X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FInst.lhs;h=ffb010491db53de80a73d97e9c48b22101179588;hp=77ca56a10e7c57dde8880f884c051c1df9401311;hb=a3a15a646977ab98f9150bb2b926d960796077e4;hpb=61d2625ae2e6a4cdae2ffc92df828905e81c24cc diff --git a/compiler/typecheck/Inst.lhs b/compiler/typecheck/Inst.lhs index 77ca56a..ffb0104 100644 --- a/compiler/typecheck/Inst.lhs +++ b/compiler/typecheck/Inst.lhs @@ -1,7 +1,9 @@ % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % -\section[Inst]{The @Inst@ type: dictionaries or method instances} + +The @Inst@ type: dictionaries or method instances \begin{code} module Inst ( @@ -12,82 +14,67 @@ module Inst ( tidyInsts, tidyMoreInsts, - newDicts, newDictAtLoc, newDictsAtLoc, cloneDict, + newDictBndr, newDictBndrs, newDictBndrsO, + instCall, instStupidTheta, + cloneDict, shortCutFracLit, shortCutIntLit, newIPDict, newMethod, newMethodFromName, newMethodWithGivenTy, - tcInstClassOp, tcInstStupidTheta, + tcInstClassOp, tcSyntaxName, isHsVar, tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, ipNamesOfInst, ipNamesOfInsts, fdPredsOfInst, fdPredsOfInsts, - instLoc, getDictClassTys, dictPred, + getDictClassTys, dictPred, - lookupInst, LookupInstResult(..), lookupPred, + lookupSimpleInst, LookupInstResult(..), lookupPred, tcExtendLocalInstEnv, tcGetInstEnvs, getOverlapFlag, - isDict, isClassDict, isMethod, - isLinearInst, linearInstType, isIPDict, isInheritableInst, - isTyVarDict, isMethodFor, + isDict, isClassDict, isMethod, isImplicInst, + isIPDict, isInheritableInst, isMethodOrLit, + isTyVarDict, isMethodFor, getDefaultableDicts, zonkInst, zonkInsts, - instToId, instName, + instToId, instToVar, instName, - InstOrigin(..), InstLoc(..), pprInstLoc + InstOrigin(..), InstLoc, pprInstLoc ) where #include "HsVersions.h" import {-# SOURCE #-} TcExpr( tcPolyExpr ) +import {-# SOURCE #-} TcUnify( unifyType ) -import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..), LHsExpr, mkHsApp, - nlHsLit, nlHsVar ) -import TcHsSyn ( mkHsTyApp, mkHsDictApp, zonkId ) +import HsSyn +import TcHsSyn import TcRnMonad -import TcEnv ( tcLookupId, checkWellStaged, topIdLvl, tcMetaTy ) -import InstEnv ( DFunId, InstEnv, Instance(..), OverlapFlag(..), - lookupInstEnv, extendInstEnv, pprInstances, - instanceHead, instanceDFunId, setInstanceDFunId ) -import FunDeps ( checkFunDeps ) -import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, zonkTcThetaType, - tcInstTyVar, tcInstSkolType - ) -import TcType ( Type, TcType, TcThetaType, TcTyVarSet, TcPredType, - BoxyRhoType, - PredType(..), SkolemInfo(..), typeKind, mkSigmaTy, - tcSplitForAllTys, applyTys, - tcSplitPhiTy, tcSplitDFunHead, - isIntTy,isFloatTy, isIntegerTy, isDoubleTy, - mkPredTy, mkTyVarTys, - tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tidyPred, - isClassPred, isTyVarClassPred, isLinearPred, - getClassPredTys, mkPredName, - isInheritablePred, isIPPred, - tidyType, tidyTypes, tidyFreeTyVars, tcSplitSigmaTy, - pprPred, pprParendType, pprTheta - ) -import Type ( TvSubst, substTy, substTyVar, substTyWith, substTheta, zipTopTvSubst, - notElemTvSubst, extendTvSubstList ) -import Unify ( tcMatchTys ) -import Module ( modulePackageId ) -import Kind ( isSubKind ) -import HscTypes ( ExternalPackageState(..), HscEnv(..) ) -import CoreFVs ( idFreeTyVars ) -import DataCon ( DataCon, dataConTyVars, dataConStupidTheta, dataConName, dataConWrapId ) -import Id ( Id, idName, idType, mkUserLocal, mkLocalId ) -import Name ( Name, mkMethodOcc, getOccName, getSrcLoc, nameModule, - isInternalName, setNameUnique ) -import NameSet ( addOneToNameSet ) -import Literal ( inIntRange ) -import Var ( TyVar, tyVarKind, setIdType ) -import VarEnv ( TidyEnv, emptyTidyEnv ) -import VarSet ( elemVarSet, emptyVarSet, unionVarSet, mkVarSet ) -import TysWiredIn ( floatDataCon, doubleDataCon ) -import PrelNames ( integerTyConName, fromIntegerName, fromRationalName, rationalTyConName ) -import BasicTypes( IPName(..), mapIPName, ipNameName ) -import UniqSupply( uniqsFromSupply ) -import SrcLoc ( mkSrcSpan, noLoc, unLoc, Located(..) ) -import DynFlags ( DynFlag(..), DynFlags(..), dopt ) -import Maybes ( isJust ) +import TcEnv +import InstEnv +import FunDeps +import TcMType +import TcType +import Type +import Class +import Unify +import Module +import Coercion +import HscTypes +import CoreFVs +import DataCon +import Id +import Name +import NameSet +import Literal +import Var ( Var, TyVar ) +import qualified Var +import VarEnv +import VarSet +import TysWiredIn +import PrelNames +import BasicTypes +import SrcLoc +import DynFlags +import Maybes +import Util import Outputable \end{code} @@ -99,18 +86,43 @@ instName :: Inst -> Name instName inst = idName (instToId inst) instToId :: Inst -> TcId -instToId (LitInst nm _ ty _) = mkLocalId nm ty -instToId (Dict nm pred _) = mkLocalId nm (mkPredTy pred) -instToId (Method id _ _ _ _) = id - -instLoc (Dict _ _ loc) = loc -instLoc (Method _ _ _ _ loc) = loc -instLoc (LitInst _ _ _ loc) = loc - -dictPred (Dict _ pred _ ) = pred -dictPred inst = pprPanic "dictPred" (ppr inst) - -getDictClassTys (Dict _ pred _) = getClassPredTys pred +instToId inst = ASSERT2( isId id, ppr inst ) id + where + id = instToVar inst + +instToVar :: Inst -> Var +instToVar (LitInst {tci_name = nm, tci_ty = ty}) + = mkLocalId nm ty +instToVar (Method {tci_id = id}) + = id +instToVar (Dict {tci_name = nm, tci_pred = pred}) + | isEqPred pred = Var.mkCoVar nm (mkPredTy pred) + | otherwise = mkLocalId nm (mkPredTy pred) +instToVar (ImplicInst {tci_name = nm, tci_tyvars = tvs, tci_given = givens, + tci_wanted = wanteds}) + = mkLocalId nm (mkImplicTy tvs givens wanteds) + +instType :: Inst -> Type +instType (LitInst {tci_ty = ty}) = ty +instType (Method {tci_id = id}) = idType id +instType (Dict {tci_pred = pred}) = mkPredTy pred +instType imp@(ImplicInst {}) = mkImplicTy (tci_tyvars imp) (tci_given imp) + (tci_wanted imp) + +mkImplicTy tvs givens wanteds -- The type of an implication constraint + = -- pprTrace "mkImplicTy" (ppr givens) $ + mkForAllTys tvs $ + mkPhiTy (map dictPred givens) $ + if isSingleton wanteds then + instType (head wanteds) + else + mkTupleTy Boxed (length wanteds) (map instType wanteds) + +dictPred (Dict {tci_pred = pred}) = pred +dictPred inst = pprPanic "dictPred" (ppr inst) + +getDictClassTys (Dict {tci_pred = pred}) = getClassPredTys pred +getDictClassTys inst = pprPanic "getDictClassTys" (ppr inst) -- fdPredsOfInst is used to get predicates that contain functional -- dependencies *or* might do so. The "might do" part is because @@ -118,34 +130,41 @@ getDictClassTys (Dict _ pred _) = getClassPredTys pred -- Leaving these in is really important for the call to fdPredsOfInsts -- in TcSimplify.inferLoop, because the result is fed to 'grow', -- which is supposed to be conservative -fdPredsOfInst (Dict _ pred _) = [pred] -fdPredsOfInst (Method _ _ _ theta _) = theta -fdPredsOfInst other = [] -- LitInsts etc +fdPredsOfInst (Dict {tci_pred = pred}) = [pred] +fdPredsOfInst (Method {tci_theta = theta}) = theta +fdPredsOfInst (ImplicInst {tci_given = gs, + tci_wanted = ws}) = fdPredsOfInsts (gs ++ ws) +fdPredsOfInst (LitInst {}) = [] fdPredsOfInsts :: [Inst] -> [PredType] fdPredsOfInsts insts = concatMap fdPredsOfInst insts -isInheritableInst (Dict _ pred _) = isInheritablePred pred -isInheritableInst (Method _ _ _ theta _) = all isInheritablePred theta -isInheritableInst other = True +isInheritableInst (Dict {tci_pred = pred}) = isInheritablePred pred +isInheritableInst (Method {tci_theta = theta}) = all isInheritablePred theta +isInheritableInst other = True +--------------------------------- +-- Get the implicit parameters mentioned by these Insts +-- NB: the results of these functions are insensitive to zonking + ipNamesOfInsts :: [Inst] -> [Name] ipNamesOfInst :: Inst -> [Name] --- Get the implicit parameters mentioned by these Insts --- NB: ?x and %x get different Names ipNamesOfInsts insts = [n | inst <- insts, n <- ipNamesOfInst inst] -ipNamesOfInst (Dict _ (IParam n _) _) = [ipNameName n] -ipNamesOfInst (Method _ _ _ theta _) = [ipNameName n | IParam n _ <- theta] -ipNamesOfInst other = [] +ipNamesOfInst (Dict {tci_pred = IParam n _}) = [ipNameName n] +ipNamesOfInst (Method {tci_theta = 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 {tci_ty = ty}) = tyVarsOfType ty +tyVarsOfInst (Dict {tci_pred = pred}) = tyVarsOfPred pred +tyVarsOfInst (Method {tci_oid = id, tci_tys = tys}) = tyVarsOfTypes tys `unionVarSet` idFreeTyVars id + -- The id might have free type variables; in the case of + -- locally-overloaded class methods, for example +tyVarsOfInst (ImplicInst {tci_tyvars = tvs, tci_given = givens, tci_wanted = wanteds}) + = (tyVarsOfInsts givens `unionVarSet` tyVarsOfInsts wanteds) `minusVarSet` mkVarSet tvs tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts @@ -156,42 +175,58 @@ Predicates ~~~~~~~~~~ \begin{code} isDict :: Inst -> Bool -isDict (Dict _ _ _) = True -isDict other = False +isDict (Dict {}) = True +isDict other = False isClassDict :: Inst -> Bool -isClassDict (Dict _ pred _) = isClassPred pred -isClassDict other = False +isClassDict (Dict {tci_pred = pred}) = isClassPred pred +isClassDict other = False isTyVarDict :: Inst -> Bool -isTyVarDict (Dict _ pred _) = isTyVarClassPred pred -isTyVarDict other = False +isTyVarDict (Dict {tci_pred = pred}) = isTyVarClassPred pred +isTyVarDict other = False isIPDict :: Inst -> Bool -isIPDict (Dict _ pred _) = isIPPred pred -isIPDict other = False +isIPDict (Dict {tci_pred = pred}) = isIPPred pred +isIPDict other = False + +isImplicInst (ImplicInst {}) = True +isImplicInst 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 - -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 TcExpr.tcId - -linearInstType :: Inst -> TcType -- %x::t --> t -linearInstType (Dict _ (IParam _ ty) _) = ty -\end{code} +isMethodFor ids (Method {tci_oid = id}) = id `elemVarSet` ids +isMethodFor ids inst = False +isMethodOrLit :: Inst -> Bool +isMethodOrLit (Method {}) = True +isMethodOrLit (LitInst {}) = True +isMethodOrLit other = False +\end{code} +\begin{code} +getDefaultableDicts :: [Inst] -> ([(Inst, Class, TcTyVar)], TcTyVarSet) +-- Look for free dicts of the form (C tv), even inside implications +-- *and* the set of tyvars mentioned by all *other* constaints +-- This disgustingly ad-hoc function is solely to support defaulting +getDefaultableDicts insts + = (concat ps, unionVarSets tvs) + where + (ps, tvs) = mapAndUnzip get insts + get d@(Dict {tci_pred = ClassP cls [ty]}) + | Just tv <- tcGetTyVar_maybe ty = ([(d,cls,tv)], emptyVarSet) + | otherwise = ([], tyVarsOfType ty) + get (ImplicInst {tci_tyvars = tvs, tci_wanted = wanteds}) + = ([ up | up@(_,_,tv) <- ups, not (tv `elemVarSet` tv_set)], + ftvs `minusVarSet` tv_set) + where + tv_set = mkVarSet tvs + (ups, ftvs) = getDefaultableDicts wanteds + get inst = ([], tyVarsOfInst inst) +\end{code} %************************************************************************ %* * @@ -199,37 +234,80 @@ linearInstType (Dict _ (IParam _ ty) _) = ty %* * %************************************************************************ -\begin{code} -newDicts :: InstOrigin - -> TcThetaType - -> TcM [Inst] -newDicts orig theta - = getInstLoc orig `thenM` \ loc -> - newDictsAtLoc loc theta +-- newDictBndrs makes a dictionary at a binding site +-- instCall makes a dictionary at an occurrence site +-- and throws it into the LIE -cloneDict :: Inst -> TcM Inst -cloneDict (Dict nm ty loc) = newUnique `thenM` \ uniq -> - returnM (Dict (setNameUnique nm uniq) ty loc) - -newDictAtLoc :: InstLoc -> TcPredType -> TcM Inst -newDictAtLoc inst_loc pred +\begin{code} +---------------- +newDictBndrsO :: InstOrigin -> TcThetaType -> TcM [Inst] +newDictBndrsO orig theta = do { loc <- getInstLoc orig + ; newDictBndrs loc theta } + +newDictBndrs :: InstLoc -> TcThetaType -> TcM [Inst] +newDictBndrs inst_loc theta = mapM (newDictBndr inst_loc) theta + +newDictBndr :: InstLoc -> TcPredType -> TcM Inst +newDictBndr inst_loc pred + = do { uniq <- newUnique + ; let name = mkPredName uniq inst_loc pred + ; return (Dict {tci_name = name, tci_pred = pred, tci_loc = inst_loc}) } + +---------------- +instCall :: InstOrigin -> [TcType] -> TcThetaType -> TcM HsWrapper +-- Instantiate the constraints of a call +-- (instCall o tys theta) +-- (a) Makes fresh dictionaries as necessary for the constraints (theta) +-- (b) Throws these dictionaries into the LIE +-- (c) Eeturns an HsWrapper ([.] tys dicts) + +instCall orig tys theta + = do { loc <- getInstLoc orig + ; (dicts, dict_app) <- instCallDicts loc theta + ; extendLIEs dicts + ; return (dict_app <.> mkWpTyApps tys) } + +---------------- +instStupidTheta :: InstOrigin -> TcThetaType -> TcM () +-- Similar to instCall, but only emit the constraints in the LIE +-- Used exclusively for the 'stupid theta' of a data constructor +instStupidTheta orig theta + = do { loc <- getInstLoc orig + ; (dicts, _) <- instCallDicts loc theta + ; extendLIEs dicts } + +---------------- +instCallDicts :: InstLoc -> TcThetaType -> TcM ([Inst], HsWrapper) +-- This is the key place where equality predicates +-- are unleashed into the world +instCallDicts loc [] = return ([], idHsWrapper) + +instCallDicts loc (EqPred ty1 ty2 : preds) + = do { unifyType ty1 ty2 -- For now, we insist that they unify right away + -- Later on, when we do associated types, + -- unifyType :: Type -> Type -> TcM ([Inst], Coercion) + ; (dicts, co_fn) <- instCallDicts loc preds + ; return (dicts, co_fn <.> WpTyApp ty1) } + -- We use type application to apply the function to the + -- coercion; here ty1 *is* the appropriate identity coercion + +instCallDicts loc (pred : preds) = do { uniq <- newUnique - ; return (mkDict inst_loc uniq pred) } + ; let name = mkPredName uniq loc pred + dict = Dict {tci_name = name, tci_pred = pred, tci_loc = loc} + ; (dicts, co_fn) <- instCallDicts loc preds + ; return (dict:dicts, co_fn <.> WpApp (instToId dict)) } -newDictsAtLoc :: InstLoc -> TcThetaType -> TcM [Inst] -newDictsAtLoc inst_loc theta - = newUniqueSupply `thenM` \ us -> - returnM (zipWith (mkDict inst_loc) (uniqsFromSupply us) theta) - -mkDict inst_loc uniq pred - = Dict name pred inst_loc - where - name = mkPredName uniq (instLocSrcLoc inst_loc) pred +------------- +cloneDict :: Inst -> TcM Inst -- Only used for linear implicit params +cloneDict dict@(Dict nm ty loc) = do { uniq <- newUnique + ; return (dict {tci_name = setNameUnique nm uniq}) } +cloneDict other = pprPanic "cloneDict" (ppr other) -- 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. +-- scope, so we make up a new namea. newIPDict :: InstOrigin -> IPName Name -> Type -> TcM (IPName Id, Inst) newIPDict orig ip_name ty @@ -237,13 +315,22 @@ newIPDict orig ip_name ty newUnique `thenM` \ uniq -> let pred = IParam ip_name ty - name = mkPredName uniq (instLocSrcLoc inst_loc) pred - dict = Dict name pred inst_loc + name = mkPredName uniq inst_loc pred + dict = Dict {tci_name = name, tci_pred = pred, tci_loc = inst_loc} in returnM (mapIPName (\n -> instToId dict) ip_name, dict) \end{code} +\begin{code} +mkPredName :: Unique -> InstLoc -> PredType -> Name +mkPredName uniq loc pred_ty + = mkInternalName uniq occ (srcSpanStart (instLocSpan loc)) + where + occ = case pred_ty of + ClassP cls tys -> mkDictOcc (getOccName cls) + IParam ip ty -> getOccName (ipNameName ip) +\end{code} %************************************************************************ %* * @@ -253,20 +340,6 @@ newIPDict orig ip_name ty \begin{code} -tcInstStupidTheta :: DataCon -> [TcType] -> TcM () --- Instantiate the "stupid theta" of the data con, and throw --- the constraints into the constraint set -tcInstStupidTheta data_con inst_tys - | null stupid_theta - = return () - | otherwise - = do { stupid_dicts <- newDicts (OccurrenceOf (dataConName data_con)) - (substTheta tenv stupid_theta) - ; extendLIEs stupid_dicts } - where - stupid_theta = dataConStupidTheta data_con - tenv = zipTopTvSubst (dataConTyVars data_con) inst_tys - newMethodFromName :: InstOrigin -> BoxyRhoType -> Name -> TcM TcId newMethodFromName origin ty name = tcLookupId name `thenM` \ id -> @@ -309,12 +382,12 @@ checkKind :: TyVar -> TcType -> TcM () checkKind tv ty = do { let ty1 = ty -- ty1 <- zonkTcType ty - ; if typeKind ty1 `isSubKind` tyVarKind tv + ; if typeKind ty1 `isSubKind` Var.tyVarKind tv then return () else pprPanic "checkKind: adding kind constraint" - (vcat [ppr tv <+> ppr (tyVarKind tv), + (vcat [ppr tv <+> ppr (Var.tyVarKind tv), ppr ty <+> ppr ty1 <+> ppr (typeKind ty1)]) } -- do { tv1 <- tcInstTyVar tv @@ -327,8 +400,9 @@ newMethod inst_loc id tys let (theta,tau) = tcSplitPhiTy (applyTys (idType id) tys) meth_id = mkUserLocal (mkMethodOcc (getOccName id)) new_uniq tau loc - inst = Method meth_id id tys theta inst_loc - loc = instLocSrcLoc inst_loc + inst = Method {tci_id = meth_id, tci_oid = id, tci_tys = tys, + tci_theta = theta, tci_loc = inst_loc} + loc = srcSpanStart (instLocSpan inst_loc) in returnM inst \end{code} @@ -380,11 +454,11 @@ Zonking makes sure that the instance types are fully zonked. \begin{code} zonkInst :: Inst -> TcM Inst -zonkInst (Dict name pred loc) +zonkInst dict@(Dict { tci_pred = pred}) = zonkTcPredType pred `thenM` \ new_pred -> - returnM (Dict name new_pred loc) + returnM (dict {tci_pred = new_pred}) -zonkInst (Method m id tys theta loc) +zonkInst meth@(Method {tci_oid = id, tci_tys = tys, tci_theta = theta}) = zonkId id `thenM` \ new_id -> -- Essential to zonk the id in case it's a local variable -- Can't use zonkIdOcc because the id might itself be @@ -392,11 +466,18 @@ zonkInst (Method m id tys theta loc) zonkTcTypes tys `thenM` \ new_tys -> zonkTcThetaType theta `thenM` \ new_theta -> - returnM (Method m new_id new_tys new_theta loc) + returnM (meth { tci_oid = new_id, tci_tys = new_tys, tci_theta = new_theta }) + -- No need to zonk the tci_id -zonkInst (LitInst nm lit ty loc) +zonkInst lit@(LitInst {tci_ty = ty}) = zonkTcType ty `thenM` \ new_ty -> - returnM (LitInst nm lit new_ty loc) + returnM (lit {tci_ty = new_ty}) + +zonkInst implic@(ImplicInst {}) + = ASSERT( all isImmutableTyVar (tci_tyvars implic) ) + do { givens' <- zonkInsts (tci_given implic) + ; wanteds' <- zonkInsts (tci_wanted implic) + ; return (implic {tci_given = givens',tci_wanted = wanteds'}) } zonkInsts insts = mappM zonkInst insts \end{code} @@ -417,36 +498,41 @@ instance Outputable Inst where pprDictsTheta :: [Inst] -> SDoc -- Print in type-like fashion (Eq a, Show b) -pprDictsTheta dicts = pprTheta (map dictPred dicts) +-- The Inst can be an implication constraint, but not a Method or LitInst +pprDictsTheta insts = parens (sep (punctuate comma (map (ppr . instType) insts))) pprDictsInFull :: [Inst] -> SDoc -- Print in type-like fashion, but with source location pprDictsInFull dicts = vcat (map go dicts) where - go dict = sep [quotes (ppr (dictPred dict)), nest 2 (pprInstLoc (instLoc dict))] + go dict = sep [quotes (ppr (instType dict)), nest 2 (pprInstArising dict)] pprInsts :: [Inst] -> SDoc -- Debugging: print the evidence :: type -pprInsts insts = brackets (interpp'SP insts) +pprInsts insts = brackets (interpp'SP insts) pprInst, pprInstInFull :: Inst -> SDoc -- Debugging: print the evidence :: type -pprInst (LitInst nm lit ty loc) = ppr nm <+> dcolon <+> ppr ty -pprInst (Dict nm pred loc) = ppr nm <+> dcolon <+> pprPred pred - -pprInst m@(Method inst_id id tys theta loc) - = ppr inst_id <+> dcolon <+> - braces (sep [ppr id <+> ptext SLIT("at"), - brackets (sep (map pprParendType tys))]) +pprInst inst = ppr (instName inst) <+> dcolon + <+> (braces (ppr (instType inst)) $$ + ifPprDebug implic_stuff) + where + implic_stuff | isImplicInst inst = ppr (tci_reft inst) + | otherwise = empty -pprInstInFull inst - = sep [quotes (pprInst inst), nest 2 (pprInstLoc (instLoc inst))] +pprInstInFull inst = sep [quotes (pprInst inst), nest 2 (pprInstArising inst)] tidyInst :: TidyEnv -> Inst -> Inst -tidyInst env (LitInst nm lit ty loc) = LitInst nm lit (tidyType env ty) loc -tidyInst env (Dict nm pred loc) = Dict nm (tidyPred env pred) loc -tidyInst env (Method u id tys theta loc) = Method u id (tidyTypes env tys) theta loc +tidyInst env lit@(LitInst {tci_ty = ty}) = lit {tci_ty = tidyType env ty} +tidyInst env dict@(Dict {tci_pred = pred}) = dict {tci_pred = tidyPred env pred} +tidyInst env meth@(Method {tci_tys = tys}) = meth {tci_tys = tidyTypes env tys} +tidyInst env implic@(ImplicInst {}) + = implic { tci_tyvars = tvs' + , tci_given = map (tidyInst env') (tci_given implic) + , tci_wanted = map (tidyInst env') (tci_wanted implic) } + where + (env', tvs') = mapAccumL tidyTyVarBndr env (tci_tyvars implic) tidyMoreInsts :: TidyEnv -> [Inst] -> (TidyEnv, [Inst]) -- This function doesn't assume that the tyvars are in scope @@ -496,7 +582,7 @@ addLocalInst home_ie ispec -- We use tcInstSkolType because we don't want to allocate fresh -- *meta* type variables. let dfun = instanceDFunId ispec - ; (tvs', theta', tau') <- tcInstSkolType (InstSkol dfun) (idType dfun) + ; (tvs', theta', tau') <- tcInstSkolType InstSkol (idType dfun) ; let (cls, tys') = tcSplitDFunHead tau' dfun' = setIdType dfun (mkSigmaTy tvs' theta' tau') ispec' = setInstanceDFunId ispec dfun' @@ -568,45 +654,46 @@ addDictLoc ispec thing_inside \begin{code} data LookupInstResult = NoInstance - | SimpleInst (LHsExpr TcId) -- Just a variable, type application, or literal - | GenInst [Inst] (LHsExpr TcId) -- The expression and its needed insts + | GenInst [Inst] (LHsExpr TcId) -- The expression and its needed insts + +lookupSimpleInst :: Inst -> TcM LookupInstResult +-- This is "simple" in tthat it returns NoInstance for implication constraints -lookupInst :: Inst -> TcM LookupInstResult -- It's important that lookupInst does not put any new stuff into -- the LIE. Instead, any Insts needed by the lookup are returned in -- the LookupInstResult, where they can be further processed by tcSimplify +--------------------- Implications ------------------------ +lookupSimpleInst (ImplicInst {}) = return NoInstance --- Methods - -lookupInst inst@(Method _ id tys theta loc) - = newDictsAtLoc loc theta `thenM` \ dicts -> - returnM (GenInst dicts (mkHsDictApp (mkHsTyApp (L span (HsVar id)) tys) (map instToId dicts))) +--------------------- Methods ------------------------ +lookupSimpleInst (Method {tci_oid = id, tci_tys = tys, tci_theta = theta, tci_loc = loc}) + = do { (dicts, dict_app) <- instCallDicts loc theta + ; let co_fn = dict_app <.> mkWpTyApps tys + ; return (GenInst dicts (L span $ HsWrap co_fn (HsVar id))) } where - span = instLocSrcSpan loc - --- Literals + span = instLocSpan loc +--------------------- 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 _nm (HsIntegral i from_integer_name) ty loc) +lookupSimpleInst (LitInst {tci_lit = HsIntegral i from_integer_name, tci_ty = ty, tci_loc = loc}) | Just expr <- shortCutIntLit i ty - = returnM (GenInst [] (noLoc expr)) -- GenInst, not SimpleInst, because - -- expr may be a constructor application + = returnM (GenInst [] (noLoc expr)) | otherwise = ASSERT( from_integer_name `isHsVar` fromIntegerName ) -- A LitInst invariant tcLookupId fromIntegerName `thenM` \ from_integer -> tcInstClassOp loc from_integer [ty] `thenM` \ method_inst -> mkIntegerLit i `thenM` \ integer_lit -> returnM (GenInst [method_inst] - (mkHsApp (L (instLocSrcSpan loc) + (mkHsApp (L (instLocSpan loc) (HsVar (instToId method_inst))) integer_lit)) -lookupInst inst@(LitInst _nm (HsFractional f from_rat_name) ty loc) +lookupSimpleInst (LitInst {tci_lit = HsFractional f from_rat_name, tci_ty = ty, tci_loc = loc}) | Just expr <- shortCutFracLit f ty = returnM (GenInst [] (noLoc expr)) @@ -615,11 +702,11 @@ lookupInst inst@(LitInst _nm (HsFractional f from_rat_name) ty loc) tcLookupId fromRationalName `thenM` \ from_rational -> tcInstClassOp loc from_rational [ty] `thenM` \ method_inst -> mkRatLit f `thenM` \ rat_lit -> - returnM (GenInst [method_inst] (mkHsApp (L (instLocSrcSpan loc) + returnM (GenInst [method_inst] (mkHsApp (L (instLocSpan loc) (HsVar (instToId method_inst))) rat_lit)) --- Dictionaries -lookupInst (Dict _ pred loc) +--------------------- Dictionaries ------------------------ +lookupSimpleInst (Dict {tci_pred = pred, tci_loc = loc}) = do { mb_result <- lookupPred pred ; case mb_result of { Nothing -> return NoInstance ; @@ -654,14 +741,15 @@ lookupInst (Dict _ pred loc) -- any nested for-alls in rho. So the in-scope set is unchanged dfun_rho = substTy tenv' rho (theta, _) = tcSplitPhiTy dfun_rho - ty_app = mkHsTyApp (L (instLocSrcSpan loc) (HsVar dfun_id)) - (map (substTyVar tenv') tyvars) + src_loc = instLocSpan loc + dfun = HsVar dfun_id + tys = map (substTyVar tenv') tyvars ; if null theta then - returnM (SimpleInst ty_app) + returnM (GenInst [] (L src_loc $ HsWrap (mkWpTyApps tys) dfun)) else do - { dicts <- newDictsAtLoc loc theta - ; let rhs = mkHsDictApp ty_app (map instToId dicts) - ; returnM (GenInst dicts rhs) + { (dicts, dict_app) <- instCallDicts loc theta + ; let co_fn = dict_app <.> mkWpTyApps tys + ; returnM (GenInst dicts (L src_loc $ HsWrap co_fn dfun)) }}}} --------------- @@ -695,7 +783,7 @@ lookupPred pred@(ClassP clas tys) ; return Nothing } }} -lookupPred ip_pred = return Nothing +lookupPred ip_pred = return Nothing -- Implicit parameters record_dfun_usage dfun_id = do { hsc_env <- getTopEnv @@ -784,7 +872,7 @@ syntaxNameCtxt name orig ty tidy_env msg = vcat [ptext SLIT("When checking that") <+> quotes (ppr name) <+> ptext SLIT("(needed by a syntactic construct)"), nest 2 (ptext SLIT("has the required type:") <+> ppr (tidyType tidy_env ty)), - nest 2 (pprInstLoc inst_loc)] + nest 2 (ptext SLIT("arising from") <+> pprInstLoc inst_loc)] in returnM (tidy_env, msg) \end{code}