import Type ( splitTyConApp_maybe )
import Variance ( calcTyConArgVrcs )
import Class ( Class, mkClass, classTyCon )
-import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..),
+import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..), DataConDetails(..), visibleDataCons,
tyConKind, tyConTyVars, tyConDataCons, isNewTyCon,
mkSynTyCon, mkAlgTyCon, mkClassTyCon, mkForeignTyCon,
)
kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = context, tcdCons = con_decls})
= kcTyClDeclBody decl $ \ result_kind ->
kcHsContext context `thenTc_`
- mapTc_ kc_con_decl con_decls
+ mapTc_ kc_con_decl (visibleDataCons con_decls)
where
kc_con_decl (ConDecl _ _ ex_tvs ex_ctxt details loc)
= kcHsTyVars ex_tvs `thenNF_Tc` \ kind_env ->
argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
- (TyData {tcdND = data_or_new, tcdName = tycon_name, tcdTyVars = tyvar_names,
- tcdNCons = nconstrs, tcdSysNames = sys_names})
+ (TyData {tcdND = data_or_new, tcdName = tycon_name,
+ tcdTyVars = tyvar_names, tcdSysNames = sys_names})
= ATyCon tycon
where
tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
- data_cons nconstrs sel_ids
+ data_cons sel_ids
flavour is_rec gen_info
gen_info | not (dopt Opt_Generics dflags) = Nothing
-- so flavour has to be able to answer this question without consulting rec_details
flavour = case data_or_new of
NewType -> NewTyCon (mkNewTyConRep tycon)
- DataType | all (null . dataConOrigArgTys) data_cons -> EnumTyCon
- | otherwise -> DataTyCon
+ DataType | all_nullary data_cons -> EnumTyCon
+ | otherwise -> DataTyCon
+
+ all_nullary (DataCons cons) = all (null . dataConOrigArgTys) cons
+ all_nullary other = False -- Safe choice for unknown data types
-- NB (null . dataConOrigArgTys). It used to say isNullaryDataCon
-- but that looks at the *representation* arity, and that in turn
-- depends on deciding whether to unpack the args, and that