2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 getGlobalNames, exportsFromAvail
11 #include "HsVersions.h"
13 import CmdLineOpts ( DynFlag(..) )
15 import HsSyn ( HsModule(..), HsDecl(..), IE(..), ieName, ImportDecl(..),
17 collectLocatedHsBinders
19 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl,
20 RdrNameHsModule, RdrNameHsDecl
22 import RnIfaces ( recordLocalSlurps )
23 import RnHiFiles ( getTyClDeclBinders, loadInterface )
28 import PrelNames ( pRELUDE_Name, mAIN_Name, main_RDR_Unqual, isUnboundName )
29 import Module ( ModuleName, moduleName, WhereFrom(..) )
30 import Name ( Name, nameSrcLoc, nameOccName )
33 import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv,
34 GenAvailInfo(..), AvailInfo, Avails, AvailEnv,
35 Deprecations(..), ModIface(..)
37 import RdrName ( rdrNameOcc, setRdrNameOcc )
38 import OccName ( setOccNameSpace, dataName )
39 import NameSet ( elemNameSet, emptyNameSet )
41 import Maybes ( maybeToBool, catMaybes, mapMaybe )
42 import ListSetOps ( removeDups )
43 import Util ( sortLt )
44 import List ( partition )
49 %************************************************************************
51 \subsection{Get global names}
53 %************************************************************************
56 getGlobalNames :: Module -> RdrNameHsModule
57 -> RnMG (GlobalRdrEnv, -- Maps all in-scope things
58 GlobalRdrEnv, -- Maps just *local* things
59 ExportAvails) -- The exported stuff
61 getGlobalNames this_mod (HsModule _ _ _ imports decls _ mod_loc)
62 = -- PROCESS LOCAL DECLS
63 -- Do these *first* so that the correct provenance gets
64 -- into the global name cache.
65 importsFromLocalDecls this_mod decls `thenRn` \ (local_gbl_env, local_mod_avails) ->
67 -- PROCESS IMPORT DECLS
68 -- Do the non {- SOURCE -} ones first, so that we get a helpful
69 -- warning for {- SOURCE -} ones that are unnecessary
70 doptRn Opt_NoImplicitPrelude `thenRn` \ opt_no_prelude ->
72 all_imports = mk_prel_imports opt_no_prelude ++ imports
73 (source, ordinary) = partition is_source_import all_imports
74 is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True
75 is_source_import other = False
77 get_imports = importsFromImportDecl this_mod_name
79 mapAndUnzipRn get_imports ordinary `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
80 mapAndUnzipRn get_imports source `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
83 -- We put the local env second, so that a local provenance
84 -- "wins", even if a module imports itself.
86 gbl_env :: GlobalRdrEnv
87 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
88 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
90 all_avails :: ExportAvails
91 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
95 returnRn (gbl_env, local_gbl_env, all_avails)
97 this_mod_name = moduleName this_mod
99 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
100 -- because the former doesn't even look at Prelude.hi for instance declarations,
101 -- whereas the latter does.
102 mk_prel_imports no_prelude
103 | this_mod_name == pRELUDE_Name ||
104 explicit_prelude_import ||
108 | otherwise = [ImportDecl pRELUDE_Name
110 False {- Not qualified -}
111 Nothing {- No "as" -}
112 Nothing {- No import list -}
115 explicit_prelude_import
116 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
120 importsFromImportDecl :: ModuleName
122 -> RnMG (GlobalRdrEnv,
125 importsFromImportDecl this_mod_name (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
126 = pushSrcLocRn iloc $
128 loadInterface (ppr imp_mod_name <+> ptext SLIT("is directly imported"))
129 imp_mod_name from `thenRn` \ iface ->
131 imp_mod = mi_module iface
132 avails_by_module = mi_exports iface
133 deprecs = mi_deprecs iface
136 avails = [ avail | (mod_name, avails) <- avails_by_module,
137 mod_name /= this_mod_name,
139 -- If the module exports anything defined in this module, just ignore it.
140 -- Reason: otherwise it looks as if there are two local definition sites
141 -- for the thing, and an error gets reported. Easiest thing is just to
142 -- filter them out up front. This situation only arises if a module
143 -- imports itself, or another module that imported it. (Necessarily,
144 -- this invoves a loop.)
146 -- Tiresome consequence: if you say
151 -- module B( AType ) where
152 -- import {-# SOURCE #-} A( AType )
154 -- then you'll get a 'B does not export AType' message. Oh well.
157 if null avails_by_module then
158 -- If there's an error in loadInterface, (e.g. interface
159 -- file not found) we get lots of spurious errors from 'filterImports'
160 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
163 -- Complain if we import a deprecated module
164 ifOptRn Opt_WarnDeprecations (
166 DeprecAll txt -> addWarnRn (moduleDeprec imp_mod_name txt)
170 -- Filter the imports according to the import list
171 filterImports imp_mod_name from import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
174 unqual_imp = not qual_only -- Maybe want unqualified names
175 qual_mod = case as_mod of
176 Nothing -> imp_mod_name
177 Just another_name -> another_name
179 mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
180 gbl_env = mkGlobalRdrEnv qual_mod unqual_imp mk_prov filtered_avails hides deprecs
181 exports = mkExportAvails qual_mod unqual_imp gbl_env filtered_avails
183 returnRn (gbl_env, exports)
188 importsFromLocalDecls this_mod decls
189 = mapRn (getLocalDeclBinders this_mod) decls `thenRn` \ avails_s ->
190 -- The avails that are returned don't include the "system" names
192 avails = concat avails_s
194 all_names :: [Name] -- All the defns; no dups eliminated
195 all_names = [name | avail <- avails, name <- availNames avail]
198 (_, dups) = removeDups compare all_names
200 -- Check for duplicate definitions
201 -- The complaint will come out as "Multiple declarations of Foo.f" because
202 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
203 -- printer returns False. It seems awkward to fix, unfortunately.
204 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
207 -- Record that locally-defined things are available
208 recordLocalSlurps (availsToNameSet avails) `thenRn_`
210 mod_name = moduleName this_mod
211 unqual_imp = True -- Want unqualified names
212 mk_prov n = LocalDef -- Provenance is local
213 hides = [] -- Hide nothing
215 gbl_env = mkGlobalRdrEnv mod_name unqual_imp mk_prov avails hides NoDeprecs
216 -- NoDeprecs: don't complain about locally defined names
217 -- For a start, we may be exporting a deprecated thing
218 -- Also we may use a deprecated thing in the defn of another
219 -- deprecated things. We may even use a deprecated thing in
220 -- the defn of a non-deprecated thing, when changing a module's
223 exports = mkExportAvails mod_name unqual_imp gbl_env avails
225 returnRn (gbl_env, exports)
227 ---------------------------
228 getLocalDeclBinders :: Module -> RdrNameHsDecl -> RnMG [AvailInfo]
229 getLocalDeclBinders mod (TyClD tycl_decl)
230 = -- For type and class decls, we generate Global names, with
231 -- no export indicator. They need to be global because they get
232 -- permanently bound into the TyCons and Classes. They don't need
233 -- an export indicator because they are all implicitly exported.
234 getTyClDeclBinders mod tycl_decl `thenRn` \ (avail, sys_names) ->
236 -- Record that the system names are available
237 recordLocalSlurps (mkNameSet sys_names) `thenRn_`
240 getLocalDeclBinders mod (ValD binds)
241 = mapRn new (collectLocatedHsBinders binds) `thenRn` \ avails ->
244 new (rdr_name, loc) = newTopBinder mod rdr_name loc `thenRn` \ name ->
245 returnRn (Avail name)
247 getLocalDeclBinders mod (ForD (ForeignImport nm _ _ loc))
248 = newTopBinder mod nm loc `thenRn` \ name ->
249 returnRn [Avail name]
250 getLocalDeclBinders mod (ForD _)
253 getLocalDeclBinders mod (FixD _) = returnRn []
254 getLocalDeclBinders mod (DeprecD _) = returnRn []
255 getLocalDeclBinders mod (DefD _) = returnRn []
256 getLocalDeclBinders mod (InstD _) = returnRn []
257 getLocalDeclBinders mod (RuleD _) = returnRn []
261 %************************************************************************
263 \subsection{Filtering imports}
265 %************************************************************************
267 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
268 available, and filters it through the import spec (if any).
271 filterImports :: ModuleName -- The module being imported
272 -> WhereFrom -- Tells whether it's a {-# SOURCE #-} import
273 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
274 -> [AvailInfo] -- What's available
275 -> RnMG ([AvailInfo], -- "chosens"
276 [AvailInfo], -- "hides"
277 -- The true imports are "chosens" - "hides"
278 -- (It's convenient to return both the above sets, because
279 -- the substraction can be done more efficiently when
280 -- building the environment.)
281 NameSet) -- What was imported explicitly
283 -- Complains if import spec mentions things that the module doesn't export
284 -- Warns/informs if import spec contains duplicates.
285 filterImports mod from Nothing imports
286 = returnRn (imports, [], emptyNameSet)
288 filterImports mod from (Just (want_hiding, import_items)) total_avails
289 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
291 (item_avails, explicits_s) = unzip avails_w_explicits
292 explicits = foldl addListToNameSet emptyNameSet explicits_s
296 -- All imported; item_avails to be hidden
297 returnRn (total_avails, item_avails, emptyNameSet)
299 -- Just item_avails imported; nothing to be hidden
300 returnRn (item_avails, [], explicits)
302 import_fm :: FiniteMap OccName AvailInfo
303 import_fm = listToFM [ (nameOccName name, avail)
304 | avail <- total_avails,
305 name <- availNames avail]
306 -- Even though availNames returns data constructors too,
307 -- they won't make any difference because naked entities like T
308 -- in an import list map to TcOccs, not VarOccs.
310 bale_out item = addErrRn (badImportItemErr mod from item) `thenRn_`
313 get_item :: RdrNameIE -> RnMG [(AvailInfo, [Name])]
314 get_item item@(IEModuleContents _) = bale_out item
316 get_item item@(IEThingAll _)
317 = case check_item item of
318 Nothing -> bale_out item
319 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
320 -- only export T abstractly. The single [n]
321 -- in the AvailTC is the type or class itself
322 ifOptRn Opt_WarnMisc (addWarnRn (dodgyImportWarn mod item)) `thenRn_`
323 returnRn [(avail, [availName avail])]
324 Just avail -> returnRn [(avail, [availName avail])]
326 get_item item@(IEThingAbs n)
327 | want_hiding -- hiding( C )
328 -- Here the 'C' can be a data constructor *or* a type/class
329 = case catMaybes [check_item item, check_item (IEVar data_n)] of
331 avails -> returnRn [(a, []) | a <- avails]
332 -- The 'explicits' list is irrelevant when hiding
334 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
337 = case check_item item of
338 Nothing -> bale_out item
339 Just avail -> returnRn [(avail, availNames avail)]
342 | not (maybeToBool maybe_in_import_avails) ||
343 not (maybeToBool maybe_filtered_avail)
347 = Just filtered_avail
350 wanted_occ = rdrNameOcc (ieName item)
351 maybe_in_import_avails = lookupFM import_fm wanted_occ
353 Just avail = maybe_in_import_avails
354 maybe_filtered_avail = filterAvail item avail
355 Just filtered_avail = maybe_filtered_avail
360 %************************************************************************
362 \subsection{Qualifiying imports}
364 %************************************************************************
367 mkEmptyExportAvails :: ModuleName -> ExportAvails
368 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyNameEnv)
370 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
371 mkExportAvails mod_name unqual_imp gbl_env avails
372 = (mod_avail_env, entity_avail_env)
374 mod_avail_env = unitFM mod_name unqual_avails
376 -- unqual_avails is the Avails that are visible in *unqualfied* form
377 -- (1.4 Report, Section 5.1.1)
379 -- import T hiding( f )
380 -- we delete f from avails
382 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
383 | otherwise = mapMaybe prune avails
385 prune (Avail n) | unqual_in_scope n = Just (Avail n)
386 prune (Avail n) | otherwise = Nothing
387 prune (AvailTC n ns) | null uqs = Nothing
388 | otherwise = Just (AvailTC n uqs)
390 uqs = filter unqual_in_scope ns
392 unqual_in_scope n = unQualInScope gbl_env n
394 entity_avail_env = mkNameEnv [ (name,avail) | avail <- avails,
395 name <- availNames avail]
397 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
398 plusExportAvails (m1, e1) (m2, e2)
399 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
400 -- ToDo: wasteful: we do this once for each constructor!
404 %************************************************************************
406 \subsection{Export list processing}
408 %************************************************************************
410 Processing the export list.
412 You might think that we should record things that appear in the export list
413 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
414 We do check (here) that they are in scope,
415 but there is no need to slurp in their actual declaration
416 (which is what @addOccurrenceName@ forces).
418 Indeed, doing so would big trouble when
419 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
420 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
423 type ExportAccum -- The type of the accumulating parameter of
424 -- the main worker function in exportsFromAvail
425 = ([ModuleName], -- 'module M's seen so far
426 ExportOccMap, -- Tracks exported occurrence names
427 AvailEnv) -- The accumulated exported stuff, kept in an env
428 -- so we can common-up related AvailInfos
430 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
431 -- Tracks what a particular exported OccName
432 -- in an export list refers to, and which item
433 -- it came from. It's illegal to export two distinct things
434 -- that have the same occurrence name
437 exportsFromAvail :: ModuleName
438 -> Maybe [RdrNameIE] -- Export spec
442 -- Complains if two distinct exports have same OccName
443 -- Warns about identical exports.
444 -- Complains about exports items not in scope
445 exportsFromAvail this_mod Nothing export_avails global_name_env
446 = exportsFromAvail this_mod true_exports export_avails global_name_env
448 true_exports = Just $ if this_mod == mAIN_Name
449 then [IEVar main_RDR_Unqual]
450 -- export Main.main *only* unless otherwise specified,
451 else [IEModuleContents this_mod]
452 -- but for all other modules export everything.
454 exportsFromAvail this_mod (Just export_items)
455 (mod_avail_env, entity_avail_env)
457 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
458 foldlRn (exports_from_item warn_dup_exports)
459 ([], emptyFM, emptyAvailEnv) export_items
460 `thenRn` \ (_, _, export_avail_map) ->
462 export_avails :: [AvailInfo]
463 export_avails = nameEnvElts export_avail_map
465 returnRn export_avails
468 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
470 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
471 | mod `elem` mods -- Duplicate export of M
472 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
476 = case lookupFM mod_avail_env mod of
477 Nothing -> failWithRn acc (modExportErr mod)
478 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
481 avails' = foldl addAvail avails mod_avails
483 returnRn (mod:mods, occs', avails')
485 exports_from_item warn_dups acc@(mods, occs, avails) ie
486 = lookupSrcName global_name_env (ieName ie) `thenRn` \ name ->
488 -- See what's available in the current environment
489 case lookupNameEnv entity_avail_env name of {
490 Nothing -> -- Presumably this happens because lookupSrcName didn't find
491 -- the name and returned an unboundName, which won't be in
492 -- the entity_avail_env, of course
493 WARN( not (isUnboundName name), ppr name )
498 -- Filter out the bits we want
499 case filterAvail ie avail of {
500 Nothing -> -- Not enough availability
501 failWithRn acc (exportItemErr ie) ;
505 -- Phew! It's OK! Now to check the occurrence stuff!
506 warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
507 check_occs ie occs export_avail `thenRn` \ occs' ->
508 returnRn (mods, occs', addAvail avails export_avail)
513 ok_item (IEThingAll _) (AvailTC _ [n]) = False
514 -- This occurs when you import T(..), but
515 -- only export T abstractly. The single [n]
516 -- in the AvailTC is the type or class itself
519 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
520 check_occs ie occs avail
521 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
522 foldlRn (check warn_dup_exports) occs (availNames avail)
524 check warn_dup occs name
525 = case lookupFM occs name_occ of
526 Nothing -> returnRn (addToFM occs name_occ (name, ie))
528 | name == name' -> -- Duplicate export
530 (dupExportWarn name_occ ie ie')
531 `thenRn_` returnRn occs
533 | otherwise -> -- Same occ name but different names: an error
534 failWithRn occs (exportClashErr name_occ ie ie')
536 name_occ = nameOccName name
539 %************************************************************************
543 %************************************************************************
546 badImportItemErr mod from ie
547 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
548 ptext SLIT("does not export"), quotes (ppr ie)]
550 source_import = case from of
551 ImportByUserSource -> ptext SLIT("(hi-boot interface)")
554 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
555 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
557 dodgyMsg kind item@(IEThingAll tc)
558 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
559 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
560 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
563 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
565 exportItemErr export_item
566 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
567 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
569 exportClashErr occ_name ie1 ie2
570 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
571 ,ptext SLIT("and"), quotes (ppr ie2)
572 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
575 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
576 nest 4 (vcat (map ppr sorted_locs))]
578 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
579 occ'ed_before a b = LT == compare a b
581 dupExportWarn occ_name ie1 ie2
582 = hsep [quotes (ppr occ_name),
583 ptext SLIT("is exported by"), quotes (ppr ie1),
584 ptext SLIT("and"), quotes (ppr ie2)]
587 = hsep [ptext SLIT("Duplicate"),
588 quotes (ptext SLIT("Module") <+> ppr mod),
589 ptext SLIT("in export list")]
592 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),