import VarSet
import BasicTypes
import Name
-import OccName
import MkId
import Class
import TyCon
import TcRnMonad
import Util ( count )
import Outputable
-
-import Data.List
\end{code}
; tycon <- fixM (\ tycon_rec -> do
{ parent <- mkParentInfo mb_family tc_name tvs tycon_rec
; let { tycon = mkAlgTyCon tc_name kind tvs stupid_theta rhs
- fields parent is_rec want_generics gadt_syn
- ; kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
- ; fields = mkTyConSelIds tycon rhs
+ parent is_rec want_generics gadt_syn
+ ; kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
}
; return tycon
})
mkDataTyConRhs :: [DataCon] -> AlgTyConRhs
mkDataTyConRhs cons
- = DataTyCon { data_cons = cons, is_enum = all isNullarySrcDataCon cons }
+ = DataTyCon {
+ data_cons = cons,
+ is_enum = -- We define datatypes with no constructors to not be
+ -- enumerations; this fixes trac #2578, Otherwise we
+ -- end up generating an empty table for
+ -- <mod>_<type>_closure_tbl
+ -- which is used by tagToEnum# to map Int# to constructors
+ -- in an enumeration. The empty table apparently upset
+ -- the linker.
+ not (null cons) &&
+ all isNullarySrcDataCon cons
+ }
mkNewTyConRhs :: Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
-- Monadic because it makes a Name for the coercion TyCon
arg_tyvars = tyVarsOfTypes arg_tys
in_arg_tys pred = not $ isEmptyVarSet $
tyVarsOfPred pred `intersectVarSet` arg_tyvars
-
-------------------------------------------------------
-mkTyConSelIds :: TyCon -> AlgTyConRhs -> [Id]
-mkTyConSelIds tycon rhs
- = [ mkRecordSelId tycon fld
- | fld <- nub (concatMap dataConFieldLabels (visibleDataCons rhs)) ]
- -- We'll check later that fields with the same name
- -- from different constructors have the same type.
\end{code}
let { rec_tycon = classTyCon rec_clas
; op_tys = [ty | (_,_,ty) <- sig_stuff]
+ ; op_names = [op | (op,_,_) <- sig_stuff]
; op_items = [ (mkDictSelId no_unf op_name rec_clas, dm_info)
| (op_name, dm_info, _) <- sig_stuff ] }
-- Build the selector id and default method id
- ; dict_con <- buildDataCon datacon_name
- False -- Not declared infix
- (map (const NotMarkedStrict) op_tys)
- [{- No labelled fields -}]
- tvs [{- no existentials -}]
- [{- No GADT equalities -}] sc_theta
- op_tys
- (mkTyConApp rec_tycon (mkTyVarTys tvs))
- rec_tycon
-
; let n_value_preds = count (not . isEqPred) sc_theta
all_value_preds = n_value_preds == length sc_theta
-- We only make selectors for the *value* superclasses,
-- i.e. exactly one operation or superclass taken together
-- See note [Class newtypes and equality predicates]
+ -- We play a bit fast and loose by treating the superclasses
+ -- as ordinary arguments. That means that in the case of
+ -- class C a => D a
+ -- we don't get a newtype with no arguments!
+ args = sc_sel_names ++ op_names
+ arg_tys = map mkPredTy sc_theta ++ op_tys
+
+ ; dict_con <- buildDataCon datacon_name
+ False -- Not declared infix
+ (map (const NotMarkedStrict) args)
+ [{- No fields -}]
+ tvs [{- no existentials -}]
+ [{- No GADT equalities -}] [{- No theta -}]
+ arg_tys
+ (mkTyConApp rec_tycon (mkTyVarTys tvs))
+ rec_tycon
+
; rhs <- if use_newtype
then mkNewTyConRhs tycon_name rec_tycon dict_con
else return (mkDataTyConRhs [dict_con])