X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=23eab62fd70c9135ab1e53826e23b35bc2527507;hb=a8176b20a96ec219f0eb4269f908efbd5f5d9902;hp=8d6c8698a919c6c4bd3e7dca5ef01bb62e06f68a;hpb=05446f0f1e826cd95c8bbcc355015a02ec8595ca;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index 8d6c869..23eab62 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -9,74 +9,71 @@ module Inst ( plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE, Inst, - pprInst, pprInsts, pprInstsInFull, tidyInst, tidyInsts, + pprInst, pprInsts, pprInstsInFull, tidyInsts, tidyMoreInsts, - newDictFromOld, newDicts, newClassDicts, newDictsAtLoc, - newMethod, newMethodWithGivenTy, newOverloadedLit, - newIPDict, instOverloadedFun, - instantiateFdClassTys, instFunDeps, instFunDepsOfTheta, - newFunDepFromDict, + newDictsFromOld, newDicts, cloneDict, + newMethod, newMethodWithGivenTy, newMethodAtLoc, + newOverloadedLit, newIPDict, tcInstId, - tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, instLoc, getDictClassTys, - getDictPred_maybe, getMethodTheta_maybe, - getFunDeps, getFunDepsOfLIE, - getIPs, getIPsOfLIE, - getAllFunDeps, getAllFunDepsOfLIE, + tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, + ipNamesOfInst, ipNamesOfInsts, predsOfInst, predsOfInsts, + instLoc, getDictClassTys, dictPred, lookupInst, lookupSimpleInst, LookupInstResult(..), - isDict, isClassDict, isMethod, - isTyVarDict, isStdClassTyVarDict, isMethodFor, notFunDep, + isDict, isClassDict, isMethod, isLinearInst, linearInstType, + isTyVarDict, isStdClassTyVarDict, isMethodFor, instBindingRequired, instCanBeGeneralised, - zonkInst, zonkInsts, zonkFunDeps, zonkTvFunDeps, - instToId, instToIdBndr, ipToId, + zonkInst, zonkInsts, + instToId, instName, InstOrigin(..), InstLoc, pprInstLoc ) where #include "HsVersions.h" +import CmdLineOpts ( opt_NoMethodSharing ) import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) ) -import RnHsSyn ( RenamedHsOverLit ) import TcHsSyn ( TcExpr, TcId, mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId ) import TcMonad -import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupGlobalId ) -import InstEnv ( InstLookupResult(..), lookupInstEnv ) -import TcType ( TcThetaType, - TcType, TcTauType, TcTyVarSet, - zonkTcTyVars, zonkTcType, zonkTcTypes, - zonkTcThetaType +import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupId ) +import InstEnv ( InstLookupResult(..), lookupInstEnv ) +import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, + zonkTcThetaType, tcInstTyVar, tcInstType, ) -import Bag -import Class ( Class, FunDep ) -import FunDeps ( instantiateFdClassTys ) -import Id ( Id, idFreeTyVars, idType, mkUserLocal, mkSysLocal ) +import TcType ( Type, TcType, TcThetaType, TcPredType, TcTauType, TcTyVarSet, + 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 CoreFVs ( idFreeTyVars ) +import Class ( Class ) +import Id ( Id, idName, idType, mkUserLocal, mkSysLocal, mkLocalId, setIdUnique ) import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) -import Name ( mkDictOcc, mkMethodOcc, mkIPOcc, getOccName, nameUnique ) +import Name ( Name, mkMethodOcc, getOccName ) import PprType ( pprPred ) -import Type ( Type, PredType(..), - isTyVarTy, mkDictTy, mkPredTy, - splitForAllTys, splitSigmaTy, funArgTy, - splitRhoTy, tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, - tidyOpenType, tidyOpenTypes - ) -import Subst ( emptyInScopeSet, mkSubst, mkInScopeSet, - substTy, substClasses, mkTyVarSubst, mkTopTyVarSubst +import Subst ( emptyInScopeSet, mkSubst, + substTy, substTyWith, substTheta, mkTyVarSubst, mkTopTyVarSubst ) import Literal ( inIntRange ) import VarEnv ( TidyEnv, lookupSubstEnv, SubstResult(..) ) import VarSet ( elemVarSet, emptyVarSet, unionVarSet ) -import TysWiredIn ( isIntTy, - floatDataCon, isFloatTy, - doubleDataCon, isDoubleTy, - isIntegerTy, voidTy - ) -import PrelNames( Unique, hasKey, fromIntName, fromIntegerClassOpKey ) -import Maybe ( catMaybes ) -import Util ( thenCmp, zipWithEqual, mapAccumL ) +import TysWiredIn ( floatDataCon, doubleDataCon ) +import PrelNames( fromIntegerName, fromRationalName ) +import Util ( thenCmp, equalLength ) +import BasicTypes( IPName(..), mapIPName, ipNameName ) + +import Bag import Outputable \end{code} @@ -103,7 +100,7 @@ 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 @@ -129,12 +126,12 @@ type Int, represented by \begin{code} data Inst = Dict - Unique + Id TcPredType InstLoc | Method - Unique + Id TcId -- The overloaded function -- This function will be a global, local, or ClassOpId; @@ -158,15 +155,9 @@ data Inst -- type of (f tys dicts(from theta)) = tau | LitInst - Unique - RenamedHsOverLit -- The literal from the occurrence site - TcType -- The type at which the literal is used - InstLoc - - | FunDep - Unique - Class -- the class from which this arises - [FunDep TcType] + Id + HsOverLit -- The literal from the occurrence site + TcType -- The type at which the literal is used InstLoc \end{code} @@ -185,20 +176,16 @@ instance Eq Inst where EQ -> True other -> False -cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = (pred1 `compare` pred2) +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 _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2) cmpInst (Method _ _ _ _ _ _) other = LT -cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `compare` ty2) -cmpInst (LitInst _ _ _ _) (FunDep _ _ _ _) = LT +cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2) cmpInst (LitInst _ _ _ _) other = GT -cmpInst (FunDep _ clas1 fds1 _) (FunDep _ clas2 fds2 _) = (clas1 `compare` clas2) `thenCmp` (fds1 `compare` fds2) -cmpInst (FunDep _ _ _ _) other = GT - -- and they can only have HsInt or HsFracs in them. \end{code} @@ -206,56 +193,54 @@ cmpInst (FunDep _ _ _ _) other = GT Selection ~~~~~~~~~ \begin{code} -instLoc (Dict u pred loc) = loc -instLoc (Method u _ _ _ _ loc) = loc -instLoc (LitInst u lit ty loc) = loc -instLoc (FunDep _ _ _ loc) = loc - -getDictPred_maybe (Dict _ p _) = Just p -getDictPred_maybe _ = Nothing +instName :: Inst -> Name +instName inst = idName (instToId inst) -getMethodTheta_maybe (Method _ _ _ theta _ _) = Just theta -getMethodTheta_maybe _ = Nothing +instToId :: Inst -> TcId +instToId (Dict id _ _) = id +instToId (Method id _ _ _ _ _) = id +instToId (LitInst id _ _ _) = id -getDictClassTys (Dict u (Class clas tys) _) = (clas, tys) +instLoc (Dict _ _ loc) = loc +instLoc (Method _ _ _ _ _ loc) = loc +instLoc (LitInst _ _ _ loc) = loc -getFunDeps (FunDep _ clas fds _) = Just (clas, fds) -getFunDeps _ = Nothing +dictPred (Dict _ pred _ ) = pred +dictPred inst = pprPanic "dictPred" (ppr inst) -getFunDepsOfLIE lie = catMaybes (map getFunDeps (lieToList lie)) +getDictClassTys (Dict _ pred _) = getClassPredTys pred -getIPsOfPred (IParam n ty) = [(n, ty)] -getIPsOfPred _ = [] -getIPsOfTheta theta = concatMap getIPsOfPred theta +predsOfInsts :: [Inst] -> [PredType] +predsOfInsts insts = concatMap predsOfInst insts -getIPs (Dict u (IParam n ty) loc) = [(n, ty)] -getIPs (Method u id _ theta t loc) = getIPsOfTheta theta -getIPs _ = [] +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. -getIPsOfLIE lie = concatMap getIPs (lieToList lie) +ipNamesOfInsts :: [Inst] -> [Name] +ipNamesOfInst :: Inst -> [Name] +-- Get the implicit parameters mentioned by these Insts +-- NB: ?x and %x get different Names -getAllFunDeps (FunDep _ clas fds _) = fds -getAllFunDeps inst = map (\(n,ty) -> ([], [ty])) (getIPs inst) +ipNamesOfInsts insts = [n | inst <- insts, n <- ipNamesOfInst inst] -getAllFunDepsOfLIE lie = concat (map getAllFunDeps (lieToList lie)) +ipNamesOfInst (Dict _ (IParam n _) _) = [ipNameName n] +ipNamesOfInst (Method _ _ _ theta _ _) = [ipNameName n | IParam n _ <- theta] +ipNamesOfInst other = [] 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 -tyVarsOfInst (FunDep _ _ fds _) - = foldr unionVarSet emptyVarSet (map tyVarsOfFd fds) - where tyVarsOfFd (ts1, ts2) = - tyVarsOfTypes ts1 `unionVarSet` tyVarsOfTypes ts2 - -tyVarsOfInsts insts - = foldr unionVarSet emptyVarSet (map tyVarsOfInst insts) -tyVarsOfLIE lie - = foldr unionVarSet emptyVarSet (map tyVarsOfInst insts) - where insts = lieToList lie +tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts +tyVarsOfLIE lie = tyVarsOfInsts (lieToList lie) \end{code} Predicates @@ -266,8 +251,12 @@ isDict (Dict _ _ _) = True isDict other = False isClassDict :: Inst -> Bool -isClassDict (Dict _ (Class _ _) _) = True -isClassDict other = False +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 @@ -277,18 +266,25 @@ isMethodFor :: TcIdSet -> Inst -> Bool isMethodFor ids (Method uniq id tys _ _ loc) = id `elemVarSet` ids isMethodFor ids inst = False -isTyVarDict :: Inst -> Bool -isTyVarDict (Dict _ (Class _ tys) _) = all isTyVarTy tys -isTyVarDict other = False +isLinearInst :: Inst -> Bool +isLinearInst (Dict _ pred _) = isLinearPred pred +isLinearInst other = False + -- We never build Method Insts that have + -- linear implicit paramters in them. + -- Hence no need to look for Methods + -- See Inst.tcInstId -isStdClassTyVarDict (Dict _ (Class clas [ty]) _) - = isStandardClass clas && isTyVarTy ty -isStdClassTyVarDict other - = False +isLinearPred :: TcPredType -> Bool +isLinearPred (IParam (Linear n) _) = True +isLinearPred other = False -notFunDep :: Inst -> Bool -notFunDep (FunDep _ _ _ _) = False -notFunDep other = True +linearInstType :: Inst -> TcType -- %x::t --> t +linearInstType (Dict _ (IParam _ ty) _) = ty + + +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 @@ -298,109 +294,164 @@ must be witnessed by an actual binding; the second tells whether an \begin{code} instBindingRequired :: Inst -> Bool -instBindingRequired (Dict _ (Class clas _) _) = not (isNoDictClass clas) -instBindingRequired (Dict _ (IParam _ _) _) = False -instBindingRequired other = True +instBindingRequired (Dict _ (ClassP clas _) _) = not (isNoDictClass clas) +instBindingRequired other = True instCanBeGeneralised :: Inst -> Bool -instCanBeGeneralised (Dict _ (Class 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 (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 -newClassDicts :: InstOrigin - -> [(Class,[TcType])] - -> NF_TcM (LIE, [TcId]) -newClassDicts orig theta - = newDicts orig (map (uncurry Class) theta) +cloneDict :: Inst -> NF_TcM Inst +cloneDict (Dict id ty loc) = tcGetUnique `thenNF_Tc` \ uniq -> + returnNF_Tc (Dict (setIdUnique id uniq) ty loc) + +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 ([Inst], [TcId]) -newDictsAtLoc loc theta = - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u pred = Dict u pred 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 vanilla implicit parameters, there is only one in scope +-- at any time, so we used to use the name of the implicit parameter itself +-- But with splittable implicit parameters there may be many in +-- scope, so we make up a new name. +newIPDict :: InstOrigin -> IPName Name -> Type + -> NF_TcM (IPName Id, Inst) +newIPDict orig ip_name ty + = tcGetInstLoc orig `thenNF_Tc` \ inst_loc@(_,loc,_) -> + tcGetUnique `thenNF_Tc` \ uniq -> + let + pred = IParam ip_name ty + id = mkLocalId (mkPredName uniq loc pred) (mkPredTy pred) + in + returnNF_Tc (mapIPName (\n -> id) ip_name, Dict id pred inst_loc) +\end{code} -newDictFromOld :: Inst -> Class -> [TcType] -> NF_TcM Inst -newDictFromOld (Dict _ _ loc) clas tys - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (Dict uniq (Class 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 + = loop (HsVar fun) emptyLIE (idType fun) + where + orig = OccurrenceOf fun + loop fun lie fun_ty = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) -> + loop_help fun lie (mkTyVarTys tyvars) theta tau + + loop_help fun lie arg_tys [] tau -- Not overloaded + = returnNF_Tc (mkHsTyApp fun arg_tys, lie, tau) + + loop_help (HsVar fun_id) lie arg_tys theta tau + | can_share theta -- Sharable method binding + = newMethodWithGivenTy orig fun_id arg_tys theta tau `thenNF_Tc` \ meth -> + loop (HsVar (instToId meth)) + (unitLIE meth `plusLIE` lie) tau + + loop_help fun lie arg_tys theta tau -- The general case + = newDicts orig theta `thenNF_Tc` \ dicts -> + loop (mkHsDictApp (mkHsTyApp fun arg_tys) (map instToId dicts)) + (mkLIE dicts `plusLIE` lie) tau + + can_share theta | opt_NoMethodSharing = False + | otherwise = not (any isLinearPred theta) + -- This is a slight hack. + -- If f :: (%x :: T) => Int -> Int + -- Then if we have two separate calls, (f 3, f 4), we cannot + -- make a method constraint that then gets shared, thus: + -- let m = f %x in (m 3, m 4) + -- because that loses the linearity of the constraint. + -- The simplest thing to do is never to construct a method constraint + -- in the first place that has a linear implicit parameter in it. newMethod :: InstOrigin -> TcId -> [TcType] - -> NF_TcM (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 v arg_tys theta tau --- This is where we introduce new functional dependencies into the LIE - = newMethodWithGivenTy orig v arg_tys theta tau `thenNF_Tc` \ inst -> - instFunDeps orig theta `thenNF_Tc` \ fds -> - returnNF_Tc (instToId inst, mkLIE (inst : fds)) - -instFunDeps orig theta - = tcGetUnique `thenNF_Tc` \ uniq -> - tcGetInstLoc orig `thenNF_Tc` \ loc -> - let ifd (Class clas tys) = - let fds = instantiateFdClassTys clas tys in - if null fds then Nothing else Just (FunDep uniq clas fds loc) - ifd _ = Nothing - in returnNF_Tc (catMaybes (map ifd theta)) - -instFunDepsOfTheta theta - = let ifd (Class clas tys) = instantiateFdClassTys clas tys - ifd (IParam n ty) = [([], [ty])] - in concat (map ifd theta) + newMethodWithGivenTy orig id tys [pred] tau newMethodWithGivenTy orig id tys theta tau = tcGetInstLoc orig `thenNF_Tc` \ loc -> - newMethodWith id tys theta tau loc + newMethodWith loc id tys theta tau -newMethodWith id tys theta tau loc +newMethodWith inst_loc@(_,loc,_) id tys theta tau = tcGetUnique `thenNF_Tc` \ new_uniq -> - returnNF_Tc (Method new_uniq id tys theta tau loc) + let + meth_id = mkUserLocal (mkMethodOcc (getOccName id)) new_uniq tau loc + in + returnNF_Tc (Method meth_id id tys theta tau inst_loc) newMethodAtLoc :: InstLoc -> Id -> [TcType] -> NF_TcM (Inst, TcId) -newMethodAtLoc loc real_id tys -- Local function, similar to newMethod but with - -- slightly different interface +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} @@ -411,94 +462,57 @@ cases (the rest are caught in lookupInst). \begin{code} newOverloadedLit :: InstOrigin - -> RenamedHsOverLit + -> HsOverLit -> TcType -> NF_TcM (TcExpr, LIE) -newOverloadedLit orig (HsIntegral i _) ty - | isIntTy ty && inIntRange i -- Short cut for Int - = returnNF_Tc (int_lit, emptyLIE) +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 - int_lit = HsLit (HsInt i) - integer_lit = HsLit (HsInteger i) - -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} -newFunDepFromDict dict - | isClassDict dict - = tcGetUnique `thenNF_Tc` \ uniq -> - let (clas, tys) = getDictClassTys dict - fds = instantiateFdClassTys clas tys - inst = FunDep uniq clas fds (instLoc dict) - in - if null fds then returnNF_Tc Nothing else returnNF_Tc (Just inst) - | otherwise - = returnNF_Tc Nothing -\end{code} -\begin{code} -newIPDict name ty loc - = tcGetUnique `thenNF_Tc` \ new_uniq -> - let d = Dict new_uniq (IParam name ty) loc in - returnNF_Tc d +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} -\begin{code} -instToId :: Inst -> TcId -instToId inst = instToIdBndr inst - -instToIdBndr :: Inst -> TcId -instToIdBndr (Dict u (Class clas tys) (_,loc,_)) - = mkUserLocal (mkDictOcc (getOccName clas)) u (mkDictTy clas tys) loc -instToIdBndr (Dict u (IParam n ty) (_,loc,_)) - = ipToId n 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 - -instToIdBndr (FunDep u clas fds _) - = mkSysLocal SLIT("FunDep") u voidTy - -ipToId n ty loc - = mkUserLocal (mkIPOcc (getOccName n)) (nameUnique n) (mkPredTy (IParam n ty)) loc -\end{code} +%************************************************************************ +%* * +\subsection{Zonking} +%* * +%************************************************************************ -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} -zonkPred :: TcPredType -> NF_TcM TcPredType -zonkPred (Class clas tys) - = zonkTcTypes tys `thenNF_Tc` \ new_tys -> - returnNF_Tc (Class clas new_tys) -zonkPred (IParam n ty) - = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (IParam n new_ty) - zonkInst :: Inst -> NF_TcM Inst -zonkInst (Dict u pred loc) - = zonkPred pred `thenNF_Tc` \ new_pred -> - returnNF_Tc (Dict u new_pred loc) +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 @@ -507,36 +521,22 @@ 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) - -zonkInst (FunDep u clas fds loc) - = zonkFunDeps fds `thenNF_Tc` \ fds' -> - returnNF_Tc (FunDep u clas fds' loc) + returnNF_Tc (LitInst id lit new_ty loc) zonkInsts insts = mapNF_Tc zonkInst insts - -zonkFunDeps fds = mapNF_Tc zonkFd fds - where - zonkFd (ts1, ts2) - = zonkTcTypes ts1 `thenNF_Tc` \ ts1' -> - zonkTcTypes ts2 `thenNF_Tc` \ ts2' -> - returnNF_Tc (ts1', ts2') - -zonkTvFunDeps fds = mapNF_Tc zonkFd fds - where - zonkFd (tvs1, tvs2) - = zonkTcTyVars tvs1 `thenNF_Tc` \ tvs1' -> - zonkTcTyVars tvs2 `thenNF_Tc` \ tvs2' -> - returnNF_Tc (tvs1', tvs2') \end{code} -Printing -~~~~~~~~ +%************************************************************************ +%* * +\subsection{Printing} +%* * +%************************************************************************ + ToDo: improve these pretty-printing things. The ``origin'' is really only relevant in error messages. @@ -552,53 +552,34 @@ pprInst (Dict u pred loc) = pprPred pred <+> show_uniq u pprInst m@(Method u id tys theta tau loc) = hsep [ppr id, ptext SLIT("at"), brackets (interppSP tys) {- , - ppr theta, ppr tau, + ptext SLIT("theta"), ppr theta, + ptext SLIT("tau"), ppr tau show_uniq u, ppr (instToId m) -}] -pprInst (FunDep _ clas fds loc) - = hsep [ppr clas, ppr fds] - -tidyPred :: TidyEnv -> TcPredType -> (TidyEnv, TcPredType) -tidyPred env (Class clas tys) - = (env', Class clas tys') - where - (env', tys') = tidyOpenTypes env tys -tidyPred env (IParam n ty) - = (env', IParam n ty') - where - (env', ty') = tidyOpenType env ty - -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 pred loc) - = (env', Dict u pred' loc) - where - (env', pred') = tidyPred env pred +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 + env' = tidyFreeTyVars env (tyVarsOfInsts insts) --- this case shouldn't arise... (we never print fundeps) -tidyInst env fd@(FunDep _ clas fds loc) - = (env, fd) - -tidyInsts env insts = mapAccumL tidyInst env 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} %* * %************************************************************************ @@ -613,95 +594,77 @@ lookupInst :: Inst -- Dictionaries -lookupInst dict@(Dict _ (Class clas tys) loc) - = tcGetInstEnv `thenNF_Tc` \ inst_env -> - case lookupInstEnv inst_env clas tys of +lookupInst dict@(Dict _ (ClassP clas tys) loc) + = getDOptsTc `thenNF_Tc` \ dflags -> + tcGetInstEnv `thenNF_Tc` \ inst_env -> + case lookupInstEnv dflags inst_env clas tys of FoundInst tenv dfun_id -> let - subst = mkSubst (mkInScopeSet (tyVarsOfTypes tys)) tenv - (tyvars, rho) = splitForAllTys (idType dfun_id) - ty_args = map subst_tv tyvars - dfun_rho = substTy subst rho - (theta, _) = splitRhoTy 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 + (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 + -- It's possible that not all the tyvars are in + -- the substitution, tenv. For example: + -- instance C X a => D X where ... + -- (presumably there's a functional dependency in class C) + -- Hence the mk_ty_arg to instantiate any un-substituted tyvars. + mapNF_Tc mk_ty_arg tyvars `thenNF_Tc` \ ty_args -> + let + dfun_rho = substTy (mkTyVarSubst tyvars ty_args) 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 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) 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 +-- 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 (HsIntegral i from_integer_name) 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) - - | in_int_range -- It's overloaded but small enough to fit into an Int - && from_integer_name `hasKey` fromIntegerClassOpKey -- And it's the built-in prelude fromInteger - -- (i.e. no funny business with user-defined - -- packages of numeric classes) - = -- So we can use the Prelude fromInt - tcLookupGlobalId fromIntName `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)) - - | otherwise -- Alas, it is overloaded and a big literal! - = tcLookupGlobalId from_integer_name `thenNF_Tc` \ from_integer -> + = 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 - integer_lit = HsLit (HsInteger i) - int_lit = HsLit (HsInt i) + returnNF_Tc (GenInst [method_inst] + (HsApp (HsVar method_id) (HsLit (HsInteger i)))) --- 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 (HsFractional f from_rat_name) ty loc) - | isFloatTy ty = returnNF_Tc (GenInst [] float_lit) - | isDoubleTy ty = returnNF_Tc (GenInst [] double_lit) - - | otherwise - = tcLookupGlobalId from_rat_name `thenNF_Tc` \ from_rational -> + = tcLookupId from_rat_name `thenNF_Tc` \ from_rational -> newMethodAtLoc loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> let - rational_ty = funArgTy (idType method_id) + rational_ty = tcFunArgTy (idType method_id) rational_lit = HsLit (HsRat f rational_ty) in returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit)) - - where - floatprim_lit = HsLit (HsFloatPrim f) - float_lit = mkHsConApp floatDataCon [] [floatprim_lit] - doubleprim_lit = HsLit (HsDoublePrim f) - double_lit = mkHsConApp doubleDataCon [] [doubleprim_lit] - --- there are no `instances' of functional dependencies or implicit params - -lookupInst _ = returnNF_Tc NoInstance - \end{code} There is a second, simpler interface, when you want an instance of a @@ -711,19 +674,18 @@ ambiguous dictionaries. \begin{code} lookupSimpleInst :: Class - -> [Type] -- Look up (c,t) - -> NF_TcM (Maybe [(Class,[Type])]) -- Here are the needed (c,t)s + -> [Type] -- Look up (c,t) + -> NF_TcM (Maybe ThetaType) -- Here are the needed (c,t)s lookupSimpleInst clas tys - = tcGetInstEnv `thenNF_Tc` \ inst_env -> - case lookupInstEnv inst_env clas tys of + = getDOptsTc `thenNF_Tc` \ dflags -> + tcGetInstEnv `thenNF_Tc` \ inst_env -> + case lookupInstEnv dflags inst_env clas tys of FoundInst tenv dfun - -> returnNF_Tc (Just (substClasses (mkSubst emptyInScopeSet tenv) theta')) + -> returnNF_Tc (Just (substTheta (mkSubst emptyInScopeSet tenv) theta)) where - (_, theta, _) = splitSigmaTy (idType dfun) - theta' = map (\(Class clas tys) -> (clas,tys)) theta + (_, rho) = tcSplitForAllTys (idType dfun) + (theta,_) = tcSplitRhoTy rho other -> returnNF_Tc Nothing \end{code} - -