X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDeriv.lhs;h=db21e8eb62ab6517c0d1ea55d9ce2548a2d6be3f;hb=83eef621e4a4fbb6c1343304ec638cafd6c9dc09;hp=eb10d71051c5de8db9d2783012658429266a3962;hpb=1d27115b664e2343ec06b3eec3700f6b48c6d239;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs index eb10d71..db21e8e 100644 --- a/ghc/compiler/typecheck/TcDeriv.lhs +++ b/ghc/compiler/typecheck/TcDeriv.lhs @@ -1,5 +1,5 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcDeriv]{Deriving} @@ -10,49 +10,47 @@ module TcDeriv ( tcDeriving ) where #include "HsVersions.h" -import HsSyn ( HsBinds(..), MonoBinds(..), collectMonoBinders ) -import RdrHsSyn ( RdrName, RdrNameMonoBinds ) -import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds ) +import HsSyn ( HsBinds(..), MonoBinds(..), TyClDecl(..), + collectLocatedMonoBinders ) +import RdrHsSyn ( RdrNameMonoBinds ) +import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds, RenamedTyClDecl ) +import CmdLineOpts ( DynFlag(..), DynFlags ) import TcMonad -import Inst ( InstanceMapper ) -import TcEnv ( getEnv_TyCons, tcLookupClassByKey ) -import TcKind ( TcKind ) +import TcEnv ( TcEnv, tcSetInstEnv, newDFunName, InstInfo(..), pprInstInfo, + tcLookupClass, tcLookupTyCon + ) import TcGenDeriv -- Deriv stuff -import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs ) +import InstEnv ( InstEnv, simpleDFunClassTyCon, extendInstEnv ) import TcSimplify ( tcSimplifyThetas ) import RnBinds ( rnMethodBinds, rnTopMonoBinds ) -import RnEnv ( newDfunName, bindLocatedLocalsRn ) -import RnMonad ( RnM, RnDown, SDown, RnNameSupply, - renameSourceCode, thenRn, mapRn, returnRn ) +import RnEnv ( bindLocatedLocalsRn ) +import RnMonad ( renameDerivedCode, thenRn, mapRn, returnRn ) +import HscTypes ( DFunId, PersistentRenamerState ) -import Bag ( Bag, emptyBag, unionBags, listToBag ) +import BasicTypes ( Fixity ) import Class ( classKey, Class ) -import ErrUtils ( ErrMsg ) +import ErrUtils ( dumpIfSet_dyn, Message ) import MkId ( mkDictFunId ) -import Id ( dataConArgTys, isNullaryDataCon ) +import DataCon ( dataConArgTys, isNullaryDataCon, isExistentialDataCon ) import PrelInfo ( needsDataDeclCtxtClassKeys ) -import Maybes ( maybeToBool ) -import Name ( isLocallyDefined, getSrcLoc, Provenance, - Name{--O only-}, Module, NamedThing(..), - OccName, nameOccName - ) -import SrcLoc ( mkGeneratedSrcLoc, SrcLoc ) -import TyCon ( tyConTyVars, tyConDataCons, tyConDerivings, +import Maybes ( maybeToBool, catMaybes ) +import Module ( Module ) +import Name ( Name, getSrcLoc ) +import RdrName ( RdrName ) + +import TyCon ( tyConTyVars, tyConDataCons, tyConTheta, maybeTyConSingleCon, isDataTyCon, - isEnumerationTyCon, isAlgTyCon, TyCon - ) -import Type ( GenType(..), TauType, mkTyVarTys, mkTyConApp, - mkSigmaTy, mkDictTy, isUnboxedType, - splitAlgTyConApp + isEnumerationTyCon, TyCon ) -import TysPrim ( voidTy ) -import TyVar ( GenTyVar, TyVar ) -import Unique -- Keys stuff -import Bag ( bagToList ) -import Util ( zipWithEqual, sortLt, removeDups, assoc, thenCmp ) +import Type ( TauType, PredType(..), mkTyVarTys, mkTyConApp, isUnboxedType ) +import Var ( TyVar ) +import PrelNames +import Util ( zipWithEqual, sortLt ) +import ListSetOps ( removeDups, assoc ) import Outputable +import List ( nub ) \end{code} %************************************************************************ @@ -140,12 +138,12 @@ this by simplifying the RHS to a form in which So, here are the synonyms for the ``equation'' structures: \begin{code} -type DerivEqn = (Class, TyCon, [TyVar], DerivRhs) - -- The tyvars bind all the variables in the RHS - -- NEW: it's convenient to re-use InstInfo - -- We'll "panic" out some fields... +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! + --[PredType] -- ... | Class Class [Type==TauType] type DerivSoln = DerivRhs \end{code} @@ -182,28 +180,28 @@ context to the instance decl. The "offending classes" are %************************************************************************ \begin{code} -tcDeriving :: Module -- name of module under scrutiny - -> RnNameSupply -- for "renaming" bits of generated code - -> Bag InstInfo -- What we already know about instances - -> TcM s (Bag InstInfo, -- The generated "instance decls". - RenamedHsBinds, -- Extra generated bindings - SDoc) -- Printable derived instance decls; - -- for debugging via -ddump-derivings. +tcDeriving :: PersistentRenamerState + -> Module -- name of module under scrutiny + -> InstEnv -- What we already know about instances + -> (Name -> Maybe Fixity) -- used in deriving Show and Read + -> [RenamedTyClDecl] -- All type constructors + -> TcM ([InstInfo], -- The generated "instance decls". + RenamedHsBinds) -- Extra generated bindings -tcDeriving modname rn_name_supply inst_decl_infos_in - = recoverTc (returnTc (emptyBag, EmptyBinds, empty)) $ +tcDeriving prs mod inst_env_in get_fixity tycl_decls + = recoverTc (returnTc ([], EmptyBinds)) $ -- Fish the "deriving"-related information out of the TcEnv -- and make the necessary "equations". - makeDerivEqns `thenTc` \ eqns -> + makeDerivEqns tycl_decls `thenTc` \ eqns -> if null eqns then - returnTc (emptyBag, EmptyBinds, text "No derivings") + returnTc ([], EmptyBinds) else -- 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_decl_infos_in eqns `thenTc` \ new_inst_infos -> + solveDerivEqns inst_env_in eqns `thenTc` \ new_dfuns -> -- Now augment the InstInfos, adding in the rather boring -- actual-code-to-do-the-methods binds. We may also need to @@ -211,50 +209,48 @@ tcDeriving modname rn_name_supply inst_decl_infos_in -- "con2tag" and/or "tag2con" functions. We do these -- separately. - gen_taggery_Names new_inst_infos `thenTc` \ nm_alist_etc -> - + gen_taggery_Names new_dfuns `thenTc` \ nm_alist_etc -> + tcGetEnv `thenNF_Tc` \ env -> + getDOptsTc `thenTc` \ 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 new_inst_infos - mbinders = bagToList (collectMonoBinders extra_mbinds) + 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. - (dfun_names_w_method_binds, rn_extra_binds) - = renameSourceCode modname rn_name_supply ( + (rn_method_binds_s, rn_extra_binds) + = renameDerivedCode dflags mod prs ( bindLocatedLocalsRn (ptext (SLIT("deriving"))) mbinders $ \ _ -> - rnTopMonoBinds extra_mbinds [] `thenRn` \ rn_extra_binds -> - mapRn rn_one method_binds_s `thenRn` \ dfun_names_w_method_binds -> - returnRn (dfun_names_w_method_binds, rn_extra_binds) + 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) ) - rn_one (cl_nm, tycon_nm, meth_binds) - = newDfunName cl_nm tycon_nm - Nothing mkGeneratedSrcLoc `thenRn` \ dfun_name -> - rnMethodBinds meth_binds `thenRn` \ rn_meth_binds -> - returnRn (dfun_name, rn_meth_binds) - - really_new_inst_infos = map (gen_inst_info modname) - (new_inst_infos `zip` dfun_names_w_method_binds) - ddump_deriv = ddump_deriving really_new_inst_infos rn_extra_binds + new_inst_infos = zipWith gen_inst_info new_dfuns rn_method_binds_s in - --pprTrace "derived:\n" (ddump_deriv) $ - returnTc (listToBag really_new_inst_infos, - rn_extra_binds, - ddump_deriv) + ioToTc (dumpIfSet_dyn dflags 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 pp_info inst_infos) ++ [ppr extra_binds]) + = vcat (map pprInstInfo inst_infos) $$ ppr extra_binds where - pp_info (InstInfo clas tvs [ty] inst_decl_theta _ _ mbinds _ _) - = ($$) (ppr (mkSigmaTy tvs inst_decl_theta (mkDictTy clas [ty]))) - (ppr mbinds) + + -- Make a Real dfun instead of the dummy one we have so far + gen_inst_info :: DFunId -> RenamedMonoBinds -> InstInfo + gen_inst_info dfun binds + = InstInfo { iLocal = True, iDFunId = dfun, + iBinds = binds, iPrags = [] } + + rn_meths meths = rnMethodBinds [] meths `thenRn` \ (meths', _) -> returnRn meths' + -- Ignore the free vars returned \end{code} @@ -280,111 +276,75 @@ or} has just one data constructor (e.g., tuples). all those. \begin{code} -makeDerivEqns :: TcM s [DerivEqn] +makeDerivEqns :: [RenamedTyClDecl] -> TcM [DerivEqn] -makeDerivEqns - = tcGetEnv `thenNF_Tc` \ env -> - let - local_data_tycons = filter (\tc -> isLocallyDefined tc && isAlgTyCon tc) - (getEnv_TyCons env) - in - if null local_data_tycons then - -- Bale out now; evalClass may not be loaded if there aren't any - returnTc [] - else - tcLookupClassByKey evalClassKey `thenNF_Tc` \ eval_clas -> - let - think_about_deriving = need_deriving eval_clas local_data_tycons - (derive_these, _) = removeDups cmp_deriv think_about_deriving - eqns = map mk_eqn derive_these - in - mapTc chk_out think_about_deriving `thenTc_` - returnTc eqns +makeDerivEqns tycl_decls + = mapTc mk_eqn derive_these `thenTc` \ maybe_eqns -> + returnTc (catMaybes maybe_eqns) where ------------------------------------------------------------------ - need_deriving :: Class -> [TyCon] -> [(Class, TyCon)] - -- find the tycons that have `deriving' clauses; - -- we handle the "every datatype in Eval" by - -- doing a dummy "deriving" for it. - - need_deriving eval_clas tycons_to_consider - = foldr ( \ tycon acc -> - let - acc_plus = if isLocallyDefined tycon - then (eval_clas, tycon) : acc - else acc - in - case (tyConDerivings tycon) of - [] -> acc_plus - cs -> [ (clas,tycon) | clas <- cs ] ++ acc_plus - ) - [] - tycons_to_consider + derive_these :: [(Name, Name)] + -- Find the (Class,TyCon) pairs that must be `derived' + -- NB: only source-language decls have deriving, no imported ones do + derive_these = [ (clas,tycon) + | TyData {tcdName = tycon, tcdDerivs = Just classes} <- tycl_decls, + clas <- nub classes ] ------------------------------------------------------------------ - chk_out :: (Class, TyCon) -> TcM s () - chk_out this_one@(clas, tycon) - = let - clas_key = classKey clas - - is_enumeration = isEnumerationTyCon tycon - is_single_con = maybeToBool (maybeTyConSingleCon tycon) - - 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") + mk_eqn :: (Name, Name) -> NF_TcM (Maybe DerivEqn) + -- we swizzle the tyvars and datacons out of the tycon + -- to make the rest of the equation - chk_clas clas_uniq clas_str clas_why cond - = if (clas_uniq == clas_key) - then checkTc cond (derivingThingErr clas_str clas_why tycon) - else returnTc () - in - -- Are things OK for deriving Enum (if appropriate)? - chk_clas enumClassKey (SLIT("Enum")) nullary_why is_enumeration `thenTc_` + mk_eqn (clas_name, tycon_name) + = tcLookupClass clas_name `thenNF_Tc` \ clas -> + tcLookupTyCon tycon_name `thenNF_Tc` \ tycon -> + let + clas_key = classKey clas + tyvars = tyConTyVars tycon + tyvar_tys = mkTyVarTys tyvars + ty = mkTyConApp tycon tyvar_tys + data_cons = tyConDataCons tycon + locn = getSrcLoc 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 = [] - -- Are things OK for deriving Bounded (if appropriate)? - chk_clas boundedClassKey (SLIT("Bounded")) single_nullary_why - (is_enumeration || is_single_con) `thenTc_` + offensive_class = clas_key `elem` needsDataDeclCtxtClassKeys + + mk_constraints data_con + = [ (clas, [arg_ty]) + | arg_ty <- dataConArgTys data_con tyvar_tys, + not (isUnboxedType arg_ty) -- No constraints for unboxed types? + ] + in + case chk_out clas tycon of + Just err -> addErrTc err `thenNF_Tc_` + returnNF_Tc Nothing + Nothing -> newDFunName clas [ty] locn `thenNF_Tc` \ dfun_name -> + returnNF_Tc (Just (dfun_name, clas, tycon, tyvars, constraints)) - -- Are things OK for deriving Ix (if appropriate)? - chk_clas ixClassKey (SLIT("Ix.Ix")) single_nullary_why - (is_enumeration || is_single_con) - ------------------------------------------------------------------ - cmp_deriv :: (Class, TyCon) -> (Class, TyCon) -> Ordering - cmp_deriv (c1, t1) (c2, t2) - = (c1 `compare` c2) `thenCmp` (t1 `compare` t2) ------------------------------------------------------------------ - mk_eqn :: (Class, TyCon) -> DerivEqn - -- we swizzle the tyvars and datacons out of the tycon - -- to make the rest of the equation - - mk_eqn (clas, tycon) - = (clas, tycon, tyvars, if_not_Eval constraints) - where - clas_key = classKey clas - tyvars = tyConTyVars tycon -- ToDo: Do we need new tyvars ??? - tyvar_tys = mkTyVarTys tyvars - data_cons = tyConDataCons tycon - - if_not_Eval cs = if clas_key == evalClassKey then [] else cs - - constraints = extra_constraints ++ concat (map mk_constraints data_cons) + 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 + where + is_enumeration = isEnumerationTyCon tycon + is_single_con = maybeToBool (maybeTyConSingleCon tycon) + is_enumeration_or_single = is_enumeration || is_single_con - -- "extra_constraints": see notes above about contexts on data decls - extra_constraints - | offensive_class = tyConTheta tycon - | otherwise = [] - where - offensive_class = clas_key `elem` needsDataDeclCtxtClassKeys + 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") - 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 + bog_out why = Just (derivingThingErr clas tycon why) \end{code} %************************************************************************ @@ -408,12 +368,12 @@ ordered by sorting on type varible, tv, (major key) and then class, k, \end{itemize} \begin{code} -solveDerivEqns :: Bag InstInfo +solveDerivEqns :: InstEnv -> [DerivEqn] - -> TcM s [InstInfo] -- Solns in same order as eqns. - -- This bunch is Absolutely minimal... + -> TcM [DFunId] -- Solns in same order as eqns. + -- This bunch is Absolutely minimal... -solveDerivEqns inst_decl_infos_in orig_eqns +solveDerivEqns inst_env_in orig_eqns = iterateDeriv initial_solutions where -- The initial solutions for the equations claim that each @@ -427,11 +387,12 @@ solveDerivEqns inst_decl_infos_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 s [InstInfo] + iterateDeriv :: [DerivSoln] ->TcM [DFunId] iterateDeriv current_solns - = checkNoErrsTc (iterateOnce current_solns) `thenTc` \ (new_inst_infos, new_solns) -> + = checkNoErrsTc (iterateOnce current_solns) + `thenTc` \ (new_dfuns, new_solns) -> if (current_solns == new_solns) then - returnTc new_inst_infos + returnTc new_dfuns else iterateDeriv new_solns @@ -439,75 +400,45 @@ solveDerivEqns inst_decl_infos_in orig_eqns iterateOnce current_solns = -- Extend the inst info from the explicit instance decls -- with the current set of solutions, giving a - - add_solns inst_decl_infos_in orig_eqns current_solns - `thenNF_Tc` \ (new_inst_infos, inst_mapper) -> - let - class_to_inst_env cls = inst_mapper cls - in + getDOptsTc `thenTc` \ dflags -> + let (new_dfuns, inst_env) = + add_solns dflags inst_env_in orig_eqns current_solns + in -- Simplify each RHS - - listTc [ tcAddErrCtxt (derivCtxt tc) $ - tcSimplifyThetas class_to_inst_env deriv_rhs - | (_,tc,_,deriv_rhs) <- orig_eqns ] `thenTc` \ next_solns -> + 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 ] + let canonicalised_next_solns = [ sortLt (<) next_soln | next_soln <- next_solns ] in - returnTc (new_inst_infos, canonicalised_next_solns) + returnTc (new_dfuns, canonicalised_next_solns) \end{code} \begin{code} -add_solns :: Bag InstInfo -- The global, non-derived ones +add_solns :: DynFlags + -> InstEnv -- The global, non-derived ones -> [DerivEqn] -> [DerivSoln] - -> NF_TcM s ([InstInfo], -- The new, derived ones - InstanceMapper) + -> ([DFunId], InstEnv) -- the eqns and solns move "in lockstep"; we have the eqns -- because we need the LHS info for addClassInstance. -add_solns inst_infos_in eqns solns - - = discardErrsTc (buildInstanceEnvs all_inst_infos) `thenNF_Tc` \ inst_mapper -> - -- We do the discard-errs so that we don't get repeated error messages - -- about duplicate instances. - -- They'll appear later, when we do the top-level buildInstanceEnvs. - - returnNF_Tc (new_inst_infos, inst_mapper) - where - new_inst_infos = zipWithEqual "add_solns" mk_deriv_inst_info eqns solns +add_solns dflags inst_env_in eqns solns + = (new_dfuns, inst_env) + where + new_dfuns = zipWithEqual "add_solns" mk_deriv_dfun eqns solns + (inst_env, _) = extendInstEnv dflags inst_env_in 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 - all_inst_infos = inst_infos_in `unionBags` listToBag new_inst_infos + mk_deriv_dfun (dfun_name, clas, tycon, tyvars, _) theta + = mkDictFunId dfun_name clas tyvars [mkTyConApp tycon (mkTyVarTys tyvars)] + (map pair2PredType theta) - mk_deriv_inst_info (clas, tycon, tyvars, _) theta - = InstInfo clas tyvars [mkTyConApp tycon (mkTyVarTys tyvars)] - theta - (my_panic "dfun_theta") - - dummy_dfun_id - - (my_panic "binds") (getSrcLoc tycon) - (my_panic "upragmas") - where - dummy_dfun_id - = mkDictFunId (getName tycon) dummy_dfun_ty bottom bottom - -- The name is getSrcLoc'd in an error message - where - bottom = panic "dummy_dfun_id" - - dummy_dfun_ty = mkSigmaTy tyvars theta voidTy - -- All we need from the dfun is its "theta" part, used during - -- equation simplification (tcSimplifyThetas). The final - -- dfun_id will have the superclass dictionaries as arguments too, - -- but that'll be added after the equations are solved. For now, - -- it's enough just to make a dummy dfun with the simple theta part. - -- - -- The part after the theta is dummied here as voidTy; actually it's - -- (C (T a b)), but it doesn't seem worth constructing it. - -- We can't leave it as a panic because to get the theta part we - -- have to run down the type! - - my_panic str = panic "add_soln" -- pprPanic ("add_soln:"++str) (hsep [char ':', ppr clas, ppr tycon]) + pair2PredType (clas, tautypes) = Class clas tautypes \end{code} %************************************************************************ @@ -576,51 +507,22 @@ the renamer. What a great hack! -- Generate the method bindings for the required instance -- (paired with class name, as we need that when generating dict -- names.) -gen_bind :: InstInfo -> ({-class-}OccName, {-tyCon-}OccName, RdrNameMonoBinds) -gen_bind (InstInfo clas _ [ty] _ _ _ _ _ _) - | not from_here - = (clas_nm, tycon_nm, EmptyMonoBinds) +gen_bind :: (Name -> Maybe Fixity) -> DFunId -> RdrNameMonoBinds +gen_bind get_fixity dfun + | clas `hasKey` showClassKey = gen_Show_binds get_fixity tycon + | clas `hasKey` readClassKey = gen_Read_binds get_fixity tycon | otherwise - = (clas_nm, tycon_nm, - assoc "gen_bind:bad derived class" + = assoc "gen_bind:bad derived class" [(eqClassKey, gen_Eq_binds) ,(ordClassKey, gen_Ord_binds) ,(enumClassKey, gen_Enum_binds) - ,(evalClassKey, gen_Eval_binds) ,(boundedClassKey, gen_Bounded_binds) - ,(showClassKey, gen_Show_binds) - ,(readClassKey, gen_Read_binds) ,(ixClassKey, gen_Ix_binds) ] - (classKey clas) - tycon) + (classKey clas) + tycon where - clas_nm = nameOccName (getName clas) - tycon_nm = nameOccName (getName tycon) - from_here = isLocallyDefined tycon - (tycon,_,_) = splitAlgTyConApp ty - - -gen_inst_info :: Module -- Module name - -> (InstInfo, (Name, RenamedMonoBinds)) -- the main stuff to work on - -> InstInfo -- the gen'd (filled-in) "instance decl" - -gen_inst_info modname - (InstInfo clas tyvars tys@(ty:_) inst_decl_theta _ _ _ locn _, (dfun_name, meth_binds)) - = - -- Generate the various instance-related Ids - InstInfo clas tyvars tys inst_decl_theta - dfun_theta dfun_id - meth_binds - locn [] - where - (dfun_id, dfun_theta) = mkInstanceRelatedIds - dfun_name - clas tyvars tys - inst_decl_theta - - from_here = isLocallyDefined tycon - (tycon,_,_) = splitAlgTyConApp ty + (clas, tycon) = simpleDFunClassTyCon dfun \end{code} @@ -657,21 +559,17 @@ We're deriving @Enum@, or @Ix@ (enum type only???) If we have a @tag2con@ function, we also generate a @maxtag@ constant. \begin{code} -gen_taggery_Names :: [InstInfo] - -> TcM s [(RdrName, -- for an assoc list - TyCon, -- related tycon - TagThingWanted)] - -gen_taggery_Names inst_infos - = --pprTrace "gen_taggery:\n" (vcat [hsep [ppr c, ppr t] | (c,t) <- all_CTs]) $ - foldlTc do_con2tag [] tycons_of_interest `thenTc` \ names_so_far -> +gen_taggery_Names :: [DFunId] + -> TcM [(RdrName, -- for an assoc list + TyCon, -- related tycon + TagThingWanted)] + +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 = [ (c, get_tycon ty) | (InstInfo c _ [ty] _ _ _ _ _ _) <- inst_infos ] - - get_tycon ty = case splitAlgTyConApp ty of { (tc, _, _) -> tc } - - all_tycons = map snd all_CTs + all_CTs = map simpleDFunClassTyCon dfuns + all_tycons = map snd all_CTs (tycons_of_interest, _) = removeDups compare all_tycons do_con2tag acc_Names tycon @@ -691,7 +589,8 @@ gen_taggery_Names inst_infos do_tag2con acc_Names tycon | isDataTyCon tycon && (we_are_deriving enumClassKey tycon || - we_are_deriving ixClassKey tycon) + we_are_deriving ixClassKey tycon + && isEnumerationTyCon tycon) = returnTc ( (tag2con_RDR tycon, tycon, GenTag2Con) : (maxtag_RDR tycon, tycon, GenMaxTag) : acc_Names) @@ -705,16 +604,19 @@ gen_taggery_Names inst_infos 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 :: FAST_STRING -> FAST_STRING -> TyCon -> ErrMsg +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 thing why tycon - = hang (hsep [ptext SLIT("Can't make a derived instance of"), ptext thing]) - 0 (hang (hsep [ptext SLIT("for the type"), quotes (ppr tycon)]) - 0 (parens (ptext why))) +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)")] derivCtxt tycon = ptext SLIT("When deriving classes for") <+> quotes (ppr tycon)