X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcTyClsDecls.lhs;h=88b74289b36aba1bdb177439be35bf75cd55270a;hb=6c872fff42025a842e8500ddbb13fdcca60eaf75;hp=ae2cb40e71d1fcdd73d3514515354dd29e9a8038;hpb=26741ec416bae2c502ef00a2ba0e79050a32cb67;p=ghc-hetmet.git

diff --git a/ghc/compiler/typecheck/TcTyClsDecls.lhs b/ghc/compiler/typecheck/TcTyClsDecls.lhs
index ae2cb40..88b7428 100644
--- a/ghc/compiler/typecheck/TcTyClsDecls.lhs
+++ b/ghc/compiler/typecheck/TcTyClsDecls.lhs
@@ -1,322 +1,376 @@
 %
-% (c) The AQUA Project, Glasgow University, 1996
+% (c) The AQUA Project, Glasgow University, 1996-1998
 %
 \section[TcTyClsDecls]{Typecheck type and class declarations}
 
 \begin{code}
-#include "HsVersions.h"
-
 module TcTyClsDecls (
-	tcTyAndClassDecls1
+	tcTyAndClassDecls
     ) where
 
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
 
-import HsSyn		( TyDecl(..),  ConDecl(..), BangType(..),
-			  ClassDecl(..), MonoType(..), PolyType(..),
-			  Sig(..), MonoBinds, Fake, InPat, HsBinds(..), Bind, HsExpr )
-import RnHsSyn		( isRnTyCon, RenamedTyDecl(..), RenamedClassDecl(..),
-			  RnName(..){-instance Uniquable-}
+import HsSyn		( HsDecl(..), TyClDecl(..),
+			  HsType(..), HsTyVar,
+			  ConDecl(..), ConDetails(..), BangType(..),
+			  Sig(..), HsPred(..),
+			  tyClDeclName, isClassDecl, isSynDecl
 			)
-import TcHsSyn		( TcHsBinds(..), TcIdOcc(..) )
+import RnHsSyn		( RenamedHsDecl, RenamedTyClDecl, listTyCon_name, tupleTyCon_name )
+import BasicTypes	( RecFlag(..), NewOrData(..), Arity )
+
+import TcMonad
+import Inst		( InstanceMapper )
+import TcClassDcl	( kcClassDecl, tcClassDecl1 )
+import TcEnv		( ValueEnv, TcTyThing(..),
+			  tcExtendTypeEnv, getAllEnvTyCons
+			)
+import TcTyDecls	( tcTyDecl, kcTyDecl )
+import TcMonoType	( kcHsTyVar )
+import TcType		( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
 
-import TcMonad		hiding ( rnMtoTcM )
-import Inst		( InstanceMapper(..) )
-import TcClassDcl	( tcClassDecl1 )
-import TcEnv		( tcExtendTyConEnv, tcExtendClassEnv,
-			  tcTyVarScope, tcGetEnv )
-import TcKind		( TcKind, newKindVars )
-import TcTyDecls	( tcTyDecl, mkDataBinds )
+import Type		( mkArrowKind, boxedTypeKind, mkDictTy )
 
+import Class		( Class )
+import Var		( TyVar, tyVarKind )
+import FiniteMap
 import Bag	
-import Class		( SYN_IE(Class), classSelIds )
-import Digraph		( findSCCs, SCC(..) )
-import Name		( getSrcLoc )
-import PprStyle
-import Pretty
-import UniqSet		( SYN_IE(UniqSet), emptyUniqSet,
+import VarSet
+import Digraph		( stronglyConnComp, SCC(..) )
+import Name		( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
+import Outputable
+import Maybes		( mapMaybe, expectJust )
+import UniqSet		( UniqSet, emptyUniqSet,
 			  unitUniqSet, unionUniqSets, 
 			  unionManyUniqSets, uniqSetToList ) 
+import ErrUtils		( Message )
 import SrcLoc		( SrcLoc )
-import TyCon		( TyCon )
-import Unique		( Unique )
-import Util		( panic{-, pprTrace-} )
-
+import TyCon		( TyCon, ArgVrcs )
+import Variance         ( calcTyConArgVrcs )
+import Unique		( Unique, Uniquable(..) )
+import UniqFM		( listToUFM, lookupUFM )
 \end{code}
 
 The main function
 ~~~~~~~~~~~~~~~~~
 \begin{code}
-data Decl = TyD RenamedTyDecl | ClD RenamedClassDecl
-
-tcTyAndClassDecls1 :: InstanceMapper
-		   -> Bag RenamedTyDecl -> Bag RenamedClassDecl
-		   -> TcM s (TcEnv s)
+tcTyAndClassDecls :: ValueEnv -> InstanceMapper	-- Knot tying stuff
+		  -> [RenamedHsDecl]
+		  -> TcM s TcEnv
 
-tcTyAndClassDecls1 inst_mapper rnty_decls rncls_decls
-  = sortByDependency syn_decls cls_decls decls `thenTc` \ groups ->
-    tcGroups inst_mapper groups
-  where
-    cls_decls = mapBag ClD rncls_decls
-    ty_decls  = mapBag TyD rnty_decls
-    syn_decls = filterBag is_syn_decl ty_decls
-    decls     = ty_decls `unionBags` cls_decls
-
-    is_syn_decl (TyD (TySynonym _ _ _ _)) = True
-    is_syn_decl _		          = False
+tcTyAndClassDecls unf_env inst_mapper decls
+  = sortByDependency decls 		`thenTc` \ groups ->
+    tcGroups unf_env inst_mapper groups
 
-tcGroups inst_mapper []
+tcGroups unf_env inst_mapper []
   = tcGetEnv	`thenNF_Tc` \ env ->
     returnTc env
 
-tcGroups inst_mapper (group:groups)
-  = tcGroup inst_mapper group	`thenTc` \ new_env ->
-
-	-- Extend the environment using the new tycons and classes
-    tcSetEnv new_env $
-
-	-- Do the remaining groups
-    tcGroups inst_mapper groups
+tcGroups unf_env inst_mapper (group:groups)
+  = tcGroup unf_env inst_mapper group	`thenTc` \ env ->
+    tcSetEnv env			$
+    tcGroups unf_env inst_mapper groups
 \end{code}
 
 Dealing with a group
 ~~~~~~~~~~~~~~~~~~~~
+
+The knot-tying parameters: @rec_tyclss@ is an alist mapping @Name@s to
+@TcTyThing@s.  @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
+
 \begin{code}
-tcGroup :: InstanceMapper -> Bag Decl -> TcM s (TcEnv s)
-tcGroup inst_mapper decls
-  = -- pprTrace "tcGroup: " (ppCat (map (fst.fmt_decl) (bagToList decls))) $
+tcGroup :: ValueEnv -> InstanceMapper -> SCC RenamedTyClDecl -> TcM s TcEnv
+tcGroup unf_env inst_mapper scc
+  = 	-- Do kind checking
+    mapNF_Tc getTyBinding1 decls 			`thenNF_Tc` \ ty_env_stuff1 ->
+    tcExtendTypeEnv ty_env_stuff1 (mapTc kcDecl decls)	`thenTc_`
+
+	-- Tie the knot
+--  traceTc (ppr (map fst ty_env_stuff1))		`thenTc_`
+    fixTc ( \ ~(rec_tyclss, rec_vrcs, _) ->
+	let
+	    rec_env = listToUFM rec_tyclss
+	in
+	
+		-- Do type checking
+	mapNF_Tc (getTyBinding2 rec_env) ty_env_stuff1	`thenNF_Tc` \ ty_env_stuff2 ->
+	tcExtendTypeEnv ty_env_stuff2				$
+	mapTc (tcDecl is_rec_group unf_env inst_mapper rec_vrcs) decls
+                                                                `thenTc` \ tyclss ->
+
+	tcGetEnv						`thenTc` \ env -> 
+        let
+            tycons = getAllEnvTyCons env
+            vrcs   = calcTyConArgVrcs tycons
+        in
+
+	returnTc (tyclss, vrcs, env)
+    )								`thenTc` \ (_, _, env) ->
+--  traceTc (text "done" <+> ppr (map fst ty_env_stuff1))	`thenTc_`
+    returnTc env
+  where
+    is_rec_group = case scc of
+			AcyclicSCC _ -> NonRecursive
+			CyclicSCC _  -> Recursive
+
+    decls = case scc of
+		AcyclicSCC decl -> [decl]
+		CyclicSCC decls -> decls
+\end{code}
+
+Dealing with one decl
+~~~~~~~~~~~~~~~~~~~~~
+\begin{code}
+kcDecl decl
+  = tcAddDeclCtxt decl		$
+    if isClassDecl decl then
+	kcClassDecl decl
+    else
+	kcTyDecl    decl
+
+tcDecl  :: RecFlag 			-- True => recursive group
+	 -> ValueEnv -> InstanceMapper -> FiniteMap Name ArgVrcs
+	 -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
+
+tcDecl is_rec_group unf_env inst_mapper vrcs_env decl
+  = tcAddDeclCtxt decl		$
+--  traceTc (text "Starting" <+> ppr name)	`thenTc_`
+    if isClassDecl decl then
+	tcClassDecl1 unf_env inst_mapper vrcs_env decl	`thenTc` \ clas ->
+--	traceTc (text "Finished" <+> ppr name)		`thenTc_`
+	returnTc (getName clas, AClass clas)
+    else
+	tcTyDecl is_rec_group vrcs_env decl	`thenTc` \ tycon ->
+--	traceTc (text "Finished" <+> ppr name)	`thenTc_`
+	returnTc (getName tycon, ATyCon tycon)
+
+  where
+    name = tyClDeclName decl
+		
 
-	-- TIE THE KNOT
-    fixTc ( \ ~(tycons,classes,_) ->
+tcAddDeclCtxt decl thing_inside
+  = tcAddSrcLoc loc 	$
+    tcAddErrCtxt ctxt 	$
+    thing_inside
+  where
+     (name, loc, thing)
+	= case decl of
+	    (ClassDecl _ name _ _ _ _ _ _ _ _ _ loc) -> (name, loc, "class")
+	    (TySynonym name _ _ loc)	         -> (name, loc, "type synonym")
+	    (TyData NewType  _ name _ _ _ _ loc) -> (name, loc, "data type")
+	    (TyData DataType _ name _ _ _ _ loc) -> (name, loc, "newtype")
+
+     ctxt = hsep [ptext SLIT("In the"), text thing, 
+		  ptext SLIT("declaration for"), quotes (ppr name)]
+\end{code}
 
-		-- EXTEND TYPE AND CLASS ENVIRONMENTS
-		-- NB: it's important that the tycons and classes come back in just
-		-- the same order from this fix as from get_binders, so that these
-		-- extend-env things work properly.  A bit UGH-ish.
-      tcExtendTyConEnv tycon_names_w_arities tycons		  $
-      tcExtendClassEnv class_names classes			  $
 
-		-- DEAL WITH TYPE VARIABLES
-      tcTyVarScope tyvar_names 			( \ tyvars ->
+getTyBinders
+~~~~~~~~~~~
+Extract *binding* names from type and class decls.  Type variables are
+bound in type, data, newtype and class declarations, 
+	*and* the polytypes in the class op sigs.
+	*and* the existentially quantified contexts in datacon decls
 
-		-- DEAL WITH THE DEFINITIONS THEMSELVES
-	foldBag combine (tcDecl inst_mapper)
-		(returnTc (emptyBag, emptyBag))
-		decls
-      )						`thenTc` \ (tycon_bag,class_bag) ->
-      let
-	tycons = bagToList tycon_bag
-	classes = bagToList class_bag
-      in 
+Why do we need to grab all these type variables at once, including
+those locally-quantified type variables in class op signatures?
 
-		-- SNAFFLE ENV TO RETURN
-      tcGetEnv					`thenNF_Tc` \ final_env ->
+	[Incidentally, this only works because the names are all unique by now.]
 
-      returnTc (tycons, classes, final_env)
-    ) `thenTc` \ (_, _, final_env) ->
+Because we can only commit to the final kind of a type variable when
+we've completed the mutually recursive group. For example:
 
-    returnTc final_env
+class C a where
+   op :: D b => a -> b -> b
 
-  where
-    (tyvar_rn_names, tycon_names_w_arities, class_names) = get_binders decls
+class D c where
+   bop :: (Monad c) => ...
 
-    tyvar_names = map de_rn tyvar_rn_names
-    de_rn (RnName n) = n
+Here, the kind of the locally-polymorphic type variable "b"
+depends on *all the uses of class D*.  For example, the use of
+Monad c in bop's type signature means that D must have kind Type->Type.
 
-    combine do_a do_b
-      = do_a `thenTc` \ (a1,a2) ->
-        do_b `thenTc` \ (b1,b2) ->
-	returnTc (a1 `unionBags` b1, a2 `unionBags` b2)
-\end{code}
 
-Dealing with one decl
-~~~~~~~~~~~~~~~~~~~~~
 \begin{code}
-tcDecl  :: InstanceMapper
-	-> Decl
-	-> TcM s (Bag TyCon, Bag Class)
+getTyBinding1 :: RenamedTyClDecl -> NF_TcM s (Name, (TcKind, Maybe Arity, TcTyThing))
+getTyBinding1 (TySynonym name tyvars _ _)
+ = mapNF_Tc kcHsTyVar tyvars		`thenNF_Tc` \ arg_kinds ->
+   newKindVar				`thenNF_Tc` \ result_kind  ->
+   returnNF_Tc (name, (foldr mkArrowKind result_kind arg_kinds, 
+		       Just (length tyvars), 
+		       ATyCon (pprPanic "ATyCon: syn" (ppr name))))
+
+getTyBinding1 (TyData _ _ name tyvars _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars		`thenNF_Tc` \ arg_kinds ->
+   returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds, 
+		       Nothing,  
+		       ATyCon (error "ATyCon: data")))
+
+getTyBinding1 (ClassDecl _ name tyvars _ _ _ _ _ _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars		`thenNF_Tc` \ arg_kinds ->
+   returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds, 
+		       Just (length tyvars), 
+		       AClass (error "AClass")))
+
+-- Zonk the kind to its final form, and lookup the 
+-- recursive tycon/class
+getTyBinding2 rec_env (name, (tc_kind, maybe_arity, thing))
+  = zonkTcKindToKind tc_kind		`thenNF_Tc` \ kind ->
+    returnNF_Tc (name, (kind, maybe_arity, mk_thing thing (lookupUFM rec_env name)))
+  where
+    mk_thing (ATyCon _) ~(Just (ATyCon tc))  = ATyCon tc
+    mk_thing (AClass _) ~(Just (AClass cls)) = AClass cls
+\end{code}
 
-tcDecl inst_mapper (TyD decl)
-  = tcTyDecl decl	`thenTc` \ tycon ->
-    returnTc (unitBag tycon, emptyBag)
 
-tcDecl inst_mapper (ClD decl)
-  = tcClassDecl1 inst_mapper decl   `thenTc` \ clas ->
-    returnTc (emptyBag, unitBag clas)
-\end{code}
+%************************************************************************
+%*									*
+\subsection{Dependency analysis}
+%*									*
+%************************************************************************
 
 Dependency analysis
 ~~~~~~~~~~~~~~~~~~~
 \begin{code}
-sortByDependency :: Bag Decl -> Bag Decl -> Bag Decl -> TcM s [Bag Decl]
-sortByDependency syn_decls cls_decls decls
-  = let		-- CHECK FOR SYNONYM CYCLES
-	syn_sccs   = findSCCs mk_edges syn_decls
-	syn_cycles = [map fmt_decl (bagToList decls)
-	                | CyclicSCC decls <- syn_sccs]
-
+sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedTyClDecl]
+sortByDependency decls
+  = let		-- CHECK FOR CLASS CYCLES
+	cls_sccs   = stronglyConnComp (mapMaybe mk_cls_edges tycl_decls)
+	cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
     in
-    checkTc (null syn_cycles) (typeCycleErr syn_cycles)		`thenTc_`
+    checkTc (null cls_cycles) (classCycleErr cls_cycles)	`thenTc_`
 
-    let		-- CHECK FOR CLASS CYCLES
-	cls_sccs   = findSCCs mk_edges cls_decls
-	cls_cycles = [map fmt_decl (bagToList decls)
-		        | CyclicSCC decls <- cls_sccs]
+    let		-- CHECK FOR SYNONYM CYCLES
+	syn_sccs   = stronglyConnComp (filter is_syn_decl edges)
+	syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
 
     in
-    checkTc (null cls_cycles) (classCycleErr cls_cycles)	`thenTc_`
+    checkTc (null syn_cycles) (typeCycleErr syn_cycles)		`thenTc_`
 
-		-- DO THE MAIN DEPENDENCY ANALYSIS
+    	-- DO THE MAIN DEPENDENCY ANALYSIS
     let
-	decl_sccs  = findSCCs mk_edges decls
-	scc_bags   = map bag_acyclic decl_sccs
+	decl_sccs  = stronglyConnComp edges
     in
-    returnTc (scc_bags)
-    
-  where
-   bag_acyclic (AcyclicSCC scc) = unitBag scc
-   bag_acyclic (CyclicSCC sccs) = sccs
-
-fmt_decl decl
-  = (ppr PprForUser name, getSrcLoc name)
+    returnTc decl_sccs
   where
-    name = get_name decl
-    get_name (TyD (TyData _ name _ _ _ _ _))    = name
-    get_name (TyD (TyNew  _ name _ _ _ _ _))    = name
-    get_name (TyD (TySynonym name _ _ _))       = name
-    get_name (ClD (ClassDecl _ name _ _ _ _ _)) = name
+    tycl_decls = [d | TyClD d <- decls]
+    edges      = map mk_edges tycl_decls
+    
+    is_syn_decl (d, _, _) = isSynDecl d
+    is_cls_decl (d, _, _) = isClassDecl d
 \end{code}
 
 Edges in Type/Class decls
 ~~~~~~~~~~~~~~~~~~~~~~~~~
+
 \begin{code}
-mk_edges (TyD (TyData ctxt name _ condecls derivs _ _))
-  = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecls `unionUniqSets` get_deriv derivs))
-mk_edges (TyD (TyNew  ctxt name _ condecl derivs _ _))
-  = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecl  `unionUniqSets` get_deriv derivs))
-mk_edges (TyD (TySynonym name _ rhs _))
-  = (uniqueOf name, set_to_bag (get_ty rhs))
-mk_edges (ClD (ClassDecl ctxt name _ sigs _ _ _))
-  = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_sigs sigs))
-
-get_ctxt ctxt
-  = unionManyUniqSets (map (set_name.fst) ctxt)
+----------------------------------------------------
+-- mk_cls_edges looks only at the context of class decls
+-- Its used when we are figuring out if there's a cycle in the
+-- superclass hierarchy
+
+mk_cls_edges :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Unique, [Unique])
+
+mk_cls_edges decl@(ClassDecl ctxt name _ _ _ _ _ _ _ _ _ _)
+  = Just (decl, getUnique name, map (getUnique . get_clas) ctxt)
+mk_cls_edges other_decl
+  = Nothing
+
+----------------------------------------------------
+mk_edges :: RenamedTyClDecl -> (RenamedTyClDecl, Unique, [Unique])
+
+mk_edges decl@(TyData _ ctxt name _ condecls derivs _ _)
+  = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets` 
+					 get_cons condecls `unionUniqSets` 
+					 get_deriv derivs))
+
+mk_edges decl@(TySynonym name _ rhs _)
+  = (decl, getUnique name, uniqSetToList (get_ty rhs))
+
+mk_edges decl@(ClassDecl ctxt name _ _ sigs _ _ _ _ _ _ _)
+  = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+				         get_sigs sigs))
 
+
+----------------------------------------------------
+get_ctxt ctxt = unionManyUniqSets (map (set_name . get_clas) ctxt)
+get_clas (HsPClass clas _) = clas
+
+----------------------------------------------------
 get_deriv Nothing     = emptyUniqSet
 get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
 
-get_cons cons
-  = unionManyUniqSets (map get_con cons)
-  where
-    get_con (ConDecl _ btys _)
-      = unionManyUniqSets (map get_bty btys)
-    get_con (ConOpDecl bty1 _ bty2 _)
-      = unionUniqSets (get_bty bty1) (get_bty bty2)
-    get_con (NewConDecl _ ty _)
-      = get_ty ty
-    get_con (RecConDecl _ nbtys _)
-      = unionManyUniqSets (map (get_bty.snd) nbtys)
-
-    get_bty (Banged ty)   = get_pty ty
-    get_bty (Unbanged ty) = get_pty ty
-
-get_ty (MonoTyVar tv)
-  = emptyUniqSet
-get_ty (MonoTyApp name tys)
-  = (if isRnTyCon name then set_name name else emptyUniqSet)
-    `unionUniqSets` get_tys tys
+----------------------------------------------------
+get_cons cons = unionManyUniqSets (map get_con cons)
+
+----------------------------------------------------
+get_con (ConDecl _ _ _ ctxt details _) 
+  = get_ctxt ctxt `unionUniqSets` get_con_details details
+
+----------------------------------------------------
+get_con_details (VanillaCon btys)    = unionManyUniqSets (map get_bty btys)
+get_con_details (InfixCon bty1 bty2) = unionUniqSets (get_bty bty1) (get_bty bty2)
+get_con_details (NewCon ty _)        = get_ty ty
+get_con_details (RecCon nbtys)       = unionManyUniqSets (map (get_bty.snd) nbtys)
+
+----------------------------------------------------
+get_bty (Banged ty)   = get_ty ty
+get_bty (Unbanged ty) = get_ty ty
+get_bty (Unpacked ty) = get_ty ty
+
+----------------------------------------------------
+get_ty (MonoTyVar name)
+  = if isTvOcc (nameOccName name) then emptyUniqSet else set_name name
+get_ty (MonoTyApp ty1 ty2)
+  = unionUniqSets (get_ty ty1) (get_ty ty2)
 get_ty (MonoFunTy ty1 ty2)	
   = unionUniqSets (get_ty ty1) (get_ty ty2)
 get_ty (MonoListTy ty)
-  = get_ty ty			-- careful when defining [] (,,) etc as
-get_ty (MonoTupleTy tys)	-- [ty] (ty,ty,ty) will not give edges!
-  = get_tys tys
-get_ty other = panic "TcTyClsDecls:get_ty"
-
-get_pty (HsForAllTy _ ctxt mty)
+  = set_name listTyCon_name `unionUniqSets` get_ty ty
+get_ty (MonoTupleTy tys boxed)
+  = set_name (tupleTyCon_name boxed (length tys)) `unionUniqSets` get_tys tys
+get_ty (MonoUsgTy _ ty)
+  = get_ty ty
+get_ty (MonoUsgForAllTy _ ty)
+  = get_ty ty
+get_ty (HsForAllTy _ ctxt mty)
   = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_pty other = panic "TcTyClsDecls:get_pty"
+get_ty (MonoDictTy name _)
+  = set_name name
 
+----------------------------------------------------
 get_tys tys
   = unionManyUniqSets (map get_ty tys)
 
+----------------------------------------------------
 get_sigs sigs
   = unionManyUniqSets (map get_sig sigs)
   where 
-    get_sig (ClassOpSig _ ty _ _) = get_pty ty
+    get_sig (ClassOpSig _ _ _ ty _) = get_ty ty
+    get_sig (FixSig _)		    = emptyUniqSet
     get_sig other = panic "TcTyClsDecls:get_sig"
 
-set_name name = unitUniqSet (uniqueOf name)
-
+----------------------------------------------------
+set_name name = unitUniqSet (getUnique name)
 set_to_bag set = listToBag (uniqSetToList set)
 \end{code}
 
 
-get_binders
-~~~~~~~~~~~
-Extract *binding* names from type and class decls.  Type variables are
-bound in type, data, newtype and class declarations and the polytypes
-in the class op sigs.
-
-Why do we need to grab all these type variables at once, including
-those locally-quantified type variables in class op signatures?
-Because we can only commit to the final kind of a type variable when
-we've completed the mutually recursive group. For example:
-
-class C a where
-   op :: D b => a -> b -> b
-
-class D c where
-   bop :: (Monad c) => ...
-
-Here, the kind of the locally-polymorphic type variable "b"
-depends on *all the uses of class D*.  For example, the use of
-Monad c in bop's type signature means that D must have kind Type->Type.
-
-
 \begin{code}
-get_binders :: Bag Decl
-	    -> ([RnName],		-- TyVars;  no dups
-		[(RnName, Maybe Arity)],-- Tycons;  no dups; arities for synonyms
-		[RnName])		-- Classes; no dups
+typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
 
-get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
-  where
-    (tyvars, tycons, classes) = foldBag union3 get_binders1
-					(emptyBag,emptyBag,emptyBag)
-					decls
-
-    union3 (a1,a2,a3) (b1,b2,b3)
-      = (a1 `unionBags` b1, a2 `unionBags` b2, a3 `unionBags` b3)
-
-get_binders1 (TyD (TyData _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag (name,Nothing), emptyBag)
-get_binders1 (TyD (TyNew _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag (name,Nothing), emptyBag)
-get_binders1 (TyD (TySynonym name tyvars _ _))
- = (listToBag tyvars, unitBag (name, Just (length tyvars)), emptyBag)
-get_binders1 (ClD (ClassDecl _ name tyvar sigs _ _ _))
- = (unitBag tyvar `unionBags` sigs_tvs sigs,
-    emptyBag, unitBag name)
-
-sigs_tvs sigs = unionManyBags (map sig_tvs sigs)
-  where 
-    sig_tvs (ClassOpSig _ ty  _ _) = pty_tvs ty
-    pty_tvs (HsForAllTy tvs _ _)   = listToBag tvs 	-- tvs doesn't include the class tyvar
-\end{code}
-
-
-\begin{code}
-typeCycleErr syn_cycles sty
-  = ppAboves (map (pp_cycle sty "Cycle in type declarations ...") syn_cycles)
+typeCycleErr syn_cycles
+  = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
 
-classCycleErr cls_cycles sty
-  = ppAboves (map (pp_cycle sty "Cycle in class declarations ...") cls_cycles)
+classCycleErr cls_cycles
+  = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
 
-pp_cycle sty str things
-  = ppHang (ppStr str)
-	 4 (ppAboves (map pp_thing things))
+pp_cycle str decls
+  = hang (text str)
+	 4 (vcat (map pp_decl decls))
   where
-    pp_thing (pp_name, loc)
-      = ppCat [pp_name, ppr sty loc]
+    pp_decl decl
+      = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
+     where
+        name = tyClDeclName decl
 \end{code}