2 % (c) The AQUA Project, Glasgow University, 1996-1998
4 \section[TcTyClsDecls]{Typecheck type and class declarations}
11 #include "HsVersions.h"
13 import HsSyn ( HsDecl(..), TyClDecl(..),
15 ConDecl(..), ConDetails(..), BangType(..),
17 tyClDeclName, isClassDecl, isSynDecl
19 import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name, tupleTyCon_name )
20 import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
23 import Inst ( InstanceMapper )
24 import TcClassDcl ( kcClassDecl, tcClassDecl1 )
25 import TcEnv ( ValueEnv, TcTyThing(..),
26 tcExtendTypeEnv, getAllEnvTyCons
28 import TcTyDecls ( tcTyDecl, kcTyDecl )
29 import TcMonoType ( kcHsTyVar )
30 import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
32 import Type ( mkArrowKind, boxedTypeKind )
34 import Class ( Class )
35 import Var ( TyVar, tyVarKind )
39 import Digraph ( stronglyConnComp, SCC(..) )
40 import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
42 import Maybes ( mapMaybe, catMaybes, expectJust )
43 import UniqSet ( UniqSet, emptyUniqSet,
44 unitUniqSet, unionUniqSets,
45 unionManyUniqSets, uniqSetToList )
46 import ErrUtils ( Message )
47 import SrcLoc ( SrcLoc )
48 import TyCon ( TyCon, ArgVrcs )
49 import Variance ( calcTyConArgVrcs )
50 import Unique ( Unique, Uniquable(..) )
51 import UniqFM ( listToUFM, lookupUFM )
57 tcTyAndClassDecls :: ValueEnv -> InstanceMapper -- Knot tying stuff
61 tcTyAndClassDecls unf_env inst_mapper decls
62 = sortByDependency decls `thenTc` \ groups ->
63 tcGroups unf_env inst_mapper groups
65 tcGroups unf_env inst_mapper []
66 = tcGetEnv `thenNF_Tc` \ env ->
69 tcGroups unf_env inst_mapper (group:groups)
70 = tcGroup unf_env inst_mapper group `thenTc` \ env ->
72 tcGroups unf_env inst_mapper groups
78 The knot-tying parameters: @rec_tyclss@ is an alist mapping @Name@s to
79 @TcTyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
82 tcGroup :: ValueEnv -> InstanceMapper -> SCC RenamedTyClDecl -> TcM s TcEnv
83 tcGroup unf_env inst_mapper scc
85 mapNF_Tc getTyBinding1 decls `thenNF_Tc` \ ty_env_stuff1 ->
86 tcExtendTypeEnv ty_env_stuff1 (mapTc kcDecl decls) `thenTc_`
89 -- traceTc (ppr (map fst ty_env_stuff1)) `thenTc_`
90 fixTc ( \ ~(rec_tyclss, rec_vrcs, _) ->
92 rec_env = listToUFM rec_tyclss
96 mapNF_Tc (getTyBinding2 rec_env) ty_env_stuff1 `thenNF_Tc` \ ty_env_stuff2 ->
97 tcExtendTypeEnv ty_env_stuff2 $
98 mapTc (tcDecl is_rec_group unf_env inst_mapper rec_vrcs) decls
101 tcGetEnv `thenTc` \ env ->
103 tycons = getAllEnvTyCons env
104 vrcs = calcTyConArgVrcs tycons
107 returnTc (tyclss, vrcs, env)
108 ) `thenTc` \ (_, _, env) ->
109 -- traceTc (text "done" <+> ppr (map fst ty_env_stuff1)) `thenTc_`
112 is_rec_group = case scc of
113 AcyclicSCC _ -> NonRecursive
114 CyclicSCC _ -> Recursive
117 AcyclicSCC decl -> [decl]
118 CyclicSCC decls -> decls
121 Dealing with one decl
122 ~~~~~~~~~~~~~~~~~~~~~
125 = tcAddDeclCtxt decl $
126 if isClassDecl decl then
131 tcDecl :: RecFlag -- True => recursive group
132 -> ValueEnv -> InstanceMapper -> FiniteMap Name ArgVrcs
133 -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
135 tcDecl is_rec_group unf_env inst_mapper vrcs_env decl
136 = tcAddDeclCtxt decl $
137 -- traceTc (text "Starting" <+> ppr name) `thenTc_`
138 if isClassDecl decl then
139 tcClassDecl1 unf_env inst_mapper vrcs_env decl `thenTc` \ clas ->
140 -- traceTc (text "Finished" <+> ppr name) `thenTc_`
141 returnTc (getName clas, AClass clas)
143 tcTyDecl is_rec_group vrcs_env decl `thenTc` \ tycon ->
144 -- traceTc (text "Finished" <+> ppr name) `thenTc_`
145 returnTc (getName tycon, ATyCon tycon)
148 name = tyClDeclName decl
151 tcAddDeclCtxt decl thing_inside
158 (ClassDecl _ name _ _ _ _ _ _ _ _ _ loc) -> (name, loc, "class")
159 (TySynonym name _ _ loc) -> (name, loc, "type synonym")
160 (TyData NewType _ name _ _ _ _ loc) -> (name, loc, "data type")
161 (TyData DataType _ name _ _ _ _ loc) -> (name, loc, "newtype")
163 ctxt = hsep [ptext SLIT("In the"), text thing,
164 ptext SLIT("declaration for"), quotes (ppr name)]
170 Extract *binding* names from type and class decls. Type variables are
171 bound in type, data, newtype and class declarations,
172 *and* the polytypes in the class op sigs.
173 *and* the existentially quantified contexts in datacon decls
175 Why do we need to grab all these type variables at once, including
176 those locally-quantified type variables in class op signatures?
178 [Incidentally, this only works because the names are all unique by now.]
180 Because we can only commit to the final kind of a type variable when
181 we've completed the mutually recursive group. For example:
184 op :: D b => a -> b -> b
187 bop :: (Monad c) => ...
189 Here, the kind of the locally-polymorphic type variable "b"
190 depends on *all the uses of class D*. For example, the use of
191 Monad c in bop's type signature means that D must have kind Type->Type.
195 getTyBinding1 :: RenamedTyClDecl -> NF_TcM s (Name, (TcKind, Maybe Arity, TcTyThing))
196 getTyBinding1 (TySynonym name tyvars _ _)
197 = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
198 newKindVar `thenNF_Tc` \ result_kind ->
199 returnNF_Tc (name, (foldr mkArrowKind result_kind arg_kinds,
200 Just (length tyvars),
201 ATyCon (pprPanic "ATyCon: syn" (ppr name))))
203 getTyBinding1 (TyData _ _ name tyvars _ _ _ _)
204 = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
205 returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
207 ATyCon (error "ATyCon: data")))
209 getTyBinding1 (ClassDecl _ name tyvars _ _ _ _ _ _ _ _ _)
210 = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
211 returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
212 Just (length tyvars),
213 AClass (error "AClass")))
215 -- Zonk the kind to its final form, and lookup the
216 -- recursive tycon/class
217 getTyBinding2 rec_env (name, (tc_kind, maybe_arity, thing))
218 = zonkTcKindToKind tc_kind `thenNF_Tc` \ kind ->
219 returnNF_Tc (name, (kind, maybe_arity, mk_thing thing (lookupUFM rec_env name)))
221 mk_thing (ATyCon _) ~(Just (ATyCon tc)) = ATyCon tc
222 mk_thing (AClass _) ~(Just (AClass cls)) = AClass cls
226 %************************************************************************
228 \subsection{Dependency analysis}
230 %************************************************************************
235 sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedTyClDecl]
236 sortByDependency decls
237 = let -- CHECK FOR CLASS CYCLES
238 cls_sccs = stronglyConnComp (mapMaybe mk_cls_edges tycl_decls)
239 cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
241 checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
243 let -- CHECK FOR SYNONYM CYCLES
244 syn_sccs = stronglyConnComp (filter is_syn_decl edges)
245 syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
248 checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
250 -- DO THE MAIN DEPENDENCY ANALYSIS
252 decl_sccs = stronglyConnComp edges
256 tycl_decls = [d | TyClD d <- decls]
257 edges = map mk_edges tycl_decls
259 is_syn_decl (d, _, _) = isSynDecl d
260 is_cls_decl (d, _, _) = isClassDecl d
263 Edges in Type/Class decls
264 ~~~~~~~~~~~~~~~~~~~~~~~~~
267 ----------------------------------------------------
268 -- mk_cls_edges looks only at the context of class decls
269 -- Its used when we are figuring out if there's a cycle in the
270 -- superclass hierarchy
272 mk_cls_edges :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Unique, [Unique])
274 mk_cls_edges decl@(ClassDecl ctxt name _ _ _ _ _ _ _ _ _ _)
275 = Just (decl, getUnique name, map getUnique (catMaybes (map get_clas ctxt)))
276 mk_cls_edges other_decl
279 ----------------------------------------------------
280 mk_edges :: RenamedTyClDecl -> (RenamedTyClDecl, Unique, [Unique])
282 mk_edges decl@(TyData _ ctxt name _ condecls derivs _ _)
283 = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
284 get_cons condecls `unionUniqSets`
287 mk_edges decl@(TySynonym name _ rhs _)
288 = (decl, getUnique name, uniqSetToList (get_ty rhs))
290 mk_edges decl@(ClassDecl ctxt name _ _ sigs _ _ _ _ _ _ _)
291 = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
295 ----------------------------------------------------
296 get_ctxt ctxt = unionManyUniqSets (map set_name (catMaybes (map get_clas ctxt)))
297 get_clas (HsPClass clas _) = Just clas
300 ----------------------------------------------------
301 get_deriv Nothing = emptyUniqSet
302 get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
304 ----------------------------------------------------
305 get_cons cons = unionManyUniqSets (map get_con cons)
307 ----------------------------------------------------
308 get_con (ConDecl _ _ _ ctxt details _)
309 = get_ctxt ctxt `unionUniqSets` get_con_details details
311 ----------------------------------------------------
312 get_con_details (VanillaCon btys) = unionManyUniqSets (map get_bty btys)
313 get_con_details (InfixCon bty1 bty2) = unionUniqSets (get_bty bty1) (get_bty bty2)
314 get_con_details (NewCon ty _) = get_ty ty
315 get_con_details (RecCon nbtys) = unionManyUniqSets (map (get_bty.snd) nbtys)
317 ----------------------------------------------------
318 get_bty (Banged ty) = get_ty ty
319 get_bty (Unbanged ty) = get_ty ty
320 get_bty (Unpacked ty) = get_ty ty
322 ----------------------------------------------------
323 get_ty (MonoTyVar name)
324 = if isTvOcc (nameOccName name) then emptyUniqSet else set_name name
325 get_ty (MonoTyApp ty1 ty2)
326 = unionUniqSets (get_ty ty1) (get_ty ty2)
327 get_ty (MonoFunTy ty1 ty2)
328 = unionUniqSets (get_ty ty1) (get_ty ty2)
329 get_ty (MonoListTy ty)
330 = set_name listTyCon_name `unionUniqSets` get_ty ty
331 get_ty (MonoTupleTy tys boxed)
332 = set_name (tupleTyCon_name boxed (length tys)) `unionUniqSets` get_tys tys
333 get_ty (MonoUsgTy _ ty)
335 get_ty (MonoUsgForAllTy _ ty)
337 get_ty (HsForAllTy _ ctxt mty)
338 = get_ctxt ctxt `unionUniqSets` get_ty mty
339 get_ty (MonoDictTy name _)
342 ----------------------------------------------------
344 = unionManyUniqSets (map get_ty tys)
346 ----------------------------------------------------
348 = unionManyUniqSets (map get_sig sigs)
350 get_sig (ClassOpSig _ _ _ ty _) = get_ty ty
351 get_sig (FixSig _) = emptyUniqSet
352 get_sig other = panic "TcTyClsDecls:get_sig"
354 ----------------------------------------------------
355 set_name name = unitUniqSet (getUnique name)
356 set_to_bag set = listToBag (uniqSetToList set)
361 typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
363 typeCycleErr syn_cycles
364 = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
366 classCycleErr cls_cycles
367 = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
371 4 (vcat (map pp_decl decls))
374 = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
376 name = tyClDeclName decl