%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
#include "HsVersions.h"
-import IfaceEnv ( newImplicitBinder )
+import IfaceEnv
import TcRnMonad
-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, 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, AlgTyConRhs(..),
- SynTyConRhs(..), newTyConRhs, AlgTyConParent(..) )
-import Type ( mkArrowKinds, liftedTypeKind, typeKind,
- tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
- splitTyConApp_maybe, splitAppTy_maybe,
- getTyVar_maybe,
- mkPredTys, mkTyVarTys, ThetaType, Type,
- TyThing(..),
- substTyWith, zipTopTvSubst, substTheta )
-import Coercion ( mkNewTypeCoercion, mkDataInstCoercion )
+import DataCon
+import Var
+import VarSet
+import TysWiredIn
+import BasicTypes
+import Name
+import OccName
+import MkId
+import Class
+import TyCon
+import Type
+import Coercion
import Outputable
-import List ( nub )
+import Data.List
\end{code}
-- 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
+ ; let co_tycon = mkNewTypeCoercion co_tycon_name tycon etad_tvs 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,
+ nt_etad_rhs = (etad_tvs, 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 }) }
-- Instantiate the data con with the
-- type variables from the tycon
- etad_rhs :: ([TyVar], Type)
- etad_rhs = eta_reduce (reverse tvs) rhs_ty
-
+ etad_tvs :: [TyVar] -- Matched lazily, so that mkNewTypeCoercion can
+ etad_rhs :: Type -- return a TyCon without pulling on rhs_ty
+ -- See Note [Tricky iface loop] in LoadIface
+ (etad_tvs, etad_rhs) = eta_reduce (reverse tvs) rhs_ty
+
eta_reduce :: [TyVar] -- Reversed
-> Type -- Rhs type
-> ([TyVar], Type) -- Eta-reduced version (tyvars in normal order)
; let { clas_kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
; tycon = mkClassTyCon tycon_name clas_kind tvs
- rhs rec_clas tc_isrec
+ 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 }