X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=c16ba2c541636b49a2406bd52ba09376f0b88a20;hb=de4125776d89df95684ba7d58b072df8d8f19af5;hp=cdabdd99bcd79d2b3e2bfa95c882dbbc012006a7;hpb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index cdabdd9..c16ba2c 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -4,76 +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, - - newDictFromOld, newDicts, newDictsAtLoc, + newDictsFromOld, newDicts, newMethod, newMethodWithGivenTy, newOverloadedLit, + newIPDict, tcInstId, - tyVarsOfInst, instLoc, getDictClassTys, + tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, instLoc, getDictClassTys, + getIPs, + predsOfInsts, predsOfInst, lookupInst, lookupSimpleInst, LookupInstResult(..), - isDict, isTyVarDict, isStdClassTyVarDict, isMethodFor, + isDict, isClassDict, isMethod, instMentionsIPs, + isTyVarDict, isStdClassTyVarDict, isMethodFor, instBindingRequired, instCanBeGeneralised, - zonkInst, instToId, instToIdBndr, + zonkInst, zonkInsts, + instToId, instName, - InstOrigin(..), pprOrigin + InstOrigin(..), InstLoc, pprInstLoc ) where #include "HsVersions.h" -import HsSyn ( HsLit(..), HsExpr(..) ) -import RnHsSyn ( RenamedArithSeqInfo, RenamedHsExpr, RenamedPat ) -import TcHsSyn ( TcExpr, TcIdOcc(..), TcIdBndr, - mkHsTyApp, mkHsDictApp, tcIdTyVars, zonkTcId +import CmdLineOpts ( opt_NoMethodSharing ) +import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) ) +import TcHsSyn ( TcExpr, TcId, + mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId ) import TcMonad -import TcEnv ( TcIdSet, tcLookupGlobalValueByKey, tcLookupTyConByKey, - tidyType, tidyTypes - ) -import TcType ( TcThetaType, - TcType, TcTauType, TcTyVarSet, - zonkTcType, zonkTcTypes, - zonkTcThetaType +import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupId ) +import InstEnv ( InstLookupResult(..), lookupInstEnv ) +import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, + zonkTcThetaType, tcInstTyVar, tcInstType, ) -import Bag -import Class ( classInstEnv, - Class, ClassInstEnv +import TcType ( Type, + SourceType(..), PredType, ThetaType, + tcSplitForAllTys, tcSplitForAllTys, + tcSplitMethodTy, tcSplitRhoTy, tcFunArgTy, + isIntTy,isFloatTy, isIntegerTy, isDoubleTy, + tcIsTyVarTy, mkPredTy, mkTyVarTy, mkTyVarTys, + tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tidyPred, + predMentionsIPs, isClassPred, isTyVarClassPred, + getClassPredTys, getClassPredTys_maybe, mkPredName, + tidyType, tidyTypes, tidyFreeTyVars, + tcCmpType, tcCmpTypes, tcCmpPred ) -import Id ( Id, idType, mkUserLocal, mkSysLocal ) -import VarSet ( elemVarSet ) +import CoreFVs ( idFreeTyVars ) +import Class ( Class ) +import Id ( Id, idName, idType, mkUserLocal, mkSysLocal, mkLocalId ) import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) -import Name ( OccName(..), Name, occNameString, getOccName ) -import PprType ( pprConstraint ) -import SpecEnv ( SpecEnv, lookupSpecEnv ) -import SrcLoc ( SrcLoc ) -import Type ( Type, ThetaType, substTy, - isTyVarTy, mkDictTy, splitForAllTys, splitSigmaTy, - splitRhoTy, tyVarsOfType, tyVarsOfTypes, - mkSynTy, substFlexiTy, substFlexiTheta - ) -import TyCon ( TyCon ) -import VarEnv ( zipVarEnv, lookupVarEnv ) -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 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 ) +import Bag import Outputable \end{code} @@ -84,7 +83,7 @@ import Outputable %************************************************************************ \begin{code} -type LIE s = Bag (Inst s) +type LIE = Bag Inst isEmptyLIE = isEmptyBag emptyLIE = emptyBag @@ -93,18 +92,20 @@ 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 s -> NF_TcM s (LIE s) +zonkLIE :: LIE -> NF_TcM LIE zonkLIE lie = mapBagNF_Tc zonkInst lie -pprInsts :: [Inst s] -> SDoc -pprInsts insts = parens (hsep (punctuate comma (map pprInst insts))) +pprInsts :: [Inst] -> SDoc +pprInsts insts = parens (sep (punctuate comma (map pprInst insts))) pprInstsInFull insts = vcat (map go insts) where - go inst = quotes (ppr inst) <+> pprOrigin inst + go inst = quotes (ppr inst) <+> pprInstLoc (instLoc inst) \end{code} %************************************************************************ @@ -122,49 +123,41 @@ type Int, represented by Method 34 doubleId [Int] origin \begin{code} -data Inst s +data Inst = Dict - Unique - Class -- The type of the dict is (c ts), where - [TcType s] -- c is the class and ts the types; - (InstOrigin s) - SrcLoc + Id + TcPredType + InstLoc | Method - Unique + Id - (TcIdOcc s) -- The overloaded function + TcId -- The overloaded function -- This function will be a global, local, or ClassOpId; -- inside instance decls (only) it can also be an InstId! -- The id needn't be completely polymorphic. -- You'll probably find its name (for documentation purposes) -- inside the InstOrigin - [TcType s] -- The types to which its polymorphic tyvars + [TcType] -- The types to which its polymorphic tyvars -- should be instantiated. -- These types must saturate the Id's foralls. - (TcThetaType s) -- The (types of the) dictionaries to which the function + TcThetaType -- The (types of the) dictionaries to which the function -- must be applied to get the method - (TcTauType s) -- The type of the method + TcTauType -- The type of the method - (InstOrigin s) - SrcLoc + InstLoc -- INVARIANT: in (Method u f tys theta tau loc) -- type of (f tys dicts(from theta)) = tau | LitInst - Unique - OverloadedLit - (TcType s) -- The type at which the literal is used - (InstOrigin s) -- Always a literal; but more convenient to carry this around - SrcLoc - -data OverloadedLit - = OverloadedIntegral Integer -- The number - | OverloadedFractional Rational -- The number + Id + HsOverLit -- The literal from the occurrence site + TcType -- The type at which the literal is used + InstLoc \end{code} Ordering @@ -174,79 +167,104 @@ unique. This allows the context-reduction mechanism to use standard finite maps to do their stuff. \begin{code} -instance Ord (Inst s) where +instance Ord Inst where compare = cmpInst -instance Eq (Inst s) where +instance Eq Inst where (==) i1 i2 = case i1 `cmpInst` i2 of 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} -instOrigin (Dict u clas tys origin loc) = origin -instOrigin (Method u clas ty _ _ origin loc) = origin -instOrigin (LitInst u lit ty origin loc) = origin +instName :: Inst -> Name +instName inst = idName (instToId inst) + +instToId :: Inst -> TcId +instToId (Dict id _ _) = id +instToId (Method id _ _ _ _ _) = id +instToId (LitInst id _ _ _) = id -instLoc (Dict u clas tys origin loc) = loc -instLoc (Method u clas ty _ _ origin loc) = loc -instLoc (LitInst u lit ty origin loc) = loc +instLoc (Dict _ _ loc) = loc +instLoc (Method _ _ _ _ _ loc) = loc +instLoc (LitInst _ _ _ loc) = loc -getDictClassTys (Dict u clas tys _ _) = (clas, tys) +getDictClassTys (Dict _ pred _) = getClassPredTys pred -tyVarsOfInst :: Inst s -> TcTyVarSet s -tyVarsOfInst (Dict _ _ tys _ _) = tyVarsOfTypes tys -tyVarsOfInst (Method _ id tys _ _ _ _) = tyVarsOfTypes tys `unionVarSet` tcIdTyVars id - -- The id might not be a RealId; in the case of +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. + +ipsOfPreds theta = [(n,ty) | IParam n ty <- theta] + +getIPs inst = ipsOfPreds (predsOfInst inst) + +tyVarsOfInst :: Inst -> TcTyVarSet +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 s -> Bool -isDict (Dict _ _ _ _ _) = True -isDict other = False - -isMethodFor :: TcIdSet s -> Inst s -> Bool -isMethodFor ids (Method uniq (TcId id) tys _ _ orig loc) - = id `elemVarSet` ids -isMethodFor ids inst - = False - -isTyVarDict :: Inst s -> Bool -isTyVarDict (Dict _ _ tys _ _) = all isTyVarTy tys -isTyVarDict other = False - -isStdClassTyVarDict (Dict _ clas [ty] _ _) = isStandardClass clas && isTyVarTy ty -isStdClassTyVarDict other = False +isDict :: Inst -> Bool +isDict (Dict _ _ _) = True +isDict other = False + +isClassDict :: Inst -> Bool +isClassDict (Dict _ pred _) = isClassPred pred +isClassDict other = False + +isTyVarDict :: Inst -> Bool +isTyVarDict (Dict _ pred _) = isTyVarClassPred pred +isTyVarDict other = False + +isMethod :: Inst -> Bool +isMethod (Method _ _ _ _ _ _) = True +isMethod other = False + +isMethodFor :: TcIdSet -> Inst -> Bool +isMethodFor ids (Method uniq id tys _ _ loc) = id `elemVarSet` ids +isMethodFor ids inst = False + +instMentionsIPs :: Inst -> NameSet -> Bool + -- True if the Inst mentions any of the implicit + -- parameters in the supplied set of names +instMentionsIPs (Dict _ pred _) ip_names = pred `predMentionsIPs` ip_names +instMentionsIPs (Method _ _ _ theta _ _) ip_names = any (`predMentionsIPs` ip_names) theta +instMentionsIPs other ip_names = 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 @@ -255,95 +273,153 @@ must be witnessed by an actual binding; the second tells whether an @Inst@ can be generalised over. \begin{code} -instBindingRequired :: Inst s -> Bool -instBindingRequired (Dict _ clas _ _ _) = not (isNoDictClass clas) -instBindingRequired other = True - -instCanBeGeneralised :: Inst s -> Bool -instCanBeGeneralised (Dict _ clas _ _ _) = not (isCcallishClass clas) -instCanBeGeneralised other = True +instBindingRequired :: Inst -> Bool +instBindingRequired (Dict _ (ClassP clas _) _) = not (isNoDictClass clas) +instBindingRequired (Dict _ (IParam _ _) _) = False +instBindingRequired other = True + +instCanBeGeneralised :: Inst -> Bool +instCanBeGeneralised (Dict _ (ClassP clas _) _) = not (isCcallishClass clas) +instCanBeGeneralised other = True \end{code} -Construction -~~~~~~~~~~~~ +%************************************************************************ +%* * +\subsection{Building dictionaries} +%* * +%************************************************************************ \begin{code} -newDicts :: InstOrigin s - -> TcThetaType s - -> NF_TcM s (LIE s, [TcIdOcc s]) +newDicts :: InstOrigin + -> TcThetaType + -> NF_TcM [Inst] newDicts orig theta - = tcGetSrcLoc `thenNF_Tc` \ loc -> - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, ids) -> - returnNF_Tc (listToBag dicts, ids) + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + 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 :: InstOrigin s - -> SrcLoc - -> TcThetaType s - -> NF_TcM s ([Inst s], [TcIdOcc s]) -newDictsAtLoc orig loc theta = - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, tys) = Dict u clas tys orig loc - dicts = zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta - in - returnNF_Tc (dicts, map instToId dicts) - -newDictFromOld :: Inst s -> Class -> [TcType s] -> NF_TcM s (Inst s) -newDictFromOld (Dict _ _ _ orig loc) clas tys - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (Dict uniq clas tys orig loc) - - -newMethod :: InstOrigin s - -> TcIdOcc s - -> [TcType s] - -> NF_TcM s (LIE s, TcIdOcc s) +newDictsAtLoc :: InstLoc + -> TcThetaType + -> 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} + + +%************************************************************************ +%* * +\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 Inst newMethod orig id tys = -- Get the Id type and instantiate it at the specified types - (case id of - RealId id -> let - (tyvars, rho) = splitForAllTys (idType id) - in - ASSERT( length tyvars == length tys) - returnNF_Tc (substFlexiTy (zipVarEnv tyvars tys) rho) - - TcId id -> let - (tyvars, rho) = splitForAllTys (idType id) - in - returnNF_Tc (substTy (zipVarEnv tyvars tys) rho) - ) `thenNF_Tc` \ rho_ty -> let - (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) - + newMethodWithGivenTy orig id tys [pred] tau newMethodWithGivenTy orig id tys theta tau - = tcGetSrcLoc `thenNF_Tc` \ loc -> - tcGetUnique `thenNF_Tc` \ new_uniq -> + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + 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 orig 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 :: InstOrigin s -> SrcLoc - -> Id -> [TcType s] - -> NF_TcM s (Inst s, TcIdOcc s) -newMethodAtLoc orig loc real_id tys -- Local function, similar to newMethod but with - -- slightly different interface +newMethodAtLoc :: InstLoc + -> Id -> [TcType] + -> 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) + (tyvars,rho) = tcSplitForAllTys (idType real_id) rho_ty = ASSERT( length tyvars == length tys ) - substFlexiTy (zipVarEnv tyvars tys) rho - (theta, tau) = splitRhoTy rho_ty - meth_inst = Method new_uniq (RealId real_id) tys theta tau orig loc + substTy (mkTopTyVarSubst tyvars tys) rho + (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} @@ -353,239 +429,205 @@ temporarily generating overloaded literals, but it won't catch all cases (the rest are caught in lookupInst). \begin{code} -newOverloadedLit :: InstOrigin s - -> OverloadedLit - -> TcType s - -> NF_TcM s (TcExpr s, LIE s) -newOverloadedLit orig (OverloadedIntegral i) ty - | isIntTy ty && inIntRange i -- Short cut for Int - = returnNF_Tc (int_lit, 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 - = tcGetSrcLoc `thenNF_Tc` \ loc -> +newOverloadedLit :: InstOrigin + -> HsOverLit + -> TcType + -> NF_TcM (TcExpr, LIE) +newOverloadedLit orig lit ty + | Just expr <- shortCutLit lit ty + = returnNF_Tc (expr, emptyLIE) + + | otherwise + = tcGetInstLoc orig `thenNF_Tc` \ loc -> tcGetUnique `thenNF_Tc` \ new_uniq -> let - lit_inst = LitInst new_uniq lit ty orig 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 s -> TcIdOcc s -instToId inst = TcId (instToIdBndr inst) -instToIdBndr :: Inst s -> TcIdBndr s -instToIdBndr (Dict u clas ty orig loc) - = mkUserLocal occ u (mkDictTy clas ty) - where - occ = VarOcc (SLIT("d.") _APPEND_ (occNameString (getOccName clas))) - -instToIdBndr (Method u id tys theta tau orig loc) - = mkUserLocal (getOccName id) u tau - -instToIdBndr (LitInst u list ty orig loc) - = mkSysLocal 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 s -> NF_TcM s (Inst s) -zonkInst (Dict u clas tys orig loc) - = zonkTcTypes tys `thenNF_Tc` \ new_tys -> - returnNF_Tc (Dict u clas new_tys orig loc) - -zonkInst (Method u id tys theta tau orig loc) - = zonkTcId id `thenNF_Tc` \ new_id -> - -- Essential to zonk the id in case it's a local variable +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 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 + -- an InstId, in which case it won't be in scope + 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 orig loc) + returnNF_Tc (Method m new_id new_tys new_theta new_tau loc) -zonkInst (LitInst u lit ty orig loc) +zonkInst (LitInst id lit ty loc) = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (LitInst u lit new_ty orig 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. \begin{code} -instance Outputable (Inst s) where +instance Outputable Inst where ppr inst = pprInst inst -pprInst (LitInst u lit ty orig loc) - = hsep [case lit of - OverloadedIntegral i -> integer i - OverloadedFractional f -> rational f, - ptext SLIT("at"), - ppr ty, - show_uniq u] +pprInst (LitInst u lit ty loc) + = hsep [ppr lit, ptext SLIT("at"), ppr ty, show_uniq u] -pprInst (Dict u clas tys orig loc) = pprConstraint clas tys <+> show_uniq u +pprInst (Dict u pred loc) = pprPred pred <+> show_uniq u -pprInst (Method u id tys _ _ orig 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 :: TidyTypeEnv s -> Inst s -> (TidyTypeEnv s, Inst s) -tidyInst env (LitInst u lit ty orig loc) - = (env', LitInst u lit ty' orig loc) - where - (env', ty') = tidyType env ty +show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") -tidyInst env (Dict u clas tys orig loc) - = (env', Dict u clas tys' orig loc) - where - (env', tys') = tidyTypes 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 orig loc) - = (env', Method u id tys' theta tau orig 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') = tidyTypes 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 -> ClassInstEnv -\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 s) -- Just a variable, type application, or literal - | GenInst [Inst s] (TcExpr s) -- The expression and its needed insts + | SimpleInst TcExpr -- Just a variable, type application, or literal + | GenInst [Inst] TcExpr -- The expression and its needed insts -lookupInst :: Inst s - -> NF_TcM s (LookupInstResult s) +lookupInst :: Inst + -> NF_TcM (LookupInstResult s) -- Dictionaries -lookupInst dict@(Dict _ clas tys orig loc) - = case lookupSpecEnv (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 - (tyvars, rho) = splitForAllTys (idType dfun_id) - ty_args = map (expectJust "Inst" . lookupVarEnv tenv) tyvars - -- tenv should bind all the tyvars - dfun_rho = substFlexiTy tenv rho - (theta, tau) = splitRhoTy dfun_rho - ty_app = mkHsTyApp (HsVar (RealId dfun_id)) ty_args + (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, _) = tcSplitRhoTy dfun_rho + ty_app = mkHsTyApp (HsVar dfun_id) ty_args in if null theta then returnNF_Tc (SimpleInst ty_app) else - newDictsAtLoc orig 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 --- Methods + other -> returnNF_Tc NoInstance -lookupInst inst@(Method _ id tys theta _ orig loc) - = newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids)) +lookupInst dict@(Dict _ _ loc) = returnNF_Tc NoInstance --- Literals - -lookupInst inst@(LitInst u (OverloadedIntegral i) ty orig 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) +-- Methods - | in_int_range -- It's overloaded but small enough to fit into an Int - = tcLookupGlobalValueByKey fromIntClassOpKey `thenNF_Tc` \ from_int -> - newMethodAtLoc orig loc from_int [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) int_lit)) +lookupInst inst@(Method _ id tys theta _ loc) + = newDictsAtLoc loc theta `thenNF_Tc` \ dicts -> + returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) (map instToId dicts))) - | otherwise -- Alas, it is overloaded and a big literal! - = tcLookupGlobalValueByKey fromIntegerClassOpKey `thenNF_Tc` \ from_integer -> - newMethodAtLoc orig 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] +-- Literals --- similar idea for overloaded floating point literals: if the literal is --- *definitely* a float or a double, generate the real thing here. +-- 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] + +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 -lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc) - | isFloatTy ty = returnNF_Tc (GenInst [] float_lit) - | isDoubleTy ty = returnNF_Tc (GenInst [] double_lit) +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) (HsLit (HsInteger i)))) - | otherwise - = tcLookupGlobalValueByKey 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 orig 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 @@ -594,124 +636,18 @@ appropriate dictionary if it exists. It is used only when resolving ambiguous dictionaries. \begin{code} -lookupSimpleInst :: ClassInstEnv - -> Class +lookupSimpleInst :: Class -> [Type] -- Look up (c,t) - -> NF_TcM s (Maybe ThetaType) -- Here are the needed (c,t)s - -lookupSimpleInst class_inst_env clas tys - = case lookupSpecEnv (ppr clas) class_inst_env tys of - Nothing -> returnNF_Tc Nothing + -> NF_TcM (Maybe ThetaType) -- Here are the needed (c,t)s - Just (tenv, dfun) - -> returnNF_Tc (Just (substFlexiTheta tenv theta)) +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) -\end{code} - - + (_, rho) = tcSplitForAllTys (idType dfun) + (theta,_) = tcSplitRhoTy rho -%************************************************************************ -%* * -\subsection[Inst-origin]{The @InstOrigin@ type} -%* * -%************************************************************************ - -The @InstOrigin@ type gives information about where a dictionary came from. -This is important for decent error message reporting because dictionaries -don't appear in the original source code. Doubtless this type will evolve... - -\begin{code} -data InstOrigin s - = OccurrenceOf (TcIdOcc s) -- Occurrence of an overloaded identifier - | OccurrenceOfCon Id -- Occurrence of a data constructor - - | RecordUpdOrigin - - | DataDeclOrigin -- Typechecking a data declaration - - | InstanceDeclOrigin -- Typechecking an instance decl - - | LiteralOrigin HsLit -- Occurrence of a literal - - | PatOrigin RenamedPat - - | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc - - | SignatureOrigin -- A dict created from a type signature - | Rank2Origin -- A dict created when typechecking the argument - -- of a rank-2 typed function - - | DoOrigin -- The monad for a do expression - - | ClassDeclOrigin -- Manufactured during a class decl - - | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma - Type - - -- When specialising instances the instance info attached to - -- each class is not yet ready, so we record it inside the - -- origin information. This is a bit of a hack, but it works - -- fine. (Patrick is to blame [WDP].) - - | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value - - -- Argument or result of a ccall - -- Dictionaries with this origin aren't actually mentioned in the - -- translated term, and so need not be bound. Nor should they - -- be abstracted over. - - | CCallOrigin String -- CCall label - (Maybe RenamedHsExpr) -- Nothing if it's the result - -- Just arg, for an argument - - | LitLitOrigin String -- the litlit - - | UnknownOrigin -- Help! I give up... -\end{code} - -\begin{code} -pprOrigin :: Inst s -> SDoc -pprOrigin inst - = hsep [text "arising from", pp_orig orig, text "at", ppr locn] - where - (orig, locn) = case inst of - Dict _ _ _ orig loc -> (orig,loc) - Method _ _ _ _ _ orig loc -> (orig,loc) - LitInst _ _ _ orig loc -> (orig,loc) - - pp_orig (OccurrenceOf id) - = hsep [ptext SLIT("use of"), quotes (ppr id)] - pp_orig (OccurrenceOfCon id) - = hsep [ptext SLIT("use of"), quotes (ppr id)] - pp_orig (LiteralOrigin lit) - = hsep [ptext SLIT("the literal"), quotes (ppr lit)] - pp_orig (PatOrigin pat) - = hsep [ptext SLIT("the pattern"), quotes (ppr pat)] - pp_orig (InstanceDeclOrigin) - = ptext SLIT("an instance declaration") - pp_orig (ArithSeqOrigin seq) - = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)] - pp_orig (SignatureOrigin) - = ptext SLIT("a type signature") - pp_orig (Rank2Origin) - = ptext SLIT("a function with an overloaded argument type") - pp_orig (DoOrigin) - = ptext SLIT("a do statement") - pp_orig (ClassDeclOrigin) - = ptext SLIT("a class declaration") - pp_orig (InstanceSpecOrigin clas ty) - = hsep [text "a SPECIALIZE instance pragma; class", - quotes (ppr clas), text "type:", ppr ty] - pp_orig (ValSpecOrigin name) - = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)] - pp_orig (CCallOrigin clabel Nothing{-ccall result-}) - = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)] - pp_orig (CCallOrigin clabel (Just arg_expr)) - = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma, - text "namely", quotes (ppr arg_expr)] - pp_orig (LitLitOrigin s) - = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)] - pp_orig (UnknownOrigin) - = ptext SLIT("...oops -- I don't know where the overloading came from!") + other -> returnNF_Tc Nothing \end{code}