2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnSource]{Main pass of renamer}
13 #include "HsVersions.h"
15 import {-# SOURCE #-} RnExpr( rnLExpr )
18 import RdrName ( RdrName, isRdrDataCon, elemLocalRdrEnv,
19 globalRdrEnvElts, GlobalRdrElt(..), isLocalGRE, rdrNameOcc )
20 import RdrHsSyn ( extractGenericPatTyVars, extractHsRhoRdrTyVars )
22 import RnTypes ( rnLHsType, rnLHsTypes, rnHsSigType, rnHsTypeFVs, rnContext )
23 import RnBinds ( rnTopBindsLHS, rnTopBindsRHS, rnMethodBinds, renameSigs, mkSigTvFn,
25 import RnEnv ( lookupLocalDataTcNames,
26 lookupLocatedTopBndrRn, lookupLocatedOccRn,
27 lookupOccRn, newLocalsRn,
28 bindLocatedLocalsFV, bindPatSigTyVarsFV,
29 bindTyVarsRn, extendTyVarEnvFVRn,
30 bindLocalNames, checkDupRdrNames, mapFvRn,
32 import RnNames ( getLocalNonValBinders, extendGlobalRdrEnvRn )
33 import HscTypes ( GenAvailInfo(..) )
34 import RnHsDoc ( rnHsDoc, rnMbLHsDoc )
37 import HscTypes ( Warnings(..), plusWarns )
38 import Class ( FunDep )
39 import Name ( Name, nameOccName )
47 import DynFlags ( DynFlag(..) )
48 import Maybe ( isNothing )
49 import BasicTypes ( Boxity(..) )
51 import ListSetOps (findDupsEq)
59 thenM :: Monad a => a b -> (b -> a c) -> a c
62 thenM_ :: Monad a => a b -> a c -> a c
65 returnM :: Monad m => a -> m a
68 mappM :: (Monad m) => (a -> m b) -> [a] -> m [b]
71 mappM_ :: (Monad m) => (a -> m b) -> [a] -> m ()
74 checkM :: Monad m => Bool -> m () -> m ()
78 @rnSourceDecl@ `renames' declarations.
79 It simultaneously performs dependency analysis and precedence parsing.
80 It also does the following error checks:
83 Checks that tyvars are used properly. This includes checking
84 for undefined tyvars, and tyvars in contexts that are ambiguous.
85 (Some of this checking has now been moved to module @TcMonoType@,
86 since we don't have functional dependency information at this point.)
88 Checks that all variable occurences are defined.
90 Checks the @(..)@ etc constraints in the export list.
95 -- Brings the binders of the group into scope in the appropriate places;
96 -- does NOT assume that anything is in scope already
97 rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
98 rnSrcDecls group@(HsGroup {hs_valds = val_decls,
99 hs_tyclds = tycl_decls,
100 hs_instds = inst_decls,
101 hs_derivds = deriv_decls,
102 hs_fixds = fix_decls,
103 hs_warnds = warn_decls,
104 hs_fords = foreign_decls,
105 hs_defds = default_decls,
106 hs_ruleds = rule_decls,
109 -- (A) Process the fixity declarations, creating a mapping from
110 -- FastStrings to FixItems.
111 -- Also checks for duplcates.
112 local_fix_env <- makeMiniFixityEnv fix_decls;
114 -- (B) Bring top level binders (and their fixities) into scope,
115 -- *except* for the value bindings, which get brought in below.
116 avails <- getLocalNonValBinders group ;
117 tc_envs <- extendGlobalRdrEnvRn avails local_fix_env ;
118 setEnvs tc_envs $ do {
120 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
122 -- (C) Extract the mapping from data constructors to field names and
123 -- extend the record field env.
124 -- This depends on the data constructors and field names being in
125 -- scope from (B) above
126 inNewEnv (extendRecordFieldEnv tycl_decls) $ \ _ -> do {
128 -- (D) Rename the left-hand sides of the value bindings.
129 -- This depends on everything from (B) being in scope,
130 -- and on (C) for resolving record wild cards.
131 -- It uses the fixity env from (A) to bind fixities for view patterns.
132 new_lhs <- rnTopBindsLHS local_fix_env val_decls ;
133 -- bind the LHSes (and their fixities) in the global rdr environment
134 let { lhs_binders = map unLoc $ collectHsValBinders new_lhs;
135 lhs_avails = map Avail lhs_binders
137 (tcg_env, tcl_env) <- extendGlobalRdrEnvRn lhs_avails local_fix_env ;
138 setEnvs (tcg_env, tcl_env) $ do {
140 -- Now everything is in scope, as the remaining renaming assumes.
142 -- (E) Rename type and class decls
143 -- (note that value LHSes need to be in scope for default methods)
145 -- You might think that we could build proper def/use information
146 -- for type and class declarations, but they can be involved
147 -- in mutual recursion across modules, and we only do the SCC
148 -- analysis for them in the type checker.
149 -- So we content ourselves with gathering uses only; that
150 -- means we'll only report a declaration as unused if it isn't
151 -- mentioned at all. Ah well.
152 traceRn (text "Start rnTyClDecls") ;
153 (rn_tycl_decls, src_fvs1) <- rnList rnTyClDecl tycl_decls ;
155 -- (F) Rename Value declarations right-hand sides
156 traceRn (text "Start rnmono") ;
157 (rn_val_decls, bind_dus) <- rnTopBindsRHS lhs_binders new_lhs ;
158 traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
160 -- (G) Rename Fixity and deprecations
162 -- rename fixity declarations and error if we try to
163 -- fix something from another module (duplicates were checked in (A))
164 rn_fix_decls <- rnSrcFixityDecls fix_decls ;
165 -- rename deprec decls;
166 -- check for duplicates and ensure that deprecated things are defined locally
167 -- at the moment, we don't keep these around past renaming
168 rn_warns <- rnSrcWarnDecls warn_decls ;
170 -- (H) Rename Everything else
172 (rn_inst_decls, src_fvs2) <- rnList rnSrcInstDecl inst_decls ;
173 (rn_rule_decls, src_fvs3) <- setOptM Opt_ScopedTypeVariables $
174 rnList rnHsRuleDecl rule_decls ;
175 -- Inside RULES, scoped type variables are on
176 (rn_foreign_decls, src_fvs4) <- rnList rnHsForeignDecl foreign_decls ;
177 (rn_default_decls, src_fvs5) <- rnList rnDefaultDecl default_decls ;
178 (rn_deriv_decls, src_fvs6) <- rnList rnSrcDerivDecl deriv_decls ;
179 -- Haddock docs; no free vars
180 rn_docs <- mapM (wrapLocM rnDocDecl) docs ;
182 -- (I) Compute the results and return
183 let {rn_group = HsGroup { hs_valds = rn_val_decls,
184 hs_tyclds = rn_tycl_decls,
185 hs_instds = rn_inst_decls,
186 hs_derivds = rn_deriv_decls,
187 hs_fixds = rn_fix_decls,
188 hs_warnds = [], -- warns are returned in the tcg_env
189 -- (see below) not in the HsGroup
190 hs_fords = rn_foreign_decls,
191 hs_defds = rn_default_decls,
192 hs_ruleds = rn_rule_decls,
193 hs_docs = rn_docs } ;
195 other_fvs = plusFVs [src_fvs1, src_fvs2, src_fvs6, src_fvs3,
196 src_fvs4, src_fvs5] ;
197 src_dus = bind_dus `plusDU` usesOnly other_fvs;
198 -- Note: src_dus will contain *uses* for locally-defined types
199 -- and classes, but no *defs* for them. (Because rnTyClDecl
200 -- returns only the uses.) This is a little
201 -- surprising but it doesn't actually matter at all.
203 final_tcg_env = let tcg_env' = (tcg_env `addTcgDUs` src_dus)
204 in -- we return the deprecs in the env, not in the HsGroup above
205 tcg_env' { tcg_warns = tcg_warns tcg_env' `plusWarns` rn_warns };
208 traceRn (text "finish rnSrc" <+> ppr rn_group) ;
209 traceRn (text "finish Dus" <+> ppr src_dus ) ;
210 return (final_tcg_env , rn_group)
213 -- some utils because we do this a bunch above
214 -- compute and install the new env
215 inNewEnv :: TcM TcGblEnv -> (TcGblEnv -> TcM a) -> TcM a
216 inNewEnv env cont = do e <- env
219 rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
220 -- Used for external core
221 rnTyClDecls tycl_decls = do (decls', _fvs) <- rnList rnTyClDecl tycl_decls
224 addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv
225 addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }
227 rnList :: (a -> RnM (b, FreeVars)) -> [Located a] -> RnM ([Located b], FreeVars)
228 rnList f xs = mapFvRn (wrapLocFstM f) xs
232 %*********************************************************
236 %*********************************************************
239 rnDocDecl :: DocDecl RdrName -> RnM (DocDecl Name)
240 rnDocDecl (DocCommentNext doc) = do
241 rn_doc <- rnHsDoc doc
242 return (DocCommentNext rn_doc)
243 rnDocDecl (DocCommentPrev doc) = do
244 rn_doc <- rnHsDoc doc
245 return (DocCommentPrev rn_doc)
246 rnDocDecl (DocCommentNamed str doc) = do
247 rn_doc <- rnHsDoc doc
248 return (DocCommentNamed str rn_doc)
249 rnDocDecl (DocGroup lev doc) = do
250 rn_doc <- rnHsDoc doc
251 return (DocGroup lev rn_doc)
255 %*********************************************************
257 Source-code fixity declarations
259 %*********************************************************
262 rnSrcFixityDecls :: [LFixitySig RdrName] -> RnM [LFixitySig Name]
263 -- Rename the fixity decls, so we can put
264 -- the renamed decls in the renamed syntax tree
265 -- Errors if the thing being fixed is not defined locally.
267 -- The returned FixitySigs are not actually used for anything,
268 -- except perhaps the GHCi API
269 rnSrcFixityDecls fix_decls
270 = do fix_decls <- mapM rn_decl fix_decls
271 return (concat fix_decls)
273 rn_decl :: LFixitySig RdrName -> RnM [LFixitySig Name]
274 -- GHC extension: look up both the tycon and data con
275 -- for con-like things; hence returning a list
276 -- If neither are in scope, report an error; otherwise
277 -- return a fixity sig for each (slightly odd)
278 rn_decl (L loc (FixitySig (L name_loc rdr_name) fixity))
279 = setSrcSpan name_loc $
280 -- this lookup will fail if the definition isn't local
281 do names <- lookupLocalDataTcNames rdr_name
282 return [ L loc (FixitySig (L name_loc name) fixity)
287 %*********************************************************
289 Source-code deprecations declarations
291 %*********************************************************
293 Check that the deprecated names are defined, are defined locally, and
294 that there are no duplicate deprecations.
296 It's only imported deprecations, dealt with in RnIfaces, that we
297 gather them together.
300 -- checks that the deprecations are defined locally, and that there are no duplicates
301 rnSrcWarnDecls :: [LWarnDecl RdrName] -> RnM Warnings
306 = do { -- check for duplicates
307 ; mappM_ (\ (lrdr:lrdr':_) -> addLocErr lrdr (dupWarnDecl lrdr')) warn_rdr_dups
308 ; mappM (addLocM rn_deprec) decls `thenM` \ pairs_s ->
309 returnM (WarnSome ((concat pairs_s))) }
311 rn_deprec (Warning rdr_name txt)
312 -- ensures that the names are defined locally
313 = lookupLocalDataTcNames rdr_name `thenM` \ names ->
314 returnM [(nameOccName name, txt) | name <- names]
316 -- look for duplicates among the OccNames;
317 -- we check that the names are defined above
318 -- invt: the lists returned by findDupsEq always have at least two elements
319 warn_rdr_dups = findDupsEq (\ x -> \ y -> rdrNameOcc (unLoc x) == rdrNameOcc (unLoc y))
320 (map (\ (L loc (Warning rdr_name _)) -> L loc rdr_name) decls)
322 dupWarnDecl :: Located RdrName -> RdrName -> SDoc
323 -- Located RdrName -> DeprecDecl RdrName -> SDoc
324 dupWarnDecl (L loc _) rdr_name
325 = vcat [ptext (sLit "Multiple warning declarations for") <+> quotes (ppr rdr_name),
326 ptext (sLit "also at ") <+> ppr loc]
330 %*********************************************************
332 \subsection{Source code declarations}
334 %*********************************************************
337 rnDefaultDecl :: DefaultDecl RdrName -> RnM (DefaultDecl Name, FreeVars)
338 rnDefaultDecl (DefaultDecl tys)
339 = mapFvRn (rnHsTypeFVs doc_str) tys `thenM` \ (tys', fvs) ->
340 returnM (DefaultDecl tys', fvs)
342 doc_str = text "In a `default' declaration"
345 %*********************************************************
347 \subsection{Foreign declarations}
349 %*********************************************************
352 rnHsForeignDecl :: ForeignDecl RdrName -> RnM (ForeignDecl Name, FreeVars)
353 rnHsForeignDecl (ForeignImport name ty spec)
354 = lookupLocatedTopBndrRn name `thenM` \ name' ->
355 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
356 returnM (ForeignImport name' ty' spec, fvs)
358 rnHsForeignDecl (ForeignExport name ty spec)
359 = lookupLocatedOccRn name `thenM` \ name' ->
360 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
361 returnM (ForeignExport name' ty' spec, fvs `addOneFV` unLoc name')
362 -- NB: a foreign export is an *occurrence site* for name, so
363 -- we add it to the free-variable list. It might, for example,
364 -- be imported from another module
366 fo_decl_msg :: Located RdrName -> SDoc
367 fo_decl_msg name = ptext (sLit "In the foreign declaration for") <+> ppr name
371 %*********************************************************
373 \subsection{Instance declarations}
375 %*********************************************************
378 rnSrcInstDecl :: InstDecl RdrName -> RnM (InstDecl Name, FreeVars)
379 rnSrcInstDecl (InstDecl inst_ty mbinds uprags ats)
380 -- Used for both source and interface file decls
381 = rnHsSigType (text "an instance decl") inst_ty `thenM` \ inst_ty' ->
383 -- Rename the bindings
384 -- The typechecker (not the renamer) checks that all
385 -- the bindings are for the right class
387 meth_doc = text "In the bindings in an instance declaration"
388 meth_names = collectHsBindLocatedBinders mbinds
389 (inst_tyvars, _, cls,_) = splitHsInstDeclTy (unLoc inst_ty')
391 checkDupRdrNames meth_doc meth_names `thenM_`
392 -- Check that the same method is not given twice in the
393 -- same instance decl instance C T where
397 -- We must use checkDupRdrNames because the Name of the
398 -- method is the Name of the class selector, whose SrcSpan
399 -- points to the class declaration
401 extendTyVarEnvForMethodBinds inst_tyvars (
402 -- (Slightly strangely) the forall-d tyvars scope over
403 -- the method bindings too
404 rnMethodBinds cls (\_ -> []) -- No scoped tyvars
406 ) `thenM` \ (mbinds', meth_fvs) ->
407 -- Rename the associated types
408 -- The typechecker (not the renamer) checks that all
409 -- the declarations are for the right class
411 at_doc = text "In the associated types of an instance declaration"
412 at_names = map (head . tyClDeclNames . unLoc) ats
414 checkDupRdrNames at_doc at_names `thenM_`
415 -- See notes with checkDupRdrNames for methods, above
417 rnATInsts ats `thenM` \ (ats', at_fvs) ->
419 -- Rename the prags and signatures.
420 -- Note that the type variables are not in scope here,
421 -- so that instance Eq a => Eq (T a) where
422 -- {-# SPECIALISE instance Eq a => Eq (T [a]) #-}
425 -- But the (unqualified) method names are in scope
427 binders = collectHsBindBinders mbinds'
428 bndr_set = mkNameSet binders
430 bindLocalNames binders
431 (renameSigs (Just bndr_set) okInstDclSig uprags) `thenM` \ uprags' ->
433 returnM (InstDecl inst_ty' mbinds' uprags' ats',
434 meth_fvs `plusFV` at_fvs
435 `plusFV` hsSigsFVs uprags'
436 `plusFV` extractHsTyNames inst_ty')
437 -- We return the renamed associated data type declarations so
438 -- that they can be entered into the list of type declarations
439 -- for the binding group, but we also keep a copy in the instance.
440 -- The latter is needed for well-formedness checks in the type
441 -- checker (eg, to ensure that all ATs of the instance actually
442 -- receive a declaration).
443 -- NB: Even the copies in the instance declaration carry copies of
444 -- the instance context after renaming. This is a bit
445 -- strange, but should not matter (and it would be more work
446 -- to remove the context).
449 Renaming of the associated types in instances.
452 rnATInsts :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
453 rnATInsts atDecls = rnList rnATInst atDecls
455 rnATInst tydecl@TyData {} = rnTyClDecl tydecl
456 rnATInst tydecl@TySynonym {} = rnTyClDecl tydecl
458 pprPanic "RnSource.rnATInsts: invalid AT instance"
459 (ppr (tcdName tydecl))
462 For the method bindings in class and instance decls, we extend the
463 type variable environment iff -fglasgow-exts
466 extendTyVarEnvForMethodBinds :: [LHsTyVarBndr Name]
467 -> RnM (Bag (LHsBind Name), FreeVars)
468 -> RnM (Bag (LHsBind Name), FreeVars)
469 extendTyVarEnvForMethodBinds tyvars thing_inside
470 = do { scoped_tvs <- doptM Opt_ScopedTypeVariables
472 extendTyVarEnvFVRn (map hsLTyVarName tyvars) thing_inside
477 %*********************************************************
479 \subsection{Stand-alone deriving declarations}
481 %*********************************************************
484 rnSrcDerivDecl :: DerivDecl RdrName -> RnM (DerivDecl Name, FreeVars)
485 rnSrcDerivDecl (DerivDecl ty)
486 = do ty' <- rnLHsType (text "a deriving decl") ty
487 let fvs = extractHsTyNames ty'
488 return (DerivDecl ty', fvs)
491 %*********************************************************
495 %*********************************************************
498 rnHsRuleDecl :: RuleDecl RdrName -> RnM (RuleDecl Name, FreeVars)
499 rnHsRuleDecl (HsRule rule_name act vars lhs _fv_lhs rhs _fv_rhs)
500 = bindPatSigTyVarsFV (collectRuleBndrSigTys vars) $
501 bindLocatedLocalsFV doc (map get_var vars) $ \ ids ->
502 do { (vars', fv_vars) <- mapFvRn rn_var (vars `zip` ids)
503 -- NB: The binders in a rule are always Ids
504 -- We don't (yet) support type variables
506 ; (lhs', fv_lhs') <- rnLExpr lhs
507 ; (rhs', fv_rhs') <- rnLExpr rhs
509 ; checkValidRule rule_name ids lhs' fv_lhs'
511 ; return (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
512 fv_vars `plusFV` fv_lhs' `plusFV` fv_rhs') }
514 doc = text "In the transformation rule" <+> ftext rule_name
516 get_var (RuleBndr v) = v
517 get_var (RuleBndrSig v _) = v
519 rn_var (RuleBndr (L loc _), id)
520 = returnM (RuleBndr (L loc id), emptyFVs)
521 rn_var (RuleBndrSig (L loc _) t, id)
522 = rnHsTypeFVs doc t `thenM` \ (t', fvs) ->
523 returnM (RuleBndrSig (L loc id) t', fvs)
525 badRuleVar :: FastString -> Name -> SDoc
527 = sep [ptext (sLit "Rule") <+> doubleQuotes (ftext name) <> colon,
528 ptext (sLit "Forall'd variable") <+> quotes (ppr var) <+>
529 ptext (sLit "does not appear on left hand side")]
532 Note [Rule LHS validity checking]
533 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
534 Check the shape of a transformation rule LHS. Currently we only allow
535 LHSs of the form @(f e1 .. en)@, where @f@ is not one of the
536 @forall@'d variables.
538 We used restrict the form of the 'ei' to prevent you writing rules
539 with LHSs with a complicated desugaring (and hence unlikely to match);
540 (e.g. a case expression is not allowed: too elaborate.)
542 But there are legitimate non-trivial args ei, like sections and
543 lambdas. So it seems simmpler not to check at all, and that is why
544 check_e is commented out.
547 checkValidRule :: FastString -> [Name] -> LHsExpr Name -> NameSet -> RnM ()
548 checkValidRule rule_name ids lhs' fv_lhs'
549 = do { -- Check for the form of the LHS
550 case (validRuleLhs ids lhs') of
552 Just bad -> failWithTc (badRuleLhsErr rule_name lhs' bad)
554 -- Check that LHS vars are all bound
555 ; let bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
556 ; mapM_ (addErr . badRuleVar rule_name) bad_vars }
558 validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
560 -- Just e => Not ok, and e is the offending expression
561 validRuleLhs foralls lhs
564 checkl (L _ e) = check e
566 check (OpApp e1 op _ e2) = checkl op `mplus` checkl_e e1 `mplus` checkl_e e2
567 check (HsApp e1 e2) = checkl e1 `mplus` checkl_e e2
568 check (HsVar v) | v `notElem` foralls = Nothing
569 check other = Just other -- Failure
572 checkl_e (L _ _e) = Nothing -- Was (check_e e); see Note [Rule LHS validity checking]
574 {- Commented out; see Note [Rule LHS validity checking] above
575 check_e (HsVar v) = Nothing
576 check_e (HsPar e) = checkl_e e
577 check_e (HsLit e) = Nothing
578 check_e (HsOverLit e) = Nothing
580 check_e (OpApp e1 op _ e2) = checkl_e e1 `mplus` checkl_e op `mplus` checkl_e e2
581 check_e (HsApp e1 e2) = checkl_e e1 `mplus` checkl_e e2
582 check_e (NegApp e _) = checkl_e e
583 check_e (ExplicitList _ es) = checkl_es es
584 check_e (ExplicitTuple es _) = checkl_es es
585 check_e other = Just other -- Fails
587 checkl_es es = foldr (mplus . checkl_e) Nothing es
590 badRuleLhsErr :: FastString -> LHsExpr Name -> HsExpr Name -> SDoc
591 badRuleLhsErr name lhs bad_e
592 = sep [ptext (sLit "Rule") <+> ftext name <> colon,
593 nest 4 (vcat [ptext (sLit "Illegal expression:") <+> ppr bad_e,
594 ptext (sLit "in left-hand side:") <+> ppr lhs])]
596 ptext (sLit "LHS must be of form (f e1 .. en) where f is not forall'd")
600 %*********************************************************
602 \subsection{Type, class and iface sig declarations}
604 %*********************************************************
606 @rnTyDecl@ uses the `global name function' to create a new type
607 declaration in which local names have been replaced by their original
608 names, reporting any unknown names.
610 Renaming type variables is a pain. Because they now contain uniques,
611 it is necessary to pass in an association list which maps a parsed
612 tyvar to its @Name@ representation.
613 In some cases (type signatures of values),
614 it is even necessary to go over the type first
615 in order to get the set of tyvars used by it, make an assoc list,
616 and then go over it again to rename the tyvars!
617 However, we can also do some scoping checks at the same time.
620 rnTyClDecl :: TyClDecl RdrName -> RnM (TyClDecl Name, FreeVars)
621 rnTyClDecl (ForeignType {tcdLName = name, tcdFoType = fo_type, tcdExtName = ext_name})
622 = lookupLocatedTopBndrRn name `thenM` \ name' ->
623 returnM (ForeignType {tcdLName = name', tcdFoType = fo_type, tcdExtName = ext_name},
626 -- all flavours of type family declarations ("type family", "newtype fanily",
627 -- and "data family")
628 rnTyClDecl (tydecl@TyFamily {}) =
629 rnFamily tydecl bindTyVarsRn
631 -- "data", "newtype", "data instance, and "newtype instance" declarations
632 rnTyClDecl (tydecl@TyData {tcdND = new_or_data, tcdCtxt = context,
633 tcdLName = tycon, tcdTyVars = tyvars,
634 tcdTyPats = typatsMaybe, tcdCons = condecls,
635 tcdKindSig = sig, tcdDerivs = derivs})
636 | is_vanilla -- Normal Haskell data type decl
637 = ASSERT( isNothing sig ) -- In normal H98 form, kind signature on the
638 -- data type is syntactically illegal
639 do { tyvars <- pruneTyVars tydecl
640 ; bindTyVarsRn data_doc tyvars $ \ tyvars' -> do
641 { tycon' <- if isFamInstDecl tydecl
642 then lookupLocatedOccRn tycon -- may be imported family
643 else lookupLocatedTopBndrRn tycon
644 ; context' <- rnContext data_doc context
645 ; typats' <- rnTyPats data_doc typatsMaybe
646 ; (derivs', deriv_fvs) <- rn_derivs derivs
647 ; condecls' <- rnConDecls (unLoc tycon') condecls
648 -- No need to check for duplicate constructor decls
649 -- since that is done by RnNames.extendGlobalRdrEnvRn
650 ; returnM (TyData {tcdND = new_or_data, tcdCtxt = context',
651 tcdLName = tycon', tcdTyVars = tyvars',
652 tcdTyPats = typats', tcdKindSig = Nothing,
653 tcdCons = condecls', tcdDerivs = derivs'},
654 delFVs (map hsLTyVarName tyvars') $
655 extractHsCtxtTyNames context' `plusFV`
656 plusFVs (map conDeclFVs condecls') `plusFV`
658 (if isFamInstDecl tydecl
659 then unitFV (unLoc tycon') -- type instance => use
664 = do { tycon' <- if isFamInstDecl tydecl
665 then lookupLocatedOccRn tycon -- may be imported family
666 else lookupLocatedTopBndrRn tycon
667 ; checkTc (null (unLoc context)) (badGadtStupidTheta tycon)
669 <- bindTyVarsRn data_doc tyvars $ \ tyvars' -> do
670 { typats' <- rnTyPats data_doc typatsMaybe
671 ; return (tyvars', typats') }
672 -- For GADTs, the type variables in the declaration
673 -- do not scope over the constructor signatures
674 -- data T a where { T1 :: forall b. b-> b }
676 ; (derivs', deriv_fvs) <- rn_derivs derivs
677 ; condecls' <- rnConDecls (unLoc tycon') condecls
678 -- No need to check for duplicate constructor decls
679 -- since that is done by RnNames.extendGlobalRdrEnvRn
681 ; returnM (TyData {tcdND = new_or_data, tcdCtxt = noLoc [],
682 tcdLName = tycon', tcdTyVars = tyvars',
683 tcdTyPats = typats', tcdKindSig = sig,
684 tcdCons = condecls', tcdDerivs = derivs'},
685 plusFVs (map conDeclFVs condecls') `plusFV`
687 (if isFamInstDecl tydecl
688 then unitFV (unLoc tycon') -- type instance => use
692 is_vanilla = case condecls of -- Yuk
694 L _ (ConDecl { con_res = ResTyH98 }) : _ -> True
697 data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)
699 rn_derivs Nothing = returnM (Nothing, emptyFVs)
700 rn_derivs (Just ds) = rnLHsTypes data_doc ds `thenM` \ ds' ->
701 returnM (Just ds', extractHsTyNames_s ds')
703 -- "type" and "type instance" declarations
704 rnTyClDecl tydecl@(TySynonym {tcdLName = name,
705 tcdTyPats = typatsMaybe, tcdSynRhs = ty})
706 = do { tyvars <- pruneTyVars tydecl
707 ; bindTyVarsRn syn_doc tyvars $ \ tyvars' -> do
708 { name' <- if isFamInstDecl tydecl
709 then lookupLocatedOccRn name -- may be imported family
710 else lookupLocatedTopBndrRn name
711 ; typats' <- rnTyPats syn_doc typatsMaybe
712 ; (ty', fvs) <- rnHsTypeFVs syn_doc ty
713 ; returnM (TySynonym {tcdLName = name', tcdTyVars = tyvars',
714 tcdTyPats = typats', tcdSynRhs = ty'},
715 delFVs (map hsLTyVarName tyvars') $
717 (if isFamInstDecl tydecl
718 then unitFV (unLoc name') -- type instance => use
722 syn_doc = text "In the declaration for type synonym" <+> quotes (ppr name)
724 rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = cname,
725 tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs,
726 tcdMeths = mbinds, tcdATs = ats, tcdDocs = docs})
727 = do { cname' <- lookupLocatedTopBndrRn cname
729 -- Tyvars scope over superclass context and method signatures
730 ; (tyvars', context', fds', ats', ats_fvs, sigs')
731 <- bindTyVarsRn cls_doc tyvars $ \ tyvars' -> do
732 { context' <- rnContext cls_doc context
733 ; fds' <- rnFds cls_doc fds
734 ; (ats', ats_fvs) <- rnATs ats
735 ; sigs' <- renameSigs Nothing okClsDclSig sigs
736 ; return (tyvars', context', fds', ats', ats_fvs, sigs') }
738 -- No need to check for duplicate associated type decls
739 -- since that is done by RnNames.extendGlobalRdrEnvRn
741 -- Check the signatures
742 -- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
743 ; let sig_rdr_names_w_locs = [op | L _ (TypeSig op _) <- sigs]
744 ; checkDupRdrNames sig_doc sig_rdr_names_w_locs
745 -- Typechecker is responsible for checking that we only
746 -- give default-method bindings for things in this class.
747 -- The renamer *could* check this for class decls, but can't
748 -- for instance decls.
750 -- The newLocals call is tiresome: given a generic class decl
753 -- op {| x+y |} (Inl a) = ...
754 -- op {| x+y |} (Inr b) = ...
755 -- op {| a*b |} (a*b) = ...
756 -- we want to name both "x" tyvars with the same unique, so that they are
757 -- easy to group together in the typechecker.
758 ; (mbinds', meth_fvs)
759 <- extendTyVarEnvForMethodBinds tyvars' $ do
760 { name_env <- getLocalRdrEnv
761 ; let gen_rdr_tyvars_w_locs = [ tv | tv <- extractGenericPatTyVars mbinds,
762 not (unLoc tv `elemLocalRdrEnv` name_env) ]
763 -- No need to check for duplicate method signatures
764 -- since that is done by RnNames.extendGlobalRdrEnvRn
765 -- and the methods are already in scope
766 ; gen_tyvars <- newLocalsRn gen_rdr_tyvars_w_locs
767 ; rnMethodBinds (unLoc cname') (mkSigTvFn sigs') gen_tyvars mbinds }
770 ; docs' <- mapM (wrapLocM rnDocDecl) docs
772 ; return (ClassDecl { tcdCtxt = context', tcdLName = cname',
773 tcdTyVars = tyvars', tcdFDs = fds', tcdSigs = sigs',
774 tcdMeths = mbinds', tcdATs = ats', tcdDocs = docs'},
776 delFVs (map hsLTyVarName tyvars') $
777 extractHsCtxtTyNames context' `plusFV`
778 plusFVs (map extractFunDepNames (map unLoc fds')) `plusFV`
779 hsSigsFVs sigs' `plusFV`
783 cls_doc = text "In the declaration for class" <+> ppr cname
784 sig_doc = text "In the signatures for class" <+> ppr cname
786 badGadtStupidTheta :: Located RdrName -> SDoc
788 = vcat [ptext (sLit "No context is allowed on a GADT-style data declaration"),
789 ptext (sLit "(You can put a context on each contructor, though.)")]
792 %*********************************************************
794 \subsection{Support code for type/data declarations}
796 %*********************************************************
799 -- Remove any duplicate type variables in family instances may have non-linear
800 -- left-hand sides. Complain if any, but the first occurence of a type
801 -- variable has a user-supplied kind signature.
803 pruneTyVars :: TyClDecl RdrName -> RnM [LHsTyVarBndr RdrName]
805 | isFamInstDecl tydecl
806 = do { let pruned_tyvars = nubBy eqLTyVar tyvars
807 ; assertNoSigsInRepeats tyvars
808 ; return pruned_tyvars
813 tyvars = tcdTyVars tydecl
815 assertNoSigsInRepeats [] = return ()
816 assertNoSigsInRepeats (tv:tvs)
817 = do { let offending_tvs = [ tv' | tv'@(L _ (KindedTyVar _ _)) <- tvs
819 ; checkErr (null offending_tvs) $
820 illegalKindSig (head offending_tvs)
821 ; assertNoSigsInRepeats tvs
825 = hsep [ptext (sLit "Repeat variable occurrence may not have a"),
826 ptext (sLit "kind signature:"), quotes (ppr tv)]
828 tv1 `eqLTyVar` tv2 = hsLTyVarLocName tv1 `eqLocated` hsLTyVarLocName tv2
830 -- Although, we are processing type patterns here, all type variables will
831 -- already be in scope (they are the same as in the 'tcdTyVars' field of the
832 -- type declaration to which these patterns belong)
834 rnTyPats :: SDoc -> Maybe [LHsType RdrName] -> RnM (Maybe [LHsType Name])
835 rnTyPats _ Nothing = return Nothing
836 rnTyPats doc (Just typats) = liftM Just $ rnLHsTypes doc typats
838 rnConDecls :: Name -> [LConDecl RdrName] -> RnM [LConDecl Name]
839 rnConDecls _tycon condecls
840 = mappM (wrapLocM rnConDecl) condecls
842 rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name)
843 rnConDecl (ConDecl name expl tvs cxt details res_ty mb_doc)
844 = do { addLocM checkConName name
846 ; new_name <- lookupLocatedTopBndrRn name
847 ; name_env <- getLocalRdrEnv
849 -- For H98 syntax, the tvs are the existential ones
850 -- For GADT syntax, the tvs are all the quantified tyvars
851 -- Hence the 'filter' in the ResTyH98 case only
852 ; let not_in_scope = not . (`elemLocalRdrEnv` name_env) . unLoc
853 arg_tys = hsConDeclArgTys details
854 implicit_tvs = case res_ty of
855 ResTyH98 -> filter not_in_scope $
857 ResTyGADT ty -> get_rdr_tvs (ty : arg_tys)
860 Implicit -> userHsTyVarBndrs implicit_tvs
862 ; mb_doc' <- rnMbLHsDoc mb_doc
864 ; bindTyVarsRn doc tvs' $ \new_tyvars -> do
865 { new_context <- rnContext doc cxt
866 ; new_details <- rnConDeclDetails doc details
867 ; (new_details', new_res_ty) <- rnConResult doc new_details res_ty
868 ; return (ConDecl new_name expl new_tyvars new_context new_details' new_res_ty mb_doc') }}
870 doc = text "In the definition of data constructor" <+> quotes (ppr name)
871 get_rdr_tvs tys = extractHsRhoRdrTyVars cxt (noLoc (HsTupleTy Boxed tys))
874 -> HsConDetails (LHsType Name) [ConDeclField Name]
876 -> RnM (HsConDetails (LHsType Name) [ConDeclField Name],
878 rnConResult _ details ResTyH98 = return (details, ResTyH98)
880 rnConResult doc details (ResTyGADT ty) = do
881 ty' <- rnHsSigType doc ty
882 let (arg_tys, res_ty) = splitHsFunType ty'
883 -- We can split it up, now the renamer has dealt with fixities
885 PrefixCon _xs -> ASSERT( null _xs ) return (PrefixCon arg_tys, ResTyGADT res_ty)
886 RecCon _ -> return (details, ResTyGADT ty')
887 InfixCon {} -> panic "rnConResult"
889 rnConDeclDetails :: SDoc
890 -> HsConDetails (LHsType RdrName) [ConDeclField RdrName]
891 -> RnM (HsConDetails (LHsType Name) [ConDeclField Name])
892 rnConDeclDetails doc (PrefixCon tys)
893 = mappM (rnLHsType doc) tys `thenM` \ new_tys ->
894 returnM (PrefixCon new_tys)
896 rnConDeclDetails doc (InfixCon ty1 ty2)
897 = rnLHsType doc ty1 `thenM` \ new_ty1 ->
898 rnLHsType doc ty2 `thenM` \ new_ty2 ->
899 returnM (InfixCon new_ty1 new_ty2)
901 rnConDeclDetails doc (RecCon fields)
902 = do { new_fields <- mappM (rnField doc) fields
903 -- No need to check for duplicate fields
904 -- since that is done by RnNames.extendGlobalRdrEnvRn
905 ; return (RecCon new_fields) }
907 rnField :: SDoc -> ConDeclField RdrName -> RnM (ConDeclField Name)
908 rnField doc (ConDeclField name ty haddock_doc)
909 = lookupLocatedTopBndrRn name `thenM` \ new_name ->
910 rnLHsType doc ty `thenM` \ new_ty ->
911 rnMbLHsDoc haddock_doc `thenM` \ new_haddock_doc ->
912 returnM (ConDeclField new_name new_ty new_haddock_doc)
914 -- Rename family declarations
916 -- * This function is parametrised by the routine handling the index
917 -- variables. On the toplevel, these are defining occurences, whereas they
918 -- are usage occurences for associated types.
920 rnFamily :: TyClDecl RdrName
921 -> (SDoc -> [LHsTyVarBndr RdrName] ->
922 ([LHsTyVarBndr Name] -> RnM (TyClDecl Name, FreeVars)) ->
923 RnM (TyClDecl Name, FreeVars))
924 -> RnM (TyClDecl Name, FreeVars)
926 rnFamily (tydecl@TyFamily {tcdFlavour = flavour,
927 tcdLName = tycon, tcdTyVars = tyvars})
929 do { checkM (isDataFlavour flavour -- for synonyms,
930 || not (null tyvars)) $ addErr needOneIdx -- no. of indexes >= 1
931 ; bindIdxVars (family_doc tycon) tyvars $ \tyvars' -> do {
932 ; tycon' <- lookupLocatedTopBndrRn tycon
933 ; returnM (TyFamily {tcdFlavour = flavour, tcdLName = tycon',
934 tcdTyVars = tyvars', tcdKind = tcdKind tydecl},
938 isDataFlavour DataFamily = True
939 isDataFlavour _ = False
940 rnFamily d _ = pprPanic "rnFamily" (ppr d)
942 family_doc :: Located RdrName -> SDoc
943 family_doc tycon = text "In the family declaration for" <+> quotes (ppr tycon)
946 needOneIdx = text "Type family declarations requires at least one type index"
948 -- Rename associated type declarations (in classes)
950 -- * This can be family declarations and (default) type instances
952 rnATs :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
953 rnATs ats = mapFvRn (wrapLocFstM rn_at) ats
955 rn_at (tydecl@TyFamily {}) = rnFamily tydecl lookupIdxVars
956 rn_at (tydecl@TySynonym {}) =
958 checkM (isNothing (tcdTyPats tydecl)) $ addErr noPatterns
960 rn_at _ = panic "RnSource.rnATs: invalid TyClDecl"
962 lookupIdxVars _ tyvars cont =
963 do { checkForDups tyvars;
964 ; tyvars' <- mappM lookupIdxVar tyvars
967 -- Type index variables must be class parameters, which are the only
968 -- type variables in scope at this point.
969 lookupIdxVar (L l tyvar) =
971 name' <- lookupOccRn (hsTyVarName tyvar)
972 return $ L l (replaceTyVarName tyvar name')
974 -- Type variable may only occur once.
976 checkForDups [] = return ()
977 checkForDups (L loc tv:ltvs) =
978 do { setSrcSpan loc $
979 when (hsTyVarName tv `ltvElem` ltvs) $
980 addErr (repeatedTyVar tv)
984 _ `ltvElem` [] = False
985 rdrName `ltvElem` (L _ tv:ltvs)
986 | rdrName == hsTyVarName tv = True
987 | otherwise = rdrName `ltvElem` ltvs
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] -> TcM TcGblEnv
1026 extendRecordFieldEnv decls
1027 = do { tcg_env <- getGblEnv
1028 ; field_env' <- foldrM get (tcg_field_env tcg_env) decls
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 get (L _ (TyData { tcdCons = cons })) env = foldrM get_con env cons
1041 get _ env = return env
1043 get_con (L _ (ConDecl { con_name = con, con_details = RecCon flds })) env
1044 = do { con' <- lookup con
1045 ; flds' <- mappM lookup (map cd_fld_name flds)
1046 ; return $ extendNameEnv env con' flds' }
1051 %*********************************************************
1053 \subsection{Support code to rename types}
1055 %*********************************************************
1058 rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]
1061 = mappM (wrapLocM rn_fds) fds
1064 = rnHsTyVars doc tys1 `thenM` \ tys1' ->
1065 rnHsTyVars doc tys2 `thenM` \ tys2' ->
1066 returnM (tys1', tys2')
1068 rnHsTyVars :: SDoc -> [RdrName] -> RnM [Name]
1069 rnHsTyVars doc tvs = mappM (rnHsTyVar doc) tvs
1071 rnHsTyVar :: SDoc -> RdrName -> RnM Name
1072 rnHsTyVar _doc tyvar = lookupOccRn tyvar
1076 %*********************************************************
1080 %*********************************************************
1086 h = ...$(thing "f")...
1088 The splice can expand into literally anything, so when we do dependency
1089 analysis we must assume that it might mention 'f'. So we simply treat
1090 all locally-defined names as mentioned by any splice. This is terribly
1091 brutal, but I don't see what else to do. For example, it'll mean
1092 that every locally-defined thing will appear to be used, so no unused-binding
1093 warnings. But if we miss the dependency, then we might typecheck 'h' before 'f',
1094 and that will crash the type checker because 'f' isn't in scope.
1096 Currently, I'm not treating a splice as also mentioning every import,
1097 which is a bit inconsistent -- but there are a lot of them. We might
1098 thereby get some bogus unused-import warnings, but we won't crash the
1099 type checker. Not very satisfactory really.
1102 rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
1103 rnSplice (HsSplice n expr)
1104 = do { checkTH expr "splice"
1105 ; loc <- getSrcSpanM
1106 ; [n'] <- newLocalsRn [L loc n]
1107 ; (expr', fvs) <- rnLExpr expr
1109 -- Ugh! See Note [Splices] above
1110 ; lcl_rdr <- getLocalRdrEnv
1111 ; gbl_rdr <- getGlobalRdrEnv
1112 ; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr,
1114 lcl_names = mkNameSet (occEnvElts lcl_rdr)
1116 ; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
1118 checkTH :: Outputable a => a -> String -> RnM ()
1120 checkTH _ _ = returnM () -- OK
1122 checkTH e what -- Raise an error in a stage-1 compiler
1123 = addErr (vcat [ptext (sLit "Template Haskell") <+> text what <+>
1124 ptext (sLit "illegal in a stage-1 compiler"),