rm_dups [] $ concat deriv_aux_binds
aux_val_binds = ValBindsIn (listToBag aux_binds) aux_sigs
; rn_aux_lhs <- rnTopBindsLHS emptyFsEnv aux_val_binds
- ; let aux_names = collectHsValBinders rn_aux_lhs
-
- ; bindLocalNames aux_names $
- do { (rn_aux, dus_aux) <- rnTopBindsRHS (mkNameSet aux_names) rn_aux_lhs
+ ; bindLocalNames (collectHsValBinders rn_aux_lhs) $
+ do { (rn_aux, dus_aux) <- rnTopBindsRHS rn_aux_lhs
; (rn_inst_infos, fvs_insts) <- mapAndUnzipM rn_inst_info inst_infos
; return (rn_inst_infos, rn_aux `plusHsValBinds` rn_gen,
dus_gen `plusDU` dus_aux `plusDU` usesOnly (plusFVs fvs_insts)) } }
, mkFVs (map dataConName (tyConDataCons tc)))
-- See Note [Newtype deriving and unused constructors]
- rn_inst_info (InstInfo { iSpec = inst, iBinds = VanillaInst binds sigs standalone_deriv })
+ rn_inst_info inst_info@(InstInfo { iSpec = inst, iBinds = VanillaInst binds sigs standalone_deriv })
= -- Bring the right type variables into
-- scope (yuk), and rename the method binds
ASSERT( null sigs )
bindLocalNames (map Var.varName tyvars) $
do { (rn_binds, fvs) <- rnMethodBinds clas_nm (\_ -> []) [] binds
; let binds' = VanillaInst rn_binds [] standalone_deriv
- ; return (InstInfo { iSpec = inst, iBinds = binds' }, fvs) }
+ ; return (inst_info { iBinds = binds' }, fvs) }
where
(tyvars,_, clas,_) = instanceHead inst
clas_nm = className clas
= setSrcSpan loc $
addErrCtxt (standaloneCtxt deriv_ty) $
do { traceTc "Standalone deriving decl for" (ppr deriv_ty)
- ; (tvs, theta, tau) <- tcHsInstHead deriv_ty
+ ; (tvs, theta, cls, inst_tys) <- tcHsInstHead deriv_ty
; traceTc "Standalone deriving;" $ vcat
[ text "tvs:" <+> ppr tvs
, text "theta:" <+> ppr theta
- , text "tau:" <+> ppr tau ]
- ; (cls, inst_tys) <- checkValidInstance deriv_ty tvs theta tau
+ , text "cls:" <+> ppr cls
+ , text "tys:" <+> ppr inst_tys ]
+ ; checkValidInstance deriv_ty tvs theta cls inst_tys
-- C.f. TcInstDcls.tcLocalInstDecl1
; let cls_tys = take (length inst_tys - 1) inst_tys
mkEqnHelp orig tvs cls cls_tys tc_app mtheta
| Just (tycon, tc_args) <- tcSplitTyConApp_maybe tc_app
, isAlgTyCon tycon -- Check for functions, primitive types etc
- = do { (rep_tc, rep_tc_args) <- tcLookupDataFamInst tycon tc_args
- -- Be careful to test rep_tc here: in the case of families,
- -- we want to check the instance tycon, not the family tycon
-
- -- For standalone deriving (mtheta /= Nothing),
- -- check that all the data constructors are in scope.
- -- No need for this when deriving Typeable, becuase we don't need
- -- the constructors for that.
- ; rdr_env <- getGlobalRdrEnv
- ; let hidden_data_cons = isAbstractTyCon rep_tc || any not_in_scope (tyConDataCons rep_tc)
- not_in_scope dc = null (lookupGRE_Name rdr_env (dataConName dc))
- ; checkTc (isNothing mtheta ||
- not hidden_data_cons ||
- className cls `elem` typeableClassNames)
- (derivingHiddenErr tycon)
-
- ; dflags <- getDOpts
- ; if isDataTyCon rep_tc then
- mkDataTypeEqn orig dflags tvs cls cls_tys
- tycon tc_args rep_tc rep_tc_args mtheta
- else
- mkNewTypeEqn orig dflags tvs cls cls_tys
- tycon tc_args rep_tc rep_tc_args mtheta }
+ = mk_alg_eqn tycon tc_args
| otherwise
= failWithTc (derivingThingErr False cls cls_tys tc_app
(ptext (sLit "The last argument of the instance must be a data or newtype application")))
+
+ where
+ bale_out msg = failWithTc (derivingThingErr False cls cls_tys tc_app msg)
+
+ mk_alg_eqn tycon tc_args
+ | className cls `elem` typeableClassNames
+ = do { dflags <- getDOpts
+ ; case checkTypeableConditions (dflags, tycon) of
+ Just err -> bale_out err
+ Nothing -> mk_typeable_eqn orig tvs cls tycon tc_args mtheta }
+
+ | isDataFamilyTyCon tycon
+ , length tc_args /= tyConArity tycon
+ = bale_out (ptext (sLit "Unsaturated data family application"))
+
+ | otherwise
+ = do { (rep_tc, rep_tc_args) <- tcLookupDataFamInst tycon tc_args
+ -- Be careful to test rep_tc here: in the case of families,
+ -- we want to check the instance tycon, not the family tycon
+
+ -- For standalone deriving (mtheta /= Nothing),
+ -- check that all the data constructors are in scope.
+ ; rdr_env <- getGlobalRdrEnv
+ ; let hidden_data_cons = isAbstractTyCon rep_tc ||
+ any not_in_scope (tyConDataCons rep_tc)
+ not_in_scope dc = null (lookupGRE_Name rdr_env (dataConName dc))
+ ; unless (isNothing mtheta || not hidden_data_cons)
+ (bale_out (derivingHiddenErr tycon))
+
+ ; dflags <- getDOpts
+ ; if isDataTyCon rep_tc then
+ mkDataTypeEqn orig dflags tvs cls cls_tys
+ tycon tc_args rep_tc rep_tc_args mtheta
+ else
+ mkNewTypeEqn orig dflags tvs cls cls_tys
+ tycon tc_args rep_tc rep_tc_args mtheta }
\end{code}
go_for_it = mk_data_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta
bale_out msg = failWithTc (derivingThingErr False cls cls_tys (mkTyConApp tycon tc_args) msg)
-mk_data_eqn, mk_typeable_eqn
- :: CtOrigin -> [TyVar] -> Class
- -> TyCon -> [TcType] -> TyCon -> [TcType] -> DerivContext
- -> TcM EarlyDerivSpec
+mk_data_eqn :: CtOrigin -> [TyVar] -> Class
+ -> TyCon -> [TcType] -> TyCon -> [TcType] -> DerivContext
+ -> TcM EarlyDerivSpec
mk_data_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta
- | getName cls `elem` typeableClassNames
- = mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta
-
- | otherwise
= do { dfun_name <- new_dfun_name cls tycon
; loc <- getSrcSpanM
; let inst_tys = [mkTyConApp tycon tc_args]
; return (if isJust mtheta then Right spec -- Specified context
else Left spec) } -- Infer context
-mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta
+----------------------
+mk_typeable_eqn :: CtOrigin -> [TyVar] -> Class
+ -> TyCon -> [TcType] -> DerivContext
+ -> TcM EarlyDerivSpec
+mk_typeable_eqn orig tvs cls tycon tc_args mtheta
-- The Typeable class is special in several ways
-- data T a b = ... deriving( Typeable )
-- gives
= do { checkTc (cls `hasKey` typeableClassKey)
(ptext (sLit "Use deriving( Typeable ) on a data type declaration"))
; real_cls <- tcLookupClass (typeableClassNames !! tyConArity tycon)
- ; mk_typeable_eqn orig tvs real_cls tycon [] rep_tc [] (Just []) }
+ ; mk_typeable_eqn orig tvs real_cls tycon [] (Just []) }
| otherwise -- standaone deriving
= do { checkTc (null tc_args)
; return (Right $
DS { ds_loc = loc, ds_orig = orig, ds_name = dfun_name, ds_tvs = []
, ds_cls = cls, ds_tys = [mkTyConApp tycon []]
- , ds_tc = rep_tc, ds_tc_args = rep_tc_args
+ , ds_tc = tycon, ds_tc_args = []
, ds_theta = mtheta `orElse` [], ds_newtype = False }) }
-
+----------------------
inferConstraints :: [TyVar] -> Class -> [TcType] -> TyCon -> [TcType] -> ThetaType
-- Generate a sufficiently large set of constraints that typechecking the
-- generated method definitions should succeed. This set will be simplified
where
ty_args_why = quotes (ppr (mkClassPred cls cls_tys)) <+> ptext (sLit "is not a class")
+checkTypeableConditions :: Condition
+checkTypeableConditions = checkFlag Opt_DeriveDataTypeable `andCond` cond_typeableOK
+
nonStdErr :: Class -> SDoc
nonStdErr cls = quotes (ppr cls) <+> ptext (sLit "is not a derivable class")
cond_functorOK False) -- Functor/Fold/Trav works ok for rank-n types
| cls_key == traversableClassKey = Just (checkFlag Opt_DeriveTraversable `andCond`
cond_functorOK False)
- | getName cls `elem` typeableClassNames = Just (checkFlag Opt_DeriveDataTypeable `andCond` cond_typeableOK)
| otherwise = Nothing
where
cls_key = getUnique cls
orCond :: Condition -> Condition -> Condition
orCond c1 c2 tc
= case c1 tc of
- Nothing -> Nothing -- c1 succeeds
- Just x -> case c2 tc of -- c1 fails
+ Nothing -> Nothing -- c1 succeeds
+ Just x -> case c2 tc of -- c1 fails
Nothing -> Nothing
Just y -> Just (x $$ ptext (sLit " and") $$ y)
- -- Both fail
+ -- Both fail
andCond :: Condition -> Condition -> Condition
andCond c1 c2 tc = case c1 tc of
cond_stdOK (Just _) _
= Nothing -- Don't check these conservative conditions for
-- standalone deriving; just generate the code
+ -- and let the typechecker handle the result
cond_stdOK Nothing (_, rep_tc)
- | null data_cons = Just (no_cons_why $$ suggestion)
+ | null data_cons = Just (no_cons_why rep_tc $$ suggestion)
| not (null con_whys) = Just (vcat con_whys $$ suggestion)
| otherwise = Nothing
where
suggestion = ptext (sLit "Possible fix: use a standalone deriving declaration instead")
data_cons = tyConDataCons rep_tc
- no_cons_why = quotes (pprSourceTyCon rep_tc) <+>
- ptext (sLit "has no data constructors")
-
con_whys = mapCatMaybes check_con data_cons
check_con :: DataCon -> Maybe SDoc
, all isTauTy (dataConOrigArgTys con) = Nothing
| otherwise = Just (badCon con (ptext (sLit "does not have a Haskell-98 type")))
+no_cons_why :: TyCon -> SDoc
+no_cons_why rep_tc = quotes (pprSourceTyCon rep_tc) <+>
+ ptext (sLit "has no data constructors")
+
cond_enumOrProduct :: Condition
cond_enumOrProduct = cond_isEnumeration `orCond`
(cond_isProduct `andCond` cond_noUnliftedArgs)
cond_isEnumeration :: Condition
cond_isEnumeration (_, rep_tc)
- | isEnumerationTyCon rep_tc = Nothing
- | otherwise = Just why
+ | isEnumerationTyCon rep_tc = Nothing
+ | otherwise = Just why
where
- why = quotes (pprSourceTyCon rep_tc) <+>
- ptext (sLit "has non-nullary constructors")
+ why = sep [ quotes (pprSourceTyCon rep_tc) <+>
+ ptext (sLit "is not an enumeration type")
+ , nest 2 $ ptext (sLit "(an enumeration consists of one or more nullary constructors)") ]
+ -- See Note [Enumeration types] in TyCon
cond_isProduct :: Condition
cond_isProduct (_, rep_tc)
| otherwise = Just why
where
why = quotes (pprSourceTyCon rep_tc) <+>
- ptext (sLit "has more than one constructor")
+ ptext (sLit "does not have precisely one constructor")
cond_typeableOK :: Condition
-- OK for Typeable class
-- Currently: (a) args all of kind *
-- (b) 7 or fewer args
-cond_typeableOK (_, rep_tc)
- | tyConArity rep_tc > 7 = Just too_many
- | not (all (isSubArgTypeKind . tyVarKind) (tyConTyVars rep_tc))
- = Just bad_kind
- | isFamInstTyCon rep_tc = Just fam_inst -- no Typable for family insts
- | otherwise = Nothing
+cond_typeableOK (_, tc)
+ | tyConArity tc > 7 = Just too_many
+ | not (all (isSubArgTypeKind . tyVarKind) (tyConTyVars tc))
+ = Just bad_kind
+ | otherwise = Nothing
where
- too_many = quotes (pprSourceTyCon rep_tc) <+>
+ too_many = quotes (pprSourceTyCon tc) <+>
ptext (sLit "has too many arguments")
- bad_kind = quotes (pprSourceTyCon rep_tc) <+>
+ bad_kind = quotes (pprSourceTyCon tc) <+>
ptext (sLit "has arguments of kind other than `*'")
- fam_inst = quotes (pprSourceTyCon rep_tc) <+>
- ptext (sLit "is a type family")
-
functorLikeClassKeys :: [Unique]
functorLikeClassKeys = [functorClassKey, foldableClassKey, traversableClassKey]
-- (c) don't use argument in the wrong place, e.g. data T a = T (X a a)
-- (d) optionally: don't use function types
-- (e) no "stupid context" on data type
-cond_functorOK allowFunctions (dflags, rep_tc)
- | not (dopt Opt_DeriveFunctor dflags)
- = Just (ptext (sLit "You need -XDeriveFunctor to derive an instance for this class"))
-
+cond_functorOK allowFunctions (_, rep_tc)
| null tc_tvs
= Just (ptext (sLit "Data type") <+> quotes (ppr rep_tc)
<+> ptext (sLit "has no parameters"))
checkFlag :: ExtensionFlag -> Condition
checkFlag flag (dflags, _)
- | dopt flag dflags = Nothing
+ | xopt flag dflags = Nothing
| otherwise = Just why
where
why = ptext (sLit "You need -X") <> text flag_str
| can_derive_via_isomorphism -> bale_out (non_std $$ suggest_nd) -- Try newtype deriving!
| otherwise -> bale_out non_std
where
- newtype_deriving = dopt Opt_GeneralizedNewtypeDeriving dflags
+ newtype_deriving = xopt Opt_GeneralizedNewtypeDeriving dflags
go_for_it = mk_data_eqn orig tvs cls tycon tc_args rep_tycon rep_tc_args mtheta
bale_out msg = failWithTc (derivingThingErr newtype_deriving cls cls_tys inst_ty msg)
genInst :: Bool -- True <=> standalone deriving
-> OverlapFlag
-> DerivSpec -> TcM (InstInfo RdrName, DerivAuxBinds)
-genInst standalone_deriv oflag spec
- | ds_newtype spec
- = return (InstInfo { iSpec = mkInstance oflag (ds_theta spec) spec
- , iBinds = NewTypeDerived co rep_tycon }, [])
+genInst standalone_deriv oflag
+ spec@(DS { ds_tc = rep_tycon, ds_tc_args = rep_tc_args
+ , ds_theta = theta, ds_newtype = is_newtype
+ , ds_name = name, ds_cls = clas })
+ | is_newtype
+ = return (InstInfo { iSpec = inst_spec
+ , iBinds = NewTypeDerived co rep_tycon }, [])
| otherwise
- = do { let loc = getSrcSpan (ds_name spec)
- inst = mkInstance oflag (ds_theta spec) spec
- clas = ds_cls spec
-
- -- In case of a family instance, we need to use the representation
- -- tycon (after all, it has the data constructors)
- ; fix_env <- getFixityEnv
- ; let (meth_binds, aux_binds) = genDerivBinds loc fix_env clas rep_tycon
- binds = VanillaInst meth_binds [] standalone_deriv
- ; return (InstInfo { iSpec = inst, iBinds = binds }, aux_binds)
- }
+ = do { fix_env <- getFixityEnv
+ ; let loc = getSrcSpan name
+ (meth_binds, aux_binds) = genDerivBinds loc fix_env clas rep_tycon
+ -- In case of a family instance, we need to use the representation
+ -- tycon (after all, it has the data constructors)
+
+ ; return (InstInfo { iSpec = inst_spec
+ , iBinds = VanillaInst meth_binds [] standalone_deriv }
+ , aux_binds) }
where
- rep_tycon = ds_tc spec
- rep_tc_args = ds_tc_args spec
+ inst_spec = mkInstance oflag theta spec
co1 = case tyConFamilyCoercion_maybe rep_tycon of
Just co_con -> ACo (mkTyConApp co_con rep_tc_args)
Nothing -> id_co
projects / ghc-hetmet.git / blobdiff