X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDeriv.lhs;h=80dbea987d3ea2c49c3ff510babda96ffc25c1c5;hb=a63bd8f558fedec86451f36d86833c9afb934ae8;hp=80d6b10c2c99ae6b39dde285c52c1bf264b1bb42;hpb=f1080bc82f87317ffa59cffef08b322d7354bb29;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs index 80d6b10..80dbea9 100644 --- a/ghc/compiler/typecheck/TcDeriv.lhs +++ b/ghc/compiler/typecheck/TcDeriv.lhs @@ -10,50 +10,51 @@ module TcDeriv ( tcDeriving ) where #include "HsVersions.h" -import HsSyn ( HsBinds(..), MonoBinds(..), collectLocatedMonoBinders ) +import HsSyn ( HsBinds(..), MonoBinds(..), TyClDecl(..), + collectLocatedMonoBinders ) import RdrHsSyn ( RdrNameMonoBinds ) -import RnHsSyn ( RenamedHsBinds ) -import CmdLineOpts ( opt_D_dump_deriv ) +import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds, RenamedTyClDecl, RenamedHsPred ) +import CmdLineOpts ( DynFlag(..) ) import TcMonad -import TcEnv ( InstEnv, getEnvTyCons, tcSetInstEnv, newDFunName ) +import TcEnv ( tcSetInstEnv, newDFunName, InstInfo(..), pprInstInfo, + tcLookupTyCon, tcExtendTyVarEnv + ) import TcGenDeriv -- Deriv stuff -import TcInstUtil ( InstInfo(..), pprInstInfo, simpleDFunClassTyCon, extendInstEnv ) -import TcSimplify ( tcSimplifyThetas ) +import InstEnv ( InstEnv, simpleDFunClassTyCon, extendInstEnv ) +import TcMonoType ( tcHsPred ) +import TcSimplify ( tcSimplifyDeriv ) import RnBinds ( rnMethodBinds, rnTopMonoBinds ) import RnEnv ( bindLocatedLocalsRn ) -import RnMonad ( RnNameSupply, - renameSourceCode, thenRn, mapRn, returnRn ) +import RnMonad ( renameDerivedCode, thenRn, mapRn, returnRn ) +import HscTypes ( DFunId, PersistentRenamerState, FixityEnv ) -import Bag ( Bag, emptyBag, unionBags, listToBag ) -import Class ( classKey, Class ) -import ErrUtils ( dumpIfSet, Message ) +import BasicTypes ( NewOrData(..) ) +import Class ( className, classKey, classTyVars, Class ) +import ErrUtils ( dumpIfSet_dyn ) import MkId ( mkDictFunId ) -import Id ( mkVanillaId ) -import DataCon ( dataConArgTys, isNullaryDataCon, isExistentialDataCon ) +import DataCon ( dataConRepArgTys, isNullaryDataCon, isExistentialDataCon ) import PrelInfo ( needsDataDeclCtxtClassKeys ) import Maybes ( maybeToBool, catMaybes ) import Module ( Module ) -import Name ( isLocallyDefined, getSrcLoc, NamedThing(..) ) +import Name ( Name, getSrcLoc, nameUnique ) import RdrName ( RdrName ) -import RnMonad ( FixityEnv ) -import TyCon ( tyConTyVars, tyConDataCons, tyConDerivings, +import TyCon ( tyConTyVars, tyConDataCons, tyConArity, newTyConRep, tyConTheta, maybeTyConSingleCon, isDataTyCon, - isEnumerationTyCon, isAlgTyCon, TyCon - ) -import Type ( TauType, mkTyVarTys, mkTyConApp, - mkSigmaTy, mkDictTy, isUnboxedType, - splitAlgTyConApp, classesToPreds + isEnumerationTyCon, isRecursiveTyCon, TyCon ) -import TysWiredIn ( voidTy ) -import Var ( TyVar ) +import TcType ( TcType, ThetaType, mkTyVarTys, mkTyConApp, getClassPredTys_maybe, + isUnLiftedType, mkClassPred, tyVarsOfTypes, tcSplitFunTys, + tcSplitTyConApp_maybe, tcEqTypes ) +import Var ( TyVar, tyVarKind ) +import VarSet ( mkVarSet, subVarSet ) import PrelNames -import Bag ( bagToList ) -import Util ( zipWithEqual, sortLt, thenCmp ) +import Util ( zipWithEqual, sortLt, notNull ) import ListSetOps ( removeDups, assoc ) import Outputable +import Maybe ( isJust ) \end{code} %************************************************************************ @@ -145,8 +146,10 @@ type DerivEqn = (Name, Class, TyCon, [TyVar], DerivRhs) -- The Name is the name for the DFun we'll build -- The tyvars bind all the variables in the RHS -type DerivRhs = [(Class, [TauType])] -- Same as a ThetaType! +pprDerivEqn (n,c,tc,tvs,rhs) + = parens (hsep [ppr n, ppr c, ppr tc, ppr tvs] <+> equals <+> ppr rhs) +type DerivRhs = ThetaType type DerivSoln = DerivRhs \end{code} @@ -174,6 +177,12 @@ context to the instance decl. The "offending classes" are Read, Enum? +FURTHER NOTE ADDED March 2002. In fact, Haskell98 now requires that +pattern matching against a constructor from a data type with a context +gives rise to the constraints for that context -- or at least the thinned +version. So now all classes are "offending". + + %************************************************************************ %* * @@ -185,20 +194,50 @@ context to the instance decl. The "offending classes" are tcDeriving :: PersistentRenamerState -> Module -- name of module under scrutiny -> InstEnv -- What we already know about instances + -> FixityEnv -- used in deriving Show and Read + -> [RenamedTyClDecl] -- All type constructors -> TcM ([InstInfo], -- The generated "instance decls". RenamedHsBinds) -- Extra generated bindings -tcDeriving prs mod inst_env_in local_tycons +tcDeriving prs mod inst_env get_fixity tycl_decls = recoverTc (returnTc ([], EmptyBinds)) $ + getDOptsTc `thenNF_Tc` \ dflags -> -- Fish the "deriving"-related information out of the TcEnv -- and make the necessary "equations". - makeDerivEqns local_tycons `thenTc` \ eqns -> - if null eqns then - returnTc ([], EmptyBinds) - else + makeDerivEqns tycl_decls `thenTc` \ (ordinary_eqns, newtype_inst_info) -> + let + -- Add the newtype-derived instances to the inst env + -- before tacking the "ordinary" ones + inst_env1 = extend_inst_env dflags inst_env + (map iDFunId newtype_inst_info) + in + deriveOrdinaryStuff mod prs inst_env1 get_fixity + ordinary_eqns `thenTc` \ (ordinary_inst_info, binds) -> + let + inst_info = newtype_inst_info ++ ordinary_inst_info + in + + ioToTc (dumpIfSet_dyn dflags Opt_D_dump_deriv "Derived instances" + (ddump_deriving inst_info binds)) `thenTc_` + + returnTc (inst_info, binds) + + where + ddump_deriving :: [InstInfo] -> RenamedHsBinds -> SDoc + ddump_deriving inst_infos extra_binds + = vcat (map ppr_info inst_infos) $$ ppr extra_binds + + ppr_info inst_info = pprInstInfo inst_info $$ + nest 4 (ppr (iBinds inst_info)) + -- pprInstInfo doesn't print much: only the type - -- Take the equation list and solve it, to deliver a list of +----------------------------------------- +deriveOrdinaryStuff mod prs inst_env_in get_fixity [] -- Short cut + = returnTc ([], EmptyBinds) + +deriveOrdinaryStuff mod prs inst_env_in get_fixity eqns + = -- Take the equation list and solve it, to deliver a list of -- solutions, a.k.a. the contexts for the instance decls -- required for the corresponding equations. solveDerivEqns inst_env_in eqns `thenTc` \ new_dfuns -> @@ -208,52 +247,38 @@ tcDeriving prs mod inst_env_in local_tycons -- generate extra not-one-inst-decl-specific binds, notably -- "con2tag" and/or "tag2con" functions. We do these -- separately. - gen_taggery_Names new_dfuns `thenTc` \ nm_alist_etc -> tcGetEnv `thenNF_Tc` \ env -> + getDOptsTc `thenNF_Tc` \ dflags -> let extra_mbind_list = map gen_tag_n_con_monobind nm_alist_etc extra_mbinds = foldr AndMonoBinds EmptyMonoBinds extra_mbind_list - method_binds_s = map (gen_bind (tcGST env)) new_dfuns + method_binds_s = map (gen_bind get_fixity) new_dfuns mbinders = collectLocatedMonoBinders extra_mbinds -- Rename to get RenamedBinds. -- The only tricky bit is that the extra_binds must scope over the -- method bindings for the instances. (rn_method_binds_s, rn_extra_binds) - = renameSourceCode mod prs ( + = renameDerivedCode dflags mod prs ( bindLocatedLocalsRn (ptext (SLIT("deriving"))) mbinders $ \ _ -> rnTopMonoBinds extra_mbinds [] `thenRn` \ (rn_extra_binds, _) -> mapRn rn_meths method_binds_s `thenRn` \ rn_method_binds_s -> returnRn (rn_method_binds_s, rn_extra_binds) ) + new_inst_infos = zipWith gen_inst_info new_dfuns rn_method_binds_s in - mapNF_Tc gen_inst_info (new_dfuns `zip` rn_method_binds_s) `thenNF_Tc` \ new_inst_infos -> - - ioToTc (dumpIfSet opt_D_dump_deriv "Derived instances" - (ddump_deriving new_inst_infos rn_extra_binds)) `thenTc_` - returnTc (new_inst_infos, rn_extra_binds) - where - ddump_deriving :: [InstInfo] -> RenamedHsBinds -> SDoc - ddump_deriving inst_infos extra_binds - = vcat (map pprInstInfo inst_infos) $$ ppr extra_binds - where + where -- Make a Real dfun instead of the dummy one we have so far - gen_inst_info (dfun, binds) - = InstInfo { iLocal = True, - iClass = clas, iTyVars = tyvars, - iTys = tys, iTheta = theta, - iDFunId = dfun, iBinds = binds, - iLoc = getSrcLoc dfun, iPrags = [] } - where - (tyvars, theta, tau) = splitSigmaTy dfun - (clas, tys) = splitDictTy tau + gen_inst_info :: DFunId -> RenamedMonoBinds -> InstInfo + gen_inst_info dfun binds + = InstInfo { iDFunId = dfun, iBinds = binds, iPrags = [] } - rn_meths meths = rnMethodBinds [] meths `thenRn` \ (meths', _) -> returnRn meths' - -- Ignore the free vars returned + rn_meths (cls, meths) = rnMethodBinds cls [] meths `thenRn` \ (meths', _) -> + returnRn meths' -- Ignore the free vars returned \end{code} @@ -279,84 +304,172 @@ or} has just one data constructor (e.g., tuples). all those. \begin{code} -makeDerivEqns :: Module -> [TyCon] -> TcM [DerivEqn] +makeDerivEqns :: [RenamedTyClDecl] + -> TcM ([DerivEqn], -- Ordinary derivings + [InstInfo]) -- Special newtype derivings -makeDerivEqns this_mod local_tycons - = let - think_about_deriving = need_deriving local_tycons - (derive_these, _) = removeDups cmp_deriv think_about_deriving - in - if null local_data_tycons then - returnTc [] -- Bale out now - else - mapTc mk_eqn derive_these `thenTc` \ maybe_eqns -> - returnTc (catMaybes maybe_eqns) +makeDerivEqns tycl_decls + = mapAndUnzipTc mk_eqn derive_these `thenTc` \ (maybe_ordinaries, maybe_newtypes) -> + returnTc (catMaybes maybe_ordinaries, catMaybes maybe_newtypes) where ------------------------------------------------------------------ - need_deriving :: [TyCon] -> [(Class, TyCon)] - -- find the tycons that have `deriving' clauses; - - need_deriving tycons_to_consider - = foldr (\ tycon acc -> [(clas,tycon) | clas <- tyConDerivings tycon] ++ acc) - [] - tycons_to_consider - - ------------------------------------------------------------------ - cmp_deriv :: (Class, TyCon) -> (Class, TyCon) -> Ordering - cmp_deriv (c1, t1) (c2, t2) - = (c1 `compare` c2) `thenCmp` (t1 `compare` t2) + derive_these :: [(NewOrData, Name, RenamedHsPred)] + -- Find the (nd, TyCon, Pred) pairs that must be `derived' + -- NB: only source-language decls have deriving, no imported ones do + derive_these = [ (nd, tycon, pred) + | TyData {tcdND = nd, tcdName = tycon, tcdDerivs = Just preds} <- tycl_decls, + pred <- preds ] ------------------------------------------------------------------ - mk_eqn :: (Class, TyCon) -> NF_TcM (Maybe DerivEqn) - -- we swizzle the tyvars and datacons out of the tycon + mk_eqn :: (NewOrData, Name, RenamedHsPred) -> NF_TcM (Maybe DerivEqn, Maybe InstInfo) + -- We swizzle the tyvars and datacons out of the tycon -- to make the rest of the equation - mk_eqn (clas, tycon) - = case chk_out clas tycon of - Just err -> addErrTc err `thenNF_Tc_` - returnNF_Tc Nothing - Nothing -> newDFunName this_mod clas tys locn `thenNF_Tc` \ dfun_name -> - returnNF_Tc (Just (dfun_name, clas, tycon, tyvars, constraints)) + mk_eqn (new_or_data, tycon_name, pred) + = tcLookupTyCon tycon_name `thenNF_Tc` \ tycon -> + tcAddSrcLoc (getSrcLoc tycon) $ + tcAddErrCtxt (derivCtxt Nothing tycon) $ + tcExtendTyVarEnv (tyConTyVars tycon) $ -- Deriving preds may (now) mention + -- the type variables for the type constructor + tcHsPred pred `thenTc` \ pred' -> + case getClassPredTys_maybe pred' of + Nothing -> bale_out (malformedPredErr tycon pred) + Just (clas, tys) -> mk_eqn_help new_or_data tycon clas tys + + ------------------------------------------------------------------ + mk_eqn_help DataType tycon clas tys + | Just err <- chk_out clas tycon tys + = bale_out (derivingThingErr clas tys tycon tyvars err) + | otherwise + = new_dfun_name clas tycon `thenNF_Tc` \ dfun_name -> + returnNF_Tc (Just (dfun_name, clas, tycon, tyvars, constraints), Nothing) where - clas_key = classKey clas - tyvars = tyConTyVars tycon -- ToDo: Do we need new tyvars ??? - tyvar_tys = mkTyVarTys tyvars + tyvars = tyConTyVars tycon data_cons = tyConDataCons tycon - - constraints = extra_constraints ++ concat (map mk_constraints data_cons) - - -- "extra_constraints": see notes above about contexts on data decls - extra_constraints - | offensive_class = tyConTheta tycon - | otherwise = [] - where - offensive_class = clas_key `elem` needsDataDeclCtxtClassKeys - - mk_constraints data_con - = [ (clas, [arg_ty]) - | arg_ty <- instd_arg_tys, - not (isUnboxedType arg_ty) -- No constraints for unboxed types? - ] - where - instd_arg_tys = dataConArgTys data_con tyvar_tys + constraints = extra_constraints ++ + [ mkClassPred clas [arg_ty] + | data_con <- tyConDataCons tycon, + arg_ty <- dataConRepArgTys data_con, + -- Use the same type variables + -- as the type constructor, + -- hence no need to instantiate + not (isUnLiftedType arg_ty) -- No constraints for unlifted types? + ] + + -- "extra_constraints": see notes above about contexts on data decls + extra_constraints = tyConTheta tycon + + -- | offensive_class = tyConTheta tycon + -- | otherwise = [] + -- offensive_class = classKey clas `elem` needsDataDeclCtxtClassKeys + + + mk_eqn_help NewType tycon clas tys + = doptsTc Opt_GlasgowExts `thenTc` \ gla_exts -> + if can_derive_via_isomorphism && (gla_exts || standard_instance) then + -- Go ahead and use the isomorphism + new_dfun_name clas tycon `thenNF_Tc` \ dfun_name -> + returnTc (Nothing, Just (NewTypeDerived (mk_dfun dfun_name))) + else + if standard_instance then + mk_eqn_help DataType tycon clas [] -- Go via bale-out route + else + bale_out cant_derive_err + where + -- Here is the plan for newtype derivings. We see + -- newtype T a1...an = T (t ak...an) deriving (C1...Cm) + -- where aj...an do not occur free in t, and the Ci are *partial applications* of + -- classes with the last parameter missing + -- + -- We generate the instances + -- instance Ci (t ak...aj) => Ci (T a1...aj) + -- where T a1...aj is the partial application of the LHS of the correct kind + -- + -- Running example: newtype T s a = MkT (ST s a) deriving( Monad ) + + kind = tyVarKind (last (classTyVars clas)) + -- Kind of the thing we want to instance + -- e.g. argument kind of Monad, *->* + + (arg_kinds, _) = tcSplitFunTys kind + n_args_to_drop = length arg_kinds + -- Want to drop 1 arg from (T s a) and (ST s a) + -- to get instance Monad (ST s) => Monad (T s) + + (tyvars, rep_ty) = newTyConRep tycon + maybe_rep_app = tcSplitTyConApp_maybe rep_ty + Just (rep_tc, rep_ty_args) = maybe_rep_app + + n_tyvars_to_keep = tyConArity tycon - n_args_to_drop + tyvars_to_drop = drop n_tyvars_to_keep tyvars + tyvars_to_keep = take n_tyvars_to_keep tyvars + + n_args_to_keep = tyConArity rep_tc - n_args_to_drop + args_to_drop = drop n_args_to_keep rep_ty_args + args_to_keep = take n_args_to_keep rep_ty_args + + ctxt_pred = mkClassPred clas (tys ++ [mkTyConApp rep_tc args_to_keep]) + + mk_dfun dfun_name = mkDictFunId dfun_name clas tyvars + (tys ++ [mkTyConApp tycon (mkTyVarTys tyvars_to_keep)] ) + [ctxt_pred] + + -- We can only do this newtype deriving thing if: + standard_instance = null tys && classKey clas `elem` derivableClassKeys + + can_derive_via_isomorphism + = not (clas `hasKey` readClassKey) -- Never derive Read,Show this way + && not (clas `hasKey` showClassKey) + && n_tyvars_to_keep >= 0 -- Well kinded; + -- eg not: newtype T = T Int deriving( Monad ) + && isJust maybe_rep_app -- The rep type is a type constructor app + && n_args_to_keep >= 0 -- Well kinded: + -- eg not: newtype T a = T Int deriving( Monad ) + && eta_ok -- Eta reduction works + && not (isRecursiveTyCon tycon) -- Does not work for recursive tycons: + -- newtype A = MkA [A] + -- Don't want + -- instance Eq [A] => Eq A !! + + -- Check that eta reduction is OK + -- (a) the dropped-off args are identical + -- (b) the remaining type args mention + -- only the remaining type variables + eta_ok = (args_to_drop `tcEqTypes` mkTyVarTys tyvars_to_drop) + && (tyVarsOfTypes args_to_keep `subVarSet` mkVarSet tyvars_to_keep) + + cant_derive_err = derivingThingErr clas tys tycon tyvars_to_keep + (ptext SLIT("too hard for cunning newtype deriving")) + + bale_out err = addErrTc err `thenNF_Tc_` returnNF_Tc (Nothing, Nothing) ------------------------------------------------------------------ - chk_out :: Class -> TyCon -> Maybe Message - chk_out clas tycon - | clas `hasKey` enumClassKey && not is_enumeration = bog_out nullary_why - | clas `hasKey` boundedClassKey && not is_enumeration_or_single = bog_out single_nullary_why - | clas `hasKey` ixClassKey && not is_enumeration_or_single = bog_out single_nullary_why - | any isExistentialDataCon (tyConDataCons tycon) = Just (existentialErr clas tycon) - | otherwise = Nothing + chk_out :: Class -> TyCon -> [TcType] -> Maybe SDoc + chk_out clas tycon tys + | notNull tys = Just non_std_why + | not (getUnique clas `elem` derivableClassKeys) = Just non_std_why + | clas `hasKey` enumClassKey && not is_enumeration = Just nullary_why + | clas `hasKey` boundedClassKey && not is_enumeration_or_single = Just single_nullary_why + | clas `hasKey` ixClassKey && not is_enumeration_or_single = Just single_nullary_why + | null data_cons = Just no_cons_why + | any isExistentialDataCon data_cons = Just existential_why + | otherwise = Nothing where + data_cons = tyConDataCons tycon is_enumeration = isEnumerationTyCon tycon is_single_con = maybeToBool (maybeTyConSingleCon tycon) is_enumeration_or_single = is_enumeration || is_single_con - single_nullary_why = SLIT("one constructor data type or type with all nullary constructors expected") - nullary_why = SLIT("data type with all nullary constructors expected") + single_nullary_why = ptext SLIT("one constructor data type or type with all nullary constructors expected") + nullary_why = ptext SLIT("data type with all nullary constructors expected") + no_cons_why = ptext SLIT("type has no data constructors") + non_std_why = ptext SLIT("not a derivable class") + existential_why = ptext SLIT("it has existentially-quantified constructor(s)") - bog_out why = Just (derivingThingErr clas tycon why) +new_dfun_name clas tycon -- Just a simple wrapper + = newDFunName clas [mkTyConApp tycon []] (getSrcLoc tycon) + -- The type passed to newDFunName is only used to generate + -- a suitable string; hence the empty type arg list \end{code} %************************************************************************ @@ -386,7 +499,7 @@ solveDerivEqns :: InstEnv -- This bunch is Absolutely minimal... solveDerivEqns inst_env_in orig_eqns - = iterateDeriv initial_solutions + = iterateDeriv 1 initial_solutions where -- The initial solutions for the equations claim that each -- instance has an empty context; this solution is certainly @@ -399,52 +512,52 @@ solveDerivEqns inst_env_in orig_eqns -- compares it with the current one; finishes if they are the -- same, otherwise recurses with the new solutions. -- It fails if any iteration fails - iterateDeriv :: [DerivSoln] ->TcM [DFunId] - iterateDeriv current_solns - = checkNoErrsTc (iterateOnce current_solns) `thenTc` \ (new_dfuns, new_solns) -> + iterateDeriv :: Int -> [DerivSoln] ->TcM [DFunId] + iterateDeriv n current_solns + | n > 20 -- Looks as if we are in an infinite loop + -- This can happen if we have -fallow-undecidable-instances + -- (See TcSimplify.tcSimplifyDeriv.) + = pprPanic "solveDerivEqns: probable loop" + (vcat (map pprDerivEqn orig_eqns) $$ ppr current_solns) + | otherwise + = getDOptsTc `thenNF_Tc` \ dflags -> + let + dfuns = zipWithEqual "add_solns" mk_deriv_dfun orig_eqns current_solns + inst_env = extend_inst_env dflags inst_env_in dfuns + in + checkNoErrsTc ( + -- Extend the inst info from the explicit instance decls + -- with the current set of solutions, and simplify each RHS + tcSetInstEnv inst_env $ + mapTc gen_soln orig_eqns + ) `thenTc` \ new_solns -> if (current_solns == new_solns) then - returnTc new_dfuns + returnTc dfuns else - iterateDeriv new_solns + iterateDeriv (n+1) new_solns ------------------------------------------------------------------ - iterateOnce current_solns - = -- Extend the inst info from the explicit instance decls - -- with the current set of solutions, giving a - - add_solns inst_env_in orig_eqns current_solns `thenNF_Tc` \ (new_dfuns, inst_env) -> - - -- Simplify each RHS - tcSetInstEnv inst_env ( - listTc [ tcAddErrCtxt (derivCtxt tc) $ - tcSimplifyThetas deriv_rhs - | (_, _,tc,_,deriv_rhs) <- orig_eqns ] - ) `thenTc` \ next_solns -> - - -- Canonicalise the solutions, so they compare nicely - let canonicalised_next_solns = [ sortLt (<) next_soln | next_soln <- next_solns ] - in - returnTc (new_dfuns, canonicalised_next_solns) + + gen_soln (_, clas, tc,tyvars,deriv_rhs) + = tcAddSrcLoc (getSrcLoc tc) $ + tcAddErrCtxt (derivCtxt (Just clas) tc) $ + tcSimplifyDeriv tyvars deriv_rhs `thenTc` \ theta -> + returnTc (sortLt (<) theta) -- Canonicalise before returning the soluction \end{code} \begin{code} -add_solns :: InstEnv -- The global, non-derived ones - -> [DerivEqn] -> [DerivSoln] - -> ([DFunId], InstEnv) - -- the eqns and solns move "in lockstep"; we have the eqns - -- because we need the LHS info for addClassInstance. - -add_solns inst_env_in eqns solns - = (new_dfuns, inst_env) +extend_inst_env dflags inst_env new_dfuns + = new_inst_env where - new_dfuns = zipWithEqual "add_solns" mk_deriv_dfun eqns solns - (inst_env, _) = extendInstEnv inst_env_in + (new_inst_env, _errs) = extendInstEnv dflags inst_env new_dfuns -- Ignore the errors about duplicate instances. -- We don't want repeated error messages -- They'll appear later, when we do the top-level extendInstEnvs - mk_deriv_dfun (dfun_name clas, tycon, tyvars, _) theta - = mkDictFunId dfun_name clas tyvars [mkTyConApp tycon (mkTyVarTys tyvars)] theta +mk_deriv_dfun (dfun_name, clas, tycon, tyvars, _) theta + = mkDictFunId dfun_name clas tyvars + [mkTyConApp tycon (mkTyVarTys tyvars)] + theta \end{code} %************************************************************************ @@ -511,25 +624,26 @@ the renamer. What a great hack! \begin{code} -- Generate the method bindings for the required instance --- (paired with class name, as we need that when generating dict --- names.) -gen_bind :: GlobalSymbolTable -> DFunId -> RdrNameMonoBinds -gen_bind fixities inst - | not (isLocallyDefined tycon) = EmptyMonoBinds - | clas `hasKey` showClassKey = gen_Show_binds fixities tycon - | clas `hasKey` readClassKey = gen_Read_binds fixities tycon - | otherwise - = assoc "gen_bind:bad derived class" - [(eqClassKey, gen_Eq_binds) - ,(ordClassKey, gen_Ord_binds) - ,(enumClassKey, gen_Enum_binds) - ,(boundedClassKey, gen_Bounded_binds) - ,(ixClassKey, gen_Ix_binds) - ] - (classKey clas) - tycon +-- (paired with class name, as we need that when renaming +-- the method binds) +gen_bind :: FixityEnv -> DFunId -> (Name, RdrNameMonoBinds) +gen_bind get_fixity dfun + = (cls_nm, binds) where + cls_nm = className clas (clas, tycon) = simpleDFunClassTyCon dfun + + binds = assoc "gen_bind:bad derived class" gen_list + (nameUnique cls_nm) tycon + + gen_list = [(eqClassKey, gen_Eq_binds) + ,(ordClassKey, gen_Ord_binds) + ,(enumClassKey, gen_Enum_binds) + ,(boundedClassKey, gen_Bounded_binds) + ,(ixClassKey, gen_Ix_binds) + ,(showClassKey, gen_Show_binds get_fixity) + ,(readClassKey, gen_Read_binds get_fixity) + ] \end{code} @@ -544,7 +658,7 @@ data Foo ... = ... con2tag_Foo :: Foo ... -> Int# tag2con_Foo :: Int -> Foo ... -- easier if Int, not Int# -maxtag_Foo :: Int -- ditto (NB: not unboxed) +maxtag_Foo :: Int -- ditto (NB: not unlifted) We have a @con2tag@ function for a tycon if: @@ -575,7 +689,7 @@ gen_taggery_Names dfuns = foldlTc do_con2tag [] tycons_of_interest `thenTc` \ names_so_far -> foldlTc do_tag2con names_so_far tycons_of_interest where - all_CTs = map simplDFunClassTyCon dfuns + all_CTs = map simpleDFunClassTyCon dfuns all_tycons = map snd all_CTs (tycons_of_interest, _) = removeDups compare all_tycons @@ -611,21 +725,23 @@ gen_taggery_Names dfuns is_in_eqns clas_key tycon ((c,t):cts) = (clas_key == classKey c && tycon == t) || is_in_eqns clas_key tycon cts - \end{code} \begin{code} -derivingThingErr :: Class -> TyCon -> FAST_STRING -> Message - -derivingThingErr clas tycon why - = sep [hsep [ptext SLIT("Can't make a derived instance of"), quotes (ppr clas)], - hsep [ptext SLIT("for the type"), quotes (ppr tycon)], - parens (ptext why)] +derivingThingErr clas tys tycon tyvars why + = sep [hsep [ptext SLIT("Can't make a derived instance of"), quotes (ppr pred)], + parens why] + where + pred = mkClassPred clas (tys ++ [mkTyConApp tycon (mkTyVarTys tyvars)]) -existentialErr clas tycon - = sep [ptext SLIT("Can't derive any instances for type") <+> quotes (ppr tycon), - ptext SLIT("because it has existentially-quantified constructor(s)")] +malformedPredErr tycon pred = ptext SLIT("Illegal deriving item") <+> ppr pred -derivCtxt tycon - = ptext SLIT("When deriving classes for") <+> quotes (ppr tycon) +derivCtxt :: Maybe Class -> TyCon -> SDoc +derivCtxt maybe_cls tycon + = ptext SLIT("When deriving") <+> cls <+> ptext SLIT("for type") <+> quotes (ppr tycon) + where + cls = case maybe_cls of + Nothing -> ptext SLIT("instances") + Just c -> ptext SLIT("the") <+> quotes (ppr c) <+> ptext SLIT("instance") \end{code} +