2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnEnv]{Environment manipulation for the renamer monad}
7 module RnEnv where -- Export everything
9 #include "HsVersions.h"
12 import RdrHsSyn ( RdrNameIE )
13 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
14 mkRdrUnqual, mkRdrUnqual, qualifyRdrName, lookupRdrEnv
16 import HsTypes ( hsTyVarName, replaceTyVarName )
17 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
18 ImportReason(..), GlobalRdrEnv, AvailEnv,
19 AvailInfo, Avails, GenAvailInfo(..) )
21 import Name ( Name, NamedThing(..),
23 mkLocalName, mkImportedLocalName, mkGlobalName,
24 mkIPName, nameOccName, nameModule_maybe,
27 import Name ( extendNameEnv_C, plusNameEnv_C, nameEnvElts )
29 import OccName ( OccName, occNameUserString, occNameFlavour )
30 import Module ( ModuleName, moduleName, mkVanillaModule, mkSysModuleNameFS, moduleNameFS )
33 import SrcLoc ( SrcLoc, noSrcLoc )
35 import ListSetOps ( removeDups, equivClasses )
36 import Util ( sortLt )
38 import PrelNames ( mkUnboundName )
40 import FastString ( FastString )
43 %*********************************************************
45 \subsection{Making new names}
47 %*********************************************************
50 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
51 -- newTopBinder puts into the cache the binder with the
52 -- module information set correctly. When the decl is later renamed,
53 -- the binding site will thereby get the correct module.
54 -- There maybe occurrences that don't have the correct Module, but
55 -- by the typechecker will propagate the binding definition to all
56 -- the occurrences, so that doesn't matter
58 newTopBinder mod rdr_name loc
59 = -- First check the cache
60 -- traceRn (text "newTopBinder" <+> ppr mod <+> ppr loc) `thenRn_`
62 -- There should never be a qualified name in a binding position (except in instance decls)
63 -- The parser doesn't check this because the same parser parses instance decls
64 (if isQual rdr_name then
65 qualNameErr (text "its declaration") (rdr_name,loc)
70 getNameSupplyRn `thenRn` \ (us, cache, ipcache) ->
72 occ = rdrNameOcc rdr_name
73 key = (moduleName mod, occ)
75 case lookupFM cache key of
77 -- A hit in the cache! We are at the binding site of the name, and
78 -- this is the moment when we know all about
79 -- a) the Name's host Module (in particular, which
80 -- package it comes from)
81 -- b) its defining SrcLoc
82 -- So we update this info
85 new_name = setNameModuleAndLoc name mod loc
86 new_cache = addToFM cache key new_name
88 setNameSupplyRn (us, new_cache, ipcache) `thenRn_`
89 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
93 -- Build a completely new Name, and put it in the cache
94 -- Even for locally-defined names we use implicitImportProvenance;
95 -- updateProvenances will set it to rights
97 (us', us1) = splitUniqSupply us
98 uniq = uniqFromSupply us1
99 new_name = mkGlobalName uniq mod occ loc
100 new_cache = addToFM cache key new_name
102 setNameSupplyRn (us', new_cache, ipcache) `thenRn_`
103 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
107 newGlobalName :: ModuleName -> OccName -> RnM d Name
108 -- Used for *occurrences*. We make a place-holder Name, really just
109 -- to agree on its unique, which gets overwritten when we read in
110 -- the binding occurence later (newTopBinder)
111 -- The place-holder Name doesn't have the right SrcLoc, and its
112 -- Module won't have the right Package either.
114 -- (We have to pass a ModuleName, not a Module, because we may be
115 -- simply looking at an occurrence M.x in an interface file.)
117 -- This means that a renamed program may have incorrect info
118 -- on implicitly-imported occurrences, but the correct info on the
119 -- *binding* declaration. It's the type checker that propagates the
120 -- correct information to all the occurrences.
121 -- Since implicitly-imported names never occur in error messages,
122 -- it doesn't matter that we get the correct info in place till later,
123 -- (but since it affects DLL-ery it does matter that we get it right
125 newGlobalName mod_name occ
126 = getNameSupplyRn `thenRn` \ (us, cache, ipcache) ->
128 key = (mod_name, occ)
130 case lookupFM cache key of
131 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
134 Nothing -> setNameSupplyRn (us', new_cache, ipcache) `thenRn_`
135 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
138 (us', us1) = splitUniqSupply us
139 uniq = uniqFromSupply us1
140 mod = mkVanillaModule mod_name
141 name = mkGlobalName uniq mod occ noSrcLoc
142 new_cache = addToFM cache key name
145 = getNameSupplyRn `thenRn` \ (us, cache, ipcache) ->
146 case lookupFM ipcache key of
147 Just name -> returnRn name
148 Nothing -> setNameSupplyRn (us', cache, new_ipcache) `thenRn_`
151 (us', us1) = splitUniqSupply us
152 uniq = uniqFromSupply us1
153 name = mkIPName uniq key
154 new_ipcache = addToFM ipcache key name
155 where key = (rdrNameOcc rdr_name)
158 %*********************************************************
160 \subsection{Looking up names}
162 %*********************************************************
164 Looking up a name in the RnEnv.
167 lookupBndrRn rdr_name
168 = getLocalNameEnv `thenRn` \ local_env ->
169 case lookupRdrEnv local_env rdr_name of
170 Just name -> returnRn name
171 Nothing -> lookupTopBndrRn rdr_name
173 lookupTopBndrRn rdr_name
174 = getModeRn `thenRn` \ mode ->
176 InterfaceMode -> lookupIfaceName rdr_name
178 SourceMode -> -- Source mode, so look up a *qualified* version
179 -- of the name, so that we get the right one even
180 -- if there are many with the same occ name
181 -- There must *be* a binding
182 getModuleRn `thenRn` \ mod ->
183 lookupSrcGlobalOcc (qualifyRdrName (moduleName mod) rdr_name)
185 -- lookupSigOccRn is used for type signatures and pragmas
191 -- It's clear that the 'f' in the signature must refer to A.f
192 -- The Haskell98 report does not stipulate this, but it will!
193 -- So we must treat the 'f' in the signature in the same way
194 -- as the binding occurrence of 'f', using lookupBndrRn
195 lookupSigOccRn :: RdrName -> RnMS Name
196 lookupSigOccRn = lookupBndrRn
198 -- lookupOccRn looks up an occurrence of a RdrName
199 lookupOccRn :: RdrName -> RnMS Name
201 = getLocalNameEnv `thenRn` \ local_env ->
202 case lookupRdrEnv local_env rdr_name of
203 Just name -> returnRn name
204 Nothing -> lookupGlobalOccRn rdr_name
206 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
207 -- environment. It's used only for
208 -- record field names
209 -- class op names in class and instance decls
211 lookupGlobalOccRn rdr_name
212 | isOrig rdr_name -- Can occur in source code too
213 = lookupOrigName rdr_name
216 = getModeRn `thenRn` \ mode ->
218 SourceMode -> lookupSrcGlobalOcc rdr_name
219 InterfaceMode -> lookupIfaceUnqual rdr_name
221 lookupSrcGlobalOcc rdr_name
222 -- Lookup a source-code rdr-name; may be qualified or not
223 = getGlobalNameEnv `thenRn` \ global_env ->
224 case lookupRdrEnv global_env rdr_name of
225 Just [(name,_)] -> returnRn name
226 Just stuff@((name,_):_) -> addNameClashErrRn rdr_name stuff `thenRn_`
228 Nothing -> failWithRn (mkUnboundName rdr_name)
229 (unknownNameErr rdr_name)
231 lookupOrigName :: RdrName -> RnM d Name
232 lookupOrigName rdr_name
233 = ASSERT( isOrig rdr_name )
234 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
236 lookupIfaceUnqual :: RdrName -> RnM d Name
237 lookupIfaceUnqual rdr_name
238 = ASSERT( isUnqual rdr_name )
239 -- An Unqual is allowed; interface files contain
240 -- unqualified names for locally-defined things, such as
241 -- constructors of a data type.
242 getModuleRn `thenRn ` \ mod ->
243 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
245 lookupIfaceName :: RdrName -> RnM d Name
246 lookupIfaceName rdr_name
247 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
248 | otherwise = lookupOrigName rdr_name
250 lookupGlobalRn :: GlobalRdrEnv -> RdrName -> RnM d (Maybe Name)
251 -- Checks that there is exactly one
252 lookupGlobalRn global_env rdr_name
253 = case lookupRdrEnv global_env rdr_name of
254 Just [(name,_)] -> returnRn (Just name)
255 Just stuff@((name,_):_) -> addNameClashErrRn rdr_name stuff `thenRn_`
257 Nothing -> returnRn Nothing
260 @lookupOrigName@ takes an RdrName representing an {\em original}
261 name, and adds it to the occurrence pool so that it'll be loaded
262 later. This is used when language constructs (such as monad
263 comprehensions, overloaded literals, or deriving clauses) require some
264 stuff to be loaded that isn't explicitly mentioned in the code.
266 This doesn't apply in interface mode, where everything is explicit,
267 but we don't check for this case: it does no harm to record an
268 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
269 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
270 calls it at all I think).
272 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
274 For List and Tuple types it's important to get the correct
275 @isLocallyDefined@ flag, which is used in turn when deciding
276 whether there are any instance decls in this module are ``special''.
277 The name cache should have the correct provenance, though.
280 lookupOrigNames :: [RdrName] -> RnM d NameSet
281 lookupOrigNames rdr_names
282 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
283 returnRn (mkNameSet names)
286 lookupSysBinder is used for the "system binders" of a type, class, or instance decl.
287 It ensures that the module is set correctly in the name cache, and sets the provenance
288 on the returned name too. The returned name will end up actually in the type, class,
292 lookupSysBinder rdr_name
293 = ASSERT( isUnqual rdr_name )
294 getModuleRn `thenRn` \ mod ->
295 getSrcLocRn `thenRn` \ loc ->
296 newTopBinder mod rdr_name loc
301 %*********************************************************
305 %*********************************************************
308 newLocalsRn :: [(RdrName,SrcLoc)]
310 newLocalsRn rdr_names_w_loc
311 = getNameSupplyRn `thenRn` \ (us, cache, ipcache) ->
313 n = length rdr_names_w_loc
314 (us', us1) = splitUniqSupply us
315 uniqs = uniqsFromSupply n us1
316 names = [ mkLocalName uniq (rdrNameOcc rdr_name) loc
317 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
320 setNameSupplyRn (us', cache, ipcache) `thenRn_`
324 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
325 -> [(RdrName,SrcLoc)]
326 -> ([Name] -> RnMS a)
328 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
329 = getModeRn `thenRn` \ mode ->
330 getLocalNameEnv `thenRn` \ name_env ->
332 -- Check for duplicate names
333 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
335 doptRn Opt_WarnNameShadowing `thenRn` \ warn_shadow ->
337 -- Warn about shadowing, but only in source modules
339 SourceMode | warn_shadow -> mapRn_ (check_shadow name_env) rdr_names_w_loc
343 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
345 new_local_env = addListToRdrEnv name_env (map fst rdr_names_w_loc `zip` names)
347 setLocalNameEnv new_local_env (enclosed_scope names)
350 check_shadow name_env (rdr_name,loc)
351 = case lookupRdrEnv name_env rdr_name of
352 Nothing -> returnRn ()
353 Just name -> pushSrcLocRn loc $
354 addWarnRn (shadowedNameWarn rdr_name)
356 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
357 -- A specialised variant when renaming stuff from interface
358 -- files (of which there is a lot)
360 -- * no checks for shadowing
362 -- * deal with free vars
363 bindCoreLocalRn rdr_name enclosed_scope
364 = getSrcLocRn `thenRn` \ loc ->
365 getLocalNameEnv `thenRn` \ name_env ->
366 getNameSupplyRn `thenRn` \ (us, cache, ipcache) ->
368 (us', us1) = splitUniqSupply us
369 uniq = uniqFromSupply us1
370 name = mkImportedLocalName uniq (rdrNameOcc rdr_name) loc
372 setNameSupplyRn (us', cache, ipcache) `thenRn_`
374 new_name_env = extendRdrEnv name_env rdr_name name
376 setLocalNameEnv new_name_env (enclosed_scope name)
378 bindCoreLocalsRn [] thing_inside = thing_inside []
379 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
380 bindCoreLocalsRn bs $ \ names' ->
381 thing_inside (name':names')
383 bindLocalNames names enclosed_scope
384 = getLocalNameEnv `thenRn` \ name_env ->
385 setLocalNameEnv (addListToRdrEnv name_env pairs)
388 pairs = [(mkRdrUnqual (nameOccName n), n) | n <- names]
390 -------------------------------------
391 bindLocalRn doc rdr_name enclosed_scope
392 = getSrcLocRn `thenRn` \ loc ->
393 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
397 bindLocalsRn doc rdr_names enclosed_scope
398 = getSrcLocRn `thenRn` \ loc ->
399 bindLocatedLocalsRn doc
400 (rdr_names `zip` repeat loc)
403 -- binLocalsFVRn is the same as bindLocalsRn
404 -- except that it deals with free vars
405 bindLocalsFVRn doc rdr_names enclosed_scope
406 = bindLocalsRn doc rdr_names $ \ names ->
407 enclosed_scope names `thenRn` \ (thing, fvs) ->
408 returnRn (thing, delListFromNameSet fvs names)
410 -------------------------------------
411 bindUVarRn :: RdrName -> (Name -> RnMS a) -> RnMS a
412 bindUVarRn = bindCoreLocalRn
414 -------------------------------------
415 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
416 -- This tiresome function is used only in rnDecl on InstDecl
417 extendTyVarEnvFVRn tyvars enclosed_scope
418 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
419 returnRn (thing, delListFromNameSet fvs tyvars)
421 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
422 -> ([HsTyVarBndr Name] -> RnMS a)
424 bindTyVarsRn doc_str tyvar_names enclosed_scope
425 = bindTyVars2Rn doc_str tyvar_names $ \ names tyvars ->
426 enclosed_scope tyvars
428 -- Gruesome name: return Names as well as HsTyVars
429 bindTyVars2Rn :: SDoc -> [HsTyVarBndr RdrName]
430 -> ([Name] -> [HsTyVarBndr Name] -> RnMS a)
432 bindTyVars2Rn doc_str tyvar_names enclosed_scope
433 = getSrcLocRn `thenRn` \ loc ->
435 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
437 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
438 enclosed_scope names (zipWith replaceTyVarName tyvar_names names)
440 bindTyVarsFVRn :: SDoc -> [HsTyVarBndr RdrName]
441 -> ([HsTyVarBndr Name] -> RnMS (a, FreeVars))
442 -> RnMS (a, FreeVars)
443 bindTyVarsFVRn doc_str rdr_names enclosed_scope
444 = bindTyVars2Rn doc_str rdr_names $ \ names tyvars ->
445 enclosed_scope tyvars `thenRn` \ (thing, fvs) ->
446 returnRn (thing, delListFromNameSet fvs names)
448 bindTyVarsFV2Rn :: SDoc -> [HsTyVarBndr RdrName]
449 -> ([Name] -> [HsTyVarBndr Name] -> RnMS (a, FreeVars))
450 -> RnMS (a, FreeVars)
451 bindTyVarsFV2Rn doc_str rdr_names enclosed_scope
452 = bindTyVars2Rn doc_str rdr_names $ \ names tyvars ->
453 enclosed_scope names tyvars `thenRn` \ (thing, fvs) ->
454 returnRn (thing, delListFromNameSet fvs names)
456 bindNakedTyVarsFVRn :: SDoc -> [RdrName]
457 -> ([Name] -> RnMS (a, FreeVars))
458 -> RnMS (a, FreeVars)
459 bindNakedTyVarsFVRn doc_str tyvar_names enclosed_scope
460 = getSrcLocRn `thenRn` \ loc ->
462 located_tyvars = [(tv, loc) | tv <- tyvar_names]
464 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
465 enclosed_scope names `thenRn` \ (thing, fvs) ->
466 returnRn (thing, delListFromNameSet fvs names)
469 -------------------------------------
470 checkDupOrQualNames, checkDupNames :: SDoc
471 -> [(RdrName, SrcLoc)]
473 -- Works in any variant of the renamer monad
475 checkDupOrQualNames doc_str rdr_names_w_loc
476 = -- Check for use of qualified names
477 mapRn_ (qualNameErr doc_str) quals `thenRn_`
478 checkDupNames doc_str rdr_names_w_loc
480 quals = filter (isQual . fst) rdr_names_w_loc
482 checkDupNames doc_str rdr_names_w_loc
483 = -- Check for duplicated names in a binding group
484 mapRn_ (dupNamesErr doc_str) dups
486 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
490 %************************************************************************
492 \subsection{GlobalRdrEnv}
494 %************************************************************************
497 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
498 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
500 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> (Name,Provenance) -> GlobalRdrEnv
501 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
503 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
504 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
506 combine_globals :: [(Name,Provenance)] -- Old
507 -> [(Name,Provenance)] -- New
508 -> [(Name,Provenance)]
509 combine_globals ns_old ns_new -- ns_new is often short
510 = foldr add ns_old ns_new
512 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
515 choose n m | n `beats` m = n
518 (n,pn) `beats` (m,pm) = n==m && pn `hasBetterProv` pm
520 is_duplicate :: (Name,Provenance) -> (Name,Provenance) -> Bool
521 is_duplicate (n1,LocalDef) (n2,LocalDef) = False
522 is_duplicate (n1,_) (n2,_) = n1 == n2
525 We treat two bindings of a locally-defined name as a duplicate,
526 because they might be two separate, local defns and we want to report
527 and error for that, {\em not} eliminate a duplicate.
529 On the other hand, if you import the same name from two different
530 import statements, we {\em do} want to eliminate the duplicate, not report
533 If a module imports itself then there might be a local defn and an imported
534 defn of the same name; in this case the names will compare as equal, but
535 will still have different provenances.
538 @unQualInScope@ returns a function that takes a @Name@ and tells whether
539 its unqualified name is in scope. This is put as a boolean flag in
540 the @Name@'s provenance to guide whether or not to print the name qualified
544 unQualInScope :: GlobalRdrEnv -> Name -> Bool
548 lookup name = case lookupRdrEnv env (mkRdrUnqual (nameOccName name)) of
549 Just [(name',_)] -> name == name'
554 %************************************************************************
558 %************************************************************************
561 plusAvail (Avail n1) (Avail n2) = Avail n1
562 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
565 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
568 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
569 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
571 emptyAvailEnv = emptyNameEnv
572 unitAvailEnv :: AvailInfo -> AvailEnv
573 unitAvailEnv a = unitNameEnv (availName a) a
575 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
576 plusAvailEnv = plusNameEnv_C plusAvail
578 availEnvElts = nameEnvElts
580 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
581 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
583 availsToNameSet :: [AvailInfo] -> NameSet
584 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
586 availName :: GenAvailInfo name -> name
587 availName (Avail n) = n
588 availName (AvailTC n _) = n
590 availNames :: GenAvailInfo name -> [name]
591 availNames (Avail n) = [n]
592 availNames (AvailTC n ns) = ns
594 -------------------------------------
595 addSysAvails :: AvailInfo -> [Name] -> AvailInfo
596 addSysAvails avail [] = avail
597 addSysAvails (AvailTC n ns) sys = AvailTC n (sys ++ ns)
599 -------------------------------------
600 filterAvail :: RdrNameIE -- Wanted
601 -> AvailInfo -- Available
602 -> Maybe AvailInfo -- Resulting available;
603 -- Nothing if (any of the) wanted stuff isn't there
605 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
606 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
607 | otherwise = Nothing
609 is_wanted name = nameOccName name `elem` wanted_occs
610 sub_names_ok = all (`elem` avail_occs) wanted_occs
611 avail_occs = map nameOccName ns
612 wanted_occs = map rdrNameOcc (want:wants)
614 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
617 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
619 filterAvail (IEVar _) avail@(Avail n) = Just avail
620 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
622 wanted n = nameOccName n == occ
624 -- The second equation happens if we import a class op, thus
626 -- where op is a class operation
628 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
629 -- We don't complain even if the IE says T(..), but
630 -- no constrs/class ops of T are available
631 -- Instead that's caught with a warning by the caller
633 filterAvail ie avail = Nothing
635 -------------------------------------
636 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
637 -- Group by module and sort by occurrence
638 -- This keeps the list in canonical order
639 groupAvails this_mod avails
640 = [ (mkSysModuleNameFS fs, sortLt lt avails)
641 | (fs,avails) <- fmToList groupFM
644 groupFM :: FiniteMap FastString Avails
645 -- Deliberately use the FastString so we
646 -- get a canonical ordering
647 groupFM = foldl add emptyFM avails
649 add env avail = addToFM_C combine env mod_fs [avail']
651 mod_fs = moduleNameFS (moduleName avail_mod)
652 avail_mod = case nameModule_maybe (availName avail) of
655 combine old _ = avail':old
656 avail' = sortAvail avail
658 a1 `lt` a2 = occ1 < occ2
660 occ1 = nameOccName (availName a1)
661 occ2 = nameOccName (availName a2)
663 sortAvail :: AvailInfo -> AvailInfo
664 -- Sort the sub-names into canonical order.
665 -- The canonical order has the "main name" at the beginning
666 -- (if it's there at all)
667 sortAvail (Avail n) = Avail n
668 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
669 | otherwise = AvailTC n ( sortLt lt ns)
671 n1 `lt` n2 = nameOccName n1 < nameOccName n2
675 %************************************************************************
677 \subsection{Free variable manipulation}
679 %************************************************************************
683 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
685 (ys, fvs_s) = unzip stuff
687 returnRn (ys, plusFVs fvs_s)
691 %************************************************************************
693 \subsection{Envt utility functions}
695 %************************************************************************
698 warnUnusedModules :: [ModuleName] -> RnM d ()
699 warnUnusedModules mods
700 = doptRn Opt_WarnUnusedImports `thenRn` \ warn ->
701 if warn then mapRn_ (addWarnRn . unused_mod) mods
704 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
705 text "is imported, but nothing from it is used",
706 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
709 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
710 warnUnusedImports names
711 = doptRn Opt_WarnUnusedImports `thenRn` \ warn ->
712 if warn then warnUnusedBinds names else returnRn ()
714 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
715 warnUnusedLocalBinds names
716 = doptRn Opt_WarnUnusedBinds `thenRn` \ warn ->
717 if warn then warnUnusedBinds [(n,LocalDef) | n<-names]
720 warnUnusedMatches names
721 = doptRn Opt_WarnUnusedMatches `thenRn` \ warn ->
722 if warn then warnUnusedGroup [(n,LocalDef) | n<-names]
725 -------------------------
727 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
728 warnUnusedBinds names
729 = mapRn_ warnUnusedGroup groups
731 -- Group by provenance
732 groups = equivClasses cmp names
733 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
736 -------------------------
738 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
739 warnUnusedGroup names
740 | null filtered_names = returnRn ()
741 | not is_local = returnRn ()
743 = pushSrcLocRn def_loc $
745 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
747 filtered_names = filter reportable names
748 (name1, prov1) = head filtered_names
749 (is_local, def_loc, msg)
751 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
753 NonLocalDef (UserImport mod loc _) _
754 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
756 reportable (name,_) = case occNameUserString (nameOccName name) of
759 -- Haskell 98 encourages compilers to suppress warnings about
760 -- unused names in a pattern if they start with "_".
764 addNameClashErrRn rdr_name (np1:nps)
765 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
766 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
768 msg1 = ptext SLIT("either") <+> mk_ref np1
769 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
770 mk_ref (name,prov) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
772 fixityClashErr (rdr_name, ((_,how_in_scope1), (_, how_in_scope2)))
773 = hang (hsep [ptext SLIT("Conflicting fixities for"), quotes (ppr rdr_name)])
774 4 (vcat [ppr how_in_scope1,
777 shadowedNameWarn shadow
778 = hsep [ptext SLIT("This binding for"),
780 ptext SLIT("shadows an existing binding")]
783 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
785 flavour = occNameFlavour (rdrNameOcc name)
787 qualNameErr descriptor (name,loc)
789 addErrRn (hsep [ ptext SLIT("Invalid use of qualified name"),
794 dupNamesErr descriptor ((name,loc) : dup_things)
796 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
798 (ptext SLIT("in") <+> descriptor))