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 )
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_unqual_fn :: Name -> Bool -- Is this chap in scope unqualified?
71 rec_unqual_fn = unQualInScope rec_gbl_env
73 rec_exp_fn :: Name -> Bool
74 rec_exp_fn = mk_export_fn (availsToNameSet rec_export_avails)
77 -- PROCESS LOCAL DECLS
78 -- Do these *first* so that the correct provenance gets
79 -- into the global name cache.
80 importsFromLocalDecls this_mod rec_exp_fn decls `thenRn` \ (local_gbl_env, local_mod_avails) ->
82 -- PROCESS IMPORT DECLS
83 -- Do the non {- SOURCE -} ones first, so that we get a helpful
84 -- warning for {- SOURCE -} ones that are unnecessary
85 doptRn Opt_NoImplicitPrelude `thenRn` \ opt_no_prelude ->
87 all_imports = mk_prel_imports opt_no_prelude ++ imports
88 (source, ordinary) = partition is_source_import all_imports
89 is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True
90 is_source_import other = False
92 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) ordinary `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
93 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) source `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
96 -- We put the local env second, so that a local provenance
97 -- "wins", even if a module imports itself.
99 gbl_env :: GlobalRdrEnv
100 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
101 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
103 all_avails :: ExportAvails
104 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
106 (_, global_avail_env) = all_avails
109 -- PROCESS EXPORT LIST (but not if we've had errors already)
110 checkErrsRn `thenRn` \ no_errs_so_far ->
111 (if no_errs_so_far then
112 exportsFromAvail this_mod_name exports all_avails gbl_env
115 ) `thenRn` \ export_avails ->
118 returnRn (gbl_env, local_gbl_env, export_avails, global_avail_env)
121 this_mod_name = moduleName this_mod
123 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
124 -- because the former doesn't even look at Prelude.hi for instance declarations,
125 -- whereas the latter does.
126 mk_prel_imports no_prelude
127 | this_mod_name == pRELUDE_Name ||
128 explicit_prelude_import ||
132 | otherwise = [ImportDecl pRELUDE_Name
134 False {- Not qualified -}
135 Nothing {- No "as" -}
136 Nothing {- No import list -}
139 explicit_prelude_import
140 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
144 importsFromImportDecl :: (Name -> Bool) -- OK to omit qualifier
146 -> RnMG (GlobalRdrEnv,
149 importsFromImportDecl is_unqual (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
150 = pushSrcLocRn iloc $
151 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails_by_module) ->
153 if null avails_by_module then
154 -- If there's an error in getInterfaceExports, (e.g. interface
155 -- file not found) we get lots of spurious errors from 'filterImports'
156 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
161 avails = concat (map snd avails_by_module)
163 filterImports imp_mod_name import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
166 mk_provenance name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
170 qualifyImports imp_mod_name
171 (not qual_only) -- Maybe want unqualified names
179 importsFromLocalDecls this_mod rec_exp_fn decls
180 = mapRn (getLocalDeclBinders this_mod rec_exp_fn) decls `thenRn` \ avails_s ->
183 avails = concat avails_s
185 all_names :: [Name] -- All the defns; no dups eliminated
186 all_names = [name | avail <- avails, name <- availNames avail]
189 (_, dups) = removeDups compare all_names
191 -- Check for duplicate definitions
192 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
194 -- Record that locally-defined things are available
195 recordLocalSlurps avails `thenRn_`
197 -- Build the environment
198 qualifyImports (moduleName this_mod)
199 True -- Want unqualified names
202 (\n -> LocalDef) -- Provenance is local
205 ---------------------------
206 getLocalDeclBinders :: Module
207 -> (Name -> Bool) -- Whether exported
208 -> RdrNameHsDecl -> RnMG Avails
209 getLocalDeclBinders mod rec_exp_fn (TyClD tycl_decl)
210 = -- For type and class decls, we generate Global names, with
211 -- no export indicator. They need to be global because they get
212 -- permanently bound into the TyCons and Classes. They don't need
213 -- an export indicator because they are all implicitly exported.
214 getTyClDeclBinders mod tycl_decl `thenRn` \ avail ->
217 getLocalDeclBinders mod rec_exp_fn (ValD binds)
218 = mapRn (newLocalBinder mod rec_exp_fn)
219 (bagToList (collectTopBinders binds))
221 getLocalDeclBinders mod rec_exp_fn (ForD (ForeignDecl nm kind _ ext_nm _ loc))
222 | binds_haskell_name kind
223 = newLocalBinder mod rec_exp_fn (nm, loc) `thenRn` \ avail ->
226 | otherwise -- a foreign export
229 binds_haskell_name (FoImport _) = True
230 binds_haskell_name FoLabel = True
231 binds_haskell_name FoExport = isDynamicExtName ext_nm
233 getLocalDeclBinders mod rec_exp_fn (FixD _) = returnRn []
234 getLocalDeclBinders mod rec_exp_fn (DeprecD _) = returnRn []
235 getLocalDeclBinders mod rec_exp_fn (DefD _) = returnRn []
236 getLocalDeclBinders mod rec_exp_fn (InstD _) = returnRn []
237 getLocalDeclBinders mod rec_exp_fn (RuleD _) = returnRn []
239 ---------------------------
240 newLocalBinder mod rec_exp_fn (rdr_name, loc)
241 = -- Generate a local name, and with a suitable export indicator
242 newTopBinder mod rdr_name loc `thenRn` \ name ->
243 returnRn (Avail (setLocalNameSort name (rec_exp_fn name)))
247 %************************************************************************
249 \subsection{Filtering imports}
251 %************************************************************************
253 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
254 available, and filters it through the import spec (if any).
257 filterImports :: ModuleName -- The module being imported
258 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
259 -> [AvailInfo] -- What's available
260 -> RnMG ([AvailInfo], -- What's actually imported
261 [AvailInfo], -- What's to be hidden
262 -- (the unqualified version, that is)
263 -- (We need to return both the above sets, because
264 -- the qualified version is never hidden; so we can't
265 -- implement hiding by reducing what's imported.)
266 NameSet) -- What was imported explicitly
268 -- Complains if import spec mentions things that the module doesn't export
269 -- Warns/informs if import spec contains duplicates.
270 filterImports mod Nothing imports
271 = returnRn (imports, [], emptyNameSet)
273 filterImports mod (Just (want_hiding, import_items)) total_avails
274 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
276 (item_avails, explicits_s) = unzip avails_w_explicits
277 explicits = foldl addListToNameSet emptyNameSet explicits_s
281 -- All imported; item_avails to be hidden
282 returnRn (total_avails, item_avails, emptyNameSet)
284 -- Just item_avails imported; nothing to be hidden
285 returnRn (item_avails, [], explicits)
287 import_fm :: FiniteMap OccName AvailInfo
288 import_fm = listToFM [ (nameOccName name, avail)
289 | avail <- total_avails,
290 name <- availNames avail]
291 -- Even though availNames returns data constructors too,
292 -- they won't make any difference because naked entities like T
293 -- in an import list map to TcOccs, not VarOccs.
295 bale_out item = addErrRn (badImportItemErr mod item) `thenRn_`
298 get_item item@(IEModuleContents _) = bale_out item
300 get_item item@(IEThingAll _)
301 = case check_item item of
302 Nothing -> bale_out item
303 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
304 -- only export T abstractly. The single [n]
305 -- in the AvailTC is the type or class itself
306 addWarnRn (dodgyImportWarn mod item) `thenRn_`
307 returnRn [(avail, [availName avail])]
308 Just avail -> returnRn [(avail, [availName avail])]
310 get_item item@(IEThingAbs n)
311 | want_hiding -- hiding( C )
312 -- Here the 'C' can be a data constructor *or* a type/class
313 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
315 avails -> returnRn [(a, []) | a <- avails]
316 -- The 'explicits' list is irrelevant when hiding
318 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
321 = case check_item item of
322 Nothing -> bale_out item
323 Just avail -> returnRn [(avail, availNames avail)]
326 | not (maybeToBool maybe_in_import_avails) ||
327 not (maybeToBool maybe_filtered_avail)
331 = Just filtered_avail
334 wanted_occ = rdrNameOcc (ieName item)
335 maybe_in_import_avails = lookupFM import_fm wanted_occ
337 Just avail = maybe_in_import_avails
338 maybe_filtered_avail = filterAvail item avail
339 Just filtered_avail = maybe_filtered_avail
344 %************************************************************************
346 \subsection{Qualifiying imports}
348 %************************************************************************
350 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
351 of an import decl, and deals with producing an @RnEnv@ with the
352 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
353 fully fledged @Names@.
356 qualifyImports :: ModuleName -- Imported module
357 -> Bool -- True <=> want unqualified import
358 -> Maybe ModuleName -- Optional "as M" part
359 -> [AvailInfo] -- What's to be hidden
360 -> (Name -> Provenance)
361 -> Avails -- Whats imported and how
362 -> RnMG (GlobalRdrEnv, ExportAvails)
364 qualifyImports this_mod unqual_imp as_mod hides mk_provenance avails
366 -- Make the name environment. We're talking about a
367 -- single module here, so there must be no name clashes.
368 -- In practice there only ever will be if it's the module
371 -- Add the things that are available
372 name_env1 = foldl add_avail emptyRdrEnv avails
374 -- Delete things that are hidden
375 name_env2 = foldl del_avail name_env1 hides
377 -- Create the export-availability info
378 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
380 returnRn (name_env2, export_avails)
383 qual_mod = case as_mod of
385 Just another_name -> another_name
387 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
388 add_avail env avail = foldl add_name env (availNames avail)
394 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) (name,prov)
395 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) (name,prov)
396 occ = nameOccName name
397 prov = mk_provenance name
399 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
401 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
404 mkEmptyExportAvails :: ModuleName -> ExportAvails
405 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
407 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
408 mkExportAvails mod_name unqual_imp name_env avails
409 = (mod_avail_env, entity_avail_env)
411 mod_avail_env = unitFM mod_name unqual_avails
413 -- unqual_avails is the Avails that are visible in *unqualfied* form
414 -- (1.4 Report, Section 5.1.1)
416 -- import T hiding( f )
417 -- we delete f from avails
419 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
420 | otherwise = mapMaybe prune avails
422 prune (Avail n) | unqual_in_scope n = Just (Avail n)
423 prune (Avail n) | otherwise = Nothing
424 prune (AvailTC n ns) | null uqs = Nothing
425 | otherwise = Just (AvailTC n uqs)
427 uqs = filter unqual_in_scope ns
429 unqual_in_scope n = unQualInScope name_env n
431 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
432 name <- availNames avail]
434 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
435 plusExportAvails (m1, e1) (m2, e2)
436 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
437 -- ToDo: wasteful: we do this once for each constructor!
441 %************************************************************************
443 \subsection{Export list processing}
445 %************************************************************************
447 Processing the export list.
449 You might think that we should record things that appear in the export list
450 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
451 We do check (here) that they are in scope,
452 but there is no need to slurp in their actual declaration
453 (which is what @addOccurrenceName@ forces).
455 Indeed, doing so would big trouble when
456 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
457 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
460 type ExportAccum -- The type of the accumulating parameter of
461 -- the main worker function in exportsFromAvail
462 = ([ModuleName], -- 'module M's seen so far
463 ExportOccMap, -- Tracks exported occurrence names
464 AvailEnv) -- The accumulated exported stuff, kept in an env
465 -- so we can common-up related AvailInfos
467 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
468 -- Tracks what a particular exported OccName
469 -- in an export list refers to, and which item
470 -- it came from. It's illegal to export two distinct things
471 -- that have the same occurrence name
474 exportsFromAvail :: ModuleName
475 -> Maybe [RdrNameIE] -- Export spec
479 -- Complains if two distinct exports have same OccName
480 -- Warns about identical exports.
481 -- Complains about exports items not in scope
482 exportsFromAvail this_mod Nothing export_avails global_name_env
483 = exportsFromAvail this_mod true_exports export_avails global_name_env
485 true_exports = Just $ if this_mod == mAIN_Name
486 then [IEVar main_RDR]
487 -- export Main.main *only* unless otherwise specified,
488 else [IEModuleContents this_mod]
489 -- but for all other modules export everything.
491 exportsFromAvail this_mod (Just export_items)
492 (mod_avail_env, entity_avail_env)
494 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
495 foldlRn (exports_from_item warn_dup_exports)
496 ([], emptyFM, emptyAvailEnv) export_items
497 `thenRn` \ (_, _, export_avail_map) ->
499 export_avails :: [AvailInfo]
500 export_avails = nameEnvElts export_avail_map
502 returnRn export_avails
505 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
507 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
508 | mod `elem` mods -- Duplicate export of M
509 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
513 = case lookupFM mod_avail_env mod of
514 Nothing -> failWithRn acc (modExportErr mod)
515 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
518 avails' = foldl addAvail avails mod_avails
520 returnRn (mod:mods, occs', avails')
522 exports_from_item warn_dups acc@(mods, occs, avails) ie
523 | not (maybeToBool maybe_in_scope)
524 = failWithRn acc (unknownNameErr (ieName ie))
526 | not (null dup_names)
527 = addNameClashErrRn rdr_name ((name,prov):dup_names) `thenRn_`
531 -- I can't see why this should ever happen; if the thing is in scope
532 -- at all it ought to have some availability
533 | not (maybeToBool maybe_avail)
534 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
539 = failWithRn acc (exportItemErr ie)
541 | otherwise -- Phew! It's OK! Now to check the occurrence stuff!
544 = warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
545 check_occs ie occs export_avail `thenRn` \ occs' ->
546 returnRn (mods, occs', addAvail avails export_avail)
550 maybe_in_scope = lookupFM global_name_env rdr_name
551 Just ((name,prov):dup_names) = maybe_in_scope
552 maybe_avail = lookupUFM entity_avail_env name
553 Just avail = maybe_avail
554 maybe_export_avail = filterAvail ie avail
555 enough_avail = maybeToBool maybe_export_avail
556 Just export_avail = maybe_export_avail
558 ok_item (IEThingAll _) (AvailTC _ [n]) = False
559 -- This occurs when you import T(..), but
560 -- only export T abstractly. The single [n]
561 -- in the AvailTC is the type or class itself
564 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
565 check_occs ie occs avail
566 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
567 foldlRn (check warn_dup_exports) occs (availNames avail)
569 check warn_dup occs name
570 = case lookupFM occs name_occ of
571 Nothing -> returnRn (addToFM occs name_occ (name, ie))
573 | name == name' -> -- Duplicate export
575 (dupExportWarn name_occ ie ie')
576 `thenRn_` returnRn occs
578 | otherwise -> -- Same occ name but different names: an error
579 failWithRn occs (exportClashErr name_occ ie ie')
581 name_occ = nameOccName name
583 mk_export_fn :: NameSet -> (Name -> Bool) -- True => exported
584 mk_export_fn exported_names = \name -> name `elemNameSet` exported_names
587 %************************************************************************
591 %************************************************************************
594 badImportItemErr mod ie
595 = sep [ptext SLIT("Module"), quotes (ppr mod),
596 ptext SLIT("does not export"), quotes (ppr ie)]
598 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
599 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
601 dodgyMsg kind item@(IEThingAll tc)
602 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
603 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
604 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
607 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
609 exportItemErr export_item
610 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
611 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
613 exportClashErr occ_name ie1 ie2
614 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
615 ,ptext SLIT("and"), quotes (ppr ie2)
616 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
619 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
620 nest 4 (vcat (map ppr sorted_locs))]
622 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
623 occ'ed_before a b = LT == compare a b
625 dupExportWarn occ_name ie1 ie2
626 = hsep [quotes (ppr occ_name),
627 ptext SLIT("is exported by"), quotes (ppr ie1),
628 ptext SLIT("and"), quotes (ppr ie2)]
631 = hsep [ptext SLIT("Duplicate"),
632 quotes (ptext SLIT("Module") <+> ppr mod),
633 ptext SLIT("in export list")]