2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
11 #include "HsVersions.h"
13 import CmdLineOpts ( DynFlag(..) )
15 import HsSyn ( HsModule(..), HsDecl(..), IE(..), ieName, ImportDecl(..),
16 ForeignDecl(..), ForKind(..), isDynamicExtName,
19 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl,
20 RdrNameHsModule, RdrNameHsDecl
22 import RnIfaces ( getInterfaceExports, recordLocalSlurps )
23 import RnHiFiles ( getTyClDeclBinders )
28 import PrelNames ( pRELUDE_Name, mAIN_Name, main_RDR_Unqual, isUnboundName )
29 import UniqFM ( lookupUFM )
30 import Bag ( bagToList )
31 import Module ( ModuleName, moduleName, WhereFrom(..) )
33 import Name ( Name, nameSrcLoc,
34 setLocalNameSort, nameOccName, nameEnvElts )
35 import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv,
36 GenAvailInfo(..), AvailInfo, Avails, AvailEnv )
37 import RdrName ( RdrName, rdrNameOcc, setRdrNameOcc, mkRdrQual, mkRdrUnqual )
38 import OccName ( setOccNameSpace, dataName )
39 import NameSet ( elemNameSet, emptyNameSet )
41 import Maybes ( maybeToBool, catMaybes, mapMaybe )
42 import UniqFM ( emptyUFM, listToUFM )
43 import ListSetOps ( removeDups )
44 import Util ( sortLt )
45 import List ( partition )
50 %************************************************************************
52 \subsection{Get global names}
54 %************************************************************************
57 getGlobalNames :: Module -> RdrNameHsModule
58 -> RnMG (GlobalRdrEnv, -- Maps all in-scope things
59 GlobalRdrEnv, -- Maps just *local* things
60 Avails, -- The exported stuff
61 AvailEnv) -- Maps a name to its parent AvailInfo
62 -- Just for in-scope things only
64 getGlobalNames this_mod (HsModule _ _ exports imports decls _ mod_loc)
65 = -- These two fix-loops are to get the right
66 -- provenance information into a Name
67 fixRn ( \ ~(rec_gbl_env, _, rec_export_avails, _) ->
70 rec_exp_fn :: Name -> Bool
71 rec_exp_fn = mk_export_fn (availsToNameSet rec_export_avails)
74 -- PROCESS LOCAL DECLS
75 -- Do these *first* so that the correct provenance gets
76 -- into the global name cache.
77 importsFromLocalDecls this_mod rec_exp_fn decls `thenRn` \ (local_gbl_env, local_mod_avails) ->
79 -- PROCESS IMPORT DECLS
80 -- Do the non {- SOURCE -} ones first, so that we get a helpful
81 -- warning for {- SOURCE -} ones that are unnecessary
82 doptRn Opt_NoImplicitPrelude `thenRn` \ opt_no_prelude ->
84 all_imports = mk_prel_imports opt_no_prelude ++ imports
85 (source, ordinary) = partition is_source_import all_imports
86 is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True
87 is_source_import other = False
89 get_imports = importsFromImportDecl this_mod_name
91 mapAndUnzipRn get_imports ordinary `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
92 mapAndUnzipRn get_imports source `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
95 -- We put the local env second, so that a local provenance
96 -- "wins", even if a module imports itself.
98 gbl_env :: GlobalRdrEnv
99 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
100 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
102 all_avails :: ExportAvails
103 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
105 (_, global_avail_env) = all_avails
108 -- PROCESS EXPORT LIST (but not if we've had errors already)
109 checkErrsRn `thenRn` \ no_errs_so_far ->
110 (if no_errs_so_far then
111 exportsFromAvail this_mod_name exports all_avails gbl_env
114 ) `thenRn` \ export_avails ->
117 returnRn (gbl_env, local_gbl_env, export_avails, global_avail_env)
120 this_mod_name = moduleName this_mod
122 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
123 -- because the former doesn't even look at Prelude.hi for instance declarations,
124 -- whereas the latter does.
125 mk_prel_imports no_prelude
126 | this_mod_name == pRELUDE_Name ||
127 explicit_prelude_import ||
131 | otherwise = [ImportDecl pRELUDE_Name
133 False {- Not qualified -}
134 Nothing {- No "as" -}
135 Nothing {- No import list -}
138 explicit_prelude_import
139 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
143 importsFromImportDecl :: ModuleName
145 -> RnMG (GlobalRdrEnv,
148 importsFromImportDecl this_mod_name (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
149 = pushSrcLocRn iloc $
150 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails_by_module) ->
152 if null avails_by_module then
153 -- If there's an error in getInterfaceExports, (e.g. interface
154 -- file not found) we get lots of spurious errors from 'filterImports'
155 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
160 avails = [ avail | (mod_name, avails) <- avails_by_module,
161 mod_name /= this_mod_name,
163 -- If the module exports anything defined in this module, just ignore it.
164 -- Reason: otherwise it looks as if there are two local definition sites
165 -- for the thing, and an error gets reported. Easiest thing is just to
166 -- filter them out up front. This situation only arises if a module
167 -- imports itself, or another module that imported it. (Necessarily,
168 -- this invoves a loop.)
170 -- Tiresome consequence: if you say
175 -- module B( AType ) where
176 -- import {-# SOURCE #-} A( AType )
178 -- then you'll get a 'B does not export AType' message. Oh well.
181 filterImports imp_mod_name from import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
184 mk_provenance name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
187 qualifyImports imp_mod_name
188 (not qual_only) -- Maybe want unqualified names
196 importsFromLocalDecls this_mod rec_exp_fn decls
197 = mapRn (getLocalDeclBinders this_mod rec_exp_fn) decls `thenRn` \ avails_s ->
200 avails = concat avails_s
202 all_names :: [Name] -- All the defns; no dups eliminated
203 all_names = [name | avail <- avails, name <- availNames avail]
206 (_, dups) = removeDups compare all_names
208 -- Check for duplicate definitions
209 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
211 -- Record that locally-defined things are available
212 recordLocalSlurps avails `thenRn_`
214 -- Build the environment
215 qualifyImports (moduleName this_mod)
216 True -- Want unqualified names
219 (\n -> LocalDef) -- Provenance is local
222 ---------------------------
223 getLocalDeclBinders :: Module
224 -> (Name -> Bool) -- Whether exported
225 -> RdrNameHsDecl -> RnMG Avails
226 getLocalDeclBinders mod rec_exp_fn (TyClD tycl_decl)
227 = -- For type and class decls, we generate Global names, with
228 -- no export indicator. They need to be global because they get
229 -- permanently bound into the TyCons and Classes. They don't need
230 -- an export indicator because they are all implicitly exported.
231 getTyClDeclBinders mod tycl_decl `thenRn` \ avail ->
234 getLocalDeclBinders mod rec_exp_fn (ValD binds)
235 = mapRn (newLocalBinder mod rec_exp_fn)
236 (bagToList (collectTopBinders binds))
238 getLocalDeclBinders mod rec_exp_fn (ForD (ForeignDecl nm kind _ ext_nm _ loc))
239 | binds_haskell_name kind
240 = newLocalBinder mod rec_exp_fn (nm, loc) `thenRn` \ avail ->
243 | otherwise -- a foreign export
246 binds_haskell_name (FoImport _) = True
247 binds_haskell_name FoLabel = True
248 binds_haskell_name FoExport = isDynamicExtName ext_nm
250 getLocalDeclBinders mod rec_exp_fn (FixD _) = returnRn []
251 getLocalDeclBinders mod rec_exp_fn (DeprecD _) = returnRn []
252 getLocalDeclBinders mod rec_exp_fn (DefD _) = returnRn []
253 getLocalDeclBinders mod rec_exp_fn (InstD _) = returnRn []
254 getLocalDeclBinders mod rec_exp_fn (RuleD _) = returnRn []
256 ---------------------------
257 newLocalBinder mod rec_exp_fn (rdr_name, loc)
258 = -- Generate a local name, and with a suitable export indicator
259 newTopBinder mod rdr_name loc `thenRn` \ name ->
260 returnRn (Avail (setLocalNameSort name (rec_exp_fn name)))
264 %************************************************************************
266 \subsection{Filtering imports}
268 %************************************************************************
270 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
271 available, and filters it through the import spec (if any).
274 filterImports :: ModuleName -- The module being imported
275 -> WhereFrom -- Tells whether it's a {-# SOURCE #-} import
276 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
277 -> [AvailInfo] -- What's available
278 -> RnMG ([AvailInfo], -- What's actually imported
279 [AvailInfo], -- What's to be hidden
280 -- (the unqualified version, that is)
281 -- (We need to return both the above sets, because
282 -- the qualified version is never hidden; so we can't
283 -- implement hiding by reducing what's imported.)
284 NameSet) -- What was imported explicitly
286 -- Complains if import spec mentions things that the module doesn't export
287 -- Warns/informs if import spec contains duplicates.
288 filterImports mod from Nothing imports
289 = returnRn (imports, [], emptyNameSet)
291 filterImports mod from (Just (want_hiding, import_items)) total_avails
292 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
294 (item_avails, explicits_s) = unzip avails_w_explicits
295 explicits = foldl addListToNameSet emptyNameSet explicits_s
299 -- All imported; item_avails to be hidden
300 returnRn (total_avails, item_avails, emptyNameSet)
302 -- Just item_avails imported; nothing to be hidden
303 returnRn (item_avails, [], explicits)
305 import_fm :: FiniteMap OccName AvailInfo
306 import_fm = listToFM [ (nameOccName name, avail)
307 | avail <- total_avails,
308 name <- availNames avail]
309 -- Even though availNames returns data constructors too,
310 -- they won't make any difference because naked entities like T
311 -- in an import list map to TcOccs, not VarOccs.
313 bale_out item = addErrRn (badImportItemErr mod from item) `thenRn_`
316 get_item item@(IEModuleContents _) = bale_out item
318 get_item item@(IEThingAll _)
319 = case check_item item of
320 Nothing -> bale_out item
321 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
322 -- only export T abstractly. The single [n]
323 -- in the AvailTC is the type or class itself
324 addWarnRn (dodgyImportWarn mod item) `thenRn_`
325 returnRn [(avail, [availName avail])]
326 Just avail -> returnRn [(avail, [availName avail])]
328 get_item item@(IEThingAbs n)
329 | want_hiding -- hiding( C )
330 -- Here the 'C' can be a data constructor *or* a type/class
331 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
333 avails -> returnRn [(a, []) | a <- avails]
334 -- The 'explicits' list is irrelevant when hiding
336 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
339 = case check_item item of
340 Nothing -> bale_out item
341 Just avail -> returnRn [(avail, availNames avail)]
344 | not (maybeToBool maybe_in_import_avails) ||
345 not (maybeToBool maybe_filtered_avail)
349 = Just filtered_avail
352 wanted_occ = rdrNameOcc (ieName item)
353 maybe_in_import_avails = lookupFM import_fm wanted_occ
355 Just avail = maybe_in_import_avails
356 maybe_filtered_avail = filterAvail item avail
357 Just filtered_avail = maybe_filtered_avail
362 %************************************************************************
364 \subsection{Qualifiying imports}
366 %************************************************************************
368 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
369 of an import decl, and deals with producing an @RnEnv@ with the
370 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
371 fully fledged @Names@.
374 qualifyImports :: ModuleName -- Imported module
375 -> Bool -- True <=> want unqualified import
376 -> Maybe ModuleName -- Optional "as M" part
377 -> [AvailInfo] -- What's to be hidden
378 -> (Name -> Provenance)
379 -> Avails -- Whats imported and how
380 -> RnMG (GlobalRdrEnv, ExportAvails)
382 qualifyImports this_mod unqual_imp as_mod hides mk_provenance avails
384 -- Make the name environment. We're talking about a
385 -- single module here, so there must be no name clashes.
386 -- In practice there only ever will be if it's the module
389 -- Add the things that are available
390 name_env1 = foldl add_avail emptyRdrEnv avails
392 -- Delete things that are hidden
393 name_env2 = foldl del_avail name_env1 hides
395 -- Create the export-availability info
396 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
398 returnRn (name_env2, export_avails)
401 qual_mod = case as_mod of
403 Just another_name -> another_name
405 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
406 add_avail env avail = foldl add_name env (availNames avail)
412 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) (name,prov)
413 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) (name,prov)
414 occ = nameOccName name
415 prov = mk_provenance name
417 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
419 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
422 mkEmptyExportAvails :: ModuleName -> ExportAvails
423 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
425 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
426 mkExportAvails mod_name unqual_imp name_env avails
427 = (mod_avail_env, entity_avail_env)
429 mod_avail_env = unitFM mod_name unqual_avails
431 -- unqual_avails is the Avails that are visible in *unqualfied* form
432 -- (1.4 Report, Section 5.1.1)
434 -- import T hiding( f )
435 -- we delete f from avails
437 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
438 | otherwise = mapMaybe prune avails
440 prune (Avail n) | unqual_in_scope n = Just (Avail n)
441 prune (Avail n) | otherwise = Nothing
442 prune (AvailTC n ns) | null uqs = Nothing
443 | otherwise = Just (AvailTC n uqs)
445 uqs = filter unqual_in_scope ns
447 unqual_in_scope n = unQualInScope name_env n
449 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
450 name <- availNames avail]
452 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
453 plusExportAvails (m1, e1) (m2, e2)
454 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
455 -- ToDo: wasteful: we do this once for each constructor!
459 %************************************************************************
461 \subsection{Export list processing}
463 %************************************************************************
465 Processing the export list.
467 You might think that we should record things that appear in the export list
468 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
469 We do check (here) that they are in scope,
470 but there is no need to slurp in their actual declaration
471 (which is what @addOccurrenceName@ forces).
473 Indeed, doing so would big trouble when
474 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
475 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
478 type ExportAccum -- The type of the accumulating parameter of
479 -- the main worker function in exportsFromAvail
480 = ([ModuleName], -- 'module M's seen so far
481 ExportOccMap, -- Tracks exported occurrence names
482 AvailEnv) -- The accumulated exported stuff, kept in an env
483 -- so we can common-up related AvailInfos
485 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
486 -- Tracks what a particular exported OccName
487 -- in an export list refers to, and which item
488 -- it came from. It's illegal to export two distinct things
489 -- that have the same occurrence name
492 exportsFromAvail :: ModuleName
493 -> Maybe [RdrNameIE] -- Export spec
497 -- Complains if two distinct exports have same OccName
498 -- Warns about identical exports.
499 -- Complains about exports items not in scope
500 exportsFromAvail this_mod Nothing export_avails global_name_env
501 = exportsFromAvail this_mod true_exports export_avails global_name_env
503 true_exports = Just $ if this_mod == mAIN_Name
504 then [IEVar main_RDR_Unqual]
505 -- export Main.main *only* unless otherwise specified,
506 else [IEModuleContents this_mod]
507 -- but for all other modules export everything.
509 exportsFromAvail this_mod (Just export_items)
510 (mod_avail_env, entity_avail_env)
512 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
513 foldlRn (exports_from_item warn_dup_exports)
514 ([], emptyFM, emptyAvailEnv) export_items
515 `thenRn` \ (_, _, export_avail_map) ->
517 export_avails :: [AvailInfo]
518 export_avails = nameEnvElts export_avail_map
520 returnRn export_avails
523 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
525 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
526 | mod `elem` mods -- Duplicate export of M
527 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
531 = case lookupFM mod_avail_env mod of
532 Nothing -> failWithRn acc (modExportErr mod)
533 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
536 avails' = foldl addAvail avails mod_avails
538 returnRn (mod:mods, occs', avails')
540 exports_from_item warn_dups acc@(mods, occs, avails) ie
541 = lookupSrcName global_name_env (ieName ie) `thenRn` \ name ->
543 -- See what's available in the current environment
544 case lookupUFM entity_avail_env name of {
545 Nothing -> -- Presumably this happens because lookupSrcName didn't find
546 -- the name and returned an unboundName, which won't be in
547 -- the entity_avail_env, of course
548 WARN( not (isUnboundName name), ppr name )
553 -- Filter out the bits we want
554 case filterAvail ie avail of {
555 Nothing -> -- Not enough availability
556 failWithRn acc (exportItemErr ie) ;
560 -- Phew! It's OK! Now to check the occurrence stuff!
561 warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
562 check_occs ie occs export_avail `thenRn` \ occs' ->
563 returnRn (mods, occs', addAvail avails export_avail)
568 ok_item (IEThingAll _) (AvailTC _ [n]) = False
569 -- This occurs when you import T(..), but
570 -- only export T abstractly. The single [n]
571 -- in the AvailTC is the type or class itself
574 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
575 check_occs ie occs avail
576 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
577 foldlRn (check warn_dup_exports) occs (availNames avail)
579 check warn_dup occs name
580 = case lookupFM occs name_occ of
581 Nothing -> returnRn (addToFM occs name_occ (name, ie))
583 | name == name' -> -- Duplicate export
585 (dupExportWarn name_occ ie ie')
586 `thenRn_` returnRn occs
588 | otherwise -> -- Same occ name but different names: an error
589 failWithRn occs (exportClashErr name_occ ie ie')
591 name_occ = nameOccName name
593 mk_export_fn :: NameSet -> (Name -> Bool) -- True => exported
594 mk_export_fn exported_names = \name -> name `elemNameSet` exported_names
597 %************************************************************************
601 %************************************************************************
604 badImportItemErr mod from ie
605 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
606 ptext SLIT("does not export"), quotes (ppr ie)]
608 source_import = case from of
609 ImportByUserSource -> ptext SLIT("(hi-boot interface)")
612 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
613 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
615 dodgyMsg kind item@(IEThingAll tc)
616 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
617 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
618 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
621 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
623 exportItemErr export_item
624 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
625 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
627 exportClashErr occ_name ie1 ie2
628 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
629 ,ptext SLIT("and"), quotes (ppr ie2)
630 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
633 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
634 nest 4 (vcat (map ppr sorted_locs))]
636 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
637 occ'ed_before a b = LT == compare a b
639 dupExportWarn occ_name ie1 ie2
640 = hsep [quotes (ppr occ_name),
641 ptext SLIT("is exported by"), quotes (ppr ie1),
642 ptext SLIT("and"), quotes (ppr ie2)]
645 = hsep [ptext SLIT("Duplicate"),
646 quotes (ptext SLIT("Module") <+> ppr mod),
647 ptext SLIT("in export list")]