import IfaceEnv ( newImplicitBinder )
import TcRnMonad
-import DataCon ( DataCon, isNullarySrcDataCon, dataConUnivTyVars,
- mkDataCon, dataConFieldLabels, dataConInstOrigArgTys,
- dataConTyCon )
+import DataCon ( DataCon, isNullarySrcDataCon,
+ mkDataCon, dataConFieldLabels, dataConInstOrigArgTys )
import Var ( tyVarKind, TyVar, Id )
import VarSet ( isEmptyVarSet, intersectVarSet, elemVarSet )
import TysWiredIn ( unitTy )
import Name ( Name )
import OccName ( mkDataConWrapperOcc, mkDataConWorkerOcc,
mkClassTyConOcc, mkClassDataConOcc,
- mkSuperDictSelOcc, mkNewTyCoOcc, mkInstTyTcOcc,
+ 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, tyConArity, AlgTyConRhs(..),
+ isRecursiveTyCon, AlgTyConRhs(..),
SynTyConRhs(..), newTyConRhs, AlgTyConParent(..) )
import Type ( mkArrowKinds, liftedTypeKind, typeKind,
tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
splitTyConApp_maybe, splitAppTy_maybe,
getTyVar_maybe,
- mkPredTys, mkTyVarTys, ThetaType, Type, Kind,
+ mkPredTys, mkTyVarTys, ThetaType, Type,
TyThing(..),
- substTyWith, zipTopTvSubst, substTheta, mkForAllTys,
- mkTyConApp, mkTyVarTy )
+ substTyWith, zipTopTvSubst, substTheta )
import Coercion ( mkNewTypeCoercion, mkDataInstCoercion )
import Outputable
import List ( nub )
-> RecFlag
-> Bool -- True <=> want generics functions
-> Bool -- True <=> was declared in GADT syntax
- -> Maybe (TyCon, [Type]) -- Just (family, tys)
- -- <=> instance of `family' at `tys'
+ -> Maybe (TyCon, [Type]) -- family instance if applicable
-> TcRnIf m n TyCon
buildAlgTyCon tc_name tvs stupid_theta rhs is_rec want_generics gadt_syn
= 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
- { (final_name, parent) <- maybeComputeFamilyInfo mb_family tycon_rec
- ; let { tycon = mkAlgTyCon final_name kind tvs stupid_theta rhs
+ { 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
}
where
-- If a family tycon with instance types is given, the current tycon is an
- -- instance of that family and we have to perform three extra tasks:
+ -- instance of that family and we need to
--
- -- (1) The instance tycon (representing the family at a particular type
- -- instance) need to get a new, derived name - we may not reuse the
- -- family name.
- -- (2) Create a coercion that identifies the family instance type and the
+ -- (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.
- -- (3) Produce a `AlgTyConParent' value containing the parent and coercion
+ -- `F' the family tycon and `R' the (derived) representation tycon,
+ -- and
+ -- (2) produce a `AlgTyConParent' value containing the parent and coercion
-- information.
--
- maybeComputeFamilyInfo Nothing rep_tycon =
- return (tc_name, NoParentTyCon)
- maybeComputeFamilyInfo (Just (family, instTys)) rep_tycon =
- do { -- (1) New, derived name for the instance tycon
- ; uniq <- newUnique
- ; final_name <- newImplicitBinder tc_name (mkInstTyTcOcc uniq)
-
- -- (2) Create the coercion.
- ; co_tycon_name <- newImplicitBinder tc_name (mkInstTyCoOcc uniq)
+ 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
-
- -- (3) Produce parent information.
- ; return (final_name, FamilyTyCon family instTys co_tycon)
+ ; return $ FamilyTyCon family instTys co_tycon
}
-- 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 tvs rhs_ty
- cocon_maybe
- | all_coercions || isRecursiveTyCon tycon
- = Just co_tycon
- | otherwise
- = Nothing
- ; return (NewTyCon { data_con = con,
+ ; 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_rhs = rhs_ty,
- nt_etad_rhs = eta_reduce tvs rhs_ty,
nt_rep = mkNewTyConRep tycon rhs_ty }) }
where
- -- if all_coercions is True then we use coercions for all newtypes
+ -- 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
-- Instantiate the data con with the
-- type variables from the tycon
- eta_reduce [] ty = ([], ty)
- eta_reduce (a:as) ty | null as',
- Just (fun, arg) <- splitAppTy_maybe ty',
+ 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
projects / ghc-hetmet.git / blobdiff