X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=5968b1ee0ee7877f59c5c48a66e65744b40eb253;hb=cb5f88f09f87208fa74a424e4da7141fb5204aa2;hp=71d7651383022e017ec8991f5b95fab3e3ae07ee;hpb=f9120c200bcf613b58d742802172fb4c08171f0d;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index 71d7651..5968b1e 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -1,68 +1,82 @@ % -% (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, - InstOrigin(..), OverloadedLit(..), - LIE(..), emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, plusLIEs, + Inst, OverloadedLit(..), + pprInst, pprInsts, pprInstsInFull, tidyInst, tidyInsts, - InstanceMapper(..), + InstanceMapper, - newDicts, newDictsAtLoc, newMethod, newMethodWithGivenTy, newOverloadedLit, + newDictFromOld, newDicts, newDictsAtLoc, + newMethod, newMethodWithGivenTy, newOverloadedLit, instOverloadedFun, - instType, tyVarsOfInst, lookupInst, + tyVarsOfInst, instLoc, getDictClassTys, - isDict, isTyVarDict, + lookupInst, lookupSimpleInst, LookupInstResult(..), - zonkInst, instToId, + isDict, isTyVarDict, isStdClassTyVarDict, isMethodFor, + instBindingRequired, instCanBeGeneralised, - matchesInst, - instBindingRequired, instCanBeGeneralised + zonkInst, instToId, instToIdBndr, + InstOrigin(..), InstLoc, pprInstLoc ) where -import Ubiq - -import HsSyn ( HsLit(..), HsExpr(..), HsBinds, - InPat, OutPat, Stmt, Qual, Match, - ArithSeqInfo, PolyType, Fake ) -import RnHsSyn ( RenamedArithSeqInfo(..), RenamedHsExpr(..) ) -import TcHsSyn ( TcIdOcc(..), TcExpr(..), TcIdBndr(..), - mkHsTyApp, mkHsDictApp ) +#include "HsVersions.h" +import HsSyn ( HsLit(..), HsExpr(..) ) +import RnHsSyn ( RenamedArithSeqInfo, RenamedHsExpr, RenamedPat ) +import TcHsSyn ( TcExpr, TcId, + mkHsTyApp, mkHsDictApp, zonkId + ) import TcMonad -import TcEnv ( tcLookupGlobalValueByKey ) -import TcType ( TcType(..), TcRhoType(..), TcMaybe, TcTyVarSet(..), - tcInstType, tcInstTcType, zonkTcType ) - -import Bag ( emptyBag, unitBag, unionBags, unionManyBags, listToBag, consBag ) -import Class ( Class(..), GenClass, ClassInstEnv(..), getClassInstEnv ) -import Id ( GenId, idType, mkInstId ) -import MatchEnv ( lookupMEnv, insertMEnv ) -import Name ( mkLocalName, Name ) +import TcEnv ( TcIdSet, tcLookupValueByKey, tcLookupTyConByKey ) +import TcType ( TcThetaType, + TcType, TcTauType, TcTyVarSet, + zonkTcType, zonkTcTypes, + zonkTcThetaType + ) +import Bag +import Class ( classInstEnv, Class ) +import Id ( Id, idFreeTyVars, idType, mkUserLocal, mkSysLocal ) +import VarSet ( elemVarSet ) +import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) +import Name ( OccName, Name, mkDictOcc, mkMethodOcc, getOccName ) +import PprType ( pprConstraint ) +import InstEnv ( InstEnv, lookupInstEnv ) +import SrcLoc ( SrcLoc ) +import Type ( Type, ThetaType, + mkTyVarTy, isTyVarTy, mkDictTy, splitForAllTys, splitSigmaTy, + splitRhoTy, tyVarsOfType, tyVarsOfTypes, + mkSynTy, tidyOpenType, tidyOpenTypes + ) +import InstEnv ( InstEnv ) +import Subst ( emptyInScopeSet, mkSubst, + substTy, substTheta, mkTyVarSubst, mkTopTyVarSubst + ) +import TyCon ( TyCon ) +import VarEnv ( lookupVarEnv, TidyEnv, + lookupSubstEnv, SubstResult(..) + ) +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 Maybes ( expectJust ) +import Util ( thenCmp, zipWithEqual, mapAccumL ) import Outputable -import PprType ( GenClass, TyCon, GenType, GenTyVar ) -import PprStyle ( PprStyle(..) ) -import Pretty -import RnHsSyn ( RnName{-instance NamedThing-} ) -import SpecEnv ( SpecEnv(..) ) -import SrcLoc ( SrcLoc, mkUnknownSrcLoc ) -import Type ( GenType, eqSimpleTy, - isTyVarTy, mkDictTy, splitForAllTy, splitSigmaTy, - splitRhoTy, matchTy, tyVarsOfType, tyVarsOfTypes ) -import TyVar ( GenTyVar ) -import TysPrim ( intPrimTy ) -import TysWiredIn ( intDataCon ) -import Unique ( Unique, showUnique, - fromRationalClassOpKey, fromIntClassOpKey, fromIntegerClassOpKey ) -import Util ( panic, zipEqual, zipWithEqual, assoc, assertPanic ) - \end{code} %************************************************************************ @@ -72,16 +86,27 @@ import Util ( panic, zipEqual, zipWithEqual, assoc, assertPanic ) %************************************************************************ \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 -zonkLIE :: LIE s -> NF_TcM s (LIE s) +zonkLIE :: LIE -> NF_TcM s 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} %************************************************************************ @@ -99,238 +124,290 @@ 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 + Class -- The type of the dict is (c ts), where + [TcType] -- c is the class and ts the types; + InstLoc | Method Unique - (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 - (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 + TcType -- The type at which the literal is used + InstLoc 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 \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 -> - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, ty) = Dict u clas ty orig loc - dicts = zipWithEqual mk_dict new_uniqs theta - in - returnNF_Tc (listToBag dicts, map instToId dicts) - -newDictsAtLoc orig loc theta -- Local function, similar to newDicts, - -- but with slightly different interface - = tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, ty) = Dict u clas ty orig loc - dicts = zipWithEqual 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 tcInstType (tyvars `zipEqual` tys) rho - TcId id -> let (tyvars, rho) = splitForAllTy (idType id) - in tcInstTcType (tyvars `zipEqual` 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 (tyvars `zipEqual` 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) +instance Ord Inst where + compare = cmpInst + +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 (Method _ _ _ _ _ _) (Dict _ _ _ _) + = GT +cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) + = (id1 `compare` id2) `thenCmp` (tys1 `compare` tys2) +cmpInst (Method _ _ _ _ _ _) other + = LT + +cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) + = (lit1 `cmpOverLit` lit2) `thenCmp` (ty1 `compare` 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 \end{code} +Selection +~~~~~~~~~ \begin{code} -instToId :: Inst s -> TcIdOcc s -instToId (Dict u clas ty orig loc) - = TcId (mkInstId u (mkDictTy clas ty) (mkLocalName u SLIT("dict") loc)) -instToId (Method u id tys rho_ty orig loc) - = TcId (mkInstId u tau_ty (mkLocalName u (getLocalName id) loc)) - where - (_, tau_ty) = splitRhoTy rho_ty -- NB The method Id has just the tau type -instToId (LitInst u list ty orig loc) - = TcId (mkInstId u ty (mkLocalName u SLIT("lit") loc)) +instLoc (Dict u clas tys loc) = loc +instLoc (Method u _ _ _ _ loc) = loc +instLoc (LitInst u lit ty loc) = loc + +getDictClassTys (Dict u clas tys _) = (clas, tys) + +tyVarsOfInst :: Inst -> TcTyVarSet +tyVarsOfInst (Dict _ _ tys _) = tyVarsOfTypes tys +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 \end{code} +Predicates +~~~~~~~~~~ \begin{code} -instType :: Inst s -> TcType s -instType (Dict _ clas ty _ _) = mkDictTy clas ty -instType (LitInst _ _ ty _ _) = ty -instType (Method _ id tys ty _ _) = ty +isDict :: Inst -> Bool +isDict (Dict _ _ _ _) = True +isDict other = False + +isMethodFor :: TcIdSet -> Inst -> Bool +isMethodFor ids (Method uniq id tys _ _ loc) + = id `elemVarSet` ids +isMethodFor ids inst + = False + +isTyVarDict :: Inst -> Bool +isTyVarDict (Dict _ _ tys _) = all isTyVarTy tys +isTyVarDict other = False + +isStdClassTyVarDict (Dict _ clas [ty] _) = isStandardClass clas && isTyVarTy ty +isStdClassTyVarDict other = False \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. +Two predicates which deal with the case where class constraints don't +necessarily result in bindings. The first tells whether an @Inst@ +must be witnessed by an actual binding; the second tells whether an +@Inst@ can be generalised over. \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) +instBindingRequired :: Inst -> Bool +instBindingRequired (Dict _ clas _ _) = not (isNoDictClass clas) +instBindingRequired other = True -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) - -zonkInst (LitInst u lit ty orig loc) - = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (LitInst u lit new_ty orig loc) +instCanBeGeneralised :: Inst -> Bool +instCanBeGeneralised (Dict _ clas _ _) = not (isCcallishClass clas) +instCanBeGeneralised other = True \end{code} +Construction +~~~~~~~~~~~~ + \begin{code} -tyVarsOfInst :: Inst s -> TcTyVarSet s -tyVarsOfInst (Dict _ _ ty _ _) = tyVarsOfType ty -tyVarsOfInst (Method _ _ tys rho _ _) = tyVarsOfTypes tys -tyVarsOfInst (LitInst _ _ ty _ _) = tyVarsOfType ty +newDicts :: InstOrigin + -> TcThetaType + -> NF_TcM s (LIE, [TcId]) +newDicts orig theta + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + newDictsAtLoc loc theta `thenNF_Tc` \ (dicts, ids) -> + returnNF_Tc (listToBag dicts, ids) + +-- Local function, similar to newDicts, +-- but with slightly different interface +newDictsAtLoc :: InstLoc + -> TcThetaType + -> NF_TcM s ([Inst], [TcId]) +newDictsAtLoc loc theta = + tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> + let + mk_dict u (clas, tys) = Dict u clas tys loc + dicts = zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta + in + returnNF_Tc (dicts, map instToId dicts) + +newDictFromOld :: Inst -> Class -> [TcType] -> NF_TcM s Inst +newDictFromOld (Dict _ _ _ loc) clas tys + = tcGetUnique `thenNF_Tc` \ uniq -> + returnNF_Tc (Dict uniq clas tys loc) + + +newMethod :: InstOrigin + -> TcId + -> [TcType] + -> NF_TcM s (LIE, TcId) +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 + in + newMethodWithGivenTy orig id tys theta tau `thenNF_Tc` \ meth_inst -> + returnNF_Tc (unitLIE meth_inst, instToId meth_inst) + +instOverloadedFun orig (HsVar v) arg_tys theta tau + = newMethodWithGivenTy orig v arg_tys theta tau `thenNF_Tc` \ inst -> + returnNF_Tc (HsVar (instToId inst), unitLIE inst) + +newMethodWithGivenTy orig id tys theta tau + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + tcGetUnique `thenNF_Tc` \ new_uniq -> + let + meth_inst = Method new_uniq id tys theta tau loc + in + returnNF_Tc meth_inst + +newMethodAtLoc :: InstLoc + -> Id -> [TcType] + -> NF_TcM s (Inst, TcId) +newMethodAtLoc 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 + tcGetUnique `thenNF_Tc` \ new_uniq -> + let + (tyvars,rho) = splitForAllTys (idType real_id) + rho_ty = ASSERT( length tyvars == length tys ) + substTy (mkTopTyVarSubst tyvars tys) rho + (theta, tau) = splitRhoTy rho_ty + meth_inst = Method new_uniq real_id tys theta tau loc + in + returnNF_Tc (meth_inst, instToId meth_inst) \end{code} -@matchesInst@ checks when two @Inst@s are instances of the same -thing at the same type, even if their uniques differ. +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} -matchesInst :: Inst s -> Inst s -> Bool - -matchesInst (Dict _ clas1 ty1 _ _) (Dict _ clas2 ty2 _ _) - = clas1 == clas2 && ty1 `eqSimpleTy` ty2 +newOverloadedLit :: InstOrigin + -> OverloadedLit + -> TcType + -> NF_TcM s (TcExpr, LIE) +newOverloadedLit orig (OverloadedIntegral i) ty + | isIntTy ty && inIntRange i -- Short cut for Int + = returnNF_Tc (int_lit, emptyLIE) -matchesInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) - = id1 == id2 - && and (zipWith eqSimpleTy tys1 tys2) - && length tys1 == length tys2 + | isIntegerTy ty -- Short cut for Integer + = returnNF_Tc (integer_lit, emptyLIE) -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 - -matchesInst other1 other2 = False + 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 + = tcGetInstLoc orig `thenNF_Tc` \ loc -> + tcGetUnique `thenNF_Tc` \ new_uniq -> + let + lit_inst = LitInst new_uniq lit ty loc + in + returnNF_Tc (HsVar (instToId lit_inst), unitLIE lit_inst) \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 +instToId :: Inst -> TcId +instToId inst = instToIdBndr inst + +instToIdBndr :: Inst -> TcId +instToIdBndr (Dict u clas ty (_,loc,_)) + = mkUserLocal (mkDictOcc (getOccName clas)) u (mkDictTy clas ty) loc + +instToIdBndr (Method u id tys theta tau (_,loc,_)) + = mkUserLocal (mkMethodOcc (getOccName id)) u tau loc + +instToIdBndr (LitInst u list ty loc) + = mkSysLocal SLIT("lit") u ty \end{code} -Two predicates which deal with the case where class constraints don't -necessarily result in bindings. The first tells whether an @Inst@ -must be witnessed by an actual binding; the second tells whether an -@Inst@ can be generalised over. + +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. \begin{code} -instBindingRequired :: Inst s -> Bool -instBindingRequired inst - = case getInstOrigin inst of - CCallOrigin _ _ -> False -- No binding required - LitLitOrigin _ -> False - OccurrenceOfCon _ -> False - other -> True - -instCanBeGeneralised :: Inst s -> Bool -instCanBeGeneralised inst - = case getInstOrigin inst of - CCallOrigin _ _ -> False -- Can't be generalised - LitLitOrigin _ -> False -- Can't be generalised - other -> True +zonkInst :: Inst -> NF_TcM s Inst +zonkInst (Dict u clas tys loc) + = zonkTcTypes tys `thenNF_Tc` \ new_tys -> + returnNF_Tc (Dict u clas new_tys loc) + +zonkInst (Method u 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 loc) + +zonkInst (LitInst u lit ty loc) + = zonkTcType ty `thenNF_Tc` \ new_ty -> + returnNF_Tc (LitInst u lit new_ty loc) \end{code} @@ -340,45 +417,47 @@ ToDo: improve these pretty-printing things. The ``origin'' is really only relevant in error messages. \begin{code} -instance Outputable (Inst s) where - ppr sty (LitInst uniq lit ty orig loc) - = ppHang (ppSep [case lit of - OverloadedIntegral i -> ppInteger i - OverloadedFractional f -> ppRational f, - ppStr "at", - ppr sty ty, - show_uniq sty uniq - ]) - 4 (show_origin sty orig) - - ppr sty (Dict uniq clas ty orig loc) - = ppHang (ppSep [ppr sty clas, - ppStr "at", - ppr sty ty, - show_uniq sty uniq - ]) - 4 (show_origin sty orig) - - ppr sty (Method uniq id tys rho orig loc) - = ppHang (ppSep [ppr sty id, - ppStr "at", - ppr sty tys, - show_uniq sty uniq - ]) - 4 (show_origin sty orig) - -show_uniq PprDebug uniq = ppr PprDebug uniq -show_uniq sty uniq = ppNil - -show_origin sty orig = ppBesides [ppLparen, pprOrigin sty orig, ppRparen] -\end{code} +instance Outputable Inst where + ppr inst = pprInst inst + +pprInst (LitInst u lit ty loc) + = hsep [case lit of + OverloadedIntegral i -> integer i + OverloadedFractional f -> rational f, + ptext SLIT("at"), + ppr ty, + show_uniq u] + +pprInst (Dict u clas tys loc) = pprConstraint clas tys <+> show_uniq u + +pprInst (Method u id tys _ _ loc) + = hsep [ppr id, ptext SLIT("at"), + brackets (interppSP tys), + show_uniq u] + +tidyInst :: TidyEnv -> Inst -> (TidyEnv, Inst) +tidyInst env (LitInst u lit ty loc) + = (env', LitInst u lit ty' loc) + where + (env', ty') = tidyOpenType env ty -Printing in error messages +tidyInst env (Dict u clas tys loc) + = (env', Dict u clas tys' loc) + where + (env', tys') = tidyOpenTypes env tys -\begin{code} -noInstanceErr inst sty = ppHang (ppPStr SLIT("No instance for:")) 4 (ppr sty inst) +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 + where + (env', tys') = tidyOpenTypes env tys + +tidyInsts env insts = mapAccumL tidyInst env insts + +show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") \end{code} + %************************************************************************ %* * \subsection[InstEnv-types]{Type declarations} @@ -386,7 +465,7 @@ noInstanceErr inst sty = ppHang (ppPStr SLIT("No instance for:")) 4 (ppr sty ins %************************************************************************ \begin{code} -type InstanceMapper = Class -> (ClassInstEnv, ClassOp -> SpecEnv) +type InstanceMapper = Class -> InstEnv \end{code} A @ClassInstEnv@ lives inside a class, and identifies all the instances @@ -405,246 +484,118 @@ 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], - (TcIdOcc s, TcExpr s)) -- The new binding +data LookupInstResult s + = NoInstance + | SimpleInst TcExpr -- Just a variable, type application, or literal + | GenInst [Inst] TcExpr -- The expression and its needed insts + +lookupInst :: Inst + -> NF_TcM s (LookupInstResult s) -- Dictionaries -lookupInst dict@(Dict _ clas ty orig loc) - = case lookupMEnv matchTy (get_inst_env clas orig) ty of - Nothing -> failTc (noInstanceErr dict) +lookupInst dict@(Dict _ clas tys loc) + = case lookupInstEnv (ppr clas) (classInstEnv clas) tys of - Just (dfun_id, tenv) + Just (tenv, dfun_id) -> let - (tyvars, rho) = splitForAllTy (idType dfun_id) - ty_args = map (assoc "lookupInst" tenv) tyvars - -- tenv should bind all the tyvars + subst = mkSubst (tyVarsOfTypes tys) tenv + (tyvars, rho) = splitForAllTys (idType dfun_id) + ty_args = map subst_tv tyvars + dfun_rho = substTy subst rho + (theta, tau) = 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 in - tcInstType tenv rho `thenNF_Tc` \ dfun_rho -> - let - (theta, tau) = splitRhoTy dfun_rho - in - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> + if null theta then + returnNF_Tc (SimpleInst ty_app) + else + newDictsAtLoc loc theta `thenNF_Tc` \ (dicts, dict_ids) -> let - rhs = mkHsDictApp (mkHsTyApp (HsVar (RealId dfun_id)) ty_args) dict_ids + rhs = mkHsDictApp ty_app dict_ids in - returnTc (dicts, (instToId dict, rhs)) + returnNF_Tc (GenInst dicts rhs) + Nothing -> returnNF_Tc NoInstance -- Methods -lookupInst inst@(Method _ id tys rho orig loc) - = newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - returnTc (dicts, (instToId inst, mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids)) - where - (theta,_) = splitRhoTy rho +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)) -- 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], (instToId inst, HsApp (HsVar method_id) int_lit)) +lookupInst inst@(LitInst u (OverloadedIntegral i) ty loc) + | isIntTy ty && in_int_range -- Short cut for Int + = returnNF_Tc (GenInst [] int_lit) + -- GenInst, not SimpleInst, because int_lit is actually a constructor application - | 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], (instToId inst, HsApp (HsVar method_id) (HsLitOut (HsInt i) ty))) - where - intprim_lit = HsLitOut (HsIntPrim i) intPrimTy - int_lit = HsApp (HsVar (RealId intDataCon)) intprim_lit + | isIntegerTy ty -- Short cut for Integer + = returnNF_Tc (GenInst [] integer_lit) -lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc) - = tcLookupGlobalValueByKey fromRationalClassOpKey `thenNF_Tc` \ from_rational -> - newMethodAtLoc orig loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnTc ([method_inst], (instToId inst, HsApp (HsVar method_id) (HsLitOut (HsFrac f) ty))) -\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. + | in_int_range -- It's overloaded but small enough to fit into an Int + = tcLookupValueByKey fromIntClassOpKey `thenNF_Tc` \ from_int -> + newMethodAtLoc loc from_int [ty] `thenNF_Tc` \ (method_inst, method_id) -> + returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) int_lit)) -\begin{code} -lookupClassInstAtSimpleType :: Class -> Type -> Maybe Id - -lookupClassInstAtSimpleType clas ty - = case (lookupMEnv matchTy (getClassInstEnv clas) ty) of - Nothing -> Nothing - Just (dfun,_) -> ASSERT( null tyvars && null theta ) - Just dfun - where - (tyvars, theta, _) = splitSigmaTy (idType dfun) -\end{code} + | otherwise -- Alas, it is overloaded and a big literal! + = tcLookupValueByKey fromIntegerClassOpKey `thenNF_Tc` \ from_integer -> + newMethodAtLoc loc from_integer [ty] `thenNF_Tc` \ (method_inst, method_id) -> + returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) integer_lit)) + where + in_int_range = inIntRange i + intprim_lit = HsLitOut (HsIntPrim i) intPrimTy + integer_lit = HsLitOut (HsInt i) integerTy + int_lit = HsCon intDataCon [] [intprim_lit] +-- similar idea for overloaded floating point literals: if the literal is +-- *definitely* a float or a double, generate the real thing here. +-- This is essential (see nofib/spectral/nucleic). -@mkInstSpecEnv@ is used to construct the @SpecEnv@ for a dfun. -It does it by filtering the class's @InstEnv@. All pretty shady stuff. +lookupInst inst@(LitInst u (OverloadedFractional f) ty loc) + | isFloatTy ty = returnNF_Tc (GenInst [] float_lit) + | isDoubleTy ty = returnNF_Tc (GenInst [] double_lit) -\begin{code} -mkInstSpecEnv clas inst_ty inst_tvs inst_theta = panic "mkInstSpecEnv" -\end{code} + | otherwise + = tcLookupValueByKey fromRationalClassOpKey `thenNF_Tc` \ from_rational -> -\begin{pseudocode} -mkInstSpecEnv :: Class -- class - -> Type -- instance type - -> [TyVarTemplate] -- instance tyvars - -> ThetaType -- superclasses dicts - -> SpecEnv -- specenv for dfun of instance + -- The type Rational isn't wired in so we have to conjure it up + tcLookupTyConByKey rationalTyConKey `thenNF_Tc` \ rational_tycon -> + let + rational_ty = mkSynTy rational_tycon [] + rational_lit = HsLitOut (HsFrac f) rational_ty + in + newMethodAtLoc loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> + returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit)) -mkInstSpecEnv clas inst_ty inst_tvs inst_theta - = mkSpecEnv (catMaybes (map maybe_spec_info matches)) where - matches = matchMEnv matchTy (getClassInstEnv 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} + floatprim_lit = HsLitOut (HsFloatPrim f) floatPrimTy + float_lit = HsCon floatDataCon [] [floatprim_lit] + doubleprim_lit = HsLitOut (HsDoublePrim f) doublePrimTy + double_lit = HsCon doubleDataCon [] [doubleprim_lit] - -\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} - - -%************************************************************************ -%* * -\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 - - | InstanceDeclOrigin -- Typechecking an instance decl - - | LiteralOrigin HsLit -- Occurrence of a literal - - | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc - - | SignatureOrigin -- A dict created from a type signature - - | DoOrigin -- The monad for a do expression - - | ClassDeclOrigin -- Manufactured during a class decl - - | DerivingOrigin InstanceMapper - Class - TyCon - - -- 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].) - - | InstanceSpecOrigin InstanceMapper - 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].) - - | DefaultDeclOrigin -- Related to a `default' declaration - - | 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} +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 = getClassInstEnv clas - - -pprOrigin :: PprStyle -> InstOrigin s -> Pretty - -pprOrigin sty (OccurrenceOf id) - = ppBesides [ppPStr SLIT("at a use of an overloaded identifier: `"), - ppr sty id, ppChar '\''] -pprOrigin sty (OccurrenceOfCon id) - = ppBesides [ppPStr SLIT("at a use of an overloaded constructor: `"), - ppr sty id, ppChar '\''] -pprOrigin sty (InstanceDeclOrigin) - = ppStr "in an instance declaration" -pprOrigin sty (LiteralOrigin lit) - = ppCat [ppStr "at an overloaded literal:", ppr sty lit] -pprOrigin sty (ArithSeqOrigin seq) - = ppCat [ppStr "at an arithmetic sequence:", ppr sty seq] -pprOrigin sty (SignatureOrigin) - = ppStr "in a type signature" -pprOrigin sty (DoOrigin) - = ppStr "in a do statement" -pprOrigin sty (ClassDeclOrigin) - = ppStr "in a class declaration" -pprOrigin sty (DerivingOrigin _ clas tycon) - = ppBesides [ppStr "in a `deriving' clause; class `", - ppr sty clas, - ppStr "'; offending type `", - ppr sty tycon, - ppStr "'"] -pprOrigin sty (InstanceSpecOrigin _ clas ty) - = ppBesides [ppStr "in a SPECIALIZE instance pragma; class \"", - ppr sty clas, ppStr "\" type: ", ppr sty ty] -pprOrigin sty (DefaultDeclOrigin) - = ppStr "in a `default' declaration" -pprOrigin sty (ValSpecOrigin name) - = ppBesides [ppStr "in a SPECIALIZE user-pragma for `", - ppr sty name, ppStr "'"] -pprOrigin sty (CCallOrigin clabel Nothing{-ccall result-}) - = ppBesides [ppStr "in the result of the _ccall_ to `", - ppStr clabel, ppStr "'"] -pprOrigin sty (CCallOrigin clabel (Just arg_expr)) - = ppBesides [ppStr "in an argument in the _ccall_ to `", - ppStr clabel, ppStr "', namely: ", ppr sty arg_expr] -pprOrigin sty (LitLitOrigin s) - = ppBesides [ppStr "in this ``literal-literal'': ", ppStr s] -pprOrigin sty UnknownOrigin - = ppStr "in... oops -- I don't know where the overloading came from!" +lookupSimpleInst :: InstEnv + -> 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 lookupInstEnv (ppr clas) class_inst_env tys of + Nothing -> returnNF_Tc Nothing + + Just (tenv, dfun) + -> returnNF_Tc (Just (substTheta (mkSubst emptyInScopeSet tenv) theta)) + where + (_, theta, _) = splitSigmaTy (idType dfun) \end{code} - - -