2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnSource]{Main pass of renamer}
8 rnSrcDecls, addTcgDUs, rnTyClDecls
11 #include "HsVersions.h"
13 import {-# SOURCE #-} RnExpr( rnLExpr )
16 import RdrName ( RdrName, isRdrDataCon, elemLocalRdrEnv, rdrNameOcc )
17 import RdrHsSyn ( extractGenericPatTyVars, extractHsRhoRdrTyVars )
19 import RnTypes ( rnLHsType, rnLHsTypes, rnHsSigType, rnHsTypeFVs, rnContext, rnConDeclFields )
20 import RnBinds ( rnTopBindsLHS, rnTopBindsRHS, rnMethodBinds, renameSigs, mkSigTvFn,
22 import RnEnv ( lookupLocalDataTcNames, lookupLocatedOccRn,
23 lookupTopBndrRn, lookupLocatedTopBndrRn,
24 lookupOccRn, newLocalsRn,
25 bindLocatedLocalsFV, bindPatSigTyVarsFV,
26 bindTyVarsRn, extendTyVarEnvFVRn,
27 bindLocalNames, checkDupRdrNames, mapFvRn,
30 import RnNames ( getLocalNonValBinders, extendGlobalRdrEnvRn )
31 import HscTypes ( GenAvailInfo(..), availsToNameSet )
32 import RnHsDoc ( rnHsDoc, rnMbLHsDoc )
35 import HscTypes ( Warnings(..), plusWarns )
36 import Class ( FunDep )
37 import Name ( Name, nameOccName )
44 import DynFlags ( DynFlag(..) )
45 import Maybe ( isNothing )
46 import BasicTypes ( Boxity(..) )
48 import ListSetOps (findDupsEq)
55 thenM :: Monad a => a b -> (b -> a c) -> a c
58 thenM_ :: Monad a => a b -> a c -> a c
62 @rnSourceDecl@ `renames' declarations.
63 It simultaneously performs dependency analysis and precedence parsing.
64 It also does the following error checks:
67 Checks that tyvars are used properly. This includes checking
68 for undefined tyvars, and tyvars in contexts that are ambiguous.
69 (Some of this checking has now been moved to module @TcMonoType@,
70 since we don't have functional dependency information at this point.)
72 Checks that all variable occurences are defined.
74 Checks the @(..)@ etc constraints in the export list.
79 -- Brings the binders of the group into scope in the appropriate places;
80 -- does NOT assume that anything is in scope already
81 rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
82 -- Rename a HsGroup; used for normal source files *and* hs-boot files
83 rnSrcDecls group@(HsGroup {hs_valds = val_decls,
84 hs_tyclds = tycl_decls,
85 hs_instds = inst_decls,
86 hs_derivds = deriv_decls,
88 hs_warnds = warn_decls,
90 hs_fords = foreign_decls,
91 hs_defds = default_decls,
92 hs_ruleds = rule_decls,
95 -- (A) Process the fixity declarations, creating a mapping from
96 -- FastStrings to FixItems.
97 -- Also checks for duplcates.
98 local_fix_env <- makeMiniFixityEnv fix_decls;
100 -- (B) Bring top level binders (and their fixities) into scope,
101 -- *except* for the value bindings, which get brought in below.
102 -- However *do* include class ops, data constructors
103 -- And for hs-boot files *do* include the value signatures
104 tc_avails <- getLocalNonValBinders group ;
105 tc_envs <- extendGlobalRdrEnvRn tc_avails local_fix_env ;
106 setEnvs tc_envs $ do {
108 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
110 -- (C) Extract the mapping from data constructors to field names and
111 -- extend the record field env.
112 -- This depends on the data constructors and field names being in
113 -- scope from (B) above
114 inNewEnv (extendRecordFieldEnv tycl_decls inst_decls) $ \ _ -> do {
116 -- (D) Rename the left-hand sides of the value bindings.
117 -- This depends on everything from (B) being in scope,
118 -- and on (C) for resolving record wild cards.
119 -- It uses the fixity env from (A) to bind fixities for view patterns.
120 new_lhs <- rnTopBindsLHS local_fix_env val_decls ;
121 -- bind the LHSes (and their fixities) in the global rdr environment
122 let { val_binders = map unLoc $ collectHsValBinders new_lhs ;
123 val_bndr_set = mkNameSet val_binders ;
124 all_bndr_set = val_bndr_set `unionNameSets` availsToNameSet tc_avails ;
125 val_avails = map Avail val_binders
127 (tcg_env, tcl_env) <- extendGlobalRdrEnvRn val_avails local_fix_env ;
128 setEnvs (tcg_env, tcl_env) $ do {
130 -- Now everything is in scope, as the remaining renaming assumes.
132 -- (E) Rename type and class decls
133 -- (note that value LHSes need to be in scope for default methods)
135 -- You might think that we could build proper def/use information
136 -- for type and class declarations, but they can be involved
137 -- in mutual recursion across modules, and we only do the SCC
138 -- analysis for them in the type checker.
139 -- So we content ourselves with gathering uses only; that
140 -- means we'll only report a declaration as unused if it isn't
141 -- mentioned at all. Ah well.
142 traceRn (text "Start rnTyClDecls") ;
143 (rn_tycl_decls, src_fvs1) <- rnList rnTyClDecl tycl_decls ;
145 -- (F) Rename Value declarations right-hand sides
146 traceRn (text "Start rnmono") ;
147 (rn_val_decls, bind_dus) <- rnTopBindsRHS val_bndr_set new_lhs ;
148 traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
150 -- (G) Rename Fixity and deprecations
152 -- Rename fixity declarations and error if we try to
153 -- fix something from another module (duplicates were checked in (A))
154 rn_fix_decls <- rnSrcFixityDecls all_bndr_set fix_decls ;
156 -- Rename deprec decls;
157 -- check for duplicates and ensure that deprecated things are defined locally
158 -- at the moment, we don't keep these around past renaming
159 rn_warns <- rnSrcWarnDecls all_bndr_set warn_decls ;
161 -- (H) Rename Everything else
163 (rn_inst_decls, src_fvs2) <- rnList rnSrcInstDecl inst_decls ;
164 (rn_rule_decls, src_fvs3) <- setOptM Opt_ScopedTypeVariables $
165 rnList rnHsRuleDecl rule_decls ;
166 -- Inside RULES, scoped type variables are on
167 (rn_foreign_decls, src_fvs4) <- rnList rnHsForeignDecl foreign_decls ;
168 (rn_ann_decls, src_fvs5) <- rnList rnAnnDecl ann_decls ;
169 (rn_default_decls, src_fvs6) <- rnList rnDefaultDecl default_decls ;
170 (rn_deriv_decls, src_fvs7) <- rnList rnSrcDerivDecl deriv_decls ;
171 -- Haddock docs; no free vars
172 rn_docs <- mapM (wrapLocM rnDocDecl) docs ;
174 -- (I) Compute the results and return
175 let {rn_group = HsGroup { hs_valds = rn_val_decls,
176 hs_tyclds = rn_tycl_decls,
177 hs_instds = rn_inst_decls,
178 hs_derivds = rn_deriv_decls,
179 hs_fixds = rn_fix_decls,
180 hs_warnds = [], -- warns are returned in the tcg_env
181 -- (see below) not in the HsGroup
182 hs_fords = rn_foreign_decls,
183 hs_annds = rn_ann_decls,
184 hs_defds = rn_default_decls,
185 hs_ruleds = rn_rule_decls,
186 hs_docs = rn_docs } ;
188 other_fvs = plusFVs [src_fvs1, src_fvs2, src_fvs3, src_fvs4,
189 src_fvs5, src_fvs6, src_fvs7] ;
190 src_dus = bind_dus `plusDU` usesOnly other_fvs;
191 -- Note: src_dus will contain *uses* for locally-defined types
192 -- and classes, but no *defs* for them. (Because rnTyClDecl
193 -- returns only the uses.) This is a little
194 -- surprising but it doesn't actually matter at all.
196 final_tcg_env = let tcg_env' = (tcg_env `addTcgDUs` src_dus)
197 in -- we return the deprecs in the env, not in the HsGroup above
198 tcg_env' { tcg_warns = tcg_warns tcg_env' `plusWarns` rn_warns };
201 traceRn (text "finish rnSrc" <+> ppr rn_group) ;
202 traceRn (text "finish Dus" <+> ppr src_dus ) ;
203 return (final_tcg_env , rn_group)
206 -- some utils because we do this a bunch above
207 -- compute and install the new env
208 inNewEnv :: TcM TcGblEnv -> (TcGblEnv -> TcM a) -> TcM a
209 inNewEnv env cont = do e <- env
212 rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
213 -- Used for external core
214 rnTyClDecls tycl_decls = do (decls', _fvs) <- rnList rnTyClDecl tycl_decls
217 addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv
218 -- This function could be defined lower down in the module hierarchy,
219 -- but there doesn't seem anywhere very logical to put it.
220 addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }
222 rnList :: (a -> RnM (b, FreeVars)) -> [Located a] -> RnM ([Located b], FreeVars)
223 rnList f xs = mapFvRn (wrapLocFstM f) xs
227 %*********************************************************
231 %*********************************************************
234 rnDocDecl :: DocDecl RdrName -> RnM (DocDecl Name)
235 rnDocDecl (DocCommentNext doc) = do
236 rn_doc <- rnHsDoc doc
237 return (DocCommentNext rn_doc)
238 rnDocDecl (DocCommentPrev doc) = do
239 rn_doc <- rnHsDoc doc
240 return (DocCommentPrev rn_doc)
241 rnDocDecl (DocCommentNamed str doc) = do
242 rn_doc <- rnHsDoc doc
243 return (DocCommentNamed str rn_doc)
244 rnDocDecl (DocGroup lev doc) = do
245 rn_doc <- rnHsDoc doc
246 return (DocGroup lev rn_doc)
250 %*********************************************************
252 Source-code fixity declarations
254 %*********************************************************
257 rnSrcFixityDecls :: NameSet -> [LFixitySig RdrName] -> RnM [LFixitySig Name]
258 -- Rename the fixity decls, so we can put
259 -- the renamed decls in the renamed syntax tree
260 -- Errors if the thing being fixed is not defined locally.
262 -- The returned FixitySigs are not actually used for anything,
263 -- except perhaps the GHCi API
264 rnSrcFixityDecls bound_names fix_decls
265 = do fix_decls <- mapM rn_decl fix_decls
266 return (concat fix_decls)
268 rn_decl :: LFixitySig RdrName -> RnM [LFixitySig Name]
269 -- GHC extension: look up both the tycon and data con
270 -- for con-like things; hence returning a list
271 -- If neither are in scope, report an error; otherwise
272 -- return a fixity sig for each (slightly odd)
273 rn_decl (L loc (FixitySig (L name_loc rdr_name) fixity))
274 = setSrcSpan name_loc $
275 -- this lookup will fail if the definition isn't local
276 do names <- lookupLocalDataTcNames bound_names what rdr_name
277 return [ L loc (FixitySig (L name_loc name) fixity)
279 what = ptext (sLit "fixity signature")
283 %*********************************************************
285 Source-code deprecations declarations
287 %*********************************************************
289 Check that the deprecated names are defined, are defined locally, and
290 that there are no duplicate deprecations.
292 It's only imported deprecations, dealt with in RnIfaces, that we
293 gather them together.
296 -- checks that the deprecations are defined locally, and that there are no duplicates
297 rnSrcWarnDecls :: NameSet -> [LWarnDecl RdrName] -> RnM Warnings
298 rnSrcWarnDecls _bound_names []
301 rnSrcWarnDecls bound_names decls
302 = do { -- check for duplicates
303 ; mapM_ (\ (lrdr:lrdr':_) -> addLocErr lrdr (dupWarnDecl lrdr')) warn_rdr_dups
304 ; mapM (addLocM rn_deprec) decls `thenM` \ pairs_s ->
305 return (WarnSome ((concat pairs_s))) }
307 rn_deprec (Warning rdr_name txt)
308 -- ensures that the names are defined locally
309 = lookupLocalDataTcNames bound_names what rdr_name `thenM` \ names ->
310 return [(nameOccName name, txt) | name <- names]
312 what = ptext (sLit "deprecation")
314 -- look for duplicates among the OccNames;
315 -- we check that the names are defined above
316 -- invt: the lists returned by findDupsEq always have at least two elements
317 warn_rdr_dups = findDupsEq (\ x -> \ y -> rdrNameOcc (unLoc x) == rdrNameOcc (unLoc y))
318 (map (\ (L loc (Warning rdr_name _)) -> L loc rdr_name) decls)
320 dupWarnDecl :: Located RdrName -> RdrName -> SDoc
321 -- Located RdrName -> DeprecDecl RdrName -> SDoc
322 dupWarnDecl (L loc _) rdr_name
323 = vcat [ptext (sLit "Multiple warning declarations for") <+> quotes (ppr rdr_name),
324 ptext (sLit "also at ") <+> ppr loc]
328 %*********************************************************
330 \subsection{Annotation declarations}
332 %*********************************************************
335 rnAnnDecl :: AnnDecl RdrName -> RnM (AnnDecl Name, FreeVars)
336 rnAnnDecl (HsAnnotation provenance expr) = do
337 (provenance', provenance_fvs) <- rnAnnProvenance provenance
338 (expr', expr_fvs) <- rnLExpr expr
339 return (HsAnnotation provenance' expr', provenance_fvs `plusFV` expr_fvs)
341 rnAnnProvenance :: AnnProvenance RdrName -> RnM (AnnProvenance Name, FreeVars)
342 rnAnnProvenance provenance = do
343 provenance' <- modifyAnnProvenanceNameM lookupTopBndrRn provenance
344 return (provenance', maybe emptyFVs unitFV (annProvenanceName_maybe provenance'))
347 %*********************************************************
349 \subsection{Default declarations}
351 %*********************************************************
354 rnDefaultDecl :: DefaultDecl RdrName -> RnM (DefaultDecl Name, FreeVars)
355 rnDefaultDecl (DefaultDecl tys)
356 = mapFvRn (rnHsTypeFVs doc_str) tys `thenM` \ (tys', fvs) ->
357 return (DefaultDecl tys', fvs)
359 doc_str = text "In a `default' declaration"
362 %*********************************************************
364 \subsection{Foreign declarations}
366 %*********************************************************
369 rnHsForeignDecl :: ForeignDecl RdrName -> RnM (ForeignDecl Name, FreeVars)
370 rnHsForeignDecl (ForeignImport name ty spec)
371 = lookupLocatedTopBndrRn name `thenM` \ name' ->
372 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
373 return (ForeignImport name' ty' spec, fvs)
375 rnHsForeignDecl (ForeignExport name ty spec)
376 = lookupLocatedOccRn name `thenM` \ name' ->
377 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
378 return (ForeignExport name' ty' spec, fvs `addOneFV` unLoc name')
379 -- NB: a foreign export is an *occurrence site* for name, so
380 -- we add it to the free-variable list. It might, for example,
381 -- be imported from another module
383 fo_decl_msg :: Located RdrName -> SDoc
384 fo_decl_msg name = ptext (sLit "In the foreign declaration for") <+> ppr name
388 %*********************************************************
390 \subsection{Instance declarations}
392 %*********************************************************
395 rnSrcInstDecl :: InstDecl RdrName -> RnM (InstDecl Name, FreeVars)
396 rnSrcInstDecl (InstDecl inst_ty mbinds uprags ats)
397 -- Used for both source and interface file decls
398 = rnHsSigType (text "an instance decl") inst_ty `thenM` \ inst_ty' ->
400 -- Rename the bindings
401 -- The typechecker (not the renamer) checks that all
402 -- the bindings are for the right class
404 meth_doc = text "In the bindings in an instance declaration"
405 meth_names = collectHsBindLocatedBinders mbinds
406 (inst_tyvars, _, cls,_) = splitHsInstDeclTy (unLoc inst_ty')
408 checkDupRdrNames meth_doc meth_names `thenM_`
409 -- Check that the same method is not given twice in the
410 -- same instance decl instance C T where
414 -- We must use checkDupRdrNames because the Name of the
415 -- method is the Name of the class selector, whose SrcSpan
416 -- points to the class declaration
418 extendTyVarEnvForMethodBinds inst_tyvars (
419 -- (Slightly strangely) the forall-d tyvars scope over
420 -- the method bindings too
421 rnMethodBinds cls (\_ -> []) -- No scoped tyvars
423 ) `thenM` \ (mbinds', meth_fvs) ->
424 -- Rename the associated types
425 -- The typechecker (not the renamer) checks that all
426 -- the declarations are for the right class
428 at_doc = text "In the associated types of an instance declaration"
429 at_names = map (head . tyClDeclNames . unLoc) ats
431 checkDupRdrNames at_doc at_names `thenM_`
432 -- See notes with checkDupRdrNames for methods, above
434 rnATInsts ats `thenM` \ (ats', at_fvs) ->
436 -- Rename the prags and signatures.
437 -- Note that the type variables are not in scope here,
438 -- so that instance Eq a => Eq (T a) where
439 -- {-# SPECIALISE instance Eq a => Eq (T [a]) #-}
442 -- But the (unqualified) method names are in scope
444 binders = collectHsBindBinders mbinds'
445 bndr_set = mkNameSet binders
447 bindLocalNames binders
448 (renameSigs (Just bndr_set) okInstDclSig uprags) `thenM` \ uprags' ->
450 return (InstDecl inst_ty' mbinds' uprags' ats',
451 meth_fvs `plusFV` at_fvs
452 `plusFV` hsSigsFVs uprags'
453 `plusFV` extractHsTyNames inst_ty')
454 -- We return the renamed associated data type declarations so
455 -- that they can be entered into the list of type declarations
456 -- for the binding group, but we also keep a copy in the instance.
457 -- The latter is needed for well-formedness checks in the type
458 -- checker (eg, to ensure that all ATs of the instance actually
459 -- receive a declaration).
460 -- NB: Even the copies in the instance declaration carry copies of
461 -- the instance context after renaming. This is a bit
462 -- strange, but should not matter (and it would be more work
463 -- to remove the context).
466 Renaming of the associated types in instances.
469 rnATInsts :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
470 rnATInsts atDecls = rnList rnATInst atDecls
472 rnATInst tydecl@TyData {} = rnTyClDecl tydecl
473 rnATInst tydecl@TySynonym {} = rnTyClDecl tydecl
475 pprPanic "RnSource.rnATInsts: invalid AT instance"
476 (ppr (tcdName tydecl))
479 For the method bindings in class and instance decls, we extend the
480 type variable environment iff -fglasgow-exts
483 extendTyVarEnvForMethodBinds :: [LHsTyVarBndr Name]
484 -> RnM (Bag (LHsBind Name), FreeVars)
485 -> RnM (Bag (LHsBind Name), FreeVars)
486 extendTyVarEnvForMethodBinds tyvars thing_inside
487 = do { scoped_tvs <- doptM Opt_ScopedTypeVariables
489 extendTyVarEnvFVRn (map hsLTyVarName tyvars) thing_inside
494 %*********************************************************
496 \subsection{Stand-alone deriving declarations}
498 %*********************************************************
501 rnSrcDerivDecl :: DerivDecl RdrName -> RnM (DerivDecl Name, FreeVars)
502 rnSrcDerivDecl (DerivDecl ty)
503 = do ty' <- rnLHsType (text "a deriving decl") ty
504 let fvs = extractHsTyNames ty'
505 return (DerivDecl ty', fvs)
508 %*********************************************************
512 %*********************************************************
515 rnHsRuleDecl :: RuleDecl RdrName -> RnM (RuleDecl Name, FreeVars)
516 rnHsRuleDecl (HsRule rule_name act vars lhs _fv_lhs rhs _fv_rhs)
517 = bindPatSigTyVarsFV (collectRuleBndrSigTys vars) $
518 bindLocatedLocalsFV doc (map get_var vars) $ \ ids ->
519 do { (vars', fv_vars) <- mapFvRn rn_var (vars `zip` ids)
520 -- NB: The binders in a rule are always Ids
521 -- We don't (yet) support type variables
523 ; (lhs', fv_lhs') <- rnLExpr lhs
524 ; (rhs', fv_rhs') <- rnLExpr rhs
526 ; checkValidRule rule_name ids lhs' fv_lhs'
528 ; return (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
529 fv_vars `plusFV` fv_lhs' `plusFV` fv_rhs') }
531 doc = text "In the transformation rule" <+> ftext rule_name
533 get_var (RuleBndr v) = v
534 get_var (RuleBndrSig v _) = v
536 rn_var (RuleBndr (L loc _), id)
537 = return (RuleBndr (L loc id), emptyFVs)
538 rn_var (RuleBndrSig (L loc _) t, id)
539 = rnHsTypeFVs doc t `thenM` \ (t', fvs) ->
540 return (RuleBndrSig (L loc id) t', fvs)
542 badRuleVar :: FastString -> Name -> SDoc
544 = sep [ptext (sLit "Rule") <+> doubleQuotes (ftext name) <> colon,
545 ptext (sLit "Forall'd variable") <+> quotes (ppr var) <+>
546 ptext (sLit "does not appear on left hand side")]
549 Note [Rule LHS validity checking]
550 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
551 Check the shape of a transformation rule LHS. Currently we only allow
552 LHSs of the form @(f e1 .. en)@, where @f@ is not one of the
553 @forall@'d variables.
555 We used restrict the form of the 'ei' to prevent you writing rules
556 with LHSs with a complicated desugaring (and hence unlikely to match);
557 (e.g. a case expression is not allowed: too elaborate.)
559 But there are legitimate non-trivial args ei, like sections and
560 lambdas. So it seems simmpler not to check at all, and that is why
561 check_e is commented out.
564 checkValidRule :: FastString -> [Name] -> LHsExpr Name -> NameSet -> RnM ()
565 checkValidRule rule_name ids lhs' fv_lhs'
566 = do { -- Check for the form of the LHS
567 case (validRuleLhs ids lhs') of
569 Just bad -> failWithTc (badRuleLhsErr rule_name lhs' bad)
571 -- Check that LHS vars are all bound
572 ; let bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
573 ; mapM_ (addErr . badRuleVar rule_name) bad_vars }
575 validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
577 -- Just e => Not ok, and e is the offending expression
578 validRuleLhs foralls lhs
581 checkl (L _ e) = check e
583 check (OpApp e1 op _ e2) = checkl op `mplus` checkl_e e1 `mplus` checkl_e e2
584 check (HsApp e1 e2) = checkl e1 `mplus` checkl_e e2
585 check (HsVar v) | v `notElem` foralls = Nothing
586 check other = Just other -- Failure
589 checkl_e (L _ _e) = Nothing -- Was (check_e e); see Note [Rule LHS validity checking]
591 {- Commented out; see Note [Rule LHS validity checking] above
592 check_e (HsVar v) = Nothing
593 check_e (HsPar e) = checkl_e e
594 check_e (HsLit e) = Nothing
595 check_e (HsOverLit e) = Nothing
597 check_e (OpApp e1 op _ e2) = checkl_e e1 `mplus` checkl_e op `mplus` checkl_e e2
598 check_e (HsApp e1 e2) = checkl_e e1 `mplus` checkl_e e2
599 check_e (NegApp e _) = checkl_e e
600 check_e (ExplicitList _ es) = checkl_es es
601 check_e other = Just other -- Fails
603 checkl_es es = foldr (mplus . checkl_e) Nothing es
606 badRuleLhsErr :: FastString -> LHsExpr Name -> HsExpr Name -> SDoc
607 badRuleLhsErr name lhs bad_e
608 = sep [ptext (sLit "Rule") <+> ftext name <> colon,
609 nest 4 (vcat [ptext (sLit "Illegal expression:") <+> ppr bad_e,
610 ptext (sLit "in left-hand side:") <+> ppr lhs])]
612 ptext (sLit "LHS must be of form (f e1 .. en) where f is not forall'd")
616 %*********************************************************
618 \subsection{Type, class and iface sig declarations}
620 %*********************************************************
622 @rnTyDecl@ uses the `global name function' to create a new type
623 declaration in which local names have been replaced by their original
624 names, reporting any unknown names.
626 Renaming type variables is a pain. Because they now contain uniques,
627 it is necessary to pass in an association list which maps a parsed
628 tyvar to its @Name@ representation.
629 In some cases (type signatures of values),
630 it is even necessary to go over the type first
631 in order to get the set of tyvars used by it, make an assoc list,
632 and then go over it again to rename the tyvars!
633 However, we can also do some scoping checks at the same time.
636 rnTyClDecl :: TyClDecl RdrName -> RnM (TyClDecl Name, FreeVars)
637 rnTyClDecl (ForeignType {tcdLName = name, tcdFoType = fo_type, tcdExtName = ext_name})
638 = lookupLocatedTopBndrRn name `thenM` \ name' ->
639 return (ForeignType {tcdLName = name', tcdFoType = fo_type, tcdExtName = ext_name},
642 -- all flavours of type family declarations ("type family", "newtype fanily",
643 -- and "data family")
644 rnTyClDecl (tydecl@TyFamily {}) =
645 rnFamily tydecl bindTyVarsRn
647 -- "data", "newtype", "data instance, and "newtype instance" declarations
648 rnTyClDecl tydecl@TyData {tcdND = new_or_data, tcdCtxt = context,
649 tcdLName = tycon, tcdTyVars = tyvars,
650 tcdTyPats = typatsMaybe, tcdCons = condecls,
651 tcdKindSig = sig, tcdDerivs = derivs}
652 | is_vanilla -- Normal Haskell data type decl
653 = ASSERT( isNothing sig ) -- In normal H98 form, kind signature on the
654 -- data type is syntactically illegal
655 ASSERT( distinctTyVarBndrs tyvars ) -- Tyvars should be distinct
656 do { bindTyVarsRn data_doc tyvars $ \ tyvars' -> do
657 { tycon' <- if isFamInstDecl tydecl
658 then lookupLocatedOccRn tycon -- may be imported family
659 else lookupLocatedTopBndrRn tycon
660 ; context' <- rnContext data_doc context
661 ; typats' <- rnTyPats data_doc typatsMaybe
662 ; condecls' <- rnConDecls (unLoc tycon') condecls
663 -- No need to check for duplicate constructor decls
664 -- since that is done by RnNames.extendGlobalRdrEnvRn
665 ; (derivs', deriv_fvs) <- rn_derivs derivs
666 ; return (TyData {tcdND = new_or_data, tcdCtxt = context',
667 tcdLName = tycon', tcdTyVars = tyvars',
668 tcdTyPats = typats', tcdKindSig = Nothing,
669 tcdCons = condecls', tcdDerivs = derivs'},
670 delFVs (map hsLTyVarName tyvars') $
671 extractHsCtxtTyNames context' `plusFV`
672 plusFVs (map conDeclFVs condecls') `plusFV`
674 (if isFamInstDecl tydecl
675 then unitFV (unLoc tycon') -- type instance => use
680 = do { tycon' <- if isFamInstDecl tydecl
681 then lookupLocatedOccRn tycon -- may be imported family
682 else lookupLocatedTopBndrRn tycon
683 ; checkTc (null (unLoc context)) (badGadtStupidTheta tycon)
685 <- bindTyVarsRn data_doc tyvars $ \ tyvars' -> do
686 { typats' <- rnTyPats data_doc typatsMaybe
687 ; return (tyvars', typats') }
688 -- For GADTs, the type variables in the declaration
689 -- do not scope over the constructor signatures
690 -- data T a where { T1 :: forall b. b-> b }
692 ; condecls' <- rnConDecls (unLoc tycon') condecls
693 -- No need to check for duplicate constructor decls
694 -- since that is done by RnNames.extendGlobalRdrEnvRn
696 ; (derivs', deriv_fvs) <- rn_derivs derivs
697 ; return (TyData {tcdND = new_or_data, tcdCtxt = noLoc [],
698 tcdLName = tycon', tcdTyVars = tyvars',
699 tcdTyPats = typats', tcdKindSig = sig,
700 tcdCons = condecls', tcdDerivs = derivs'},
701 plusFVs (map conDeclFVs condecls') `plusFV`
703 (if isFamInstDecl tydecl
704 then unitFV (unLoc tycon') -- type instance => use
708 is_vanilla = case condecls of -- Yuk
710 L _ (ConDecl { con_res = ResTyH98 }) : _ -> True
713 data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)
715 rn_derivs Nothing = return (Nothing, emptyFVs)
716 rn_derivs (Just ds) = rnLHsTypes data_doc ds `thenM` \ ds' ->
717 return (Just ds', extractHsTyNames_s ds')
719 -- "type" and "type instance" declarations
720 rnTyClDecl tydecl@(TySynonym {tcdLName = name, tcdTyVars = tyvars,
721 tcdTyPats = typatsMaybe, tcdSynRhs = ty})
722 = ASSERT( distinctTyVarBndrs tyvars ) -- Tyvars should be distinct
723 do { bindTyVarsRn syn_doc tyvars $ \ tyvars' -> do
724 { name' <- if isFamInstDecl tydecl
725 then lookupLocatedOccRn name -- may be imported family
726 else lookupLocatedTopBndrRn name
727 ; typats' <- rnTyPats syn_doc typatsMaybe
728 ; (ty', fvs) <- rnHsTypeFVs syn_doc ty
729 ; return (TySynonym {tcdLName = name', tcdTyVars = tyvars',
730 tcdTyPats = typats', tcdSynRhs = ty'},
731 delFVs (map hsLTyVarName tyvars') $
733 (if isFamInstDecl tydecl
734 then unitFV (unLoc name') -- type instance => use
738 syn_doc = text "In the declaration for type synonym" <+> quotes (ppr name)
740 rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = cname,
741 tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs,
742 tcdMeths = mbinds, tcdATs = ats, tcdDocs = docs})
743 = do { cname' <- lookupLocatedTopBndrRn cname
745 -- Tyvars scope over superclass context and method signatures
746 ; (tyvars', context', fds', ats', ats_fvs, sigs')
747 <- bindTyVarsRn cls_doc tyvars $ \ tyvars' -> do
748 { context' <- rnContext cls_doc context
749 ; fds' <- rnFds cls_doc fds
750 ; (ats', ats_fvs) <- rnATs ats
751 ; sigs' <- renameSigs Nothing okClsDclSig sigs
752 ; return (tyvars', context', fds', ats', ats_fvs, sigs') }
754 -- No need to check for duplicate associated type decls
755 -- since that is done by RnNames.extendGlobalRdrEnvRn
757 -- Check the signatures
758 -- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
759 ; let sig_rdr_names_w_locs = [op | L _ (TypeSig op _) <- sigs]
760 ; checkDupRdrNames sig_doc sig_rdr_names_w_locs
761 -- Typechecker is responsible for checking that we only
762 -- give default-method bindings for things in this class.
763 -- The renamer *could* check this for class decls, but can't
764 -- for instance decls.
766 -- The newLocals call is tiresome: given a generic class decl
769 -- op {| x+y |} (Inl a) = ...
770 -- op {| x+y |} (Inr b) = ...
771 -- op {| a*b |} (a*b) = ...
772 -- we want to name both "x" tyvars with the same unique, so that they are
773 -- easy to group together in the typechecker.
774 ; (mbinds', meth_fvs)
775 <- extendTyVarEnvForMethodBinds tyvars' $ do
776 { name_env <- getLocalRdrEnv
777 ; let gen_rdr_tyvars_w_locs = [ tv | tv <- extractGenericPatTyVars mbinds,
778 not (unLoc tv `elemLocalRdrEnv` name_env) ]
779 -- No need to check for duplicate method signatures
780 -- since that is done by RnNames.extendGlobalRdrEnvRn
781 -- and the methods are already in scope
782 ; gen_tyvars <- newLocalsRn gen_rdr_tyvars_w_locs
783 ; rnMethodBinds (unLoc cname') (mkSigTvFn sigs') gen_tyvars mbinds }
786 ; docs' <- mapM (wrapLocM rnDocDecl) docs
788 ; return (ClassDecl { tcdCtxt = context', tcdLName = cname',
789 tcdTyVars = tyvars', tcdFDs = fds', tcdSigs = sigs',
790 tcdMeths = mbinds', tcdATs = ats', tcdDocs = docs'},
792 delFVs (map hsLTyVarName tyvars') $
793 extractHsCtxtTyNames context' `plusFV`
794 plusFVs (map extractFunDepNames (map unLoc fds')) `plusFV`
795 hsSigsFVs sigs' `plusFV`
799 cls_doc = text "In the declaration for class" <+> ppr cname
800 sig_doc = text "In the signatures for class" <+> ppr cname
802 distinctTyVarBndrs :: [LHsTyVarBndr RdrName] -> Bool
803 -- The tyvar binders should have distinct names
804 distinctTyVarBndrs tvs
805 = null (findDupsEq eq tvs)
807 eq (L _ v1) (L _ v2) = hsTyVarName v1 == hsTyVarName v2
809 badGadtStupidTheta :: Located RdrName -> SDoc
811 = vcat [ptext (sLit "No context is allowed on a GADT-style data declaration"),
812 ptext (sLit "(You can put a context on each contructor, though.)")]
816 %*********************************************************
818 \subsection{Support code for type/data declarations}
820 %*********************************************************
823 -- Although, we are processing type patterns here, all type variables will
824 -- already be in scope (they are the same as in the 'tcdTyVars' field of the
825 -- type declaration to which these patterns belong)
827 rnTyPats :: SDoc -> Maybe [LHsType RdrName] -> RnM (Maybe [LHsType Name])
828 rnTyPats _ Nothing = return Nothing
829 rnTyPats doc (Just typats) = liftM Just $ rnLHsTypes doc typats
831 rnConDecls :: Name -> [LConDecl RdrName] -> RnM [LConDecl Name]
832 rnConDecls _tycon condecls
833 = mapM (wrapLocM rnConDecl) condecls
835 rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name)
836 rnConDecl decl@(ConDecl { con_name = name, con_qvars = tvs
837 , con_cxt = cxt, con_details = details
838 , con_res = res_ty, con_doc = mb_doc
839 , con_old_rec = old_rec, con_explicit = expl })
840 = do { addLocM checkConName name
841 ; when old_rec (addWarn (deprecRecSyntax decl))
843 ; new_name <- lookupLocatedTopBndrRn name
844 ; name_env <- getLocalRdrEnv
846 -- For H98 syntax, the tvs are the existential ones
847 -- For GADT syntax, the tvs are all the quantified tyvars
848 -- Hence the 'filter' in the ResTyH98 case only
849 ; let not_in_scope = not . (`elemLocalRdrEnv` name_env) . unLoc
850 arg_tys = hsConDeclArgTys details
851 implicit_tvs = case res_ty of
852 ResTyH98 -> filter not_in_scope $
854 ResTyGADT ty -> get_rdr_tvs (ty : arg_tys)
855 new_tvs = case expl of
857 Implicit -> userHsTyVarBndrs implicit_tvs
859 ; mb_doc' <- rnMbLHsDoc mb_doc
861 ; bindTyVarsRn doc new_tvs $ \new_tyvars -> do
862 { new_context <- rnContext doc cxt
863 ; new_details <- rnConDeclDetails doc details
864 ; (new_details', new_res_ty) <- rnConResult doc new_details res_ty
865 ; return (decl { con_name = new_name, con_qvars = new_tyvars, con_cxt = new_context
866 , con_details = new_details', con_res = new_res_ty, con_doc = mb_doc' }) }}
868 doc = text "In the definition of data constructor" <+> quotes (ppr name)
869 get_rdr_tvs tys = extractHsRhoRdrTyVars cxt (noLoc (HsTupleTy Boxed tys))
872 -> HsConDetails (LHsType Name) [ConDeclField Name]
874 -> RnM (HsConDetails (LHsType Name) [ConDeclField Name],
876 rnConResult _ details ResTyH98 = return (details, ResTyH98)
877 rnConResult doc details (ResTyGADT ty)
878 = do { ty' <- rnLHsType doc ty
879 ; let (arg_tys, res_ty) = splitHsFunType ty'
880 -- We can finally split it up,
881 -- now the renamer has dealt with fixities
882 -- See Note [Sorting out the result type] in RdrHsSyn
884 details' = case details of
886 PrefixCon {} -> PrefixCon arg_tys
887 InfixCon {} -> pprPanic "rnConResult" (ppr ty)
888 -- See Note [Sorting out the result type] in RdrHsSyn
890 ; when (not (null arg_tys) && case details of { RecCon {} -> True; _ -> False })
891 (addErr (badRecResTy doc))
892 ; return (details', ResTyGADT res_ty) }
894 rnConDeclDetails :: SDoc
895 -> HsConDetails (LHsType RdrName) [ConDeclField RdrName]
896 -> RnM (HsConDetails (LHsType Name) [ConDeclField Name])
897 rnConDeclDetails doc (PrefixCon tys)
898 = mapM (rnLHsType doc) tys `thenM` \ new_tys ->
899 return (PrefixCon new_tys)
901 rnConDeclDetails doc (InfixCon ty1 ty2)
902 = rnLHsType doc ty1 `thenM` \ new_ty1 ->
903 rnLHsType doc ty2 `thenM` \ new_ty2 ->
904 return (InfixCon new_ty1 new_ty2)
906 rnConDeclDetails doc (RecCon fields)
907 = do { new_fields <- rnConDeclFields doc fields
908 -- No need to check for duplicate fields
909 -- since that is done by RnNames.extendGlobalRdrEnvRn
910 ; return (RecCon new_fields) }
912 -- Rename family declarations
914 -- * This function is parametrised by the routine handling the index
915 -- variables. On the toplevel, these are defining occurences, whereas they
916 -- are usage occurences for associated types.
918 rnFamily :: TyClDecl RdrName
919 -> (SDoc -> [LHsTyVarBndr RdrName] ->
920 ([LHsTyVarBndr Name] -> RnM (TyClDecl Name, FreeVars)) ->
921 RnM (TyClDecl Name, FreeVars))
922 -> RnM (TyClDecl Name, FreeVars)
924 rnFamily (tydecl@TyFamily {tcdFlavour = flavour,
925 tcdLName = tycon, tcdTyVars = tyvars})
927 do { bindIdxVars (family_doc tycon) tyvars $ \tyvars' -> do {
928 ; tycon' <- lookupLocatedTopBndrRn tycon
929 ; return (TyFamily {tcdFlavour = flavour, tcdLName = tycon',
930 tcdTyVars = tyvars', tcdKind = tcdKind tydecl},
933 rnFamily d _ = pprPanic "rnFamily" (ppr d)
935 family_doc :: Located RdrName -> SDoc
936 family_doc tycon = text "In the family declaration for" <+> quotes (ppr tycon)
938 -- Rename associated type declarations (in classes)
940 -- * This can be family declarations and (default) type instances
942 rnATs :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
943 rnATs ats = mapFvRn (wrapLocFstM rn_at) ats
945 rn_at (tydecl@TyFamily {}) = rnFamily tydecl lookupIdxVars
946 rn_at (tydecl@TySynonym {}) =
948 checkM (isNothing (tcdTyPats tydecl)) $ addErr noPatterns
950 rn_at _ = panic "RnSource.rnATs: invalid TyClDecl"
952 lookupIdxVars _ tyvars cont =
953 do { checkForDups tyvars;
954 ; tyvars' <- mapM lookupIdxVar tyvars
957 -- Type index variables must be class parameters, which are the only
958 -- type variables in scope at this point.
959 lookupIdxVar (L l tyvar) =
961 name' <- lookupOccRn (hsTyVarName tyvar)
962 return $ L l (replaceTyVarName tyvar name')
964 -- Type variable may only occur once.
966 checkForDups [] = return ()
967 checkForDups (L loc tv:ltvs) =
968 do { setSrcSpan loc $
969 when (hsTyVarName tv `ltvElem` ltvs) $
970 addErr (repeatedTyVar tv)
974 _ `ltvElem` [] = False
975 rdrName `ltvElem` (L _ tv:ltvs)
976 | rdrName == hsTyVarName tv = True
977 | otherwise = rdrName `ltvElem` ltvs
979 deprecRecSyntax :: ConDecl RdrName -> SDoc
981 = vcat [ ptext (sLit "Declaration of") <+> quotes (ppr (con_name decl))
982 <+> ptext (sLit "uses deprecated syntax")
983 , ptext (sLit "Instead, use the form")
984 , nest 2 (ppr decl) ] -- Pretty printer uses new form
986 badRecResTy :: SDoc -> SDoc
987 badRecResTy doc = ptext (sLit "Malformed constructor signature") $$ doc
990 noPatterns = text "Default definition for an associated synonym cannot have"
991 <+> text "type pattern"
993 repeatedTyVar :: HsTyVarBndr RdrName -> SDoc
994 repeatedTyVar tv = ptext (sLit "Illegal repeated type variable") <+>
997 -- This data decl will parse OK
999 -- treating "a" as the constructor.
1000 -- It is really hard to make the parser spot this malformation.
1001 -- So the renamer has to check that the constructor is legal
1003 -- We can get an operator as the constructor, even in the prefix form:
1004 -- data T = :% Int Int
1005 -- from interface files, which always print in prefix form
1007 checkConName :: RdrName -> TcRn ()
1008 checkConName name = checkErr (isRdrDataCon name) (badDataCon name)
1010 badDataCon :: RdrName -> SDoc
1012 = hsep [ptext (sLit "Illegal data constructor name"), quotes (ppr name)]
1016 %*********************************************************
1018 \subsection{Support code for type/data declarations}
1020 %*********************************************************
1022 Get the mapping from constructors to fields for this module.
1023 It's convenient to do this after the data type decls have been renamed
1025 extendRecordFieldEnv :: [LTyClDecl RdrName] -> [LInstDecl RdrName] -> TcM TcGblEnv
1026 extendRecordFieldEnv tycl_decls inst_decls
1027 = do { tcg_env <- getGblEnv
1028 ; field_env' <- foldrM get_con (tcg_field_env tcg_env) all_data_cons
1029 ; return (tcg_env { tcg_field_env = field_env' }) }
1031 -- we want to lookup:
1032 -- (a) a datatype constructor
1033 -- (b) a record field
1034 -- knowing that they're from this module.
1035 -- lookupLocatedTopBndrRn does this, because it does a lookupGreLocalRn,
1036 -- which keeps only the local ones.
1037 lookup x = do { x' <- lookupLocatedTopBndrRn x
1038 ; return $ unLoc x'}
1040 all_data_cons :: [ConDecl RdrName]
1041 all_data_cons = [con | L _ (TyData { tcdCons = cons }) <- all_tycl_decls
1043 all_tycl_decls = at_tycl_decls ++ tycl_decls
1044 at_tycl_decls = [at | L _ (InstDecl _ _ _ ats) <- inst_decls, at <- ats]
1045 -- Do not forget associated types!
1047 get_con (ConDecl { con_name = con, con_details = RecCon flds })
1048 (RecFields env fld_set)
1049 = do { con' <- lookup con
1050 ; flds' <- mapM lookup (map cd_fld_name flds)
1051 ; let env' = extendNameEnv env con' flds'
1052 fld_set' = addListToNameSet fld_set flds'
1053 ; return $ (RecFields env' fld_set') }
1054 get_con _ env = return env
1057 %*********************************************************
1059 \subsection{Support code to rename types}
1061 %*********************************************************
1064 rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]
1067 = mapM (wrapLocM rn_fds) fds
1070 = rnHsTyVars doc tys1 `thenM` \ tys1' ->
1071 rnHsTyVars doc tys2 `thenM` \ tys2' ->
1072 return (tys1', tys2')
1074 rnHsTyVars :: SDoc -> [RdrName] -> RnM [Name]
1075 rnHsTyVars doc tvs = mapM (rnHsTyVar doc) tvs
1077 rnHsTyVar :: SDoc -> RdrName -> RnM Name
1078 rnHsTyVar _doc tyvar = lookupOccRn tyvar