module BuildTyCl (
buildSynTyCon, buildAlgTyCon, buildDataCon,
buildClass,
- mkAbstractTyConRhs, mkNewTyConRhs, mkDataTyConRhs
+ mkAbstractTyConRhs, mkOpenDataTyConRhs, mkOpenNewTyConRhs,
+ mkNewTyConRhs, mkDataTyConRhs
) where
#include "HsVersions.h"
import IfaceEnv ( newImplicitBinder )
import TcRnMonad
-import DataCon ( DataCon, isNullarySrcDataCon, dataConTyVars,
- mkDataCon, dataConFieldLabels, dataConOrigArgTys )
+import DataCon ( DataCon, isNullarySrcDataCon,
+ mkDataCon, dataConFieldLabels, dataConInstOrigArgTys )
import Var ( tyVarKind, TyVar, Id )
import VarSet ( isEmptyVarSet, intersectVarSet, elemVarSet )
import TysWiredIn ( unitTy )
import BasicTypes ( RecFlag, StrictnessMark(..) )
import Name ( Name )
-import OccName ( mkDataConWrapperOcc, mkDataConWorkerOcc, mkClassTyConOcc,
- mkClassDataConOcc, mkSuperDictSelOcc )
+import OccName ( mkDataConWrapperOcc, mkDataConWorkerOcc,
+ mkClassTyConOcc, mkClassDataConOcc,
+ mkSuperDictSelOcc, mkNewTyCoOcc,
+ mkInstTyCoOcc )
import MkId ( mkDataConIds, mkRecordSelId, mkDictSelId )
import Class ( mkClass, Class( classTyCon), FunDep, DefMeth(..) )
-import TyCon ( mkSynTyCon, mkAlgTyCon, visibleDataCons, tyConStupidTheta,
- tyConDataCons, isNewTyCon, mkClassTyCon, TyCon( tyConTyVars ),
- isRecursiveTyCon,
- ArgVrcs, AlgTyConRhs(..), newTyConRhs )
+import TyCon ( mkSynTyCon, mkAlgTyCon, visibleDataCons,
+ tyConStupidTheta, tyConDataCons, isNewTyCon,
+ mkClassTyCon, TyCon( tyConTyVars ),
+ isRecursiveTyCon, AlgTyConRhs(..),
+ SynTyConRhs(..), newTyConRhs, AlgTyConParent(..) )
import Type ( mkArrowKinds, liftedTypeKind, typeKind,
tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
- splitTyConApp_maybe, splitAppTy_maybe, getTyVar_maybe,
+ splitTyConApp_maybe, splitAppTy_maybe,
+ getTyVar_maybe,
mkPredTys, mkTyVarTys, ThetaType, Type,
+ TyThing(..),
substTyWith, zipTopTvSubst, substTheta )
+import Coercion ( mkNewTypeCoercion, mkDataInstCoercion )
import Outputable
import List ( nub )
\begin{code}
------------------------------------------------------
-buildSynTyCon name tvs rhs_ty arg_vrcs
- = mkSynTyCon name kind tvs rhs_ty arg_vrcs
+buildSynTyCon :: Name -> [TyVar] -> SynTyConRhs -> TyCon
+buildSynTyCon name tvs rhs@(OpenSynTyCon rhs_ki)
+ = mkSynTyCon name kind tvs rhs
+ where
+ kind = mkArrowKinds (map tyVarKind tvs) rhs_ki
+buildSynTyCon name tvs rhs@(SynonymTyCon rhs_ty)
+ = mkSynTyCon name kind tvs rhs
where
kind = mkArrowKinds (map tyVarKind tvs) (typeKind rhs_ty)
buildAlgTyCon :: Name -> [TyVar]
-> ThetaType -- Stupid theta
-> AlgTyConRhs
- -> ArgVrcs -> RecFlag
+ -> RecFlag
-> Bool -- True <=> want generics functions
+ -> Bool -- True <=> was declared in GADT syntax
+ -> Maybe (TyCon, [Type]) -- family instance if applicable
-> TcRnIf m n TyCon
-buildAlgTyCon tc_name tvs stupid_theta rhs arg_vrcs is_rec want_generics
- = do { let { tycon = mkAlgTyCon tc_name kind tvs arg_vrcs stupid_theta
- rhs fields is_rec want_generics
- ; kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
- ; fields = mkTyConSelIds tycon rhs
- }
- ; return tycon }
+buildAlgTyCon tc_name tvs stupid_theta rhs is_rec want_generics gadt_syn
+ mb_family
+ = do { -- We need to tie a knot as the coercion of a data instance depends
+ -- on the instance representation tycon and vice versa.
+ ; tycon <- fixM (\ tycon_rec -> do
+ { parent <- parentInfo mb_family 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
+ }
+ ; return tycon
+ })
+ ; return tycon
+ }
+ where
+ -- If a family tycon with instance types is given, the current tycon is an
+ -- instance of that family and we need to
+ --
+ -- (1) create a coercion that identifies the family instance type and the
+ -- representation type from Step (1); ie, it is of the form
+ -- `Co tvs :: F ts :=: R tvs', where `Co' is the name of the coercion,
+ -- `F' the family tycon and `R' the (derived) representation tycon,
+ -- and
+ -- (2) produce a `AlgTyConParent' value containing the parent and coercion
+ -- information.
+ --
+ parentInfo Nothing rep_tycon =
+ return NoParentTyCon
+ parentInfo (Just (family, instTys)) rep_tycon =
+ do { -- Create the coercion
+ ; co_tycon_name <- newImplicitBinder tc_name mkInstTyCoOcc
+ ; let co_tycon = mkDataInstCoercion co_tycon_name tvs
+ family instTys rep_tycon
+ ; return $ FamilyTyCon family instTys co_tycon
+ }
+
------------------------------------------------------
mkAbstractTyConRhs :: AlgTyConRhs
mkAbstractTyConRhs = AbstractTyCon
+mkOpenDataTyConRhs :: AlgTyConRhs
+mkOpenDataTyConRhs = OpenDataTyCon
+
+mkOpenNewTyConRhs :: AlgTyConRhs
+mkOpenNewTyConRhs = OpenNewTyCon
+
mkDataTyConRhs :: [DataCon] -> AlgTyConRhs
mkDataTyConRhs cons
= DataTyCon { data_cons = cons, is_enum = all isNullarySrcDataCon cons }
-mkNewTyConRhs :: TyCon -> DataCon -> AlgTyConRhs
-mkNewTyConRhs tycon con
- = NewTyCon { data_con = con,
- nt_rhs = rhs_ty,
- nt_etad_rhs = eta_reduce tvs rhs_ty,
- nt_rep = mkNewTyConRep tycon rhs_ty }
+mkNewTyConRhs :: Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
+-- Monadic because it makes a Name for the coercion TyCon
+-- We pass the Name of the parent TyCon, as well as the TyCon itself,
+-- because the latter is part of a knot, whereas the former is not.
+mkNewTyConRhs tycon_name tycon con
+ = do { co_tycon_name <- newImplicitBinder tycon_name mkNewTyCoOcc
+ ; let co_tycon = mkNewTypeCoercion co_tycon_name tycon etad_rhs
+ cocon_maybe | all_coercions || isRecursiveTyCon tycon
+ = Just co_tycon
+ | otherwise
+ = Nothing
+ ; return (NewTyCon { data_con = con,
+ nt_rhs = rhs_ty,
+ nt_etad_rhs = etad_rhs,
+ nt_co = cocon_maybe,
+ -- Coreview looks through newtypes with a Nothing
+ -- for nt_co, or uses explicit coercions otherwise
+ nt_rep = mkNewTyConRep tycon rhs_ty }) }
where
- tvs = dataConTyVars con
- rhs_ty = head (dataConOrigArgTys con)
- -- Newtypes are guaranteed vanilla, so OrigArgTys will do
-
- eta_reduce [] ty = ([], ty)
- eta_reduce (a:as) ty | null as',
- Just (fun, arg) <- splitAppTy_maybe ty',
+ -- If all_coercions is True then we use coercions for all newtypes
+ -- otherwise we use coercions for recursive newtypes and look through
+ -- non-recursive newtypes
+ all_coercions = True
+ tvs = tyConTyVars tycon
+ rhs_ty = head (dataConInstOrigArgTys con (mkTyVarTys tvs))
+ -- Instantiate the data con with the
+ -- type variables from the tycon
+
+ etad_rhs :: ([TyVar], Type)
+ etad_rhs = eta_reduce (reverse tvs) rhs_ty
+
+ eta_reduce :: [TyVar] -- Reversed
+ -> Type -- Rhs type
+ -> ([TyVar], Type) -- Eta-reduced version (tyvars in normal order)
+ eta_reduce (a:as) ty | Just (fun, arg) <- splitAppTy_maybe ty,
Just tv <- getTyVar_maybe arg,
tv == a,
not (a `elemVarSet` tyVarsOfType fun)
- = ([], fun) -- Successful eta reduction
- | otherwise
- = (a:as', ty')
- where
- (as', ty') = eta_reduce as ty
+ = eta_reduce as fun
+ eta_reduce tvs ty = (reverse tvs, ty)
+
mkNewTyConRep :: TyCon -- The original type constructor
-> Type -- The arg type of its constructor
-> Type -- Chosen representation type
-- Remember that the representation type is the *ultimate* representation
-- type, looking through other newtypes.
--
--- The non-recursive newtypes are easy, because they look transparent
--- to splitTyConApp_maybe, but recursive ones really are represented as
--- TyConApps (see TypeRep).
+-- splitTyConApp_maybe no longer looks through newtypes, so we must
+-- deal explicitly with this case
--
-- The trick is to to deal correctly with recursive newtypes
-- such as newtype T = MkT T
= case splitTyConApp_maybe rep_ty of
Just (tc, tys)
| tc `elem` tcs -> unitTy -- Recursive loop
- | isNewTyCon tc -> ASSERT( isRecursiveTyCon tc )
- -- Non-recursive ones have been
- -- dealt with by splitTyConApp_maybe
- go (tc:tcs) (substTyWith tvs tys rhs_ty)
+ | isNewTyCon tc ->
+ if isRecursiveTyCon tc then
+ go (tc:tcs) (substTyWith tvs tys rhs_ty)
+ else
+ substTyWith tvs tys rhs_ty
where
(tvs, rhs_ty) = newTyConRhs tc
other -> rep_ty
------------------------------------------------------
-buildDataCon :: Name -> Bool -> Bool
+buildDataCon :: Name -> Bool
-> [StrictnessMark]
-> [Name] -- Field labels
- -> [TyVar]
+ -> [TyVar] -> [TyVar] -- Univ and ext
+ -> [(TyVar,Type)] -- Equality spec
-> ThetaType -- Does not include the "stupid theta"
- -> [Type] -> TyCon -> [Type]
+ -- or the GADT equalities
+ -> [Type] -> TyCon
-> TcRnIf m n DataCon
-- A wrapper for DataCon.mkDataCon that
-- a) makes the worker Id
-- b) makes the wrapper Id if necessary, including
-- allocating its unique (hence monadic)
-buildDataCon src_name declared_infix vanilla arg_stricts field_lbls
- tyvars ctxt arg_tys tycon res_tys
+buildDataCon src_name declared_infix arg_stricts field_lbls
+ univ_tvs ex_tvs eq_spec ctxt arg_tys tycon
= do { wrap_name <- newImplicitBinder src_name mkDataConWrapperOcc
; work_name <- newImplicitBinder src_name mkDataConWorkerOcc
-- This last one takes the name of the data constructor in the source
-- space, and puts it into the VarName name space
; let
- stupid_ctxt = mkDataConStupidTheta tycon arg_tys res_tys
- data_con = mkDataCon src_name declared_infix vanilla
+ stupid_ctxt = mkDataConStupidTheta tycon arg_tys univ_tvs
+ data_con = mkDataCon src_name declared_infix
arg_stricts field_lbls
- tyvars stupid_ctxt ctxt
- arg_tys tycon res_tys dc_ids
+ univ_tvs ex_tvs eq_spec ctxt
+ arg_tys tycon
+ stupid_ctxt dc_ids
dc_ids = mkDataConIds wrap_name work_name data_con
; returnM data_con }
-- The stupid context for a data constructor should be limited to
-- the type variables mentioned in the arg_tys
-mkDataConStupidTheta tycon arg_tys res_tys
+-- ToDo: Or functionally dependent on?
+-- This whole stupid theta thing is, well, stupid.
+mkDataConStupidTheta tycon arg_tys univ_tvs
| null stupid_theta = [] -- The common case
| otherwise = filter in_arg_tys stupid_theta
where
- tc_subst = zipTopTvSubst (tyConTyVars tycon) res_tys
- stupid_theta = substTheta tc_subst (tyConStupidTheta tycon)
+ tc_subst = zipTopTvSubst (tyConTyVars tycon) (mkTyVarTys univ_tvs)
+ stupid_theta = substTheta tc_subst (tyConStupidTheta tycon)
-- Start by instantiating the master copy of the
-- stupid theta, taken from the TyCon
arg_tyvars = tyVarsOfTypes arg_tys
in_arg_tys pred = not $ isEmptyVarSet $
- tyVarsOfPred pred `intersectVarSet` arg_tyvars
+ tyVarsOfPred pred `intersectVarSet` arg_tyvars
------------------------------------------------------
mkTyConSelIds :: TyCon -> AlgTyConRhs -> [Id]
\begin{code}
buildClass :: Name -> [TyVar] -> ThetaType
-> [FunDep TyVar] -- Functional dependencies
+ -> [TyThing] -- Associated types
-> [(Name, DefMeth, Type)] -- Method info
- -> RecFlag -> ArgVrcs -- Info for type constructor
+ -> RecFlag -- Info for type constructor
-> TcRnIf m n Class
-buildClass class_name tvs sc_theta fds sig_stuff tc_isrec tc_vrcs
+buildClass class_name tvs sc_theta fds ats sig_stuff tc_isrec
= do { tycon_name <- newImplicitBinder class_name mkClassTyConOcc
; datacon_name <- newImplicitBinder class_name mkClassDataConOcc
-- The class name is the 'parent' for this datacon, not its tycon,
-- (We used to call them D_C, but now we can have two different
-- superclasses both called C!)
- ; fixM (\ clas -> do { -- Only name generation inside loop
+ ; fixM (\ rec_clas -> do { -- Only name generation inside loop
- let { op_tys = [ty | (_,_,ty) <- sig_stuff]
+ let { rec_tycon = classTyCon rec_clas
+ ; op_tys = [ty | (_,_,ty) <- sig_stuff]
; sc_tys = mkPredTys sc_theta
; dict_component_tys = sc_tys ++ op_tys
- ; sc_sel_ids = [mkDictSelId sc_name clas | sc_name <- sc_sel_names]
- ; op_items = [ (mkDictSelId op_name clas, dm_info)
+ ; sc_sel_ids = [mkDictSelId sc_name rec_clas | sc_name <- sc_sel_names]
+ ; op_items = [ (mkDictSelId 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
+ ; dict_con <- buildDataCon datacon_name
False -- Not declared infix
- True -- Is vanilla; tyvars same as tycon
(map (const NotMarkedStrict) dict_component_tys)
[{- No labelled fields -}]
- tvs [{-No context-}] dict_component_tys
- (classTyCon clas) (mkTyVarTys tvs)
+ tvs [{- no existentials -}]
+ [{- No equalities -}] [{-No context-}]
+ dict_component_tys
+ rec_tycon
+
+ ; rhs <- case dict_component_tys of
+ [rep_ty] -> mkNewTyConRhs tycon_name rec_tycon dict_con
+ other -> return (mkDataTyConRhs [dict_con])
- ; let { clas = mkClass class_name tvs fds
- sc_theta sc_sel_ids op_items
- tycon
+ ; let { clas_kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
- ; tycon = mkClassTyCon tycon_name clas_kind tvs
- tc_vrcs rhs clas tc_isrec
+ ; tycon = mkClassTyCon tycon_name clas_kind tvs
+ rhs rec_clas tc_isrec
-- A class can be recursive, and in the case of newtypes
-- this matters. For example
-- class C a where { op :: C b => a -> b -> Int }
-- Because C has only one operation, it is represented by
-- a newtype, and it should be a *recursive* newtype.
-- [If we don't make it a recursive newtype, we'll expand the
- -- newtype like a synonym, but that will lead to an infinite type]
-
- ; clas_kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
-
- ; rhs = case dict_component_tys of
- [rep_ty] -> mkNewTyConRhs tycon dict_con
- other -> mkDataTyConRhs [dict_con]
+ -- newtype like a synonym, but that will lead to an infinite
+ -- type]
+ ; atTyCons = [tycon | ATyCon tycon <- ats]
}
- ; return clas
+ ; return (mkClass class_name tvs fds
+ sc_theta sc_sel_ids atTyCons op_items
+ tycon)
})}
\end{code}
projects / ghc-hetmet.git / blobdiff