%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1994
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
%
\section[TcDeriv]{Deriving}
module TcDeriv ( tcDeriving ) where
-import Ubiq
+IMP_Ubiq()
import HsSyn ( FixityDecl, Sig, HsBinds(..), Bind(..), MonoBinds(..),
GRHSsAndBinds, Match, HsExpr, HsLit, InPat,
ArithSeqInfo, Fake, MonoType )
import HsPragmas ( InstancePragmas(..) )
-import RnHsSyn ( RenamedHsBinds(..), RenamedFixityDecl(..) )
+import RnHsSyn ( mkRnName, RnName(..), RenamedHsBinds(..), RenamedFixityDecl(..) )
import TcHsSyn ( TcIdOcc )
-import TcMonad hiding ( rnMtoTcM )
-import Inst ( InstOrigin(..), InstanceMapper(..) )
-import TcEnv ( getEnv_TyCons )
+import TcMonad
+import Inst ( InstanceMapper(..) )
+import TcEnv ( getEnv_TyCons, tcLookupClassByKey )
import TcKind ( TcKind )
---import TcGenDeriv -- Deriv stuff
+import TcGenDeriv -- Deriv stuff
import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs )
import TcSimplify ( tcSimplifyThetas )
import RnMonad
-import RnUtils ( RnEnv(..) )
+import RnUtils ( RnEnv(..), extendGlobalRnEnv )
import RnBinds ( rnMethodBinds, rnTopBinds )
import Bag ( emptyBag{-ToDo:rm-}, Bag, isEmptyBag, unionBags, listToBag )
-import Class ( GenClass, classKey )
+import Class ( classKey, needsDataDeclCtxtClassKeys, GenClass )
import CmdLineOpts ( opt_CompilingPrelude )
import ErrUtils ( pprBagOfErrors, addErrLoc, Error(..) )
-import Id ( dataConSig, dataConArity )
-import Maybes ( assocMaybe, maybeToBool, Maybe(..) )
-import Outputable
+import Id ( dataConArgTys, isNullaryDataCon, mkDictFunId )
+import Maybes ( maybeToBool, Maybe(..) )
+import Name ( moduleNamePair, isLocallyDefined, getSrcLoc,
+ mkTopLevName, origName, mkImplicitName, ExportFlag(..),
+ RdrName{-instance Outputable-}, Name{--O only-}
+ )
+import Outputable ( Outputable(..){-instances e.g., (,)-} )
import PprType ( GenType, GenTyVar, GenClass, TyCon )
-import PprStyle
-import Pretty
-import SrcLoc ( mkGeneratedSrcLoc, mkUnknownSrcLoc, SrcLoc )
+import PprStyle ( PprStyle(..) )
+import Pretty ( ppAbove, ppAboves, ppCat, ppBesides, ppStr, ppHang, Pretty(..) )
+import Pretty--ToDo:rm
+import FiniteMap--ToDo:rm
+import SrcLoc ( mkGeneratedSrcLoc, SrcLoc )
import TyCon ( tyConTyVars, tyConDataCons, tyConDerivings,
- maybeTyConSingleCon, isEnumerationTyCon, TyCon )
+ tyConTheta, maybeTyConSingleCon,
+ isEnumerationTyCon, isDataTyCon, TyCon
+ )
import Type ( GenType(..), TauType(..), mkTyVarTys, applyTyCon,
mkSigmaTy, mkDictTy, isPrimType, instantiateTy,
- getAppTyCon, getAppDataTyCon
+ getAppDataTyCon, getAppTyCon
)
+import TysWiredIn ( voidTy )
import TyVar ( GenTyVar )
import UniqFM ( emptyUFM )
import Unique -- Keys stuff
-import Util ( zipWithEqual, zipEqual, sortLt, removeDups,
- thenCmp, cmpList, panic, pprPanic, pprPanic#
+import Util ( zipWithEqual, zipEqual, sortLt, removeDups, assoc,
+ thenCmp, cmpList, panic, pprPanic, pprPanic#,
+ assertPanic, pprTrace{-ToDo:rm-}
)
\end{code}
| 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
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}}
-- 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
-- and make the necessary "equations".
makeDerivEqns `thenTc` \ eqns ->
-- "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
-
- 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
- in
- gen_tag_n_con_binds deriver_rn_env nm_alist_etc `thenTc` \ extra_binds ->
+ gen_taggery_Names new_inst_infos `thenTc` \ nm_alist_etc ->
+ gen_tag_n_con_binds rn_env nm_alist_etc
+ `thenTc` \ (extra_binds, deriver_rn_env) ->
mapTc (gen_inst_info maybe_mod fixities deriver_rn_env) new_inst_infos
- `thenTc` \ really_new_inst_infos ->
+ `thenTc` \ really_new_inst_infos ->
+ let
+ ddump_deriv = ddump_deriving really_new_inst_infos extra_binds
+ in
+ --pprTrace "derived:\n" (ddump_deriv PprDebug) $
returnTc (listToBag really_new_inst_infos,
extra_binds,
- ddump_deriving really_new_inst_infos extra_binds)
+ ddump_deriv)
where
- maybe_mod = if opt_CompilingPrelude then Nothing else Just mod_name
+ maybe_mod = if opt_CompilingPrelude then Nothing else Just modname
ddump_deriving :: [InstInfo] -> RenamedHsBinds -> (PprStyle -> Pretty)
makeDerivEqns :: TcM s [DerivEqn]
makeDerivEqns
- = tcGetEnv `thenNF_Tc` \ env ->
+ = tcGetEnv `thenNF_Tc` \ env ->
+ tcLookupClassByKey evalClassKey `thenNF_Tc` \ eval_clas ->
let
- tycons = getEnv_TyCons env
- think_about_deriving = need_deriving tycons
+ tycons = filter isDataTyCon (getEnv_TyCons env)
+ -- ToDo: what about newtypes???
+ think_about_deriving = need_deriving eval_clas tycons
in
- mapTc (chk_out think_about_deriving) think_about_deriving `thenTc_`
+ mapTc chk_out think_about_deriving `thenTc_`
let
(derive_these, _) = removeDups cmp_deriv think_about_deriving
eqns = map mk_eqn derive_these
returnTc eqns
where
------------------------------------------------------------------
- need_deriving :: [TyCon] -> [(Class, TyCon)]
- -- find the tycons that have `deriving' clauses
+ 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 tycons_to_consider
+ 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
- cs -> [ (clas,tycon) | clas <- cs ] ++ acc
+ [] -> acc_plus
+ cs -> [ (clas,tycon) | clas <- cs ] ++ acc_plus
)
[]
tycons_to_consider
------------------------------------------------------------------
- chk_out :: [(Class, TyCon)] -> (Class, TyCon) -> TcM s ()
- chk_out whole_deriving_list this_one@(clas, tycon)
+ chk_out :: (Class, TyCon) -> TcM s ()
+ chk_out this_one@(clas, tycon)
= let
clas_key = classKey clas
- in
+ is_enumeration = isEnumerationTyCon tycon
+ is_single_con = maybeToBool (maybeTyConSingleCon tycon)
+
+ chk_clas clas_uniq clas_str cond
+ = if (clas_uniq == clas_key)
+ then checkTc cond (derivingThingErr clas_str tycon)
+ else returnTc ()
+ in
-- Are things OK for deriving Enum (if appropriate)?
- checkTc (clas_key == enumClassKey && not (isEnumerationTyCon tycon))
- (derivingEnumErr tycon) `thenTc_`
+ chk_clas enumClassKey "Enum" is_enumeration `thenTc_`
+
+ -- Are things OK for deriving Bounded (if appropriate)?
+ chk_clas boundedClassKey "Bounded"
+ (is_enumeration || is_single_con) `thenTc_`
-- Are things OK for deriving Ix (if appropriate)?
- checkTc (clas_key == ixClassKey
- && not (isEnumerationTyCon tycon
- || maybeToBool (maybeTyConSingleCon tycon)))
- (derivingIxErr tycon)
+ chk_clas ixClassKey "Ix.Ix" (is_enumeration || is_single_con)
------------------------------------------------------------------
cmp_deriv :: (Class, TyCon) -> (Class, TyCon) -> TAG_
-- to make the rest of the equation
mk_eqn (clas, tycon)
- = (clas, tycon, tyvars, constraints)
+ = (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
- constraints = concat (map mk_constraints data_cons)
+
+ if_not_Eval cs = if clas_key == evalClassKey then [] else cs
+
+ 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, instantiateTy inst_env arg_ty)
- | arg_ty <- arg_tys,
+ = [ (clas, arg_ty)
+ | arg_ty <- instd_arg_tys,
not (isPrimType arg_ty) -- No constraints for primitive types
]
where
- (con_tyvars, _, arg_tys, _) = dataConSig data_con
- inst_env = zipEqual "mk_eqn" con_tyvars tyvar_tys
- -- same number of tyvars in data constr and type constr!
+ instd_arg_tys = dataConArgTys data_con tyvar_tys
\end{code}
%************************************************************************
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}
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
+ class_to_inst_env cls = fst (inst_mapper cls)
in
- listTc [ tcSimplifyThetas mk_deriv_origin rhs
- | (_, _, _, rhs) <- orig_eqns
- ] `thenTc` \ next_solns ->
+ -- Simplify each RHS
+
+ listTc [ tcSimplifyThetas class_to_inst_env [{-Nothing "given"-}] deriv_rhs
+ | (_,_,_,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
+ if (current_solns `eq_solns` canonicalised_next_solns) then
returnTc new_inst_infos
else
iterateDeriv canonicalised_next_solns
\end{code}
\begin{code}
-add_solns :: FAST_STRING
- -> Bag InstInfo -- The global, non-derived ones
+add_solns :: Bag InstInfo -- The global, non-derived ones
-> [DerivEqn] -> [DerivSoln]
-> TcM s ([InstInfo], -- The new, derived ones
InstanceMapper)
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
+ (my_panic "dfun_theta")
+
+ dummy_dfun_id
+
+ (my_panic "const_meth_ids")
+ (my_panic "binds") (my_panic "from_here")
+ (my_panic "modname") mkGeneratedSrcLoc
+ (my_panic "upragmas")
where
- bottom = panic "add_soln"
-#endif
+ dummy_dfun_id
+ = mkDictFunId bottom bottom bottom dummy_dfun_ty
+ bottom bottom bottom bottom
+ 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 = pprPanic ("add_soln:"++str) (ppCat [ppChar ':', ppr PprDebug clas, ppr PprDebug tycon])
\end{code}
%************************************************************************
``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.
\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
@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.
@_tag2con_<tycon>@ 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}
-> 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 _)
+ (InstInfo clas tyvars ty inst_decl_theta _ _ _ _ _ _ locn _)
=
-- Generate the various instance-related Ids
mkInstanceRelatedIds
-- Generate the bindings for the new instance declaration,
-- rename it, and check for errors
let
- (tycon,_,_) = getAppDataTyCon ty
+ (tycon,_,_) = --pprTrace "gen_inst_info:ty" (ppCat[ppr PprDebug clas, ppr PprDebug ty]) $
+ 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"
+ = assoc "gen_inst_info: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 fixities)
+ ,(readClassKey, gen_Read_binds fixities)
+ ,(ixClassKey, gen_Ix_binds)
+ ]
+ clas_key $ tycon
+ in
+{-
+ let
+ ((qual, unqual, tc_qual, tc_unqual), stack) = deriver_rn_env
in
+ pprTrace "gen_inst:qual:" (ppCat [ppBesides[ppPStr m,ppChar '.',ppPStr n] | (n,m) <- keysFM qual]) $
+ pprTrace "gen_inst:unqual:" (ppCat (map ppPStr (keysFM unqual))) $
+ pprTrace "gen_inst:tc_qual:" (ppCat [ppBesides[ppPStr m,ppChar '.',ppPStr n] | (n,m) <- keysFM tc_qual]) $
+ pprTrace "gen_inst:tc_unqual:" (ppCat (map ppPStr (keysFM tc_unqual))) $
+-}
+ -- pprTrace "derived binds:" (ppr PprDebug proto_mbinds) $
+
rnMtoTcM deriver_rn_env (
setExtraRn emptyUFM{-no fixities-} $
rnMethodBinds clas_Name proto_mbinds
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
(if from_here then mbinds else EmptyMonoBinds)
from_here modname locn [])
where
- clas_key = classKey clas
- clas_Name
- = let (mod, nm) = moduleNamePair clas in
- ClassName clas_key (mkPreludeCoreName mod nm) []
+ clas_key = classKey clas
+ clas_Name = RnImplicitClass (mkImplicitName clas_key (origName clas))
\end{code}
%************************************************************************
\begin{code}
gen_tag_n_con_binds :: RnEnv
- -> [(RdrName, RnName, TyCon, TagThingWanted)]
- -> TcM s RenamedHsBinds
+ -> [(RdrName, TyCon, TagThingWanted)]
+ -> TcM s (RenamedHsBinds,
+ RnEnv) -- input one with any new names added
-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
+gen_tag_n_con_binds rn_env nm_alist_etc
+ =
+ let
+ -- 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.
+
+ names_to_add = [ pn | (pn,_,_) <- nm_alist_etc ]
+ in
+ tcGetUniques (length names_to_add) `thenNF_Tc` \ uniqs ->
+ let
+ pairs_to_add = [ (pn, mkRnName (mkTopLevName u pn mkGeneratedSrcLoc ExportAll []))
+ | (pn,u) <- zipEqual "gen_tag..." names_to_add uniqs ]
+
+ deriver_rn_env
+ = if null names_to_add
+ then rn_env else added_rn_env
+
+ (added_rn_env, errs_bag)
+ = extendGlobalRnEnv rn_env pairs_to_add [{-no tycons-}]
+
+ ----------------
+ proto_mbind_list = map gen_tag_n_con_monobind nm_alist_etc
+ proto_mbinds = foldr AndMonoBinds EmptyMonoBinds proto_mbind_list
in
+ ASSERT(isEmptyBag errs_bag)
rnMtoTcM deriver_rn_env (
setExtraRn emptyUFM{-no fixities-} $
) `thenNF_Tc` \ (binds, errs) ->
if not (isEmptyBag errs) then
- panic "gen_inst_info:renamer errs (2)!"
+ pprPanic "gen_tag_n_con_binds:renamer errs!\n"
+ (ppAbove (pprBagOfErrors PprDebug errs) (ppr PprDebug binds))
else
- returnTc binds
+ returnTc (binds, deriver_rn_env)
\end{code}
%************************************************************************
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
+gen_taggery_Names :: [InstInfo]
+ -> TcM s [(RdrName, -- 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 inst_infos
+ = --pprTrace "gen_taggery:\n" (ppAboves [ppCat [ppr PprDebug c, ppr PprDebug t] | (c,t) <- all_CTs]) $
+ foldlTc do_con2tag [] tycons_of_interest `thenTc` \ names_so_far ->
+ foldlTc do_tag2con names_so_far tycons_of_interest
where
+ all_CTs = [ mk_CT c ty | (InstInfo c _ ty _ _ _ _ _ _ _ _ _) <- inst_infos ]
+
+ mk_CT c ty = (c, fst (getAppTyCon ty))
+
+ all_tycons = map snd all_CTs
+ (tycons_of_interest, _) = removeDups cmp all_tycons
+
do_con2tag acc_Names tycon
= if (we_are_deriving eqClassKey tycon
- && any ( (== 0).dataConArity ) (tyConDataCons 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) )
+ returnTc ((con2tag_PN tycon, tycon, GenCon2Tag)
+ : acc_Names)
else
returnTc acc_Names
= 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)
+ returnTc ( (tag2con_PN tycon, tycon, GenTag2Con)
+ : (maxtag_PN tycon, tycon, GenMaxTag)
: acc_Names)
else
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)
+ is_in_eqns clas_key tycon ((c,t):cts)
= (clas_key == classKey c && tycon == t)
- || is_in_eqns clas_key tycon eqns
+ || 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 :: String -> TyCon -> Error
+
+derivingThingErr thing tycon sty
+ = ppHang (ppCat [ppStr "Can't make a derived instance of", ppStr thing])
+ 4 (ppBesides [ppStr "for the type `", ppr sty tycon, ppStr "'"])
\end{code}
projects / ghc-hetmet.git / blobdiff