%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1994
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
%
\section[TcDeriv]{Deriving}
Handles @deriving@ clauses on @data@ declarations.
-********** Don't forget
-
-Multi-instance checking in renamer should include deriving.
-
\begin{code}
#include "HsVersions.h"
-module TcDeriv (
- tcDeriving,
- con2tag_PN, tag2con_PN, maxtag_PN,
- TagThingWanted(..), DerivEqn(..)
- ) where
-
-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 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 )
+module TcDeriv ( tcDeriving ) where
+
+IMP_Ubiq()
+
+import HsSyn ( FixityDecl, Sig, HsBinds(..), Bind(..), MonoBinds(..),
+ GRHSsAndBinds, Match, HsExpr, HsLit, InPat,
+ ArithSeqInfo, Fake, MonoType )
+import HsPragmas ( InstancePragmas(..) )
+import RnHsSyn ( mkRnName, RnName(..), SYN_IE(RenamedHsBinds), RenamedFixityDecl(..) )
+import TcHsSyn ( TcIdOcc )
+
+import TcMonad
+import Inst ( SYN_IE(InstanceMapper) )
+import TcEnv ( getEnv_TyCons, tcLookupClassByKey )
+import SpecEnv ( SpecEnv )
+import TcKind ( TcKind )
+import TcGenDeriv -- Deriv stuff
+import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs )
import TcSimplify ( tcSimplifyThetas )
-import Unique -- *Key stuff
-import Util
+
+import RnMonad
+import RnUtils ( SYN_IE(RnEnv), extendGlobalRnEnv )
+import RnBinds ( rnMethodBinds, rnTopBinds )
+
+import Bag ( Bag, isEmptyBag, unionBags, listToBag )
+import Class ( classKey, needsDataDeclCtxtClassKeys, GenClass )
+import ErrUtils ( pprBagOfErrors, addErrLoc, SYN_IE(Error) )
+import Id ( dataConArgTys, isNullaryDataCon, mkDictFunId )
+import Maybes ( maybeToBool )
+import Name ( isLocallyDefined, getSrcLoc,
+ mkTopLevName, origName, mkImplicitName, ExportFlag(..),
+ RdrName(..), Name{--O only-}
+ )
+import Outputable ( Outputable(..){-instances e.g., (,)-} )
+import PprType ( GenType, GenTyVar, GenClass, TyCon )
+import PprStyle ( PprStyle(..) )
+import Pretty ( ppAbove, ppAboves, ppCat, ppBesides, ppStr, ppHang, SYN_IE(Pretty) )
+--import Pretty--ToDo:rm
+--import FiniteMap--ToDo:rm
+import SrcLoc ( mkGeneratedSrcLoc, SrcLoc )
+import TyCon ( tyConTyVars, tyConDataCons, tyConDerivings,
+ tyConTheta, maybeTyConSingleCon,
+ isEnumerationTyCon, isDataTyCon, TyCon
+ )
+import Type ( GenType(..), SYN_IE(TauType), mkTyVarTys, applyTyCon,
+ mkSigmaTy, mkDictTy, isPrimType, instantiateTy,
+ getAppDataTyCon, getAppTyCon
+ )
+import TysPrim ( voidTy )
+import TyVar ( GenTyVar )
+import UniqFM ( emptyUFM )
+import Unique -- Keys stuff
+import Util ( zipWithEqual, zipEqual, sortLt, removeDups, assoc,
+ thenCmp, cmpList, panic, panic#, pprPanic, pprPanic#,
+ assertPanic-- , pprTrace{-ToDo:rm-}
+ )
\end{code}
%************************************************************************
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
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
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}}
%************************************************************************
\begin{code}
-tcDeriving :: FAST_STRING -- name of module under scrutiny
- -> GlobalNameFuns -- for "renaming" bits of generated code
+tcDeriving :: Module -- name of module under scrutiny
+ -> RnEnv -- 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 ->
+ -> [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
+ = -- Fish the "deriving"-related information out of the TcEnv
+ -- and make the necessary "equations".
+ makeDerivEqns `thenTc` \ eqns ->
-- Take the equation list and solve it, to deliver a list of
-- solutions, a.k.a. the contexts for the instance decls
-- required for the corresponding equations.
- solveDerivEqns modname inst_decl_infos_in eqns
- `thenTc` \ new_inst_infos ->
+ solveDerivEqns inst_decl_infos_in eqns
+ `thenTc` \ new_inst_infos ->
-- Now augment the InstInfos, adding in the rather boring
-- actual-code-to-do-the-methods binds. We may also need to
-- "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_inst_infos `thenTc` \ nm_alist_etc ->
+ gen_tag_n_con_binds rn_env nm_alist_etc
+ `thenTc` \ (extra_binds, deriver_rn_env) ->
- 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
+ mapTc (gen_inst_info modname fixities deriver_rn_env) new_inst_infos
+ `thenTc` \ really_new_inst_infos ->
+ let
+ ddump_deriv = ddump_deriving really_new_inst_infos extra_binds
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 ->
+ --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
- ddump_deriving :: [InstInfo] -> RenamedBinds -> (PprStyle -> Pretty)
+ ddump_deriving :: [InstInfo] -> RenamedHsBinds -> (PprStyle -> Pretty)
ddump_deriving inst_infos extra_binds sty
- = ppAboves ((map (pp_1 sty) inst_infos) ++ [ppr sty extra_binds])
+ = ppAboves ((map pp_info inst_infos) ++ [ppr sty 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)))
+ pp_info (InstInfo clas tvs ty inst_decl_theta _ _ _ mbinds _ _ _ _)
+ = ppAbove (ppr sty (mkSigmaTy tvs inst_decl_theta (mkDictTy clas ty)))
(ppr sty mbinds)
\end{code}
all those.
\begin{code}
-makeDerivEqns :: TCE -> TcM [DerivEqn]
+makeDerivEqns :: TcM s [DerivEqn]
-makeDerivEqns tce
- = let
- think_about_deriving = need_deriving (rngTCE tce)
+makeDerivEqns
+ = tcGetEnv `thenNF_Tc` \ env ->
+ tcLookupClassByKey evalClassKey `thenNF_Tc` \ eval_clas ->
+ let
+ 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_`
-
- let
- (derive_these, _) = removeDups cmp think_about_deriving
+ mapTc chk_out think_about_deriving `thenTc_`
+ let
+ (derive_these, _) = removeDups cmp_deriv think_about_deriving
+ eqns = map mk_eqn derive_these
in
-
- listNF_Tc (map mk_eqn derive_these) `thenNF_Tc` \ eqns ->
-
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 ->
- case (getTyConDerivings tycon) of
- [] -> acc
- cs -> [ (clas,tycon) | clas <- cs ] ++ 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
)
- [] -- init accumulator
+ []
tycons_to_consider
------------------------------------------------------------------
- chk_out :: [(Class, TyCon)] -> (Class, TyCon) -> TcM ()
-
- 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"?
- let
- (_, super_classes, _) = getClassSig clas
- clas_key = getClassKey clas
+ 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)
+
+ 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 (maybeSingleConstructorTyCon tycon)))
- (derivingIxErr tycon)
+ chk_clas ixClassKey "Ix.Ix" (is_enumeration || is_single_con)
------------------------------------------------------------------
- cmp :: (Class, TyCon) -> (Class, TyCon) -> TAG_
-
- cmp (c1, t1) (c2, t2)
- = case cmpClass c1 c2 of
- EQ_ -> cmpTyCon t1 t2
- other -> other
+ cmp_deriv :: (Class, TyCon) -> (Class, TyCon) -> TAG_
+ cmp_deriv (c1, t1) (c2, t2)
+ = (c1 `cmp` c2) `thenCmp` (t1 `cmp` t2)
------------------------------------------------------------------
- mk_eqn :: (Class, TyCon) -> NF_TcM DerivEqn
- -- we swizzle the tyvars, data cons, etc., out of the tycon,
+ 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)
- = 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)
+ = (clas, tycon, tyvars, if_not_Eval constraints)
where
- mk_constraints tyvar_tys data_con
- = [ (clas, instantiateTy inst_env arg_ty)
- | arg_ty <- arg_tys,
+ 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)
+
+ -- "extra_constraints": see notes above about contexts on data decls
+ extra_constraints
+ | offensive_class = tyConTheta tycon
+ | otherwise = []
+ where
+ offensive_class = clas_key `elem` needsDataDeclCtxtClassKeys
+
+ mk_constraints data_con
+ = [ (clas, arg_ty)
+ | arg_ty <- instd_arg_tys,
not (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!
+ instd_arg_tys = dataConArgTys data_con tyvar_tys
\end{code}
%************************************************************************
%* *
%************************************************************************
-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.
+solveDerivEqns :: Bag InstInfo
+ -> [DerivEqn]
+ -> TcM s [InstInfo] -- Solns in same order as eqns.
-- This bunch is Absolutely minimal...
-solveDerivEqns modname inst_decl_infos_in orig_eqns
+solveDerivEqns inst_decl_infos_in orig_eqns
= iterateDeriv initial_solutions
where
-- The initial solutions for the equations claim that each
-- compares it with the current one; finishes if they are the
-- same, otherwise recurses with the new solutions.
- iterateDeriv :: [DerivSoln] ->TcM [InstInfo]
+ iterateDeriv :: [DerivSoln] ->TcM s [InstInfo]
iterateDeriv current_solns
- = -- Extend the inst info from the explicit instance decls
+ = -- 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
+ 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 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
+ 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 less_than next_soln | next_soln <- next_solns ] in
+ = [ sortLt lt_rhs next_soln | next_soln <- next_solns ] in
- if current_solns == canonicalised_next_solns then
- returnTc new_inst_infos
- else
- iterateDeriv canonicalised_next_solns
+ if (current_solns `eq_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)
+ 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
- less_than other_1 other_2
- = pprPanic "tcDeriv:less_than:" (ppCat [ppr PprDebug other_1, ppr PprDebug other_2])
+ cmp_rhs other_1 other_2
+ = panic# "tcDeriv:cmp_rhs:" --(ppCat [ppr PprDebug other_1, ppr PprDebug other_2])
#endif
+
\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 ([InstInfo], -- The new, derived ones
- InstanceMapper)
+ -> TcM s ([InstInfo], -- The new, derived ones
+ InstanceMapper)
-- 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 ->
-
+add_solns inst_infos_in eqns solns
+ = buildInstanceEnvs all_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
+ new_inst_infos = zipWithEqual "add_solns" mk_deriv_inst_info eqns solns
+
+ all_inst_infos = inst_infos_in `unionBags` listToBag new_inst_infos
- 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_inst_info (clas, tycon, tyvars, _) theta
+ = InstInfo clas tyvars (applyTyCon tycon (mkTyVarTys tyvars))
+ theta
+ (my_panic "dfun_theta")
- to_tmpl = assoc "mk_deriv_inst_info" env
+ dummy_dfun_id
- (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
- )
+ (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 = panic "add_soln" -- 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}
\begin{code}
-gen_inst_info :: FAST_STRING -- Module name
+gen_inst_info :: Module -- Module name
-> [RenamedFixityDecl] -- all known fixities;
-- may be needed for Text
- -> GlobalNameFuns -- lookup stuff for names we may use
+ -> RnEnv -- lookup stuff for names we may use
-> InstInfo -- the main stuff to work on
- -> TcM InstInfo -- the gen'd (filled-in) "instance decl"
+ -> TcM s 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 _)
- =
+gen_inst_info modname fixities deriver_rn_env
+ (InstInfo clas tyvars 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-}
+ True {-from_here-} locn modname
NoInstancePragmas
- mkGeneratedSrcLoc
- clas
- tyvar_tmpls ty
+ 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,
+ -- 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
+ (tycon,_,_) = --pprTrace "gen_inst_info:ty" (ppCat[ppr PprDebug clas, ppr PprDebug ty]) $
+ getAppDataTyCon ty
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"
+ = 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
- rn4MtoTcM deriver_name_funs (
- rnMethodBinds4 clas_Name proto_mbinds
+{-
+ 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
) `thenNF_Tc` \ (mbinds, errs) ->
if not (isEmptyBag errs) then
- pprPanic "gen_inst_info:renamer errs!\n" (ppAbove (pprBagOfErrors PprDebug errs) (ppr PprDebug proto_mbinds))
+ panic "gen_inst_info:renamer errs!\n"
+-- 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
+ 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...
+ 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 [])
where
- clas_key = getClassKey clas
- clas_Name
- = let (mod, nm) = getOrigName clas in
- PreludeClass clas_key (mkPreludeCoreName mod nm)
+ clas_key = classKey clas
+ clas_Name = RnImplicitClass (mkImplicitName clas_key (origName "gen_inst_info" clas))
\end{code}
%************************************************************************
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
+gen_tag_n_con_binds :: RnEnv
+ -> [(RdrName, TyCon, TagThingWanted)]
+ -> TcM s (RenamedHsBinds,
+ RnEnv) -- input one with any new names added
+
+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 = [ case pn of { Qual pnm pnn ->
+ (pn, mkRnName (mkTopLevName u (OrigName pnm pnn) mkGeneratedSrcLoc ExportAll [])) }
+ | (pn,u) <- zipEqual "gen_tag..." names_to_add uniqs ]
- rn4MtoTcM deriver_name_funs (
- rnTopBinds4 (SingleBind (RecBind proto_mbinds))
+ 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-} $
+ rnTopBinds (SingleBind (RecBind proto_mbinds))
) `thenNF_Tc` \ (binds, errs) ->
if not (isEmptyBag errs) then
- panic "gen_inst_info:renamer errs (2)!"
+ panic "gen_tag_n_con_binds:renamer errs!\n"
+-- 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}
-data TagThingWanted
- = GenCon2Tag | GenTag2Con | GenMaxTag
-
-gen_taggery_Names :: [DerivEqn]
- -> TcM [(ProtoName, Name, -- 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 :: [InstInfo]
+ -> TcM s [(RdrName, -- for an assoc list
+ TyCon, -- related tycon
+ TagThingWanted)]
+
+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 isNullaryDataCon (getTyConDataCons tycon))
+ && any isNullaryDataCon (tyConDataCons tycon))
|| (we_are_deriving ordClassKey tycon
- && not (maybeToBool (maybeSingleConstructorTyCon tycon)))
+ && not (maybeToBool (maybeTyConSingleCon 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) )
+ returnTc ((con2tag_PN tycon, tycon, GenCon2Tag)
+ : acc_Names)
else
returnTc acc_Names
= 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)
+ 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) -- ToDo: InstInfo
- = (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
-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
-
-tag2con_PN tycon
- = let (mod, nm) = getOrigName tycon
- tag2con = SLIT("tag2con_") _APPEND_ nm _APPEND_ SLIT("#")
- in
- Imp mod tag2con [mod] tag2con
-
-tag2con_FN tycon
- = let (mod, nm) = getOrigName tycon
- tag2con = SLIT("tag2con_") _APPEND_ nm _APPEND_ SLIT("#")
- in
- mkFullName mod tag2con InventedInThisModule NotExported mkGeneratedSrcLoc
+\end{code}
-maxtag_PN tycon
- = let (mod, nm) = getOrigName tycon
- maxtag = SLIT("maxtag_") _APPEND_ nm _APPEND_ SLIT("#")
- in
- Imp mod maxtag [mod] maxtag
+\begin{code}
+derivingThingErr :: String -> TyCon -> Error
-maxtag_FN tycon
- = let (mod, nm) = getOrigName tycon
- maxtag = SLIT("maxtag_") _APPEND_ nm _APPEND_ SLIT("#")
- in
- mkFullName mod maxtag InventedInThisModule NotExported mkGeneratedSrcLoc
+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