Moved argument position info of ATs into tycon rhs info

[ghc-hetmet.git] / compiler / iface / BuildTyCl.lhs

diff --git a/compiler/iface/BuildTyCl.lhs b/compiler/iface/BuildTyCl.lhs
index 6384ddc..aa01e70 100644 (file)
--- a/compiler/iface/BuildTyCl.lhs
+++ b/compiler/iface/BuildTyCl.lhs
@@ -1,4 +1,5 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
 
@@ -12,47 +13,31 @@ module BuildTyCl (
 
 #include "HsVersions.h"
 
-import IfaceEnv                ( newImplicitBinder )
+import IfaceEnv
 import TcRnMonad
 
-import DataCon         ( DataCon, isNullarySrcDataCon, dataConUnivTyVars,
-                         mkDataCon, dataConFieldLabels, dataConInstOrigArgTys,
-                          dataConTyCon )
-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, mkInstTyTcOcc,
-                         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(..),
-                         SynTyConRhs(..), newTyConRhs, AlgTyConParent(..) )
-import Type            ( mkArrowKinds, liftedTypeKind, typeKind, 
-                         tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
-                         splitTyConApp_maybe, splitAppTy_maybe,
-                         getTyVar_maybe, 
-                         mkPredTys, mkTyVarTys, ThetaType, Type, Kind,
-                         TyThing(..), 
-                         substTyWith, zipTopTvSubst, substTheta, mkForAllTys,
-                          mkTyConApp, mkTyVarTy )
-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}
        
 
 \begin{code}
 ------------------------------------------------------
 buildSynTyCon :: Name -> [TyVar] -> SynTyConRhs -> TyCon
-buildSynTyCon name tvs rhs@(OpenSynTyCon rhs_ki)
+buildSynTyCon name tvs rhs@(OpenSynTyCon rhs_ki _)
   = mkSynTyCon name kind tvs rhs
   where
     kind = mkArrowKinds (map tyVarKind tvs) rhs_ki
@@ -115,10 +100,10 @@ mkAbstractTyConRhs :: AlgTyConRhs
 mkAbstractTyConRhs = AbstractTyCon
 
 mkOpenDataTyConRhs :: AlgTyConRhs
-mkOpenDataTyConRhs = OpenDataTyCon
+mkOpenDataTyConRhs = OpenTyCon Nothing False
 
 mkOpenNewTyConRhs :: AlgTyConRhs
-mkOpenNewTyConRhs = OpenNewTyCon
+mkOpenNewTyConRhs = OpenTyCon Nothing True
 
 mkDataTyConRhs :: [DataCon] -> AlgTyConRhs
 mkDataTyConRhs cons
@@ -130,21 +115,20 @@ mkNewTyConRhs :: Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
 -- 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, 
-                            nt_co = cocon_maybe, 
+       ; 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_tvs, 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
@@ -153,18 +137,22 @@ mkNewTyConRhs tycon_name tycon con
        -- 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_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)
+    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
@@ -314,7 +302,7 @@ buildClass class_name tvs sc_theta fds ats sig_stuff tc_isrec
        ; 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 }