X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDeriv.lhs;h=86084ab89af5884ed759c79b4e31ac9aa49ac470;hb=d68887047bcfb9021151f768fe1a22df2d3fbe1e;hp=6e29cc601e09a83ede5242cfa38faf5a33e0d7e3;hpb=4250d64191132fd493985549eda5ca05b82a663f;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs index 6e29cc6..86084ab 100644 --- a/ghc/compiler/typecheck/TcDeriv.lhs +++ b/ghc/compiler/typecheck/TcDeriv.lhs @@ -1,59 +1,57 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1994 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcDeriv]{Deriving} Handles @deriving@ clauses on @data@ declarations. \begin{code} -#include "HsVersions.h" - -module TcDeriv ( - tcDeriving - ) where +module TcDeriv ( tcDeriving ) where -import Ubiq +#include "HsVersions.h" -import HsSyn ( FixityDecl, Sig, HsBinds(..), Bind(..), MonoBinds(..), - GRHSsAndBinds, Match, HsExpr, HsLit, InPat, - ArithSeqInfo, Fake, MonoType ) -import HsPragmas ( InstancePragmas(..) ) -import RnHsSyn ( RenamedHsBinds(..), RenamedFixityDecl(..) ) -import TcHsSyn ( TcIdOcc ) +import HsSyn ( HsBinds(..), MonoBinds(..), TyClDecl(..), + collectLocatedMonoBinders ) +import RdrHsSyn ( RdrNameMonoBinds ) +import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds, RenamedTyClDecl ) +import CmdLineOpts ( DynFlag(..), DynFlags ) import TcMonad -import Inst ( InstOrigin(..), InstanceMapper(..) ) -import TcEnv ( getEnv_TyCons ) -import TcKind ( TcKind ) ---import TcGenDeriv -- Deriv stuff -import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs ) +import TcEnv ( tcSetInstEnv, newDFunName, InstInfo(..), pprInstInfo, + tcLookupClass, tcLookupTyCon + ) +import TcGenDeriv -- Deriv stuff +import InstEnv ( InstEnv, simpleDFunClassTyCon, extendInstEnv ) import TcSimplify ( tcSimplifyThetas ) -import RnMonad -import RnUtils ( RnEnv(..) ) -import RnBinds ( rnMethodBinds, rnTopBinds ) - -import Bag ( emptyBag{-ToDo:rm-}, Bag, isEmptyBag, unionBags, listToBag ) -import Class ( GenClass, getClassKey ) -import CmdLineOpts ( opt_CompilingPrelude ) -import ErrUtils ( pprBagOfErrors, addErrLoc, Error(..) ) -import Id ( dataConSig, dataConArity ) -import Maybes ( assocMaybe, maybeToBool, Maybe(..) ) +import RnBinds ( rnMethodBinds, rnTopMonoBinds ) +import RnEnv ( bindLocatedLocalsRn ) +import RnMonad ( renameDerivedCode, thenRn, mapRn, returnRn ) +import HscTypes ( DFunId, PersistentRenamerState ) + +import BasicTypes ( Fixity ) +import Class ( classKey, Class ) +import ErrUtils ( dumpIfSet_dyn, Message ) +import MkId ( mkDictFunId ) +import DataCon ( dataConArgTys, isNullaryDataCon, isExistentialDataCon ) +import PrelInfo ( needsDataDeclCtxtClassKeys ) +import Maybes ( maybeToBool, catMaybes ) +import Module ( Module ) +import Name ( Name, getSrcLoc ) +import RdrName ( RdrName ) + +import TyCon ( tyConTyVars, tyConDataCons, + tyConTheta, maybeTyConSingleCon, isDataTyCon, + isEnumerationTyCon, TyCon + ) +import Type ( TauType, ThetaType, PredType, mkTyVarTys, mkTyConApp, + isUnLiftedType, mkClassPred ) +import Var ( TyVar ) +import PrelNames +import Util ( zipWithEqual, sortLt ) +import ListSetOps ( removeDups, assoc ) import Outputable -import PprType ( GenType, GenTyVar, GenClass, TyCon ) -import PprStyle -import Pretty -import SrcLoc ( mkGeneratedSrcLoc, mkUnknownSrcLoc, SrcLoc ) -import TyCon ( tyConTyVars, tyConDataCons, tyConDerivings, - maybeTyConSingleCon, isEnumerationTyCon, TyCon ) -import Type ( GenType(..), TauType(..), mkTyVarTys, applyTyCon, - mkSigmaTy, mkDictTy, isPrimType, instantiateTy, - getAppTyCon, getAppDataTyCon ) -import TyVar ( GenTyVar ) -import UniqFM ( emptyUFM ) -import Unique -- Keys stuff -import Util ( zipWithEqual, zipEqual, sortLt, removeDups, - thenCmp, cmpList, panic, pprPanic, pprPanic# ) +import List ( nub ) \end{code} %************************************************************************ @@ -69,6 +67,10 @@ Consider | C3 (T a a) deriving (Eq) +[NOTE: See end of these comments for what to do with + data (C a, D b) => T a b = ... +] + We want to come up with an instance declaration of the form instance (Ping a, Pong b, ...) => Eq (T a b) where @@ -137,16 +139,39 @@ 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 DerivRhs = [(Class, TauType)] -- Same as a ThetaType! +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 = ThetaType type DerivSoln = DerivRhs \end{code} + +A note about contexts on data decls +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider + + data (RealFloat a) => Complex a = !a :+ !a deriving( Read ) + +We will need an instance decl like: + + instance (Read a, RealFloat a) => Read (Complex a) where + ... + +The RealFloat in the context is because the read method for Complex is bound +to construct a Complex, and doing that requires that the argument type is +in RealFloat. + +But this ain't true for Show, Eq, Ord, etc, since they don't construct +a Complex; they only take them apart. + +Our approach: identify the offending classes, and add the data type +context to the instance decl. The "offending classes" are + + Read, Enum? + + %************************************************************************ %* * \subsection[TcDeriv-driver]{Top-level function for \tr{derivings}} @@ -154,29 +179,28 @@ type DerivSoln = DerivRhs %************************************************************************ \begin{code} -tcDeriving :: Module -- name of module under scrutiny - -> RnEnv -- for "renaming" bits of generated code - -> Bag InstInfo -- What we already know about instances - -> [RenamedFixityDecl] -- Fixity info; used by Read and Show - -> TcM s (Bag InstInfo, -- The generated "instance decls". - RenamedHsBinds, -- Extra generated bindings - PprStyle -> Pretty) -- Printable derived instance decls; - -- for debugging via -ddump-derivings. - -tcDeriving modname rn_env inst_decl_infos_in fixities - = returnTc (trace "tcDeriving:ToDo" (emptyBag, EmptyBinds, \ x -> ppNil)) -{- LATER: - -tcDeriving modname rn_env inst_decl_infos_in fixities - = -- Fish the "deriving"-related information out of the TcEnv +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 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 ([], 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 @@ -184,46 +208,48 @@ tcDeriving modname rn_env inst_decl_infos_in fixities -- "con2tag" and/or "tag2con" functions. We do these -- separately. - gen_taggery_Names eqns `thenTc` \ nm_alist_etc -> - let - nm_alist = [ (pn, n) | (pn,n,_,_) <- nm_alist_etc ] - - -- We have the renamer's final "name funs" in our hands - -- (they were passed in). So we can handle ProtoNames - -- that refer to anything "out there". But our generated - -- code may also mention "con2tag" (etc.). So we need - -- to augment to "name funs" to include those. - (rn_val_gnf, rn_tc_gnf) = renamer_name_funs - - deriv_val_gnf pname = case (assoc_maybe nm_alist pname) of - Just xx -> Just xx - Nothing -> rn_val_gnf pname + gen_taggery_Names new_dfuns `thenTc` \ nm_alist_etc -> - deriver_name_funs = (deriv_val_gnf, rn_tc_gnf) - - assoc_maybe [] _ = Nothing - assoc_maybe ((k,v) : vs) key - = if k `eqProtoName` key then Just v else assoc_maybe vs key + 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 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) + = 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 - gen_tag_n_con_binds deriver_rn_env nm_alist_etc `thenTc` \ extra_binds -> - mapTc (gen_inst_info maybe_mod fixities deriver_rn_env) new_inst_infos - `thenTc` \ really_new_inst_infos -> + ioToTc (dumpIfSet_dyn dflags Opt_D_dump_deriv "Derived instances" + (ddump_deriving new_inst_infos rn_extra_binds)) `thenTc_` - returnTc (listToBag really_new_inst_infos, - extra_binds, - ddump_deriving really_new_inst_infos extra_binds) + returnTc (new_inst_infos, rn_extra_binds) where - maybe_mod = if opt_CompilingPrelude then Nothing else Just mod_name + ddump_deriving :: [InstInfo] -> RenamedHsBinds -> SDoc + ddump_deriving inst_infos extra_binds + = vcat (map pprInstInfo inst_infos) $$ ppr extra_binds + where - ddump_deriving :: [InstInfo] -> RenamedHsBinds -> (PprStyle -> Pretty) + -- 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 { iDFunId = dfun, + iBinds = binds, iPrags = [] } - ddump_deriving inst_infos extra_binds sty - = ppAboves ((map pp_info inst_infos) ++ [ppr sty extra_binds]) - where - pp_info (InstInfo clas tvs ty inst_decl_theta _ _ _ mbinds _ _ _ _) - = ppAbove (ppr sty (mkSigmaTy tvs inst_decl_theta (mkDictTy clas ty))) - (ppr sty mbinds) + rn_meths meths = rnMethodBinds [] meths `thenRn` \ (meths', _) -> returnRn meths' + -- Ignore the free vars returned \end{code} @@ -249,78 +275,75 @@ 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 - tycons = getEnv_TyCons env - think_about_deriving = need_deriving tycons - in - mapTc (chk_out think_about_deriving) think_about_deriving `thenTc_` - let - (derive_these, _) = removeDups cmp_deriv think_about_deriving - eqns = map mk_eqn derive_these - in - returnTc eqns +makeDerivEqns tycl_decls + = mapTc mk_eqn derive_these `thenTc` \ maybe_eqns -> + returnTc (catMaybes maybe_eqns) where ------------------------------------------------------------------ - need_deriving :: [TyCon] -> [(Class, TyCon)] - -- find the tycons that have `deriving' clauses - - need_deriving tycons_to_consider - = foldr ( \ tycon acc -> - case (tyConDerivings tycon) of - [] -> acc - cs -> [ (clas,tycon) | clas <- cs ] ++ acc - ) - [] - 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)] -> (Class, TyCon) -> TcM s () - chk_out whole_deriving_list this_one@(clas, tycon) - = let - clas_key = getClassKey clas - in - - -- Are things OK for deriving Enum (if appropriate)? - checkTc (clas_key == enumClassKey && not (isEnumerationTyCon tycon)) - (derivingEnumErr tycon) `thenTc_` - - -- Are things OK for deriving Ix (if appropriate)? - checkTc (clas_key == ixClassKey - && not (isEnumerationTyCon tycon - || maybeToBool (maybeTyConSingleCon tycon))) - (derivingIxErr tycon) - - ------------------------------------------------------------------ - cmp_deriv :: (Class, TyCon) -> (Class, TyCon) -> TAG_ - cmp_deriv (c1, t1) (c2, t2) - = (c1 `cmp` c2) `thenCmp` (t1 `cmp` t2) - - ------------------------------------------------------------------ - mk_eqn :: (Class, TyCon) -> DerivEqn + 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 - mk_eqn (clas, tycon) - = (clas, tycon, tyvars, constraints) - where - tyvars = tyConTyVars tycon -- ToDo: Do we need new tyvars ??? - tyvar_tys = mkTyVarTys tyvars - data_cons = tyConDataCons tycon - constraints = concat (map mk_constraints data_cons) - - mk_constraints data_con - = [ (clas, instantiateTy inst_env arg_ty) - | arg_ty <- arg_tys, - not (isPrimType arg_ty) -- No constraints for primitive types - ] - where - (con_tyvars, _, arg_tys, _) = dataConSig data_con - inst_env = con_tyvars `zipEqual` tyvar_tys - -- same number of tyvars in data constr and type constr! + 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 = [] + + offensive_class = clas_key `elem` needsDataDeclCtxtClassKeys + + mk_constraints data_con + = [ mkClassPred clas [arg_ty] + | arg_ty <- dataConArgTys data_con tyvar_tys, + not (isUnLiftedType arg_ty) -- No constraints for unlifted 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)) + + + + ------------------------------------------------------------------ + 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 + + 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") + + bog_out why = Just (derivingThingErr clas tycon why) \end{code} %************************************************************************ @@ -334,22 +357,22 @@ terms, which is the final correct RHS for the corresponding original equation. \begin{itemize} \item -Each (k,UniTyVarTemplate tv) in a solution constrains only a type +Each (k,TyVarTy tv) in a solution constrains only a type variable, tv. \item -The (k,UniTyVarTemplate tv) pairs in a solution are canonically +The (k,TyVarTy tv) pairs in a solution are canonically ordered by sorting on type varible, tv, (major key) and then class, k, (minor key) \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 @@ -358,90 +381,63 @@ solveDerivEqns inst_decl_infos_in orig_eqns initial_solutions :: [DerivSoln] initial_solutions = [ [] | _ <- orig_eqns ] + ------------------------------------------------------------------ -- iterateDeriv calculates the next batch of solutions, -- compares it with the current one; finishes if they are the -- same, otherwise recurses with the new solutions. - - iterateDeriv :: [DerivSoln] ->TcM s [InstInfo] - + -- It fails if any iteration fails + iterateDeriv :: [DerivSoln] ->TcM [DFunId] iterateDeriv current_solns + = checkNoErrsTc (iterateOnce current_solns) + `thenTc` \ (new_dfuns, new_solns) -> + if (current_solns == new_solns) then + returnTc new_dfuns + else + iterateDeriv 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_decl_infos_in orig_eqns current_solns - `thenTc` \ (new_inst_infos, inst_mapper) -> - - -- Simplify each RHS, using a DerivingOrigin containing an - -- inst_mapper reflecting the previous solution - let - mk_deriv_origin clas ty - = DerivingOrigin inst_mapper clas tycon - where - (tycon,_) = getAppTyCon ty - in - listTc [ tcSimplifyThetas mk_deriv_origin rhs - | (_, _, _, rhs) <- orig_eqns - ] `thenTc` \ next_solns -> + getDOptsTc `thenTc` \ dflags -> + let (new_dfuns, inst_env) = + add_solns dflags inst_env_in orig_eqns current_solns + in + -- Simplify each RHS + tcSetInstEnv inst_env ( + listTc [ tcAddSrcLoc (getSrcLoc tc) $ + 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 lt_rhs next_soln | next_soln <- next_solns ] in - - if current_solns `eq_solns` canonicalised_next_solns then - returnTc new_inst_infos - else - iterateDeriv canonicalised_next_solns - - where - ------------------------------------------------------------------ - lt_rhs r1 r2 = case cmp_rhs r1 r2 of { LT_ -> True; _ -> False } - eq_solns s1 s2 = case cmp_solns s1 s2 of { EQ_ -> True; _ -> False } - cmp_solns s1 s2 = cmpList (cmpList cmp_rhs) s1 s2 - cmp_rhs (c1, TyVarTy tv1) (c2, TyVarTy tv2) - = (tv1 `cmp` tv2) `thenCmp` (c1 `cmp` c2) -#ifdef DEBUG - cmp_rhs other_1 other_2 - = pprPanic# "tcDeriv:cmp_rhs:" (ppCat [ppr PprDebug other_1, ppr PprDebug other_2]) -#endif - + let canonicalised_next_solns = [ sortLt (<) next_soln | next_soln <- next_solns ] + in + returnTc (new_dfuns, canonicalised_next_solns) \end{code} \begin{code} -add_solns :: FAST_STRING - -> Bag InstInfo -- The global, non-derived ones +add_solns :: DynFlags + -> InstEnv -- The global, non-derived ones -> [DerivEqn] -> [DerivSoln] - -> 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 - = buildInstanceEnvs all_inst_infos `thenTc` \ inst_mapper -> - returnTc (new_inst_infos, inst_mapper) - where - new_inst_infos = zipWithEqual mk_deriv_inst_info eqns solns - - all_inst_infos = inst_infos_in `unionBags` listToBag new_inst_infos - - mk_deriv_inst_info (clas, tycon, tyvars, _) theta - = InstInfo clas tyvars (applyTyCon tycon (mkTyVarTys tyvars)) - theta - theta -- Blarg. This is the dfun_theta slot, - -- which is needed by buildInstanceEnv; - -- This works ok for solving the eqns, and - -- gen_eqns sets it to its final value - -- (incl super class dicts) before we - -- finally return it. -#ifdef DEBUG - (panic "add_soln:dfun_id") (panic "add_soln:const_meth_ids") - (panic "add_soln:binds") (panic "add_soln:from_here") - (panic "add_soln:modname") mkGeneratedSrcLoc - (panic "add_soln:upragmas") -#else - bottom bottom bottom bottom bottom mkGeneratedSrcLoc bottom - where - bottom = panic "add_soln" -#endif +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 + + mk_deriv_dfun (dfun_name, clas, tycon, tyvars, _) theta + = mkDictFunId dfun_name clas tyvars + [mkTyConApp tycon (mkTyVarTys tyvars)] + theta \end{code} %************************************************************************ @@ -465,8 +461,7 @@ We want derived instances of @Eq@ and @Ord@ (both v common) to be ``you-couldn't-do-better-by-hand'' efficient. \item -Deriving @Text@---also pretty common, usually just for -@show@---should also be reasonable good code. +Deriving @Show@---also pretty common--- should also be reasonable good code. \item Deriving for the other classes isn't that common or that big a deal. @@ -476,13 +471,13 @@ PRAGMATICS: \begin{itemize} \item -Deriving @Ord@ is done mostly with our non-standard @tagCmp@ method. +Deriving @Ord@ is done mostly with the 1.3 @compare@ method. \item -Deriving @Eq@ also uses @tagCmp@, if we're deriving @Ord@, too. +Deriving @Eq@ also uses @compare@, if we're deriving @Ord@, too. \item -We {\em normally} generated code only for the non-defaulted methods; +We {\em normally} generate code only for the non-defaulted methods; there are some exceptions for @Eq@ and (especially) @Ord@... \item @@ -491,7 +486,6 @@ constructor's numeric (@Int#@) tag. These are generated by @gen_tag_n_con_binds@, and the heuristic for deciding if one of these is around is given by @hasCon2TagFun@. - The examples under the different sections below will make this clearer. @@ -500,114 +494,50 @@ Much less often (really just for deriving @Ix@), we use a @_tag2con_@ function. See the examples. \item -We use Pass~4 of the renamer!!! Reason: we're supposed to be +We use the renamer!!! Reason: we're supposed to be producing @RenamedMonoBinds@ for the methods, but that means producing correctly-uniquified code on the fly. This is entirely possible (the @TcM@ monad has a @UniqueSupply@), but it is painful. -So, instead, we produce @ProtoNameMonoBinds@ then heave 'em through +So, instead, we produce @RdrNameMonoBinds@ then heave 'em through the renamer. What a great hack! \end{itemize} \begin{code} -gen_inst_info :: Maybe Module -- Module name; Nothing => Prelude - -> [RenamedFixityDecl] -- all known fixities; - -- may be needed for Text - -> RnEnv -- lookup stuff for names we may use - -> InstInfo -- the main stuff to work on - -> TcM s InstInfo -- the gen'd (filled-in) "instance decl" - -gen_inst_info modname fixities deriver_rn_env - info@(InstInfo clas tyvars ty inst_decl_theta _ _ _ _ _ _ locn _) - = - -- Generate the various instance-related Ids - mkInstanceRelatedIds - True {-from_here-} modname - NoInstancePragmas - clas tyvars ty - inst_decl_theta - [{-no user pragmas-}] - `thenTc` \ (dfun_id, dfun_theta, const_meth_ids) -> - - -- Generate the bindings for the new instance declaration, - -- rename it, and check for errors - let - (tycon,_,_) = getAppDataTyCon ty - - proto_mbinds - | clas_key == eqClassKey = gen_Eq_binds tycon - | clas_key == showClassKey = gen_Show_binds fixities tycon - | clas_key == ordClassKey = gen_Ord_binds tycon - | clas_key == enumClassKey = gen_Enum_binds tycon - | clas_key == ixClassKey = gen_Ix_binds tycon - | clas_key == readClassKey = gen_Read_binds fixities tycon - | clas_key == binaryClassKey = gen_Binary_binds tycon - | otherwise = panic "gen_inst_info:bad derived class" - in - rnMtoTcM deriver_rn_env ( - setExtraRn emptyUFM{-no fixities-} $ - rnMethodBinds clas_Name proto_mbinds - ) `thenNF_Tc` \ (mbinds, errs) -> - - if not (isEmptyBag errs) then - pprPanic "gen_inst_info:renamer errs!\n" - (ppAbove (pprBagOfErrors PprDebug errs) (ppr PprDebug proto_mbinds)) - else - --pprTrace "derived binds:" (ppr PprDebug proto_mbinds) $ - - -- All done - let - from_here = isLocallyDefined tycon -- If so, then from here - in - returnTc (InstInfo clas tyvars ty inst_decl_theta - dfun_theta dfun_id const_meth_ids - (if from_here then mbinds else EmptyMonoBinds) - from_here modname locn []) +-- Generate the method bindings for the required instance +-- (paired with class name, as we need that when generating dict +-- names.) +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 + = 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 where - clas_key = getClassKey clas - clas_Name - = let (mod, nm) = moduleNamePair clas in - ClassName clas_key (mkPreludeCoreName mod nm) [] + (clas, tycon) = simpleDFunClassTyCon dfun \end{code} + %************************************************************************ %* * -\subsection[TcGenDeriv-con2tag-tag2con]{Generating extra binds (@con2tag@ and @tag2con@)} +\subsection[TcDeriv-taggery-Names]{What con2tag/tag2con functions are available?} %* * %************************************************************************ + data Foo ... = ... con2tag_Foo :: Foo ... -> Int# tag2con_Foo :: Int -> Foo ... -- easier if Int, not Int# -maxtag_Foo :: Int -- ditto (NB: not unboxed) - -\begin{code} -gen_tag_n_con_binds :: RnEnv - -> [(RdrName, RnName, TyCon, TagThingWanted)] - -> TcM s RenamedHsBinds - -gen_tag_n_con_binds deriver_rn_env nm_alist_etc - = let - proto_mbind_list = map gen_tag_n_con_monobind nm_alist_etc - proto_mbinds = foldr AndMonoBinds EmptyMonoBinds proto_mbind_list - in - - rnMtoTcM deriver_rn_env ( - setExtraRn emptyUFM{-no fixities-} $ - rnTopBinds (SingleBind (RecBind proto_mbinds)) - ) `thenNF_Tc` \ (binds, errs) -> +maxtag_Foo :: Int -- ditto (NB: not unlifted) - if not (isEmptyBag errs) then - panic "gen_inst_info:renamer errs (2)!" - else - returnTc binds -\end{code} - -%************************************************************************ -%* * -\subsection[TcDeriv-taggery-Names]{What con2tag/tag2con functions are available?} -%* * -%************************************************************************ We have a @con2tag@ function for a tycon if: \begin{itemize} @@ -628,64 +558,65 @@ 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 :: [DerivEqn] - -> TcM s [(RdrName, RnName, -- for an assoc list - TyCon, -- related tycon - TagThingWanted)] - -gen_taggery_Names eqns - = let - all_tycons = [ tc | (_, tc, _, _) <- eqns ] - (tycons_of_interest, _) = removeDups cmp all_tycons - in - foldlTc do_con2tag [] tycons_of_interest `thenTc` \ names_so_far -> - foldlTc do_tag2con names_so_far tycons_of_interest +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 = map simpleDFunClassTyCon dfuns + all_tycons = map snd all_CTs + (tycons_of_interest, _) = removeDups compare all_tycons + do_con2tag acc_Names tycon - = if (we_are_deriving eqClassKey tycon - && any ( (== 0).dataConArity ) (tyConDataCons tycon)) - || (we_are_deriving ordClassKey tycon + | isDataTyCon tycon && + ((we_are_deriving eqClassKey tycon + && any isNullaryDataCon (tyConDataCons tycon)) + || (we_are_deriving ordClassKey tycon && not (maybeToBool (maybeTyConSingleCon tycon))) - || (we_are_deriving enumClassKey tycon) - || (we_are_deriving ixClassKey tycon) - then - tcGetUnique `thenNF_Tc` ( \ u -> - returnTc ((con2tag_PN tycon, ValName u (con2tag_FN tycon), tycon, GenCon2Tag) - : acc_Names) ) - else - returnTc acc_Names + || (we_are_deriving enumClassKey tycon) + || (we_are_deriving ixClassKey tycon)) + + = returnTc ((con2tag_RDR tycon, tycon, GenCon2Tag) + : acc_Names) + | otherwise + = returnTc acc_Names do_tag2con acc_Names tycon - = if (we_are_deriving enumClassKey tycon) - || (we_are_deriving ixClassKey tycon) - then - tcGetUnique `thenNF_Tc` \ u1 -> - tcGetUnique `thenNF_Tc` \ u2 -> - returnTc ( (tag2con_PN tycon, ValName u1 (tag2con_FN tycon), tycon, GenTag2Con) - : (maxtag_PN tycon, ValName u2 (maxtag_FN tycon), tycon, GenMaxTag) - : acc_Names) - else - returnTc acc_Names + | isDataTyCon tycon && + (we_are_deriving enumClassKey tycon || + we_are_deriving ixClassKey tycon + && isEnumerationTyCon tycon) + = returnTc ( (tag2con_RDR tycon, tycon, GenTag2Con) + : (maxtag_RDR tycon, tycon, GenMaxTag) + : acc_Names) + | otherwise + = returnTc acc_Names we_are_deriving clas_key tycon - = is_in_eqns clas_key tycon eqns + = is_in_eqns clas_key tycon all_CTs where is_in_eqns clas_key tycon [] = False - is_in_eqns clas_key tycon ((c,t,_,_):eqns) - = (clas_key == getClassKey c && tycon == t) - || is_in_eqns clas_key tycon eqns - + 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} -derivingEnumErr :: TyCon -> Error -derivingEnumErr tycon - = addErrLoc (getSrcLoc tycon) "Can't derive an instance of `Enum'" ( \ sty -> - ppBesides [ppStr "type `", ppr sty tycon, ppStr "'"] ) - -derivingIxErr :: TyCon -> Error -derivingIxErr tycon - = addErrLoc (getSrcLoc tycon) "Can't derive an instance of `Ix'" ( \ sty -> - ppBesides [ppStr "type `", ppr sty tycon, ppStr "'"] ) --} +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)] + +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) \end{code}