2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[RnEnv]{Environment manipulation for the renamer monad}
7 module RnEnv where -- Export everything
9 #include "HsVersions.h"
11 import CmdLineOpts ( opt_WarnNameShadowing, opt_WarnUnusedMatches,
12 opt_WarnUnusedBinds, opt_WarnUnusedImports )
14 import RdrHsSyn ( RdrName(..), RdrNameIE,
15 rdrNameOcc, isQual, qual, isClassDataConRdrName
17 import HsTypes ( getTyVarName, replaceTyVarName )
18 import BasicTypes ( Fixity(..), FixityDirection(..), IfaceFlavour(..) )
20 import ErrUtils ( ErrMsg )
21 import Name ( Name, OccName(..), Provenance(..), ExportFlag(..), NamedThing(..),
22 occNameFlavour, getSrcLoc, occNameString,
23 NameSet, emptyNameSet, addListToNameSet, nameSetToList,
24 mkLocalName, mkGlobalName, modAndOcc,
25 nameOccName, setNameProvenance, isVarOcc, getNameProvenance,
26 pprOccName, isLocalName
28 import TyCon ( TyCon )
29 import TysWiredIn ( tupleTyCon, listTyCon, charTyCon )
31 import Unique ( Unique, Uniquable(..), unboundKey )
32 import UniqFM ( listToUFM, plusUFM_C )
34 import SrcLoc ( SrcLoc, noSrcLoc )
36 import Util ( removeDups )
38 import Char ( isAlphanum )
43 %*********************************************************
45 \subsection{Making new names}
47 %*********************************************************
50 newImportedGlobalName :: Module -> OccName
53 newImportedGlobalName mod occ hif
54 = -- First check the cache
55 getNameSupplyRn `thenRn` \ (us, inst_ns, cache) ->
58 prov = NonLocalDef noSrcLoc hif False
60 case lookupFM cache key of
62 -- A hit in the cache!
63 -- If it has no provenance at the moment then set its provenance
64 -- so that it has the right HiFlag component.
66 -- for known-key things. For example, GHCmain.lhs imports as SOURCE
67 -- Main; but Main.main is a known-key thing.)
68 -- Don't fiddle with the provenance if it already has one
69 Just name -> case getNameProvenance name of
71 new_name = setNameProvenance name prov
72 new_cache = addToFM cache key new_name
74 setNameSupplyRn (us, inst_ns, new_cache) `thenRn_`
76 other -> returnRn name
78 Nothing -> -- Miss in the cache!
79 -- Build a new original name, and put it in the cache
81 (us', us1) = splitUniqSupply us
83 name = mkGlobalName uniq mod occ prov
84 new_cache = addToFM cache key name
86 setNameSupplyRn (us', inst_ns, new_cache) `thenRn_`
91 pprC ((mod,occ),name) = pprModule mod <> text "." <> pprOccName occ <+> text "--->"
94 pprTrace "ng" (vcat [text "newGlobalName miss" <+> pprModule mod <+> pprOccName occ,
95 brackets (sep (map pprC (fmToList cache))),
101 newLocallyDefinedGlobalName :: Module -> OccName
102 -> (Name -> ExportFlag) -> SrcLoc
104 newLocallyDefinedGlobalName mod occ rec_exp_fn loc
105 = -- First check the cache
106 getNameSupplyRn `thenRn` \ (us, inst_ns, cache) ->
110 case lookupFM cache key of
112 -- A hit in the cache!
113 -- Overwrite whatever provenance is in the cache already;
114 -- this updates WiredIn things and known-key things,
115 -- which are there from the start, to LocalDef.
117 new_name = setNameProvenance name (LocalDef loc (rec_exp_fn new_name))
118 new_cache = addToFM cache key new_name
120 setNameSupplyRn (us, inst_ns, new_cache) `thenRn_`
123 -- Miss in the cache!
124 -- Build a new original name, and put it in the cache
126 provenance = LocalDef loc (rec_exp_fn new_name)
127 (us', us1) = splitUniqSupply us
129 new_name = mkGlobalName uniq mod occ provenance
130 new_cache = addToFM cache key new_name
132 setNameSupplyRn (us', inst_ns, new_cache) `thenRn_`
136 -- newDfunName is a variant, specially for dfuns.
137 -- When renaming derived definitions we are in *interface* mode (because we can trip
138 -- over original names), but we still want to make the Dfun locally-defined.
139 -- So we can't use whether or not we're in source mode to decide the locally-defined question.
140 newDfunName :: OccName -> OccName -> Maybe RdrName -> SrcLoc -> RnMS s Name
141 newDfunName _ _ (Just n) src_loc -- Imported ones have "Just n"
142 = getModuleRn `thenRn` \ mod_name ->
143 newImportedGlobalName mod_name (rdrNameOcc n) HiFile {- Correct? -}
144 newDfunName cl_nm tycon_nm Nothing src_loc -- Local instance decls have a "Nothing"
145 = getModuleRn `thenRn` \ mod_name ->
146 newInstUniq name `thenRn` \ inst_uniq ->
148 dfun_occ = VarOcc (_PK_ ("$d" ++ (_UNPK_ name) ++ show inst_uniq))
150 newLocallyDefinedGlobalName mod_name dfun_occ
151 (\_ -> Exported) src_loc
154 Dictionary names have the following form
158 where "n" is a positive number, and "tycon" is the
159 name of the type constructor for which a "class"
162 Prefixing dictionary names with their class and instance
163 types improves the behaviour of the recompilation checker.
164 (fewer recompilations required should an instance or type
165 declaration be added to a module.)
167 -- We're dropping the modids on purpose.
168 tycon_nm_str = occNameString tycon_nm
169 cl_nm_str = occNameString cl_nm
171 -- give up on any type constructor that starts with a
172 -- non-alphanumeric char (e.g., [] (,*)
174 | (_NULL_ tycon_nm_str) || not (isAlphanum (_HEAD_ (tycon_nm_str))) = cl_nm_str
175 | otherwise = cl_nm_str _APPEND_ tycon_nm_str
178 newLocalNames :: [(RdrName,SrcLoc)] -> RnM s d [Name]
179 newLocalNames rdr_names
180 = getNameSupplyRn `thenRn` \ (us, inst_ns, cache) ->
183 (us', us1) = splitUniqSupply us
184 uniqs = getUniques n us1
185 locals = [ mkLocalName uniq (rdrNameOcc rdr_name) loc
186 | ((rdr_name,loc), uniq) <- rdr_names `zip` uniqs
189 setNameSupplyRn (us', inst_ns, cache) `thenRn_`
192 -- mkUnboundName makes a place-holder Name; it shouldn't be looked at except possibly
193 -- during compiler debugging.
194 mkUnboundName :: RdrName -> Name
195 mkUnboundName rdr_name = mkLocalName unboundKey (rdrNameOcc rdr_name) noSrcLoc
197 isUnboundName :: Name -> Bool
198 isUnboundName name = uniqueOf name == unboundKey
202 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
203 -> [(RdrName,SrcLoc)]
204 -> ([Name] -> RnMS s a)
206 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
207 = checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
209 getLocalNameEnv `thenRn` \ name_env ->
210 (if opt_WarnNameShadowing
212 mapRn (check_shadow name_env) rdr_names_w_loc
217 newLocalNames rdr_names_w_loc `thenRn` \ names ->
219 new_name_env = addListToFM name_env (map fst rdr_names_w_loc `zip` names)
221 setLocalNameEnv new_name_env (enclosed_scope names)
223 check_shadow name_env (rdr_name,loc)
224 = case lookupFM name_env rdr_name of
225 Nothing -> returnRn ()
226 Just name -> pushSrcLocRn loc $
227 addWarnRn (shadowedNameWarn rdr_name)
229 bindLocalsRn doc_str rdr_names enclosed_scope
230 = getSrcLocRn `thenRn` \ loc ->
231 bindLocatedLocalsRn (text doc_str)
232 (rdr_names `zip` repeat loc)
235 bindTyVarsRn doc_str tyvar_names enclosed_scope
236 = getSrcLocRn `thenRn` \ loc ->
238 located_tyvars = [(getTyVarName tv, loc) | tv <- tyvar_names]
240 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
241 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
243 -- Works in any variant of the renamer monad
244 checkDupOrQualNames, checkDupNames :: SDoc
245 -> [(RdrName, SrcLoc)]
248 checkDupOrQualNames doc_str rdr_names_w_loc
249 = -- Check for use of qualified names
250 mapRn (qualNameErr doc_str) quals `thenRn_`
251 checkDupNames doc_str rdr_names_w_loc
253 quals = filter (isQual.fst) rdr_names_w_loc
255 checkDupNames doc_str rdr_names_w_loc
256 = -- Check for dupicated names in a binding group
257 mapRn (dupNamesErr doc_str) dups `thenRn_`
260 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
264 ifaceFlavour name = case getNameProvenance name of
265 NonLocalDef _ hif _ -> hif
266 other -> HiFile -- Shouldn't happen
270 %*********************************************************
272 \subsection{Looking up names}
274 %*********************************************************
276 Looking up a name in the RnEnv.
279 lookupRn :: NameEnv -> RdrName -> RnMS s Name
280 lookupRn name_env rdr_name
281 = case lookupFM name_env rdr_name of
284 Just name -> returnRn name
287 Nothing -> getModeRn `thenRn` \ mode ->
289 -- Not found when processing source code; so fail
290 SourceMode -> failWithRn (mkUnboundName rdr_name)
291 (unknownNameErr rdr_name)
293 -- Not found when processing an imported declaration,
294 -- so we create a new name for the purpose
298 Qual mod_name occ hif -> newGlobalName mod_name occ hif
300 -- An Unqual is allowed; interface files contain
301 -- unqualified names for locally-defined things, such as
302 -- constructors of a data type.
303 Unqual occ -> getModuleRn `thenRn ` \ mod_name ->
304 newGlobalName mod_name occ HiFile
307 lookupBndrRn rdr_name
308 = getNameEnv `thenRn` \ name_env ->
309 lookupRn name_env rdr_name
311 -- Just like lookupRn except that we record the occurrence too
312 -- Perhaps surprisingly, even wired-in names are recorded.
313 -- Why? So that we know which wired-in names are referred to when
314 -- deciding which instance declarations to import.
315 lookupOccRn :: RdrName -> RnMS s Name
317 = getNameEnv `thenRn` \ name_env ->
318 lookupRn name_env rdr_name `thenRn` \ name ->
319 addOccurrenceName name
321 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
322 -- environment. It's used for record field names only.
323 lookupGlobalOccRn :: RdrName -> RnMS s Name
324 lookupGlobalOccRn rdr_name
325 = getGlobalNameEnv `thenRn` \ name_env ->
326 lookupRn name_env rdr_name `thenRn` \ name ->
327 addOccurrenceName name
330 -- mungePrintUnqual is used to make *imported* *occurrences* print unqualified
331 -- if they were mentioned unqualified in the source code.
332 -- This improves error messages from the type checker.
333 -- NB: the binding site is treated differently; see lookupBndrRn
334 -- After the type checker all occurrences are replaced by the one
335 -- at the binding site.
336 mungePrintUnqual (Qual _ _ _) name = name
337 mungePrintUnqual (Unqual _) name = case new_prov of
339 Just prov' -> setNameProvenance name prov'
341 new_prov = case getNameProvenance name of
342 NonLocalDef loc hif False -> Just (NonLocalDef loc hif True)
345 -- lookupImplicitOccRn takes an RdrName representing an *original* name, and
346 -- adds it to the occurrence pool so that it'll be loaded later. This is
347 -- used when language constructs (such as monad comprehensions, overloaded literals,
348 -- or deriving clauses) require some stuff to be loaded that isn't explicitly
349 -- mentioned in the code.
351 -- This doesn't apply in interface mode, where everything is explicit, but
352 -- we don't check for this case: it does no harm to record an "extra" occurrence
353 -- and lookupImplicitOccRn isn't used much in interface mode (it's only the
354 -- Nothing clause of rnDerivs that calls it at all I think).
355 -- [Jan 98: this comment is wrong: rnHsType uses it quite a bit.]
357 -- For List and Tuple types it's important to get the correct
358 -- isLocallyDefined flag, which is used in turn when deciding
359 -- whether there are any instance decls in this module are "special".
360 -- The name cache should have the correct provenance, though.
362 lookupImplicitOccRn :: RdrName -> RnMS s Name
363 lookupImplicitOccRn (Qual mod occ hif)
364 = newImportedGlobalName mod occ hif `thenRn` \ name ->
365 addOccurrenceName name
367 addImplicitOccRn :: Name -> RnMS s Name
368 addImplicitOccRn name = addOccurrenceName name
370 addImplicitOccsRn :: [Name] -> RnMS s ()
371 addImplicitOccsRn names = addOccurrenceNames names
373 listType_RDR = qual (modAndOcc listType_name)
374 tupleType_RDR n = qual (modAndOcc (tupleType_name n))
376 charType_name = getName charTyCon
377 listType_name = getName listTyCon
378 tupleType_name n = getName (tupleTyCon n)
382 lookupFixity :: RdrName -> RnMS s Fixity
383 lookupFixity rdr_name
384 = getFixityEnv `thenRn` \ fixity_env ->
385 returnRn (lookupFixityEnv fixity_env rdr_name)
388 mkImportFn returns a function that takes a Name and tells whether
389 its unqualified name is in scope. This is put as a boolean flag in
390 the Name's provenance to guide whether or not to print the name qualified
394 mkImportFn :: RnEnv -> Name -> Bool
395 mkImportFn (RnEnv env _)
398 lookup name = case lookupFM env (Unqual (nameOccName name)) of
399 Just (name', _) -> name == name'
403 %************************************************************************
405 \subsection{Envt utility functions}
407 %************************************************************************
409 =============== RnEnv ================
411 plusRnEnv (RnEnv n1 f1) (RnEnv n2 f2)
412 = plusGlobalNameEnvRn n1 n2 `thenRn` \ n ->
413 plusFixityEnvRn f1 f2 `thenRn` \ f ->
418 =============== NameEnv ================
420 plusGlobalNameEnvRn :: GlobalNameEnv -> GlobalNameEnv -> RnM s d GlobalNameEnv
421 plusGlobalNameEnvRn env1 env2
422 = mapRn addNameClashErrRn (conflictsFM conflicting_name env1 env2) `thenRn_`
423 returnRn (env1 `plusFM` env2)
425 addOneToGlobalNameEnv :: GlobalNameEnv -> RdrName -> (Name, HowInScope) -> RnM s d GlobalNameEnv
426 addOneToGlobalNameEnv env rdr_name name
427 = case lookupFM env rdr_name of
428 Just name2 | conflicting_name name name2
429 -> addNameClashErrRn (rdr_name, (name, name2)) `thenRn_`
432 other -> returnRn (addToFM env rdr_name name)
434 delOneFromGlobalNameEnv :: GlobalNameEnv -> RdrName -> GlobalNameEnv
435 delOneFromGlobalNameEnv env rdr_name = delFromFM env rdr_name
437 conflicting_name :: (Name, HowInScope) -> (Name, HowInScope) -> Bool
438 conflicting_name (n1, FromLocalDefn _) (n2, FromLocalDefn _) = True
439 conflicting_name (n1,h1) (n2,h2) = n1 /= n2
440 -- We complain of a conflict if one RdrName maps to two different Names,
441 -- OR if one RdrName maps to the same *locally-defined* Name. The latter
442 -- case is to catch two separate, local definitions of the same thing.
444 -- If a module imports itself then there might be a local defn and an imported
445 -- defn of the same name; in this case the names will compare as equal, but
446 -- will still have different HowInScope fields
448 lookupNameEnv :: NameEnv -> RdrName -> Maybe Name
449 lookupNameEnv = lookupFM
452 =============== FixityEnv ================
454 plusFixityEnvRn f1 f2
455 = mapRn (addErrRn.fixityClashErr) (conflictsFM bad_fix f1 f2) `thenRn_`
456 returnRn (f1 `plusFM` f2)
458 addOneToFixityEnv env rdr_name fixity = addToFM env rdr_name fixity
460 lookupFixityEnv env rdr_name
461 = case lookupFM env rdr_name of
462 Just (fixity,_) -> fixity
463 Nothing -> Fixity 9 InfixL -- Default case
465 bad_fix :: (Fixity, HowInScope) -> (Fixity, HowInScope) -> Bool
466 bad_fix (f1,_) (f2,_) = f1 /= f2
468 pprFixityProvenance :: (Fixity, HowInScope) -> SDoc
469 pprFixityProvenance (fixity, how_in_scope) = ppr how_in_scope
474 =============== ExportAvails ================
476 mkExportAvails :: Module -> Bool -> GlobalNameEnv -> [AvailInfo] -> ExportAvails
477 mkExportAvails mod_name unqual_imp name_env avails
478 = (mod_avail_env, entity_avail_env)
480 mod_avail_env = unitFM mod_name unqual_avails
482 -- unqual_avails is the Avails that are visible in *unqualfied* form
483 -- (1.4 Report, Section 5.1.1)
485 -- import T hiding( f )
486 -- we delete f from avails
488 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
489 | otherwise = [prune avail | avail <- avails]
491 prune (Avail n) | unqual_in_scope n = Avail n
492 prune (Avail n) | otherwise = NotAvailable
493 prune (AvailTC n ns) = AvailTC n (filter unqual_in_scope ns)
495 unqual_in_scope n = Unqual (nameOccName n) `elemFM` name_env
497 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
498 name <- availEntityNames avail]
500 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
501 plusExportAvails (m1, e1) (m2, e2)
502 = (plusFM_C (++) m1 m2, plusUFM_C plusAvail e1 e2)
506 =============== AvailInfo ================
508 plusAvail (Avail n1) (Avail n2) = Avail n1
509 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n1 (nub (ns1 ++ ns2))
510 plusAvail a NotAvailable = a
511 plusAvail NotAvailable a = a
514 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [pprAvail a1,pprAvail a2])
517 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
518 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
520 availsToNameSet :: [AvailInfo] -> NameSet
521 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
523 availName :: AvailInfo -> Name
524 availName (Avail n) = n
525 availName (AvailTC n _) = n
527 availNames :: AvailInfo -> [Name]
528 availNames NotAvailable = []
529 availNames (Avail n) = [n]
530 availNames (AvailTC n ns) = ns
532 -- availEntityNames is used to extract the names that can appear on their own in
533 -- an export or import list. For class decls, class methods can appear on their
534 -- own, thus import A( op )
535 -- but constructors cannot; thus
537 -- means import type T from B, not constructor T.
539 availEntityNames :: AvailInfo -> [Name]
540 availEntityNames NotAvailable = []
541 availEntityNames (Avail n) = [n]
542 availEntityNames (AvailTC n ns) = n : filter (isVarOcc . nameOccName) ns
544 filterAvail :: RdrNameIE -- Wanted
545 -> AvailInfo -- Available
546 -> AvailInfo -- Resulting available;
547 -- NotAvailable if wanted stuff isn't there
549 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
550 | sub_names_ok = AvailTC n (filter is_wanted ns)
553 pprTrace "filterAvail" (hsep [ppr ie, pprAvail avail]) $
557 is_wanted name = nameOccName name `elem` wanted_occs
558 sub_names_ok = all (`elem` avail_occs) wanted_occs
559 avail_occs = map nameOccName ns
560 wanted_occs = map rdrNameOcc (want:wants)
562 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
565 filterAvail (IEThingAbs _) avail@(Avail n) = avail -- Type synonyms
567 filterAvail (IEVar _) avail@(Avail n) = avail
568 filterAvail (IEVar v) avail@(AvailTC n ns) = AvailTC n (filter wanted ns)
570 wanted n = nameOccName n == occ
572 -- The second equation happens if we import a class op, thus
574 -- where op is a class operation
576 filterAvail (IEThingAll _) avail@(AvailTC _ _) = avail
578 filterAvail ie avail = NotAvailable
581 -- In interfaces, pprAvail gets given the OccName of the "host" thing
582 pprAvail avail = getPprStyle $ \ sty ->
583 if ifaceStyle sty then
584 ppr_avail (pprOccName . nameOccName) avail
588 ppr_avail pp_name NotAvailable = ptext SLIT("NotAvailable")
589 ppr_avail pp_name (AvailTC n ns) = hsep [
591 parens $ hsep $ punctuate comma $
594 ppr_avail pp_name (Avail n) = pp_name n
600 %************************************************************************
602 \subsection{Finite map utilities}
604 %************************************************************************
607 Generally useful function on finite maps to check for overlap.
611 => (b->b->Bool) -- False <=> no conflict; you can pick either
612 -> FiniteMap a b -> FiniteMap a b
614 conflictsFM bad fm1 fm2
615 = filter (\(a,(b1,b2)) -> bad b1 b2)
616 (fmToList (intersectFM_C (\b1 b2 -> (b1,b2)) fm1 fm2))
620 -> FiniteMap a b -> a -> b
622 conflictFM bad fm key elt
623 = case lookupFM fm key of
624 Just elt' | bad elt elt' -> Just (key,(elt,elt'))
629 %************************************************************************
631 \subsection{Envt utility functions}
633 %************************************************************************
637 warnUnusedBinds, warnUnusedMatches, warnUnusedImports :: NameSet -> RnM s d ()
639 warnUnusedBinds names
640 | opt_WarnUnusedBinds = warnUnusedNames names
641 | otherwise = returnRn ()
643 warnUnusedMatches names
644 | opt_WarnUnusedMatches = warnUnusedNames names
645 | otherwise = returnRn ()
647 warnUnusedImports names
648 | opt_WarnUnusedImports = warnUnusedNames names
649 | otherwise = returnRn ()
651 warnUnusedNames :: NameSet -> RnM s d ()
652 warnUnusedNames names
653 = mapRn warn (nameSetToList names) `thenRn_`
656 warn name = pushSrcLocRn (getSrcLoc name) $
657 addWarnRn (unusedNameWarn name)
659 unusedNameWarn name = quotes (ppr name) <+> ptext SLIT("is bound but not used")
661 addNameClashErrRn (rdr_name, ((_,how_in_scope1), (_, how_in_scope2)))
662 | isClassDataConRdrName rdr_name
663 -- Nasty hack to prevent error messages complain about conflicts for ":C",
664 -- where "C" is a class. There'll be a message about C, and :C isn't
665 -- the programmer's business. There may be a better way to filter this
666 -- out, but I couldn't get up the energy to find it.
670 = addErrRn (hang (hsep [ptext SLIT("Conflicting definitions for"), quotes (ppr rdr_name)])
671 4 (vcat [ppr how_in_scope1,
674 fixityClashErr (rdr_name, ((_,how_in_scope1), (_, how_in_scope2)))
675 = hang (hsep [ptext SLIT("Conflicting fixities for"), quotes (ppr rdr_name)])
676 4 (vcat [ppr how_in_scope1,
679 shadowedNameWarn shadow
680 = hcat [ptext SLIT("This binding for"),
682 ptext SLIT("shadows an existing binding")]
685 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
687 flavour = occNameFlavour (rdrNameOcc name)
689 qualNameErr descriptor (name,loc)
691 addErrRn (hsep [ ptext SLIT("Invalid use of qualified name"),
696 dupNamesErr descriptor ((name,loc) : dup_things)
698 addErrRn (hsep [ptext SLIT("Conflicting definitions for"),
700 ptext SLIT("in"), descriptor])