X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=c16ba2c541636b49a2406bd52ba09376f0b88a20;hb=b0604aad2c311d8713c2497afa6373bd938d501b;hp=09272ad88e1f6421a5b1ef5e896b21659e2e5204;hpb=995d6dbff24982c0a57c3befb01d733a7da613f1;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index 09272ad..c16ba2c 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -1,81 +1,79 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[Inst]{The @Inst@ type: dictionaries or method instances} \begin{code} -#include "HsVersions.h" - -module Inst ( - Inst(..), -- Visible only to TcSimplify +module Inst ( + LIE, emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, + plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE, - InstOrigin(..), OverloadedLit(..), - SYN_IE(LIE), emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, plusLIEs, + Inst, + pprInst, pprInsts, pprInstsInFull, tidyInsts, tidyMoreInsts, - SYN_IE(InstanceMapper), + newDictsFromOld, newDicts, + newMethod, newMethodWithGivenTy, newOverloadedLit, + newIPDict, tcInstId, - newDicts, newDictsAtLoc, newMethod, newMethodWithGivenTy, newOverloadedLit, + tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, instLoc, getDictClassTys, + getIPs, + predsOfInsts, predsOfInst, - instType, tyVarsOfInst, lookupInst, lookupSimpleInst, + lookupInst, lookupSimpleInst, LookupInstResult(..), - isDict, isTyVarDict, + isDict, isClassDict, isMethod, instMentionsIPs, + isTyVarDict, isStdClassTyVarDict, isMethodFor, + instBindingRequired, instCanBeGeneralised, - zonkInst, instToId, + zonkInst, zonkInsts, + instToId, instName, - matchesInst, - instBindingRequired, instCanBeGeneralised, - - pprInst + InstOrigin(..), InstLoc, pprInstLoc ) where -IMP_Ubiq() -IMPORT_1_3(Ratio(Rational)) - -import HsSyn ( HsLit(..), HsExpr(..), HsBinds, Fixity, MonoBinds(..), - InPat, OutPat, Stmt, DoOrListComp, Match, GRHSsAndBinds, - ArithSeqInfo, HsType, Fake ) -import RnHsSyn ( SYN_IE(RenamedArithSeqInfo), SYN_IE(RenamedHsExpr) ) -import TcHsSyn ( TcIdOcc(..), SYN_IE(TcExpr), SYN_IE(TcIdBndr), - SYN_IE(TcDictBinds), SYN_IE(TcMonoBinds), - mkHsTyApp, mkHsDictApp, tcIdTyVars ) +#include "HsVersions.h" +import CmdLineOpts ( opt_NoMethodSharing ) +import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) ) +import TcHsSyn ( TcExpr, TcId, + mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId + ) import TcMonad -import TcEnv ( tcLookupGlobalValueByKey, tcLookupTyConByKey ) -import TcType ( SYN_IE(TcType), SYN_IE(TcRhoType), TcMaybe, SYN_IE(TcTyVarSet), - tcInstType, zonkTcType, tcSplitForAllTy, tcSplitRhoTy ) - -import Bag ( emptyBag, unitBag, unionBags, unionManyBags, - listToBag, consBag, Bag ) -import Class ( classInstEnv, - SYN_IE(Class), GenClass, SYN_IE(ClassInstEnv), SYN_IE(ClassOp) +import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupId ) +import InstEnv ( InstLookupResult(..), lookupInstEnv ) +import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, + zonkTcThetaType, tcInstTyVar, tcInstType, ) -import ErrUtils ( addErrLoc, SYN_IE(Error) ) -import Id ( GenId, idType, mkInstId, SYN_IE(Id) ) -import PrelInfo ( isCcallishClass, isNoDictClass ) -import MatchEnv ( lookupMEnv, insertMEnv ) -import Name ( OccName(..), Name, mkLocalName, - mkSysLocalName, occNameString, getOccName ) -import Outputable -import PprType ( GenClass, TyCon, GenType, GenTyVar, pprParendGenType ) -import PprStyle ( PprStyle(..) ) -import Pretty -import SpecEnv ( SpecEnv ) -import SrcLoc ( SrcLoc, noSrcLoc ) -import Type ( GenType, eqSimpleTy, instantiateTy, - isTyVarTy, mkDictTy, splitForAllTy, splitSigmaTy, - splitRhoTy, matchTy, tyVarsOfType, tyVarsOfTypes, - mkSynTy, SYN_IE(Type) +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 TyVar ( unionTyVarSets, GenTyVar ) -import TysPrim ( intPrimTy ) -import TysWiredIn ( intDataCon, integerTy ) -import Unique ( showUnique, 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 Util ( panic, zipEqual, zipWithEqual, assoc, assertPanic, pprTrace{-ToDo:rm-} ) -#if __GLASGOW_HASKELL__ >= 202 -import Maybes -#endif +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} %************************************************************************ @@ -85,16 +83,29 @@ import Maybes %************************************************************************ \begin{code} -type LIE s = Bag (Inst s) +type LIE = Bag Inst +isEmptyLIE = isEmptyBag emptyLIE = emptyBag unitLIE inst = unitBag inst +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] -> SDoc +pprInsts insts = parens (sep (punctuate comma (map pprInst insts))) + + +pprInstsInFull insts + = vcat (map go insts) + where + go inst = quotes (ppr inst) <+> pprInstLoc (instLoc inst) \end{code} %************************************************************************ @@ -112,235 +123,148 @@ 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 t), where - (TcType s) -- c is the class and t the type; - (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. - (TcRhoType s) -- Cached: (type-of-id applied to inst_tys) - -- If this type is (theta => tau) then the type of the Method - -- is tau, and the method can be built by saying - -- id inst_tys dicts - -- where dicts are constructed from theta + TcThetaType -- The (types of the) dictionaries to which the function + -- must be applied to get the method + + TcTauType -- The type of the method + + InstLoc - (InstOrigin s) - SrcLoc + -- 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 - -getInstOrigin (Dict u clas ty origin loc) = origin -getInstOrigin (Method u clas ty rho origin loc) = origin -getInstOrigin (LitInst u lit ty origin loc) = origin + Id + HsOverLit -- The literal from the occurrence site + TcType -- The type at which the literal is used + InstLoc \end{code} -Construction -~~~~~~~~~~~~ +Ordering +~~~~~~~~ +@Insts@ are ordered by their class/type info, rather than by their +unique. This allows the context-reduction mechanism to use standard finite +maps to do their stuff. \begin{code} -newDicts :: InstOrigin s - -> [(Class, TcType s)] - -> NF_TcM s (LIE s, [TcIdOcc s]) -newDicts orig theta - = tcGetSrcLoc `thenNF_Tc` \ loc -> - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, ids) -> - returnNF_Tc (listToBag dicts, ids) -{- - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, ty) = Dict u clas ty orig loc - dicts = zipWithEqual "newDicts" mk_dict new_uniqs theta - in - returnNF_Tc (listToBag dicts, map instToId dicts) --} +instance Ord Inst where + compare = cmpInst --- Local function, similar to newDicts, --- but with slightly different interface -newDictsAtLoc :: InstOrigin s - -> SrcLoc - -> [(Class, TcType s)] - -> NF_TcM s ([Inst s], [TcIdOcc s]) -newDictsAtLoc orig loc theta = - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, ty) = Dict u clas ty orig loc - dicts = zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta - in - returnNF_Tc (dicts, map instToId dicts) - -newMethod :: InstOrigin s - -> TcIdOcc s - -> [TcType s] - -> NF_TcM s (LIE s, TcIdOcc s) -newMethod orig id tys - = -- Get the Id type and instantiate it at the specified types - (case id of - RealId id -> let (tyvars, rho) = splitForAllTy (idType id) - in - (if length tyvars /= length tys then pprTrace "newMethod" (ppr PprDebug (idType id)) else \x->x) $ - tcInstType (zip{-Equal "newMethod"-} tyvars tys) rho - TcId id -> tcSplitForAllTy (idType id) `thenNF_Tc` \ (tyvars, rho) -> - returnNF_Tc (instantiateTy (zipEqual "newMethod(2)" tyvars tys) rho) - ) `thenNF_Tc` \ rho_ty -> - -- Our friend does the rest - newMethodWithGivenTy orig id tys rho_ty - - -newMethodWithGivenTy orig id tys rho_ty - = tcGetSrcLoc `thenNF_Tc` \ loc -> - tcGetUnique `thenNF_Tc` \ new_uniq -> - let - meth_inst = Method new_uniq id tys rho_ty orig loc - in - returnNF_Tc (unitLIE meth_inst, instToId meth_inst) - -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 - = -- Get the Id type and instantiate it at the specified types - let - (tyvars,rho) = splitForAllTy (idType real_id) - in - tcInstType (zipEqual "newMethodAtLoc" tyvars tys) rho `thenNF_Tc` \ rho_ty -> - tcGetUnique `thenNF_Tc` \ new_uniq -> - let - meth_inst = Method new_uniq (RealId real_id) tys rho_ty orig loc - in - returnNF_Tc (meth_inst, instToId meth_inst) - -newOverloadedLit :: InstOrigin s - -> OverloadedLit - -> TcType s - -> NF_TcM s (LIE s, TcIdOcc s) -newOverloadedLit orig lit ty - = tcGetSrcLoc `thenNF_Tc` \ loc -> - tcGetUnique `thenNF_Tc` \ new_uniq -> - let - lit_inst = LitInst new_uniq lit ty orig loc - in - returnNF_Tc (unitLIE lit_inst, instToId lit_inst) -\end{code} +instance Eq Inst where + (==) i1 i2 = case i1 `cmpInst` i2 of + EQ -> True + other -> False +cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2 +cmpInst (Dict _ _ _) other = LT -\begin{code} -instToId :: Inst s -> TcIdOcc s -instToId (Dict u clas ty orig loc) - = TcId (mkInstId u (mkDictTy clas ty) (mkLocalName u str loc)) - where - str = VarOcc (SLIT("d.") _APPEND_ (occNameString (getOccName clas))) +cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT +cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2) +cmpInst (Method _ _ _ _ _ _) other = LT -instToId (Method u id tys rho_ty orig loc) - = TcId (mkInstId u tau_ty (mkLocalName u occ loc)) - where - occ = getOccName id - (_, tau_ty) = splitRhoTy rho_ty - -- I hope we don't need tcSplitRhoTy... - -- NB The method Id has just the tau type - -instToId (LitInst u list ty orig loc) - = TcId (mkInstId u ty (mkSysLocalName u SLIT("lit") loc)) -\end{code} +cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2) +cmpInst (LitInst _ _ _ _) other = GT -\begin{code} -instType :: Inst s -> TcType s -instType (Dict _ clas ty _ _) = mkDictTy clas ty -instType (LitInst _ _ ty _ _) = ty -instType (Method _ id tys ty _ _) = ty +-- and they can only have HsInt or HsFracs in them. \end{code} -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 -need, and it's a lot of extra work. - +Selection +~~~~~~~~~ \begin{code} -zonkInst :: Inst s -> NF_TcM s (Inst s) -zonkInst (Dict u clas ty orig loc) - = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (Dict u clas new_ty orig loc) +instName :: Inst -> Name +instName inst = idName (instToId inst) -zonkInst (Method u id tys rho orig loc) -- Doesn't zonk the id! - = mapNF_Tc zonkTcType tys `thenNF_Tc` \ new_tys -> - zonkTcType rho `thenNF_Tc` \ new_rho -> - returnNF_Tc (Method u id new_tys new_rho orig loc) +instToId :: Inst -> TcId +instToId (Dict id _ _) = id +instToId (Method id _ _ _ _ _) = id +instToId (LitInst id _ _ _) = id -zonkInst (LitInst u lit ty orig loc) - = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (LitInst u lit new_ty orig loc) -\end{code} +instLoc (Dict _ _ loc) = loc +instLoc (Method _ _ _ _ _ loc) = loc +instLoc (LitInst _ _ _ loc) = loc +getDictClassTys (Dict _ pred _) = getClassPredTys pred -\begin{code} -tyVarsOfInst :: Inst s -> TcTyVarSet s -tyVarsOfInst (Dict _ _ ty _ _) = tyVarsOfType ty -tyVarsOfInst (Method _ id tys rho _ _) = tyVarsOfTypes tys `unionTyVarSets` tcIdTyVars id - -- The id might not be a RealId; in the case of - -- locally-overloaded class methods, for example -tyVarsOfInst (LitInst _ _ ty _ _) = tyVarsOfType ty -\end{code} +predsOfInsts :: [Inst] -> [PredType] +predsOfInsts insts = concatMap predsOfInst insts -@matchesInst@ checks when two @Inst@s are instances of the same -thing at the same type, even if their uniques differ. +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. -\begin{code} -matchesInst :: Inst s -> Inst s -> Bool +ipsOfPreds theta = [(n,ty) | IParam n ty <- theta] -matchesInst (Dict _ clas1 ty1 _ _) (Dict _ clas2 ty2 _ _) - = clas1 == clas2 && ty1 `eqSimpleTy` ty2 +getIPs inst = ipsOfPreds (predsOfInst inst) -matchesInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) - = id1 == id2 - && and (zipWith eqSimpleTy tys1 tys2) - && length tys1 == length tys2 - -matchesInst (LitInst _ lit1 ty1 _ _) (LitInst _ lit2 ty2 _ _) - = lit1 `eq` lit2 && ty1 `eqSimpleTy` ty2 - where - (OverloadedIntegral i1) `eq` (OverloadedIntegral i2) = i1 == i2 - (OverloadedFractional f1) `eq` (OverloadedFractional f2) = f1 == f2 - _ `eq` _ = False +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 -matchesInst other1 other2 = False +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 - -isTyVarDict :: Inst s -> Bool -isTyVarDict (Dict _ _ ty _ _) = isTyVarTy ty -isTyVarDict 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 @@ -349,326 +273,381 @@ 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} -Printing -~~~~~~~~ -ToDo: improve these pretty-printing things. The ``origin'' is really only -relevant in error messages. +%************************************************************************ +%* * +\subsection{Building dictionaries} +%* * +%************************************************************************ \begin{code} -instance Outputable (Inst s) where - ppr sty inst = ppr_inst sty empty (\ o l -> empty) inst - -pprInst sty hdr inst = ppr_inst sty hdr (\ o l -> pprOrigin hdr o l sty) inst - -ppr_inst sty hdr ppr_orig (LitInst u lit ty orig loc) - = hang (ppr_orig orig loc) - 4 (hsep [case lit of - OverloadedIntegral i -> integer i - OverloadedFractional f -> rational f, - ptext SLIT("at"), - ppr sty ty, - show_uniq sty u]) - -ppr_inst sty hdr ppr_orig (Dict u clas ty orig loc) - = hang (ppr_orig orig loc) - 4 (hsep [ppr sty clas, pprParendGenType sty ty, show_uniq sty u]) - -ppr_inst sty hdr ppr_orig (Method u id tys rho orig loc) - = hang (ppr_orig orig loc) - 4 (hsep [ppr sty id, ptext SLIT("at"), interppSP sty tys, show_uniq sty u]) - -show_uniq PprDebug u = ppr PprDebug u -show_uniq sty u = empty -\end{code} +newDicts :: InstOrigin + -> TcThetaType + -> NF_TcM [Inst] +newDicts orig theta + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + newDictsAtLoc loc theta -Printing in error messages +newDictsFromOld :: Inst -> TcThetaType -> NF_TcM [Inst] +newDictsFromOld (Dict _ _ loc) theta = newDictsAtLoc loc theta -\begin{code} -noInstanceErr inst sty = hang (ptext SLIT("No instance for:")) 4 (ppr sty inst) +-- Local function, similar to newDicts, +-- but with slightly different interface +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[InstEnv-types]{Type declarations} +\subsection{Building methods (calls of overloaded functions)} %* * %************************************************************************ -\begin{code} -type InstanceMapper = Class -> (ClassInstEnv, ClassOp -> SpecEnv) -\end{code} +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 -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} -lookupInst :: Inst s - -> TcM s ([Inst s], - TcDictBinds s) -- The new binding - --- Dictionaries - -lookupInst dict@(Dict _ clas ty orig loc) - = case lookupMEnv matchTy (get_inst_env clas orig) ty of - Nothing -> tcAddSrcLoc loc $ - tcAddErrCtxt (pprOrigin ""{-hdr-} orig loc) $ - failTc (noInstanceErr dict) - - Just (dfun_id, tenv) - -> let - (tyvars, rho) = splitForAllTy (idType dfun_id) - ty_args = map (assoc "lookupInst" tenv) tyvars - -- tenv should bind all the tyvars - in - tcInstType tenv rho `thenNF_Tc` \ dfun_rho -> - let - (theta, tau) = splitRhoTy dfun_rho - in - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - let - rhs = mkHsDictApp (mkHsTyApp (HsVar (RealId dfun_id)) ty_args) dict_ids - in - returnTc (dicts, VarMonoBind (instToId dict) rhs) - - --- Methods - -lookupInst inst@(Method _ id tys rho orig loc) - = tcSplitRhoTy rho `thenNF_Tc` \ (theta, _) -> - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - returnTc (dicts, VarMonoBind (instToId inst) (mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids)) - --- Literals - -lookupInst inst@(LitInst u (OverloadedIntegral i) ty orig loc) - | i >= toInteger minInt && i <= toInteger maxInt - = -- 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) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) int_lit)) - - | 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) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) (HsLitOut (HsInt i) integerTy))) +tcInstId :: Id -> NF_TcM (TcExpr, LIE, TcType) +tcInstId fun + | opt_NoMethodSharing = loop_noshare (HsVar fun) (idType fun) + | otherwise = loop_share fun where - intprim_lit = HsLitOut (HsIntPrim i) intPrimTy - int_lit = HsApp (HsVar (RealId intDataCon)) intprim_lit + 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 + let + (tyvars, rho) = tcSplitForAllTys (idType id) + rho_ty = substTyWith tyvars tys rho + (pred, tau) = tcSplitMethodTy rho_ty + in + newMethodWithGivenTy orig id tys [pred] tau -lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc) - = tcLookupGlobalValueByKey fromRationalClassOpKey `thenNF_Tc` \ from_rational -> +newMethodWithGivenTy orig id tys theta tau + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + newMethodWith loc id tys theta tau - -- The type Rational isn't wired in so we have to conjure it up - tcLookupTyConByKey rationalTyConKey `thenNF_Tc` \ rational_tycon -> +newMethodWith inst_loc@(_,loc,_) id tys theta tau + = tcGetUnique `thenNF_Tc` \ new_uniq -> let - rational_ty = mkSynTy rational_tycon [] - rational_lit = HsLitOut (HsFrac f) rational_ty + meth_id = mkUserLocal (mkMethodOcc (getOccName id)) new_uniq tau loc in - newMethodAtLoc orig loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) rational_lit)) -\end{code} + returnNF_Tc (Method meth_id id tys theta tau inst_loc) -There is a second, simpler interface, when you want an instance of a -class at a given nullary type constructor. It just returns the -appropriate dictionary if it exists. It is used only when resolving -ambiguous dictionaries. - -\begin{code} -lookupSimpleInst :: ClassInstEnv - -> Class - -> Type -- Look up (c,t) - -> TcM s [(Class,Type)] -- Here are the needed (c,t)s - -lookupSimpleInst class_inst_env clas ty - = case (lookupMEnv matchTy class_inst_env ty) of - Nothing -> failTc (noSimpleInst clas ty) - Just (dfun,tenv) -> returnTc [(c,instantiateTy tenv t) | (c,t) <- theta] - where - (_, theta, _) = splitSigmaTy (idType dfun) - -noSimpleInst clas ty sty - = sep [ptext SLIT("No instance for class"), ppr sty clas, - ptext SLIT("at type"), ppr sty ty] +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 + let + (tyvars,rho) = tcSplitForAllTys (idType real_id) + rho_ty = ASSERT( length tyvars == length tys ) + 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} - -@mkInstSpecEnv@ is used to construct the @SpecEnv@ for a dfun. -It does it by filtering the class's @InstEnv@. All pretty shady stuff. +In newOverloadedLit we convert directly to an Int or Integer if we +know that's what we want. This may save some time, by not +temporarily generating overloaded literals, but it won't catch all +cases (the rest are caught in lookupInst). \begin{code} -mkInstSpecEnv clas inst_ty inst_tvs inst_theta = panic "mkInstSpecEnv" -\end{code} +newOverloadedLit :: InstOrigin + -> HsOverLit + -> TcType + -> NF_TcM (TcExpr, LIE) +newOverloadedLit orig lit ty + | Just expr <- shortCutLit lit ty + = returnNF_Tc (expr, emptyLIE) -\begin{pseudocode} -mkInstSpecEnv :: Class -- class - -> Type -- instance type - -> [TyVarTemplate] -- instance tyvars - -> ThetaType -- superclasses dicts - -> SpecEnv -- specenv for dfun of instance + | otherwise + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + tcGetUnique `thenNF_Tc` \ new_uniq -> + let + 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) + +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} -mkInstSpecEnv clas inst_ty inst_tvs inst_theta - = mkSpecEnv (catMaybes (map maybe_spec_info matches)) - where - matches = matchMEnv matchTy (classInstEnv clas) inst_ty - maybe_spec_info (_, match_info, MkInstTemplate dfun _ []) - = Just (SpecInfo (map (assocMaybe match_info) inst_tvs) (length inst_theta) dfun) - maybe_spec_info (_, match_info, _) - = Nothing -\end{pseudocode} +%************************************************************************ +%* * +\subsection{Zonking} +%* * +%************************************************************************ +Zonking makes sure that the instance types are fully zonked, +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} -addClassInst - :: ClassInstEnv -- Incoming envt - -> Type -- The instance type: inst_ty - -> Id -- Dict fun id to apply. Free tyvars of inst_ty must - -- be the same as the forall'd tyvars of the dfun id. - -> MaybeErr - ClassInstEnv -- Success - (Type, Id) -- Offending overlap - -addClassInst inst_env inst_ty dfun_id = insertMEnv matchTy inst_env inst_ty dfun_id -\end{code} +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 m new_id new_tys new_theta new_tau loc) + +zonkInst (LitInst id lit ty loc) + = zonkTcType ty `thenNF_Tc` \ new_ty -> + returnNF_Tc (LitInst id lit new_ty loc) +zonkInsts insts = mapNF_Tc zonkInst insts +\end{code} %************************************************************************ %* * -\subsection[Inst-origin]{The @InstOrigin@ type} +\subsection{Printing} %* * %************************************************************************ -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... +ToDo: improve these pretty-printing things. The ``origin'' is really only +relevant in error messages. \begin{code} -data InstOrigin s - = OccurrenceOf (TcIdOcc s) -- Occurrence of an overloaded identifier - | OccurrenceOfCon Id -- Occurrence of a data constructor +instance Outputable Inst where + ppr inst = pprInst inst + +pprInst (LitInst u lit ty loc) + = hsep [ppr lit, ptext SLIT("at"), ppr ty, show_uniq u] + +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) {- , + ptext SLIT("theta"), ppr theta, + ptext SLIT("tau"), ppr tau + show_uniq u, + ppr (instToId m) -}] + +show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") + +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 + +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' = tidyFreeTyVars env (tyVarsOfInsts insts) - | RecordUpdOrigin +tidyInsts :: [Inst] -> (TidyEnv, [Inst]) +tidyInsts insts = tidyMoreInsts emptyTidyEnv insts +\end{code} - | DataDeclOrigin -- Typechecking a data declaration - | InstanceDeclOrigin -- Typechecking an instance decl +%************************************************************************ +%* * +\subsection{Looking up Insts} +%* * +%************************************************************************ - | LiteralOrigin HsLit -- Occurrence of a literal +\begin{code} +data LookupInstResult s + = NoInstance + | SimpleInst TcExpr -- Just a variable, type application, or literal + | GenInst [Inst] TcExpr -- The expression and its needed insts - | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc +lookupInst :: Inst + -> NF_TcM (LookupInstResult s) - | SignatureOrigin -- A dict created from a type signature +-- Dictionaries - | DoOrigin -- The monad for a do expression +lookupInst dict@(Dict _ (ClassP clas tys) loc) + = tcGetInstEnv `thenNF_Tc` \ inst_env -> + case lookupInstEnv inst_env clas tys of - | ClassDeclOrigin -- Manufactured during a class decl + FoundInst tenv dfun_id + -> let + (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 loc theta `thenNF_Tc` \ dicts -> + let + rhs = mkHsDictApp ty_app (map instToId dicts) + in + returnNF_Tc (GenInst dicts rhs) --- NO MORE! --- | DerivingOrigin InstanceMapper --- Class --- TyCon + other -> returnNF_Tc NoInstance - -- During "deriving" operations we have an ever changing - -- mapping of classes to instances, so we record it inside the - -- origin information. This is a bit of a hack, but it works - -- fine. (Simon is to blame [WDP].) +lookupInst dict@(Dict _ _ loc) = returnNF_Tc NoInstance - | InstanceSpecOrigin InstanceMapper - Class -- in a SPECIALIZE instance pragma - Type +-- Methods - -- 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].) +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))) --- | DefaultDeclOrigin -- Related to a `default' declaration +-- Literals - | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value +-- 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] - -- 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. +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 - | CCallOrigin String -- CCall label - (Maybe RenamedHsExpr) -- Nothing if it's the result - -- Just arg, for an argument +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)))) - | LitLitOrigin String -- the litlit - | UnknownOrigin -- Help! I give up... +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 = tcFunArgTy (idType method_id) + rational_lit = HsLit (HsRat f rational_ty) + in + returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit)) \end{code} +There is a second, simpler interface, when you want an instance of a +class at a given nullary type constructor. It just returns the +appropriate dictionary if it exists. It is used only when resolving +ambiguous dictionaries. + \begin{code} --- During deriving and instance specialisation operations --- we can't get the instances of the class from inside the --- class, because the latter ain't ready yet. Instead we --- find a mapping from classes to envts inside the dict origin. - -get_inst_env :: Class -> InstOrigin s -> ClassInstEnv --- get_inst_env clas (DerivingOrigin inst_mapper _ _) --- = fst (inst_mapper clas) -get_inst_env clas (InstanceSpecOrigin inst_mapper _ _) - = fst (inst_mapper clas) -get_inst_env clas other_orig = classInstEnv clas - - -pprOrigin :: String -> InstOrigin s -> SrcLoc -> Error - -pprOrigin hdr orig locn - = addErrLoc locn hdr $ \ sty -> - case orig of - OccurrenceOf id -> - hsep [ptext SLIT("at a use of an overloaded identifier:"), ppr sty id] - OccurrenceOfCon id -> - hsep [ptext SLIT("at a use of an overloaded constructor:"), ppr sty id] - InstanceDeclOrigin -> - ptext SLIT("in an instance declaration") - LiteralOrigin lit -> - hsep [ptext SLIT("at an overloaded literal:"), ppr sty lit] - ArithSeqOrigin seq -> - hsep [ptext SLIT("at an arithmetic sequence:"), ppr sty seq] - SignatureOrigin -> - ptext SLIT("in a type signature") - DoOrigin -> - ptext SLIT("in a do statement") - ClassDeclOrigin -> - ptext SLIT("in a class declaration") - InstanceSpecOrigin _ clas ty -> - hsep [text "in a SPECIALIZE instance pragma; class", - ppr sty clas, text "type:", ppr sty ty] - ValSpecOrigin name -> - hsep [ptext SLIT("in a SPECIALIZE user-pragma for"), ppr sty name] - CCallOrigin clabel Nothing{-ccall result-} -> - hsep [ptext SLIT("in the result of the _ccall_ to"), text clabel] - CCallOrigin clabel (Just arg_expr) -> - hsep [ptext SLIT("in an argument in the _ccall_ to"), text clabel <> comma, text "namely:", ppr sty arg_expr] - LitLitOrigin s -> - hcat [ptext SLIT("in this ``literal-literal'': "), text s] - UnknownOrigin -> - ptext SLIT("in... oops -- I don't know where the overloading came from!") +lookupSimpleInst :: Class + -> [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 + FoundInst tenv dfun + -> returnNF_Tc (Just (substTheta (mkSubst emptyInScopeSet tenv) theta)) + where + (_, rho) = tcSplitForAllTys (idType dfun) + (theta,_) = tcSplitRhoTy rho + + other -> returnNF_Tc Nothing \end{code}