2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnSource]{Main pass of renamer}
9 rnTyClDecls, checkModDeprec,
13 #include "HsVersions.h"
15 import {-# SOURCE #-} RnExpr( rnLExpr )
18 import RdrName ( RdrName, isRdrDataCon, elemLocalRdrEnv,
19 globalRdrEnvElts, GlobalRdrElt(..), isLocalGRE )
20 import RdrHsSyn ( extractGenericPatTyVars, extractHsRhoRdrTyVars )
22 import RnTypes ( rnLHsType, rnLHsTypes, rnHsSigType, rnHsTypeFVs, rnContext )
23 import RnBinds ( rnTopBinds, rnMethodBinds, renameSigs, mkSigTvFn )
24 import RnEnv ( lookupLocalDataTcNames,
25 lookupLocatedTopBndrRn, lookupLocatedOccRn,
26 lookupOccRn, lookupTopBndrRn, newLocalsRn,
27 bindLocatedLocalsFV, bindPatSigTyVarsFV,
28 bindTyVarsRn, extendTyVarEnvFVRn,
29 bindLocalNames, checkDupNames, mapFvRn
31 import RnHsDoc ( rnHsDoc, rnMbLHsDoc )
34 import HscTypes ( FixityEnv, FixItem(..),
35 Deprecations, Deprecs(..), DeprecTxt, plusDeprecs )
36 import Class ( FunDep )
37 import Name ( Name, nameOccName )
40 import OccName ( occEnvElts )
42 import SrcLoc ( Located(..), unLoc, noLoc )
43 import DynFlags ( DynFlag(..) )
44 import Maybes ( seqMaybe )
45 import Maybe ( isNothing, isJust )
46 import Monad ( liftM, when )
47 import BasicTypes ( Boxity(..) )
50 @rnSourceDecl@ `renames' declarations.
51 It simultaneously performs dependency analysis and precedence parsing.
52 It also does the following error checks:
55 Checks that tyvars are used properly. This includes checking
56 for undefined tyvars, and tyvars in contexts that are ambiguous.
57 (Some of this checking has now been moved to module @TcMonoType@,
58 since we don't have functional dependency information at this point.)
60 Checks that all variable occurences are defined.
62 Checks the @(..)@ etc constraints in the export list.
67 rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
69 rnSrcDecls (HsGroup { hs_valds = val_decls,
70 hs_tyclds = tycl_decls,
71 hs_instds = inst_decls,
72 hs_derivds = deriv_decls,
74 hs_depds = deprec_decls,
75 hs_fords = foreign_decls,
76 hs_defds = default_decls,
77 hs_ruleds = rule_decls,
80 = do { -- Deal with deprecations (returns only the extra deprecations)
81 deprecs <- rnSrcDeprecDecls deprec_decls ;
82 updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` deprecs })
85 -- Deal with top-level fixity decls
86 -- (returns the total new fixity env)
87 rn_fix_decls <- rnSrcFixityDecls fix_decls ;
88 fix_env <- rnSrcFixityDeclsEnv rn_fix_decls ;
89 updGblEnv (\gbl -> gbl { tcg_fix_env = fix_env })
92 -- Rename other declarations
93 traceRn (text "Start rnmono") ;
94 (rn_val_decls, bind_dus) <- rnTopBinds val_decls ;
95 traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
97 -- You might think that we could build proper def/use information
98 -- for type and class declarations, but they can be involved
99 -- in mutual recursion across modules, and we only do the SCC
100 -- analysis for them in the type checker.
101 -- So we content ourselves with gathering uses only; that
102 -- means we'll only report a declaration as unused if it isn't
103 -- mentioned at all. Ah well.
104 traceRn (text "Start rnTyClDecls") ;
105 (rn_tycl_decls, src_fvs1)
106 <- mapFvRn (wrapLocFstM rnTyClDecl) tycl_decls ;
107 traceRn (text "finish rnTyClDecls") ;
108 (rn_inst_decls, src_fvs2)
109 <- mapFvRn (wrapLocFstM rnSrcInstDecl) inst_decls ;
110 (rn_deriv_decls, src_fvs_deriv)
111 <- mapFvRn (wrapLocFstM rnSrcDerivDecl) deriv_decls ;
112 (rn_rule_decls, src_fvs3)
113 <- mapFvRn (wrapLocFstM rnHsRuleDecl) rule_decls ;
114 (rn_foreign_decls, src_fvs4)
115 <- mapFvRn (wrapLocFstM rnHsForeignDecl) foreign_decls ;
116 (rn_default_decls, src_fvs5)
117 <- mapFvRn (wrapLocFstM rnDefaultDecl) default_decls ;
119 rn_docs <- rnDocEntities docs ;
122 rn_group = HsGroup { hs_valds = rn_val_decls,
123 hs_tyclds = rn_tycl_decls,
124 hs_instds = rn_inst_decls,
125 hs_derivds = rn_deriv_decls,
126 hs_fixds = rn_fix_decls,
128 hs_fords = rn_foreign_decls,
129 hs_defds = rn_default_decls,
130 hs_ruleds = rn_rule_decls,
131 hs_docs = rn_docs } ;
133 other_fvs = plusFVs [src_fvs1, src_fvs2, src_fvs_deriv, src_fvs3,
134 src_fvs4, src_fvs5] ;
135 src_dus = bind_dus `plusDU` usesOnly other_fvs
136 -- Note: src_dus will contain *uses* for locally-defined types
137 -- and classes, but no *defs* for them. (Because rnTyClDecl
138 -- returns only the uses.) This is a little
139 -- surprising but it doesn't actually matter at all.
142 traceRn (text "finish rnSrc" <+> ppr rn_group) ;
143 traceRn (text "finish Dus" <+> ppr src_dus ) ;
144 tcg_env <- getGblEnv ;
145 return (tcg_env `addTcgDUs` src_dus, rn_group)
148 rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
149 rnTyClDecls tycl_decls = do
150 (decls', fvs) <- mapFvRn (wrapLocFstM rnTyClDecl) tycl_decls
153 addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv
154 addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }
158 %*********************************************************
162 %*********************************************************
165 rnDocEntities :: [DocEntity RdrName] -> RnM [DocEntity Name]
167 = ifErrsM (return []) $
168 -- Yuk: stop if we have found errors. Otherwise
169 -- the rnDocEntity stuff reports the errors again.
170 mapM rnDocEntity ents
172 rnDocEntity :: DocEntity RdrName -> RnM (DocEntity Name)
173 rnDocEntity (DocEntity docdecl) = do
174 rn_docdecl <- rnDocDecl docdecl
175 return (DocEntity rn_docdecl)
176 rnDocEntity (DeclEntity name) = do
177 rn_name <- lookupTopBndrRn name
178 return (DeclEntity rn_name)
180 rnDocDecl :: DocDecl RdrName -> RnM (DocDecl Name)
181 rnDocDecl (DocCommentNext doc) = do
182 rn_doc <- rnHsDoc doc
183 return (DocCommentNext rn_doc)
184 rnDocDecl (DocCommentPrev doc) = do
185 rn_doc <- rnHsDoc doc
186 return (DocCommentPrev rn_doc)
187 rnDocDecl (DocCommentNamed str doc) = do
188 rn_doc <- rnHsDoc doc
189 return (DocCommentNamed str rn_doc)
190 rnDocDecl (DocGroup lev doc) = do
191 rn_doc <- rnHsDoc doc
192 return (DocGroup lev rn_doc)
196 %*********************************************************
198 Source-code fixity declarations
200 %*********************************************************
203 rnSrcFixityDecls :: [LFixitySig RdrName] -> RnM [LFixitySig Name]
204 rnSrcFixityDecls fix_decls
205 = do fix_decls <- mapM rnFixityDecl fix_decls
206 return (concat fix_decls)
208 rnFixityDecl :: LFixitySig RdrName -> RnM [LFixitySig Name]
209 rnFixityDecl (L loc (FixitySig (L nameLoc rdr_name) fixity))
210 = setSrcSpan nameLoc $
211 -- GHC extension: look up both the tycon and data con
212 -- for con-like things
213 -- If neither are in scope, report an error; otherwise
214 -- add both to the fixity env
215 do names <- lookupLocalDataTcNames rdr_name
216 return [ L loc (FixitySig (L nameLoc name) fixity)
219 rnSrcFixityDeclsEnv :: [LFixitySig Name] -> RnM FixityEnv
220 rnSrcFixityDeclsEnv fix_decls
221 = getGblEnv `thenM` \ gbl_env ->
222 foldlM rnFixityDeclEnv (tcg_fix_env gbl_env)
223 fix_decls `thenM` \ fix_env ->
224 traceRn (text "fixity env" <+> pprFixEnv fix_env) `thenM_`
227 rnFixityDeclEnv :: FixityEnv -> LFixitySig Name -> RnM FixityEnv
228 rnFixityDeclEnv fix_env (L loc (FixitySig (L nameLoc name) fixity))
229 = case lookupNameEnv fix_env name of
230 Just (FixItem _ _ loc')
231 -> do addLocErr (L nameLoc name) (dupFixityDecl loc')
234 -> return (extendNameEnv fix_env name fix_item)
235 where fix_item = FixItem (nameOccName name) fixity nameLoc
237 pprFixEnv :: FixityEnv -> SDoc
239 = pprWithCommas (\ (FixItem n f _) -> ppr f <+> ppr n)
242 dupFixityDecl loc rdr_name
243 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
244 ptext SLIT("also at ") <+> ppr loc
249 %*********************************************************
251 Source-code deprecations declarations
253 %*********************************************************
255 For deprecations, all we do is check that the names are in scope.
256 It's only imported deprecations, dealt with in RnIfaces, that we
257 gather them together.
260 rnSrcDeprecDecls :: [LDeprecDecl RdrName] -> RnM Deprecations
264 rnSrcDeprecDecls decls
265 = mappM (addLocM rn_deprec) decls `thenM` \ pairs_s ->
266 returnM (DeprecSome (mkNameEnv (concat pairs_s)))
268 rn_deprec (Deprecation rdr_name txt)
269 = lookupLocalDataTcNames rdr_name `thenM` \ names ->
270 returnM [(name, (nameOccName name, txt)) | name <- names]
272 checkModDeprec :: Maybe DeprecTxt -> Deprecations
273 -- Check for a module deprecation; done once at top level
274 checkModDeprec Nothing = NoDeprecs
275 checkModDeprec (Just txt) = DeprecAll txt
278 %*********************************************************
280 \subsection{Source code declarations}
282 %*********************************************************
285 rnDefaultDecl (DefaultDecl tys)
286 = mapFvRn (rnHsTypeFVs doc_str) tys `thenM` \ (tys', fvs) ->
287 returnM (DefaultDecl tys', fvs)
289 doc_str = text "In a `default' declaration"
292 %*********************************************************
294 \subsection{Foreign declarations}
296 %*********************************************************
299 rnHsForeignDecl (ForeignImport name ty spec)
300 = lookupLocatedTopBndrRn name `thenM` \ name' ->
301 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
302 returnM (ForeignImport name' ty' spec, fvs)
304 rnHsForeignDecl (ForeignExport name ty spec)
305 = lookupLocatedOccRn name `thenM` \ name' ->
306 rnHsTypeFVs (fo_decl_msg name) ty `thenM` \ (ty', fvs) ->
307 returnM (ForeignExport name' ty' spec, fvs )
308 -- NB: a foreign export is an *occurrence site* for name, so
309 -- we add it to the free-variable list. It might, for example,
310 -- be imported from another module
312 fo_decl_msg name = ptext SLIT("In the foreign declaration for") <+> ppr name
316 %*********************************************************
318 \subsection{Instance declarations}
320 %*********************************************************
323 rnSrcInstDecl (InstDecl inst_ty mbinds uprags ats)
324 -- Used for both source and interface file decls
325 = rnHsSigType (text "an instance decl") inst_ty `thenM` \ inst_ty' ->
327 -- Rename the associated types
328 -- The typechecker (not the renamer) checks that all
329 -- the declarations are for the right class
331 at_doc = text "In the associated types of an instance declaration"
332 at_names = map (head . tyClDeclNames . unLoc) ats
334 checkDupNames at_doc at_names `thenM_`
335 rnATInsts ats `thenM` \ (ats', at_fvs) ->
337 -- Rename the bindings
338 -- The typechecker (not the renamer) checks that all
339 -- the bindings are for the right class
341 meth_doc = text "In the bindings in an instance declaration"
342 meth_names = collectHsBindLocatedBinders mbinds
343 (inst_tyvars, _, cls,_) = splitHsInstDeclTy (unLoc inst_ty')
345 checkDupNames meth_doc meth_names `thenM_`
346 extendTyVarEnvForMethodBinds inst_tyvars (
347 -- (Slightly strangely) the forall-d tyvars scope over
348 -- the method bindings too
349 rnMethodBinds cls (\n->[]) -- No scoped tyvars
351 ) `thenM` \ (mbinds', meth_fvs) ->
352 -- Rename the prags and signatures.
353 -- Note that the type variables are not in scope here,
354 -- so that instance Eq a => Eq (T a) where
355 -- {-# SPECIALISE instance Eq a => Eq (T [a]) #-}
358 -- But the (unqualified) method names are in scope
360 binders = collectHsBindBinders mbinds'
361 ok_sig = okInstDclSig (mkNameSet binders)
363 bindLocalNames binders (renameSigs ok_sig uprags) `thenM` \ uprags' ->
365 returnM (InstDecl inst_ty' mbinds' uprags' ats',
366 meth_fvs `plusFV` at_fvs
367 `plusFV` hsSigsFVs uprags'
368 `plusFV` extractHsTyNames inst_ty')
369 -- We return the renamed associated data type declarations so
370 -- that they can be entered into the list of type declarations
371 -- for the binding group, but we also keep a copy in the instance.
372 -- The latter is needed for well-formedness checks in the type
373 -- checker (eg, to ensure that all ATs of the instance actually
374 -- receive a declaration).
375 -- NB: Even the copies in the instance declaration carry copies of
376 -- the instance context after renaming. This is a bit
377 -- strange, but should not matter (and it would be more work
378 -- to remove the context).
381 Renaming of the associated types in instances.
384 rnATInsts :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
386 mapFvRn (wrapLocFstM rnATInst) atDecls
388 rnATInst tydecl@TyData {} = rnTyClDecl tydecl
389 rnATInst tydecl@TySynonym {} = rnTyClDecl tydecl
391 pprPanic "RnSource.rnATInsts: invalid AT instance"
392 (ppr (tcdName tydecl))
395 For the method bindings in class and instance decls, we extend the
396 type variable environment iff -fglasgow-exts
399 extendTyVarEnvForMethodBinds tyvars thing_inside
400 = doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
401 if opt_GlasgowExts then
402 extendTyVarEnvFVRn (map hsLTyVarName tyvars) thing_inside
407 %*********************************************************
409 \subsection{Stand-alone deriving declarations}
411 %*********************************************************
414 rnSrcDerivDecl :: DerivDecl RdrName -> RnM (DerivDecl Name, FreeVars)
415 rnSrcDerivDecl (DerivDecl ty)
416 = do ty' <- rnLHsType (text "a deriving decl") ty
417 let fvs = extractHsTyNames ty'
418 return (DerivDecl ty', fvs)
421 %*********************************************************
425 %*********************************************************
428 rnHsRuleDecl (HsRule rule_name act vars lhs fv_lhs rhs fv_rhs)
429 = bindPatSigTyVarsFV (collectRuleBndrSigTys vars) $
431 bindLocatedLocalsFV doc (map get_var vars) $ \ ids ->
432 mapFvRn rn_var (vars `zip` ids) `thenM` \ (vars', fv_vars) ->
434 rnLExpr lhs `thenM` \ (lhs', fv_lhs') ->
435 rnLExpr rhs `thenM` \ (rhs', fv_rhs') ->
437 checkValidRule rule_name ids lhs' fv_lhs' `thenM_`
439 returnM (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
440 fv_vars `plusFV` fv_lhs' `plusFV` fv_rhs')
442 doc = text "In the transformation rule" <+> ftext rule_name
444 get_var (RuleBndr v) = v
445 get_var (RuleBndrSig v _) = v
447 rn_var (RuleBndr (L loc v), id)
448 = returnM (RuleBndr (L loc id), emptyFVs)
449 rn_var (RuleBndrSig (L loc v) t, id)
450 = rnHsTypeFVs doc t `thenM` \ (t', fvs) ->
451 returnM (RuleBndrSig (L loc id) t', fvs)
454 = sep [ptext SLIT("Rule") <+> doubleQuotes (ftext name) <> colon,
455 ptext SLIT("Forall'd variable") <+> quotes (ppr var) <+>
456 ptext SLIT("does not appear on left hand side")]
459 Note [Rule LHS validity checking]
460 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
461 Check the shape of a transformation rule LHS. Currently we only allow
462 LHSs of the form @(f e1 .. en)@, where @f@ is not one of the
463 @forall@'d variables.
465 We used restrict the form of the 'ei' to prevent you writing rules
466 with LHSs with a complicated desugaring (and hence unlikely to match);
467 (e.g. a case expression is not allowed: too elaborate.)
469 But there are legitimate non-trivial args ei, like sections and
470 lambdas. So it seems simmpler not to check at all, and that is why
471 check_e is commented out.
474 checkValidRule rule_name ids lhs' fv_lhs'
475 = do { -- Check for the form of the LHS
476 case (validRuleLhs ids lhs') of
478 Just bad -> failWithTc (badRuleLhsErr rule_name lhs' bad)
480 -- Check that LHS vars are all bound
481 ; let bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
482 ; mappM (addErr . badRuleVar rule_name) bad_vars }
484 validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
486 -- Just e => Not ok, and e is the offending expression
487 validRuleLhs foralls lhs
490 checkl (L loc e) = check e
492 check (OpApp e1 op _ e2) = checkl op `seqMaybe` checkl_e e1 `seqMaybe` checkl_e e2
493 check (HsApp e1 e2) = checkl e1 `seqMaybe` checkl_e e2
494 check (HsVar v) | v `notElem` foralls = Nothing
495 check other = Just other -- Failure
498 checkl_e (L loc e) = Nothing -- Was (check_e e); see Note [Rule LHS validity checking]
500 {- Commented out; see Note [Rule LHS validity checking] above
501 check_e (HsVar v) = Nothing
502 check_e (HsPar e) = checkl_e e
503 check_e (HsLit e) = Nothing
504 check_e (HsOverLit e) = Nothing
506 check_e (OpApp e1 op _ e2) = checkl_e e1 `seqMaybe` checkl_e op `seqMaybe` checkl_e e2
507 check_e (HsApp e1 e2) = checkl_e e1 `seqMaybe` checkl_e e2
508 check_e (NegApp e _) = checkl_e e
509 check_e (ExplicitList _ es) = checkl_es es
510 check_e (ExplicitTuple es _) = checkl_es es
511 check_e other = Just other -- Fails
513 checkl_es es = foldr (seqMaybe . checkl_e) Nothing es
516 badRuleLhsErr name lhs bad_e
517 = sep [ptext SLIT("Rule") <+> ftext name <> colon,
518 nest 4 (vcat [ptext SLIT("Illegal expression:") <+> ppr bad_e,
519 ptext SLIT("in left-hand side:") <+> ppr lhs])]
521 ptext SLIT("LHS must be of form (f e1 .. en) where f is not forall'd")
525 %*********************************************************
527 \subsection{Type, class and iface sig declarations}
529 %*********************************************************
531 @rnTyDecl@ uses the `global name function' to create a new type
532 declaration in which local names have been replaced by their original
533 names, reporting any unknown names.
535 Renaming type variables is a pain. Because they now contain uniques,
536 it is necessary to pass in an association list which maps a parsed
537 tyvar to its @Name@ representation.
538 In some cases (type signatures of values),
539 it is even necessary to go over the type first
540 in order to get the set of tyvars used by it, make an assoc list,
541 and then go over it again to rename the tyvars!
542 However, we can also do some scoping checks at the same time.
545 rnTyClDecl (ForeignType {tcdLName = name, tcdFoType = fo_type, tcdExtName = ext_name})
546 = lookupLocatedTopBndrRn name `thenM` \ name' ->
547 returnM (ForeignType {tcdLName = name', tcdFoType = fo_type, tcdExtName = ext_name},
550 -- all flavours of type family declarations ("type family", "newtype fanily",
551 -- and "data family")
552 rnTyClDecl (tydecl@TyFamily {}) =
553 rnFamily tydecl bindTyVarsRn
555 -- "data", "newtype", "data instance, and "newtype instance" declarations
556 rnTyClDecl (tydecl@TyData {tcdND = new_or_data, tcdCtxt = context,
557 tcdLName = tycon, tcdTyVars = tyvars,
558 tcdTyPats = typatsMaybe, tcdCons = condecls,
559 tcdKindSig = sig, tcdDerivs = derivs})
560 | is_vanilla -- Normal Haskell data type decl
561 = ASSERT( isNothing sig ) -- In normal H98 form, kind signature on the
562 -- data type is syntactically illegal
563 bindTyVarsRn data_doc tyvars $ \ tyvars' ->
564 do { tycon' <- if isFamInstDecl tydecl
565 then lookupLocatedOccRn tycon -- may be imported family
566 else lookupLocatedTopBndrRn tycon
567 ; context' <- rnContext data_doc context
568 ; typats' <- rnTyPats data_doc typatsMaybe
569 ; (derivs', deriv_fvs) <- rn_derivs derivs
570 ; checkDupNames data_doc con_names
571 ; condecls' <- rnConDecls (unLoc tycon') condecls
572 ; returnM (TyData {tcdND = new_or_data, tcdCtxt = context',
573 tcdLName = tycon', tcdTyVars = tyvars',
574 tcdTyPats = typats', tcdKindSig = Nothing,
575 tcdCons = condecls', tcdDerivs = derivs'},
576 delFVs (map hsLTyVarName tyvars') $
577 extractHsCtxtTyNames context' `plusFV`
578 plusFVs (map conDeclFVs condecls') `plusFV`
580 (if isFamInstDecl tydecl
581 then unitFV (unLoc tycon') -- type instance => use
586 = ASSERT( none typatsMaybe ) -- GADTs cannot have type patterns for now
587 do { tycon' <- if isFamInstDecl tydecl
588 then lookupLocatedOccRn tycon -- may be imported family
589 else lookupLocatedTopBndrRn tycon
590 ; checkTc (null (unLoc context)) (badGadtStupidTheta tycon)
591 ; tyvars' <- bindTyVarsRn data_doc tyvars
592 (\ tyvars' -> return tyvars')
593 -- For GADTs, the type variables in the declaration
594 -- do not scope over the constructor signatures
595 -- data T a where { T1 :: forall b. b-> b }
596 ; (derivs', deriv_fvs) <- rn_derivs derivs
597 ; checkDupNames data_doc con_names
598 ; condecls' <- rnConDecls (unLoc tycon') condecls
599 ; returnM (TyData {tcdND = new_or_data, tcdCtxt = noLoc [],
600 tcdLName = tycon', tcdTyVars = tyvars',
601 tcdTyPats = Nothing, tcdKindSig = sig,
602 tcdCons = condecls', tcdDerivs = derivs'},
603 plusFVs (map conDeclFVs condecls') `plusFV`
605 (if isFamInstDecl tydecl
606 then unitFV (unLoc tycon') -- type instance => use
610 is_vanilla = case condecls of -- Yuk
612 L _ (ConDecl { con_res = ResTyH98 }) : _ -> True
616 none (Just []) = True
619 data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)
620 con_names = map con_names_helper condecls
622 con_names_helper (L _ c) = con_name c
624 rn_derivs Nothing = returnM (Nothing, emptyFVs)
625 rn_derivs (Just ds) = rnLHsTypes data_doc ds `thenM` \ ds' ->
626 returnM (Just ds', extractHsTyNames_s ds')
628 -- "type" and "type instance" declarations
629 rnTyClDecl tydecl@(TySynonym {tcdLName = name, tcdTyVars = tyvars,
630 tcdTyPats = typatsMaybe, tcdSynRhs = ty})
631 = bindTyVarsRn syn_doc tyvars $ \ tyvars' ->
632 do { name' <- if isFamInstDecl tydecl
633 then lookupLocatedOccRn name -- may be imported family
634 else lookupLocatedTopBndrRn name
635 ; typats' <- rnTyPats syn_doc typatsMaybe
636 ; (ty', fvs) <- rnHsTypeFVs syn_doc ty
637 ; returnM (TySynonym {tcdLName = name', tcdTyVars = tyvars',
638 tcdTyPats = typats', tcdSynRhs = ty'},
639 delFVs (map hsLTyVarName tyvars') $
641 (if isFamInstDecl tydecl
642 then unitFV (unLoc name') -- type instance => use
646 syn_doc = text "In the declaration for type synonym" <+> quotes (ppr name)
648 rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = cname,
649 tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs,
650 tcdMeths = mbinds, tcdATs = ats, tcdDocs = docs})
651 = do { cname' <- lookupLocatedTopBndrRn cname
653 -- Tyvars scope over superclass context and method signatures
654 ; (tyvars', context', fds', ats', ats_fvs, sigs')
655 <- bindTyVarsRn cls_doc tyvars $ \ tyvars' -> do
656 { context' <- rnContext cls_doc context
657 ; fds' <- rnFds cls_doc fds
658 ; (ats', ats_fvs) <- rnATs ats
659 ; sigs' <- renameSigs okClsDclSig sigs
660 ; return (tyvars', context', fds', ats', ats_fvs, sigs') }
662 -- Check for duplicates among the associated types
663 ; let at_rdr_names_w_locs = [tcdLName ty | L _ ty <- ats]
664 ; checkDupNames at_doc at_rdr_names_w_locs
666 -- Check the signatures
667 -- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
668 ; let sig_rdr_names_w_locs = [op | L _ (TypeSig op _) <- sigs]
669 ; checkDupNames sig_doc sig_rdr_names_w_locs
670 -- Typechecker is responsible for checking that we only
671 -- give default-method bindings for things in this class.
672 -- The renamer *could* check this for class decls, but can't
673 -- for instance decls.
675 -- The newLocals call is tiresome: given a generic class decl
678 -- op {| x+y |} (Inl a) = ...
679 -- op {| x+y |} (Inr b) = ...
680 -- op {| a*b |} (a*b) = ...
681 -- we want to name both "x" tyvars with the same unique, so that they are
682 -- easy to group together in the typechecker.
683 ; (mbinds', meth_fvs)
684 <- extendTyVarEnvForMethodBinds tyvars' $ do
685 { name_env <- getLocalRdrEnv
686 ; let meth_rdr_names_w_locs = collectHsBindLocatedBinders mbinds
687 gen_rdr_tyvars_w_locs = [ tv | tv <- extractGenericPatTyVars mbinds,
688 not (unLoc tv `elemLocalRdrEnv` name_env) ]
689 ; checkDupNames meth_doc meth_rdr_names_w_locs
690 ; gen_tyvars <- newLocalsRn gen_rdr_tyvars_w_locs
691 ; rnMethodBinds (unLoc cname') (mkSigTvFn sigs') gen_tyvars mbinds }
693 -- Sigh. Check the Haddock docs after the methods, to avoid duplicate errors
694 -- Example: class { op :: a->a; op2 x = x }
695 -- Don't want a duplicate complait about op2
696 ; docs' <- bindLocalNames (map hsLTyVarName tyvars') $ rnDocEntities docs
698 ; return (ClassDecl { tcdCtxt = context', tcdLName = cname',
699 tcdTyVars = tyvars', tcdFDs = fds', tcdSigs = sigs',
700 tcdMeths = mbinds', tcdATs = ats', tcdDocs = docs'},
702 delFVs (map hsLTyVarName tyvars') $
703 extractHsCtxtTyNames context' `plusFV`
704 plusFVs (map extractFunDepNames (map unLoc fds')) `plusFV`
705 hsSigsFVs sigs' `plusFV`
709 meth_doc = text "In the default-methods for class" <+> ppr cname
710 cls_doc = text "In the declaration for class" <+> ppr cname
711 sig_doc = text "In the signatures for class" <+> ppr cname
712 at_doc = text "In the associated types for class" <+> ppr cname
714 badGadtStupidTheta tycon
715 = vcat [ptext SLIT("No context is allowed on a GADT-style data declaration"),
716 ptext SLIT("(You can put a context on each contructor, though.)")]
719 %*********************************************************
721 \subsection{Support code for type/data declarations}
723 %*********************************************************
726 -- Although, we are processing type patterns here, all type variables will
727 -- already be in scope (they are the same as in the 'tcdTyVars' field of the
728 -- type declaration to which these patterns belong)
730 rnTyPats :: SDoc -> Maybe [LHsType RdrName] -> RnM (Maybe [LHsType Name])
731 rnTyPats _ Nothing = return Nothing
732 rnTyPats doc (Just typats) = liftM Just $ rnLHsTypes doc typats
734 rnConDecls :: Name -> [LConDecl RdrName] -> RnM [LConDecl Name]
735 rnConDecls tycon condecls
736 = mappM (wrapLocM rnConDecl) condecls
738 rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name)
739 rnConDecl (ConDecl name expl tvs cxt details res_ty mb_doc)
740 = do { addLocM checkConName name
742 ; new_name <- lookupLocatedTopBndrRn name
743 ; name_env <- getLocalRdrEnv
745 -- For H98 syntax, the tvs are the existential ones
746 -- For GADT syntax, the tvs are all the quantified tyvars
747 -- Hence the 'filter' in the ResTyH98 case only
748 ; let not_in_scope = not . (`elemLocalRdrEnv` name_env) . unLoc
749 arg_tys = hsConArgs details
750 implicit_tvs = case res_ty of
751 ResTyH98 -> filter not_in_scope $
753 ResTyGADT ty -> get_rdr_tvs (ty : arg_tys)
756 Implicit -> userHsTyVarBndrs implicit_tvs
758 ; mb_doc' <- rnMbLHsDoc mb_doc
760 ; bindTyVarsRn doc tvs' $ \new_tyvars -> do
761 { new_context <- rnContext doc cxt
762 ; new_details <- rnConDetails doc details
763 ; (new_details', new_res_ty) <- rnConResult doc new_details res_ty
764 ; return (ConDecl new_name expl new_tyvars new_context new_details' new_res_ty mb_doc') }}
766 doc = text "In the definition of data constructor" <+> quotes (ppr name)
767 get_rdr_tvs tys = extractHsRhoRdrTyVars cxt (noLoc (HsTupleTy Boxed tys))
769 rnConResult _ details ResTyH98 = return (details, ResTyH98)
771 rnConResult doc details (ResTyGADT ty) = do
772 ty' <- rnHsSigType doc ty
773 let (arg_tys, res_ty) = splitHsFunType ty'
774 -- We can split it up, now the renamer has dealt with fixities
776 PrefixCon _xs -> ASSERT( null _xs ) return (PrefixCon arg_tys, ResTyGADT res_ty)
777 RecCon fields -> return (details, ResTyGADT ty')
778 InfixCon {} -> panic "rnConResult"
780 rnConDetails doc (PrefixCon tys)
781 = mappM (rnLHsType doc) tys `thenM` \ new_tys ->
782 returnM (PrefixCon new_tys)
784 rnConDetails doc (InfixCon ty1 ty2)
785 = rnLHsType doc ty1 `thenM` \ new_ty1 ->
786 rnLHsType doc ty2 `thenM` \ new_ty2 ->
787 returnM (InfixCon new_ty1 new_ty2)
789 rnConDetails doc (RecCon fields)
790 = checkDupNames doc field_names `thenM_`
791 mappM (rnField doc) fields `thenM` \ new_fields ->
792 returnM (RecCon new_fields)
794 field_names = [ name | HsRecField name _ _ <- fields ]
796 -- Document comments are renamed to Nothing here
797 rnField doc (HsRecField name ty haddock_doc)
798 = lookupLocatedTopBndrRn name `thenM` \ new_name ->
799 rnLHsType doc ty `thenM` \ new_ty ->
800 rnMbLHsDoc haddock_doc `thenM` \ new_haddock_doc ->
801 returnM (HsRecField new_name new_ty new_haddock_doc)
803 -- Rename family declarations
805 -- * This function is parametrised by the routine handling the index
806 -- variables. On the toplevel, these are defining occurences, whereas they
807 -- are usage occurences for associated types.
809 rnFamily :: TyClDecl RdrName
810 -> (SDoc -> [LHsTyVarBndr RdrName] ->
811 ([LHsTyVarBndr Name] -> RnM (TyClDecl Name, FreeVars)) ->
812 RnM (TyClDecl Name, FreeVars))
813 -> RnM (TyClDecl Name, FreeVars)
815 rnFamily (tydecl@TyFamily {tcdFlavour = flavour,
816 tcdLName = tycon, tcdTyVars = tyvars})
818 do { checkM (isDataFlavour flavour -- for synonyms,
819 || not (null tyvars)) $ addErr needOneIdx -- #indexes >= 1
820 ; bindIdxVars (family_doc tycon) tyvars $ \tyvars' -> do {
821 ; tycon' <- lookupLocatedTopBndrRn tycon
822 ; returnM (TyFamily {tcdFlavour = flavour, tcdLName = tycon',
823 tcdTyVars = tyvars', tcdKind = tcdKind tydecl},
827 isDataFlavour (DataFamily _) = True
828 isDataFlavour _ = False
830 family_doc tycon = text "In the family declaration for" <+> quotes (ppr tycon)
831 needOneIdx = text "Type family declarations requires at least one type index"
833 -- Rename associated type declarations (in classes)
835 -- * This can be family declarations and (default) type instances
837 rnATs :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars)
838 rnATs ats = mapFvRn (wrapLocFstM rn_at) ats
840 rn_at (tydecl@TyFamily {}) = rnFamily tydecl lookupIdxVars
841 rn_at (tydecl@TySynonym {}) =
843 checkM (isNothing (tcdTyPats tydecl)) $ addErr noPatterns
845 rn_at _ = panic "RnSource.rnATs: invalid TyClDecl"
847 lookupIdxVars _ tyvars cont =
848 do { checkForDups tyvars;
849 ; tyvars' <- mappM lookupIdxVar tyvars
852 -- Type index variables must be class parameters, which are the only
853 -- type variables in scope at this point.
854 lookupIdxVar (L l tyvar) =
856 name' <- lookupOccRn (hsTyVarName tyvar)
857 return $ L l (replaceTyVarName tyvar name')
859 -- Type variable may only occur once.
861 checkForDups [] = return ()
862 checkForDups (L loc tv:ltvs) =
863 do { setSrcSpan loc $
864 when (hsTyVarName tv `ltvElem` ltvs) $
865 addErr (repeatedTyVar tv)
869 rdrName `ltvElem` [] = False
870 rdrName `ltvElem` (L _ tv:ltvs)
871 | rdrName == hsTyVarName tv = True
872 | otherwise = rdrName `ltvElem` ltvs
874 noPatterns = text "Default definition for an associated synonym cannot have"
875 <+> text "type pattern"
877 repeatedTyVar tv = ptext SLIT("Illegal repeated type variable") <+>
880 -- This data decl will parse OK
882 -- treating "a" as the constructor.
883 -- It is really hard to make the parser spot this malformation.
884 -- So the renamer has to check that the constructor is legal
886 -- We can get an operator as the constructor, even in the prefix form:
887 -- data T = :% Int Int
888 -- from interface files, which always print in prefix form
890 checkConName name = checkErr (isRdrDataCon name) (badDataCon name)
893 = hsep [ptext SLIT("Illegal data constructor name"), quotes (ppr name)]
897 %*********************************************************
899 \subsection{Support code to rename types}
901 %*********************************************************
904 rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]
907 = mappM (wrapLocM rn_fds) fds
910 = rnHsTyVars doc tys1 `thenM` \ tys1' ->
911 rnHsTyVars doc tys2 `thenM` \ tys2' ->
912 returnM (tys1', tys2')
914 rnHsTyVars doc tvs = mappM (rnHsTyvar doc) tvs
915 rnHsTyvar doc tyvar = lookupOccRn tyvar
919 %*********************************************************
923 %*********************************************************
929 h = ...$(thing "f")...
931 The splice can expand into literally anything, so when we do dependency
932 analysis we must assume that it might mention 'f'. So we simply treat
933 all locally-defined names as mentioned by any splice. This is terribly
934 brutal, but I don't see what else to do. For example, it'll mean
935 that every locally-defined thing will appear to be used, so no unused-binding
936 warnings. But if we miss the dependency, then we might typecheck 'h' before 'f',
937 and that will crash the type checker because 'f' isn't in scope.
939 Currently, I'm not treating a splice as also mentioning every import,
940 which is a bit inconsistent -- but there are a lot of them. We might
941 thereby get some bogus unused-import warnings, but we won't crash the
942 type checker. Not very satisfactory really.
945 rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
946 rnSplice (HsSplice n expr)
947 = do { checkTH expr "splice"
949 ; [n'] <- newLocalsRn [L loc n]
950 ; (expr', fvs) <- rnLExpr expr
952 -- Ugh! See Note [Splices] above
953 ; lcl_rdr <- getLocalRdrEnv
954 ; gbl_rdr <- getGlobalRdrEnv
955 ; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr,
957 lcl_names = mkNameSet (occEnvElts lcl_rdr)
959 ; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
962 checkTH e what = returnM () -- OK
964 checkTH e what -- Raise an error in a stage-1 compiler
965 = addErr (vcat [ptext SLIT("Template Haskell") <+> text what <+>
966 ptext SLIT("illegal in a stage-1 compiler"),