X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDeriv.lhs;h=db21e8eb62ab6517c0d1ea55d9ce2548a2d6be3f;hb=83eef621e4a4fbb6c1343304ec638cafd6c9dc09;hp=37e72fe02642478675ec7cd538ea4d7e3e13afb4;hpb=10521d8418fd3a1cf32882718b5bd28992db36fd;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs index 37e72fe..db21e8e 100644 --- a/ghc/compiler/typecheck/TcDeriv.lhs +++ b/ghc/compiler/typecheck/TcDeriv.lhs @@ -1,61 +1,56 @@ % -% (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. -********** Don't forget - -Multi-instance checking in renamer should include deriving. - \begin{code} +module TcDeriv ( tcDeriving ) where + #include "HsVersions.h" -module TcDeriv ( - tcDeriving, - con2tag_PN, tag2con_PN, maxtag_PN, - TagThingWanted(..), DerivEqn(..) - ) where +import HsSyn ( HsBinds(..), MonoBinds(..), TyClDecl(..), + collectLocatedMonoBinders ) +import RdrHsSyn ( RdrNameMonoBinds ) +import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds, RenamedTyClDecl ) +import CmdLineOpts ( DynFlag(..), DynFlags ) -IMPORT_Trace -- ToDo:rm debugging -import Outputable -import Pretty - -import TcMonad -- typechecking monad machinery -import TcMonadFns ( copyTyVars ) -import AbsSyn -- the stuff being typechecked -import TcGenDeriv -- support code that generates all the grimy bindings - -- for derived instance decls. - -import AbsPrel ( mkFunTy ) -import AbsUniType -import UniType ( UniType(..) ) -- *********** CHEATING!!! **************** -import Bag -import CE ( CE(..) ) -import CmdLineOpts ( GlobalSwitch(..) ) -import E ( E ) -import Errors -import HsCore -- ****** NEED TO SEE CONSTRUCTORS ****** -import HsPragmas -- InstancePragmas(..) -import Id ( getDataConSig, isNullaryDataCon, DataCon(..) ) -import IdInfo -import Inst ( InstOrigin(..) ) -import InstEnv -import Maybes ( assocMaybe, maybeToBool, Maybe(..) ) -import NameTypes ( mkFullName, mkPreludeCoreName, - Provenance(..), FullName, ShortName +import TcMonad +import TcEnv ( TcEnv, tcSetInstEnv, newDFunName, InstInfo(..), pprInstInfo, + tcLookupClass, tcLookupTyCon ) -import ProtoName ( eqProtoName, ProtoName(..), Name ) -import RenameAuxFuns -- why not? take all of it... -import RenameBinds4 ( rnMethodBinds4, rnTopBinds4 ) -import RenameMonad4 -- initRn4, etc. -import SrcLoc ( mkGeneratedSrcLoc, mkUnknownSrcLoc, SrcLoc ) -import TCE -- ( rngTCE, TCE(..), UniqFM ) -import TcInstDcls ( InstInfo(..), buildInstanceEnvs, mkInstanceRelatedIds ) +import TcGenDeriv -- Deriv stuff +import InstEnv ( InstEnv, simpleDFunClassTyCon, extendInstEnv ) import TcSimplify ( tcSimplifyThetas ) -import Unique -- *Key stuff -import Util + +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, PredType(..), mkTyVarTys, mkTyConApp, isUnboxedType ) +import Var ( TyVar ) +import PrelNames +import Util ( zipWithEqual, sortLt ) +import ListSetOps ( removeDups, assoc ) +import Outputable +import List ( nub ) \end{code} %************************************************************************ @@ -66,11 +61,15 @@ import Util Consider - data T a b = C1 (Foo a) (Bar b) - | C2 Int (T b a) + data T a b = C1 (Foo a) (Bar b) + | C2 Int (T b a) | 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 @@ -122,10 +121,10 @@ Next iteration: u Eq (T a a) -- From C3 After simplification: - = Eq a u Ping b + = Eq a u Ping b u (Eq b u Ping a) u (Eq a u Ping a) - + = Eq a u Ping b u Eq b u Ping a The next iteration gives the same result, so this is the fixpoint. We @@ -139,16 +138,41 @@ 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! +type DerivRhs = [(Class, [TauType])] -- Same as a ThetaType! + --[PredType] -- ... | Class Class [Type==TauType] 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}} @@ -156,26 +180,28 @@ type DerivSoln = DerivRhs %************************************************************************ \begin{code} -tcDeriving :: FAST_STRING -- name of module under scrutiny - -> GlobalNameFuns -- for "renaming" bits of generated code - -> Bag InstInfo -- What we already know about instances - -> TCE -- All known TyCon info - -> [RenamedFixityDecl] -- Fixity info; may be used for Text - -> TcM (Bag InstInfo, -- The generated "instance decls". - RenamedBinds, -- Extra generated bindings - PprStyle -> Pretty) -- Printable derived instance decls; - -- for debugging via -ddump-derivings. - -tcDeriving modname renamer_name_funs inst_decl_infos_in tce fixities - = -- Fish the "deriving"-related information out of the TCE, - -- from which we make the necessary "equations". - makeDerivEqns tce `thenTc` \ eqns -> +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 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 modname 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 @@ -183,45 +209,48 @@ tcDeriving modname renamer_name_funs inst_decl_infos_in tce 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 + gen_taggery_Names new_dfuns `thenTc` \ nm_alist_etc -> - deriv_val_gnf pname = case (assoc_maybe nm_alist pname) of - Just xx -> Just xx - Nothing -> rn_val_gnf pname - - deriver_name_funs = (deriv_val_gnf, rn_tc_gnf) - - assoc_maybe [] _ = Nothing - assoc_maybe ((v,xxx) : vs) key - = if v `eqProtoName` key then Just xxx 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_name_funs nm_alist_etc `thenTc` \ extra_binds -> - mapTc (gen_inst_info modname fixities deriver_name_funs) 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 - ddump_deriving :: [InstInfo] -> RenamedBinds -> (PprStyle -> Pretty) - - ddump_deriving inst_infos extra_binds sty - = ppAboves ((map (pp_1 sty) inst_infos) ++ [ppr sty extra_binds]) + ddump_deriving :: [InstInfo] -> RenamedHsBinds -> SDoc + ddump_deriving inst_infos extra_binds + = vcat (map pprInstInfo inst_infos) $$ ppr extra_binds where - pp_1 sty (InstInfo clas tv_tmpls ty inst_decl_theta _ _ _ mbinds _ _ _ _) - = ppAbove (ppr sty (mkSigmaTy tv_tmpls inst_decl_theta - (UniDict clas ty))) - (ppr sty 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} @@ -247,92 +276,75 @@ or} has just one data constructor (e.g., tuples). all those. \begin{code} -makeDerivEqns :: TCE -> TcM [DerivEqn] - -makeDerivEqns tce - = let - think_about_deriving = need_deriving (rngTCE tce) - in - mapTc (chk_out think_about_deriving) think_about_deriving `thenTc_` - - let - (derive_these, _) = removeDups cmp think_about_deriving - in +makeDerivEqns :: [RenamedTyClDecl] -> TcM [DerivEqn] - listNF_Tc (map mk_eqn derive_these) `thenNF_Tc` \ eqns -> - - 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 (getTyConDerivings tycon) of - [] -> acc - cs -> [ (clas,tycon) | clas <- cs ] ++ acc - ) - [] -- init accumulator - 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 () + 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_out whole_deriving_list this_one@(clas, tycon) - = -- Are the relevant superclasses catered for? - -- E.g., for "... deriving Ord", is there an - -- instance of "Eq"? + mk_eqn (clas_name, tycon_name) + = tcLookupClass clas_name `thenNF_Tc` \ clas -> + tcLookupTyCon tycon_name `thenNF_Tc` \ tycon -> let - (_, super_classes, _) = getClassSig clas - 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 (maybeSingleConstructorTyCon tycon))) - (derivingIxErr tycon) + 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 + = [ (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)) - ------------------------------------------------------------------ - cmp :: (Class, TyCon) -> (Class, TyCon) -> TAG_ - cmp (c1, t1) (c2, t2) - = case cmpClass c1 c2 of - EQ_ -> cmpTyCon t1 t2 - other -> other ------------------------------------------------------------------ - mk_eqn :: (Class, TyCon) -> NF_TcM DerivEqn - -- we swizzle the tyvars, data cons, etc., out of the tycon, - -- to make the rest of the equation - - mk_eqn (clas, tycon) - = let - tyvar_tmpls = getTyConTyVarTemplates tycon - data_cons = getTyConDataCons tycon - in - copyTyVars tyvar_tmpls `thenNF_Tc` \ (_, tyvars, tyvar_tys) -> - - let - constraints = concat [mk_constraints tyvar_tys con | con <- data_cons] - in - returnNF_Tc (clas, tycon, tyvars, constraints) - where - mk_constraints tyvar_tys data_con - = [ (clas, instantiateTy inst_env arg_ty) - | arg_ty <- arg_tys, - not (isPrimType arg_ty) -- No constraints for primitive types - ] - where - (con_tyvar_tmpls, _, arg_tys, _) = getDataConSig data_con - inst_env = con_tyvar_tmpls `zipEqual` tyvar_tys - -- Type vars in data contructor should be same in number - -- as in the type contsructor! + 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} %************************************************************************ @@ -341,28 +353,27 @@ makeDerivEqns tce %* * %************************************************************************ -A ``solution'' (to one of the equations) is a list of (k,UniTyVar tv) +A ``solution'' (to one of the equations) is a list of (k,TyVarTy tv) 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 :: FAST_STRING - -> Bag InstInfo - -> [DerivEqn] - -> TcM [InstInfo] -- Solns in same order as eqns. - -- This bunch is Absolutely minimal... +solveDerivEqns :: InstEnv + -> [DerivEqn] + -> TcM [DFunId] -- Solns in same order as eqns. + -- This bunch is Absolutely minimal... -solveDerivEqns modname 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 @@ -371,108 +382,63 @@ solveDerivEqns modname 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 [InstInfo] - + -- It fails if any iteration fails + iterateDeriv :: [DerivSoln] ->TcM [DFunId] iterateDeriv current_solns - = -- Extend the inst info from the explicit instance decls - -- with the current set of solutions, giving a - - add_solns modname inst_decl_infos_in orig_eqns current_solns - `thenTc` \ (new_inst_infos, inst_mapper) -> + = checkNoErrsTc (iterateOnce current_solns) + `thenTc` \ (new_dfuns, new_solns) -> + if (current_solns == new_solns) then + returnTc new_dfuns + else + iterateDeriv new_solns - -- Simplify each RHS, using a DerivingOrigin containing an - -- inst_mapper reflecting the previous solution - let - mk_deriv_origin clas ty - = DerivingOrigin inst_mapper clas is_fun_type tycon locn - where - is_fun_type = isFunType ty - (tycon,_,_) = getUniDataTyCon ty - locn = if is_fun_type then mkUnknownSrcLoc{-sigh-} else getSrcLoc tycon - in - listTc [ tcSimplifyThetas mk_deriv_origin rhs - | (_, _, _, rhs) <- orig_eqns - ] `thenTc` \ next_solns -> + ------------------------------------------------------------------ + iterateOnce current_solns + = -- Extend the inst info from the explicit instance decls + -- with the current set of solutions, giving a + 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 [ 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 less_than next_soln | next_soln <- next_solns ] in - - if current_solns == canonicalised_next_solns then - returnTc new_inst_infos - else - iterateDeriv canonicalised_next_solns - - where - ------------------------------------------------------------------ - less_than :: (Class, TauType) -> (Class, TauType) -> Bool - - less_than (clas1, UniTyVar tv1) (clas2, UniTyVar tv2) - = tv1 < tv2 || (tv1 == tv2 && clas1 < clas2) -#ifdef DEBUG - less_than other_1 other_2 - = pprPanic "tcDeriv:less_than:" (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 ([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 modname inst_infos_in eqns solns - = listTc (zipWith mk_deriv_inst_info eqns solns) `thenTc` \ new_inst_infos -> - - buildInstanceEnvs (inst_infos_in `unionBags` - listToBag new_inst_infos) `thenTc` \ inst_mapper -> - - returnTc (new_inst_infos, inst_mapper) - where - mk_deriv_inst_info (clas, tycon, tyvars, _) theta - -- The complication here is rather boring: InstInfos need TyVarTemplates, - -- and we have only TyVars in our hand. - = let - tyvar_tmpls = mkTemplateTyVars tyvars - tv_tmpl_tys = map mkTyVarTemplateTy tyvar_tmpls +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 - env = tyvars `zipEqual` tv_tmpl_tys - - tycon_tmpl_ty = applyTyCon tycon tv_tmpl_tys - theta_tmpl = [(clas, mapOverTyVars to_tmpl ty) | (clas,ty) <- theta] + mk_deriv_dfun (dfun_name, clas, tycon, tyvars, _) theta + = mkDictFunId dfun_name clas tyvars [mkTyConApp tycon (mkTyVarTys tyvars)] + (map pair2PredType theta) - to_tmpl = assoc "mk_deriv_inst_info" env - - (class_tyvar, super_classes, _, class_ops, _, _) = getClassBigSig clas - in - returnTc ( - InstInfo clas tyvar_tmpls tycon_tmpl_ty - theta_tmpl - theta_tmpl -- 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. -#ifndef 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 + pair2PredType (clas, tautypes) = Class clas tautypes \end{code} %************************************************************************ @@ -496,8 +462,7 @@ 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. @@ -507,13 +472,13 @@ 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 @@ -522,7 +487,6 @@ 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. @@ -531,119 +495,50 @@ 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 :: FAST_STRING -- Module name - -> [RenamedFixityDecl] -- all known fixities; - -- may be needed for Text - -> GlobalNameFuns -- lookup stuff for names we may use - -> InstInfo -- the main stuff to work on - -> TcM InstInfo -- the gen'd (filled-in) "instance decl" - -gen_inst_info modname fixities deriver_name_funs - info@(InstInfo clas tyvar_tmpls ty inst_decl_theta _ _ _ _ _ _ locn _) - = - -- Generate the various instance-related Ids - mkInstanceRelatedIds - (panic "add_solns:E") - -- These two are only needed if there are pragmas to typecheck; - -- but there ain't since we are generating the code right here. - True {-yes, from_here-} - NoInstancePragmas - mkGeneratedSrcLoc - clas - tyvar_tmpls 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 - getSwitchCheckerTc `thenNF_Tc` \ sw_chkr -> - let - (tycon,_,_) = getUniDataTyCon ty - - omit_readsPrec = sw_chkr OmitDerivedRead - - proto_mbinds - = if clas_key == textClassKey then gen_Text_binds fixities omit_readsPrec tycon - else if clas_key == eqClassKey then gen_Eq_binds tycon - else if clas_key == ordClassKey then gen_Ord_binds tycon - else if clas_key == enumClassKey then gen_Enum_binds tycon - else if clas_key == ixClassKey then gen_Ix_binds tycon - else if clas_key == binaryClassKey then gen_Binary_binds tycon - else panic "gen_inst_info:bad derived class" - in - rn4MtoTcM deriver_name_funs ( - rnMethodBinds4 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 tyvar_tmpls ty - inst_decl_theta dfun_theta dfun_id const_meth_ids - -- and here comes the main point... - (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) = getOrigName clas in - PreludeClass 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 :: GlobalNameFuns - -> [(ProtoName, Name, TyCon, TagThingWanted)] - -> TcM RenamedBinds - -gen_tag_n_con_binds deriver_name_funs 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 - - rn4MtoTcM deriver_name_funs ( - rnTopBinds4 (SingleBind (RecBind proto_mbinds)) - ) `thenNF_Tc` \ (binds, errs) -> - - 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} @@ -664,91 +559,65 @@ We're deriving @Enum@, or @Ix@ (enum type only???) If we have a @tag2con@ function, we also generate a @maxtag@ constant. \begin{code} -data TagThingWanted - = GenCon2Tag | GenTag2Con | GenMaxTag - -gen_taggery_Names :: [DerivEqn] - -> TcM [(ProtoName, Name, -- for an assoc list - TyCon, -- related tycon +gen_taggery_Names :: [DFunId] + -> TcM [(RdrName, -- for an assoc list + TyCon, -- related tycon TagThingWanted)] -gen_taggery_Names eqns - = let all_tycons = [ tc | (_, tc, _, _) <- eqns ] - (tycons_of_interest, _) = removeDups cmpTyCon 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 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 isNullaryDataCon (getTyConDataCons tycon)) - || (we_are_deriving ordClassKey tycon - && not (maybeToBool (maybeSingleConstructorTyCon tycon))) - || (we_are_deriving enumClassKey tycon) - || (we_are_deriving ixClassKey tycon) - then - getUniqueTc `thenNF_Tc` ( \ u -> - returnTc ((con2tag_PN tycon, OtherTopId u (con2tag_FN tycon), tycon, GenCon2Tag) - : acc_Names) ) - else - returnTc acc_Names + | 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)) + + = 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 - getUniqueTc `thenNF_Tc` \ u1 -> - getUniqueTc `thenNF_Tc` \ u2 -> - returnTc ( (tag2con_PN tycon, OtherTopId u1 (tag2con_FN tycon), tycon, GenTag2Con) - : (maxtag_PN tycon, OtherTopId 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) -- ToDo: InstInfo - = (clas_key == getClassKey c && tycon == t) - || is_in_eqns clas_key tycon eqns - -con2tag_PN, tag2con_PN, maxtag_PN :: TyCon -> ProtoName -con2tag_FN, tag2con_FN, maxtag_FN :: TyCon -> FullName - -con2tag_PN tycon - = let (mod, nm) = getOrigName tycon - con2tag = SLIT("con2tag_") _APPEND_ nm _APPEND_ SLIT("#") - in - Imp mod con2tag [mod] con2tag - -con2tag_FN tycon - = let (mod, nm) = getOrigName tycon - con2tag = SLIT("con2tag_") _APPEND_ nm _APPEND_ SLIT("#") - in - mkFullName mod con2tag InventedInThisModule NotExported mkGeneratedSrcLoc + is_in_eqns clas_key tycon ((c,t):cts) + = (clas_key == classKey c && tycon == t) + || is_in_eqns clas_key tycon cts +\end{code} -tag2con_PN tycon - = let (mod, nm) = getOrigName tycon - tag2con = SLIT("tag2con_") _APPEND_ nm _APPEND_ SLIT("#") - in - Imp mod tag2con [mod] tag2con +\begin{code} +derivingThingErr :: Class -> TyCon -> FAST_STRING -> Message -tag2con_FN tycon - = let (mod, nm) = getOrigName tycon - tag2con = SLIT("tag2con_") _APPEND_ nm _APPEND_ SLIT("#") - in - mkFullName mod tag2con InventedInThisModule NotExported mkGeneratedSrcLoc +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)] -maxtag_PN tycon - = let (mod, nm) = getOrigName tycon - maxtag = SLIT("maxtag_") _APPEND_ nm _APPEND_ SLIT("#") - in - Imp mod maxtag [mod] maxtag +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)")] -maxtag_FN tycon - = let (mod, nm) = getOrigName tycon - maxtag = SLIT("maxtag_") _APPEND_ nm _APPEND_ SLIT("#") - in - mkFullName mod maxtag InventedInThisModule NotExported mkGeneratedSrcLoc +derivCtxt tycon + = ptext SLIT("When deriving classes for") <+> quotes (ppr tycon) \end{code}