the real thing here. --- This is essential (see nofib/spectral/nucleic). - -lookupInst inst@(LitInst u (OverloadedFractional f) ty loc) - | isFloatTy ty = returnNF_Tc (GenInst [] float_lit) - | isDoubleTy ty = returnNF_Tc (GenInst [] double_lit) + returnNF_Tc (GenInst [method_inst] + (HsApp (HsVar method_id) (HsLit (HsInteger i)))) - | otherwise - = tcLookupValueByKey fromRationalClassOpKey `thenNF_Tc` \ from_rational -> - -- The type Rational isn't wired in so we have to conjure it up - tcLookupTyConByKey rationalTyConKey `thenNF_Tc` \ rational_tycon -> +lookupInst inst@(LitInst u (HsFractional f from_rat_name) ty loc) + = tcLookupId from_rat_name `thenNF_Tc` \ from_rational -> + newMethodAtLoc loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> let - rational_ty = mkSynTy rational_tycon [] - rational_lit = HsLitOut (HsFrac f) rational_ty + rational_ty = tcFunArgTy (idType method_id) + rational_lit = HsLit (HsRat f rational_ty) in - newMethodAtLoc loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit)) - - where - floatprim_lit = HsLitOut (HsFloatPrim f) floatPrimTy - float_lit = HsCon floatDataCon [] [floatprim_lit] - doubleprim_lit = HsLitOut (HsDoublePrim f) doublePrimTy - double_lit = HsCon doubleDataCon [] [doubleprim_lit] - \end{code} There is a second, simpler interface, when you want an instance of a @@ -586,17 +635,18 @@ appropriate dictionary if it exists. It is used only when resolving ambiguous dictionaries. \begin{code} -lookupSimpleInst :: InstEnv - -> Class +lookupSimpleInst :: Class -> [Type] -- Look up (c,t) - -> NF_TcM s (Maybe ThetaType) -- Here are the needed (c,t)s + -> NF_TcM (Maybe ThetaType) -- Here are the needed (c,t)s -lookupSimpleInst class_inst_env clas tys - = case lookupInstEnv (ppr clas) class_inst_env tys of - Nothing -> returnNF_Tc Nothing - - Just (tenv, dfun) +lookupSimpleInst clas tys + = tcGetInstEnv `thenNF_Tc` \ inst_env -> + case lookupInstEnv inst_env clas tys of + FoundInst tenv dfun -> returnNF_Tc (Just (substTheta (mkSubst emptyInScopeSet tenv) theta)) where - (_, theta, _) = splitSigmaTy (idType dfun) + (_, rho) = tcSplitForAllTys (idType dfun) + (theta,_) = tcSplitRhoTy rho + + other -> returnNF_Tc Nothing \end{code}