%
-% (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
-import 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(..), HsTyVarBndr,
+ ConDecl(..), ConDetails(..), BangType(..),
+ Sig(..), HsPred(..), HsTupCon(..),
+ tyClDeclName, isClassDecl, isSynDecl
)
-import TcHsSyn ( TcHsBinds(..), TcIdOcc(..) )
+import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name )
+import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
import TcMonad
-import Inst ( InstanceMapper(..) )
-import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( tcExtendTyConEnv, tcExtendClassEnv,
- tcExtendGlobalValEnv,
- tcTyVarScope, tcGetEnv )
-import TcKind ( TcKind, newKindVars )
-import TcTyDecls ( tcTyDecl, mkDataBinds )
+import TcClassDcl ( kcClassDecl, tcClassDecl1 )
+import TcEnv ( ValueEnv, TcTyThing(..),
+ tcExtendTypeEnv, getEnvAllTyCons
+ )
+import TcTyDecls ( tcTyDecl, kcTyDecl )
+import TcMonoType ( kcHsTyVar )
+import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
+
+import Type ( mkArrowKind, boxedTypeKind )
+import Class ( Class )
+import Var ( TyVar, tyVarKind )
+import FiniteMap
import Bag
-import Class ( Class(..), classSelIds )
-import Digraph ( findSCCs, SCC(..) )
-import Name ( getSrcLoc )
-import PprStyle
-import Pretty
-import UniqSet ( UniqSet(..), emptyUniqSet,
+import VarSet
+import Digraph ( stronglyConnComp, SCC(..) )
+import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
+import Outputable
+import Maybes ( mapMaybe, catMaybes, expectJust )
+import UniqSet ( UniqSet, emptyUniqSet,
unitUniqSet, unionUniqSets,
unionManyUniqSets, uniqSetToList )
+import ErrUtils ( Message )
import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, tyConDataCons, isDataTyCon, isSynTyCon )
-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
+tcTyAndClassDecls :: ValueEnv -- Knot tying stuff
+ -> [RenamedHsDecl]
+ -> TcM s TcEnv
+
+tcTyAndClassDecls unf_env decls
+ = sortByDependency decls `thenTc` \ groups ->
+ tcGroups unf_env groups
+
+tcGroups unf_env []
+ = tcGetEnv `thenNF_Tc` \ env ->
+ returnTc env
+
+tcGroups unf_env (group:groups)
+ = tcGroup unf_env group `thenTc` \ env ->
+ tcSetEnv env $
+ tcGroups unf_env groups
+\end{code}
-tcTyAndClassDecls1 :: InstanceMapper
- -> Bag RenamedTyDecl -> Bag RenamedClassDecl
- -> TcM s (TcEnv s, TcHsBinds s)
+Dealing with a group
+~~~~~~~~~~~~~~~~~~~~
-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
+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.
- is_syn_decl (TyD (TySynonym _ _ _ _)) = True
- is_syn_decl _ = False
+\begin{code}
+tcGroup :: ValueEnv -> SCC RenamedTyClDecl -> TcM s TcEnv
+tcGroup unf_env 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, _) ->
+ let
+ rec_env = listToUFM rec_tyclss
+ rec_tycons = getEnvAllTyCons rec_tyclss
+ rec_vrcs = calcTyConArgVrcs rec_tycons
+ 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 rec_vrcs) decls `thenTc` \ tyclss ->
+
+ tcGetEnv `thenTc` \ env ->
+ returnTc (tyclss, 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
-tcGroups inst_mapper []
- = tcGetEnv `thenNF_Tc` \ env ->
- returnTc (env, EmptyBinds)
+ decls = case scc of
+ AcyclicSCC decl -> [decl]
+ CyclicSCC decls -> decls
+\end{code}
-tcGroups inst_mapper (group:groups)
- = tcGroup inst_mapper group `thenTc` \ (new_env, binds1) ->
+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 -> FiniteMap Name ArgVrcs
+ -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
+
+tcDecl is_rec_group unf_env vrcs_env decl
+ = tcAddDeclCtxt decl $
+ if isClassDecl decl then
+ tcClassDecl1 unf_env vrcs_env decl
+ else
+ tcTyDecl is_rec_group vrcs_env decl
+
+
+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 the environment using the new tycons and classes
- tcSetEnv new_env $
- -- Do the remaining groups
- tcGroups inst_mapper groups `thenTc` \ (final_env, binds2) ->
+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
- returnTc (final_env, binds1 `ThenBinds` binds2)
-\end{code}
+Why do we need to grab all these type variables at once, including
+those locally-quantified type variables in class op signatures?
-Dealing with a group
-~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-tcGroup :: InstanceMapper -> Bag Decl -> TcM s (TcEnv s, TcHsBinds s)
-tcGroup inst_mapper decls
- = --pprTrace "tcGroup: " (ppCat (map (fst.fmt_decl) (bagToList decls))) $
-
- -- TIE THE KNOT
- fixTc ( \ ~(tycons,classes,_) ->
-
- -- EXTEND TYPE AND CLASS ENVIRONMENTS
- -- including their data constructors and class operations
- -- 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 ->
-
- -- 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
-
- -- SNAFFLE ENV TO RETURN
- tcGetEnv `thenNF_Tc` \ final_env ->
-
- returnTc (tycons, classes, final_env)
- ) `thenTc` \ (tycons, classes, final_env) ->
-
-
- -- Create any necessary record selector Ids and their bindings
- -- "Necessary" includes data and newtype declarations
- mapAndUnzipTc mkDataBinds (filter (not.isSynTyCon) tycons) `thenTc` \ (data_ids_s, binds) ->
-
- -- Extend the global value environment with
- -- a) constructors
- -- b) record selectors
- -- c) class op selectors
+ [Incidentally, this only works because the names are all unique by now.]
- tcSetEnv final_env $
- tcExtendGlobalValEnv (concat data_ids_s) $
- tcExtendGlobalValEnv (concat (map classSelIds classes)) $
- tcGetEnv `thenNF_Tc` \ really_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 (really_final_env, foldr ThenBinds EmptyBinds binds)
+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}
+ [April 00: looks as if we've dropped this subtlety; I'm not sure when]
-Dealing with one decl
-~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tcDecl :: InstanceMapper
- -> Decl
- -> TcM s (Bag TyCon, Bag Class)
+getTyBinding1 :: RenamedTyClDecl -> NF_TcM s (Name, (TcKind, 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,
+ ASynTyCon (pprPanic "ATyCon: syn" (ppr name)) (length tyvars)))
+
+getTyBinding1 (TyData _ _ name tyvars _ _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
+ ADataTyCon (error "ATyCon: data")))
+
+getTyBinding1 (ClassDecl _ name tyvars _ _ _ _ _ _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
+ AClass (pprPanic "AClass" (ppr name)) (length tyvars)))
+
+-- Zonk the kind to its final form, and lookup the
+-- recursive tycon/class
+getTyBinding2 rec_env (name, (tc_kind, thing))
+ = zonkTcKindToKind tc_kind `thenNF_Tc` \ kind ->
+ returnNF_Tc (name, (kind, mk_thing thing (lookupUFM rec_env name)))
+ where
+ mk_thing (ADataTyCon _) ~(Just (ADataTyCon tc)) = ADataTyCon tc
+ mk_thing (ASynTyCon _ arity) ~(Just (ASynTyCon tc _)) = ASynTyCon tc arity
+ mk_thing (AClass _ arity) ~(Just (AClass cls _)) = AClass cls arity
+\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
\end{code}
Edges in Type/Class decls
~~~~~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-mk_edges (TyD (TyData ctxt name _ condecls _ _ _))
- = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecls))
-mk_edges (TyD (TyNew ctxt name _ condecl _ _ _))
- = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecl))
-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)
-
-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_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)
- = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_pty other = panic "TcTyClsDecls:get_pty"
-
-get_tys tys
- = unionManyUniqSets (map get_ty tys)
+\begin{code}
+----------------------------------------------------
+-- 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 (catMaybes (map 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 (catMaybes (map get_clas ctxt)))
+get_clas (HsPClass clas _) = Just clas
+get_clas _ = Nothing
+
+----------------------------------------------------
+get_deriv Nothing = emptyUniqSet
+get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
+
+----------------------------------------------------
+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 (HsTyVar name) | isTvOcc (nameOccName name) = emptyUniqSet
+ | otherwise = set_name name
+get_ty (HsAppTy ty1 ty2) = unionUniqSets (get_ty ty1) (get_ty ty2)
+get_ty (HsFunTy ty1 ty2) = unionUniqSets (get_ty ty1) (get_ty ty2)
+get_ty (HsListTy ty) = set_name listTyCon_name `unionUniqSets` get_ty ty
+get_ty (HsTupleTy (HsTupCon n _) tys) = set_name n `unionUniqSets` get_tys tys
+get_ty (HsUsgTy _ ty) = get_ty ty
+get_ty (HsUsgForAllTy _ ty) = get_ty ty
+get_ty (HsForAllTy _ ctxt mty) = get_ctxt ctxt `unionUniqSets` get_ty mty
+get_ty (HsPredTy (HsPClass name _)) = set_name name
+get_ty (HsPredTy (HsPIParam _ _)) = emptyUniqSet -- I think
+
+----------------------------------------------------
+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
-
-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}
+typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
+typeCycleErr syn_cycles
+ = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
-\begin{code}
-typeCycleErr syn_cycles sty
- = ppAboves (map (pp_cycle sty "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}