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 get_imports = importsFromImportDecl this_mod_name rec_unqual_fn
94 mapAndUnzipRn get_imports ordinary `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
95 mapAndUnzipRn get_imports source `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
98 -- We put the local env second, so that a local provenance
99 -- "wins", even if a module imports itself.
101 gbl_env :: GlobalRdrEnv
102 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
103 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
105 all_avails :: ExportAvails
106 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
108 (_, global_avail_env) = all_avails
111 -- PROCESS EXPORT LIST (but not if we've had errors already)
112 checkErrsRn `thenRn` \ no_errs_so_far ->
113 (if no_errs_so_far then
114 exportsFromAvail this_mod_name exports all_avails gbl_env
117 ) `thenRn` \ export_avails ->
120 returnRn (gbl_env, local_gbl_env, export_avails, global_avail_env)
123 this_mod_name = moduleName this_mod
125 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
126 -- because the former doesn't even look at Prelude.hi for instance declarations,
127 -- whereas the latter does.
128 mk_prel_imports no_prelude
129 | this_mod_name == pRELUDE_Name ||
130 explicit_prelude_import ||
134 | otherwise = [ImportDecl pRELUDE_Name
136 False {- Not qualified -}
137 Nothing {- No "as" -}
138 Nothing {- No import list -}
141 explicit_prelude_import
142 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
146 importsFromImportDecl :: ModuleName
147 -> (Name -> Bool) -- OK to omit qualifier
149 -> RnMG (GlobalRdrEnv,
152 importsFromImportDecl this_mod_name is_unqual (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
153 = pushSrcLocRn iloc $
154 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails_by_module) ->
156 if null avails_by_module then
157 -- If there's an error in getInterfaceExports, (e.g. interface
158 -- file not found) we get lots of spurious errors from 'filterImports'
159 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
164 avails = [ avail | (mod_name, avails) <- avails_by_module,
165 mod_name /= this_mod_name,
167 -- If the module exports anything defined in this module, just ignore it.
168 -- Reason: otherwise it looks as if there are two local definition sites
169 -- for the thing, and an error gets reported. Easiest thing is just to
170 -- filter them out up front. This situation only arises if a module
171 -- imports itself, or another module that imported it. (Necessarily,
172 -- this invoves a loop.)
174 -- Tiresome consequence: if you say
179 -- module B( AType ) where
180 -- import {-# SOURCE #-} A( AType )
182 -- then you'll get a 'B does not export AType' message. Oh well.
185 filterImports imp_mod_name import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
188 mk_provenance name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
192 qualifyImports imp_mod_name
193 (not qual_only) -- Maybe want unqualified names
201 importsFromLocalDecls this_mod rec_exp_fn decls
202 = mapRn (getLocalDeclBinders this_mod rec_exp_fn) decls `thenRn` \ avails_s ->
205 avails = concat avails_s
207 all_names :: [Name] -- All the defns; no dups eliminated
208 all_names = [name | avail <- avails, name <- availNames avail]
211 (_, dups) = removeDups compare all_names
213 -- Check for duplicate definitions
214 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
216 -- Record that locally-defined things are available
217 recordLocalSlurps avails `thenRn_`
219 -- Build the environment
220 qualifyImports (moduleName this_mod)
221 True -- Want unqualified names
224 (\n -> LocalDef) -- Provenance is local
227 ---------------------------
228 getLocalDeclBinders :: Module
229 -> (Name -> Bool) -- Whether exported
230 -> RdrNameHsDecl -> RnMG Avails
231 getLocalDeclBinders mod rec_exp_fn (TyClD tycl_decl)
232 = -- For type and class decls, we generate Global names, with
233 -- no export indicator. They need to be global because they get
234 -- permanently bound into the TyCons and Classes. They don't need
235 -- an export indicator because they are all implicitly exported.
236 getTyClDeclBinders mod tycl_decl `thenRn` \ avail ->
239 getLocalDeclBinders mod rec_exp_fn (ValD binds)
240 = mapRn (newLocalBinder mod rec_exp_fn)
241 (bagToList (collectTopBinders binds))
243 getLocalDeclBinders mod rec_exp_fn (ForD (ForeignDecl nm kind _ ext_nm _ loc))
244 | binds_haskell_name kind
245 = newLocalBinder mod rec_exp_fn (nm, loc) `thenRn` \ avail ->
248 | otherwise -- a foreign export
251 binds_haskell_name (FoImport _) = True
252 binds_haskell_name FoLabel = True
253 binds_haskell_name FoExport = isDynamicExtName ext_nm
255 getLocalDeclBinders mod rec_exp_fn (FixD _) = returnRn []
256 getLocalDeclBinders mod rec_exp_fn (DeprecD _) = returnRn []
257 getLocalDeclBinders mod rec_exp_fn (DefD _) = returnRn []
258 getLocalDeclBinders mod rec_exp_fn (InstD _) = returnRn []
259 getLocalDeclBinders mod rec_exp_fn (RuleD _) = returnRn []
261 ---------------------------
262 newLocalBinder mod rec_exp_fn (rdr_name, loc)
263 = -- Generate a local name, and with a suitable export indicator
264 newTopBinder mod rdr_name loc `thenRn` \ name ->
265 returnRn (Avail (setLocalNameSort name (rec_exp_fn name)))
269 %************************************************************************
271 \subsection{Filtering imports}
273 %************************************************************************
275 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
276 available, and filters it through the import spec (if any).
279 filterImports :: ModuleName -- The module being imported
280 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
281 -> [AvailInfo] -- What's available
282 -> RnMG ([AvailInfo], -- What's actually imported
283 [AvailInfo], -- What's to be hidden
284 -- (the unqualified version, that is)
285 -- (We need to return both the above sets, because
286 -- the qualified version is never hidden; so we can't
287 -- implement hiding by reducing what's imported.)
288 NameSet) -- What was imported explicitly
290 -- Complains if import spec mentions things that the module doesn't export
291 -- Warns/informs if import spec contains duplicates.
292 filterImports mod Nothing imports
293 = returnRn (imports, [], emptyNameSet)
295 filterImports mod (Just (want_hiding, import_items)) total_avails
296 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
298 (item_avails, explicits_s) = unzip avails_w_explicits
299 explicits = foldl addListToNameSet emptyNameSet explicits_s
303 -- All imported; item_avails to be hidden
304 returnRn (total_avails, item_avails, emptyNameSet)
306 -- Just item_avails imported; nothing to be hidden
307 returnRn (item_avails, [], explicits)
309 import_fm :: FiniteMap OccName AvailInfo
310 import_fm = listToFM [ (nameOccName name, avail)
311 | avail <- total_avails,
312 name <- availNames avail]
313 -- Even though availNames returns data constructors too,
314 -- they won't make any difference because naked entities like T
315 -- in an import list map to TcOccs, not VarOccs.
317 bale_out item = addErrRn (badImportItemErr mod item) `thenRn_`
320 get_item item@(IEModuleContents _) = bale_out item
322 get_item item@(IEThingAll _)
323 = case check_item item of
324 Nothing -> bale_out item
325 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
326 -- only export T abstractly. The single [n]
327 -- in the AvailTC is the type or class itself
328 addWarnRn (dodgyImportWarn mod item) `thenRn_`
329 returnRn [(avail, [availName avail])]
330 Just avail -> returnRn [(avail, [availName avail])]
332 get_item item@(IEThingAbs n)
333 | want_hiding -- hiding( C )
334 -- Here the 'C' can be a data constructor *or* a type/class
335 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
337 avails -> returnRn [(a, []) | a <- avails]
338 -- The 'explicits' list is irrelevant when hiding
340 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
343 = case check_item item of
344 Nothing -> bale_out item
345 Just avail -> returnRn [(avail, availNames avail)]
348 | not (maybeToBool maybe_in_import_avails) ||
349 not (maybeToBool maybe_filtered_avail)
353 = Just filtered_avail
356 wanted_occ = rdrNameOcc (ieName item)
357 maybe_in_import_avails = lookupFM import_fm wanted_occ
359 Just avail = maybe_in_import_avails
360 maybe_filtered_avail = filterAvail item avail
361 Just filtered_avail = maybe_filtered_avail
366 %************************************************************************
368 \subsection{Qualifiying imports}
370 %************************************************************************
372 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
373 of an import decl, and deals with producing an @RnEnv@ with the
374 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
375 fully fledged @Names@.
378 qualifyImports :: ModuleName -- Imported module
379 -> Bool -- True <=> want unqualified import
380 -> Maybe ModuleName -- Optional "as M" part
381 -> [AvailInfo] -- What's to be hidden
382 -> (Name -> Provenance)
383 -> Avails -- Whats imported and how
384 -> RnMG (GlobalRdrEnv, ExportAvails)
386 qualifyImports this_mod unqual_imp as_mod hides mk_provenance avails
388 -- Make the name environment. We're talking about a
389 -- single module here, so there must be no name clashes.
390 -- In practice there only ever will be if it's the module
393 -- Add the things that are available
394 name_env1 = foldl add_avail emptyRdrEnv avails
396 -- Delete things that are hidden
397 name_env2 = foldl del_avail name_env1 hides
399 -- Create the export-availability info
400 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
402 returnRn (name_env2, export_avails)
405 qual_mod = case as_mod of
407 Just another_name -> another_name
409 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
410 add_avail env avail = foldl add_name env (availNames avail)
416 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) (name,prov)
417 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) (name,prov)
418 occ = nameOccName name
419 prov = mk_provenance name
421 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
423 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
426 mkEmptyExportAvails :: ModuleName -> ExportAvails
427 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
429 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
430 mkExportAvails mod_name unqual_imp name_env avails
431 = (mod_avail_env, entity_avail_env)
433 mod_avail_env = unitFM mod_name unqual_avails
435 -- unqual_avails is the Avails that are visible in *unqualfied* form
436 -- (1.4 Report, Section 5.1.1)
438 -- import T hiding( f )
439 -- we delete f from avails
441 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
442 | otherwise = mapMaybe prune avails
444 prune (Avail n) | unqual_in_scope n = Just (Avail n)
445 prune (Avail n) | otherwise = Nothing
446 prune (AvailTC n ns) | null uqs = Nothing
447 | otherwise = Just (AvailTC n uqs)
449 uqs = filter unqual_in_scope ns
451 unqual_in_scope n = unQualInScope name_env n
453 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
454 name <- availNames avail]
456 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
457 plusExportAvails (m1, e1) (m2, e2)
458 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
459 -- ToDo: wasteful: we do this once for each constructor!
463 %************************************************************************
465 \subsection{Export list processing}
467 %************************************************************************
469 Processing the export list.
471 You might think that we should record things that appear in the export list
472 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
473 We do check (here) that they are in scope,
474 but there is no need to slurp in their actual declaration
475 (which is what @addOccurrenceName@ forces).
477 Indeed, doing so would big trouble when
478 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
479 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
482 type ExportAccum -- The type of the accumulating parameter of
483 -- the main worker function in exportsFromAvail
484 = ([ModuleName], -- 'module M's seen so far
485 ExportOccMap, -- Tracks exported occurrence names
486 AvailEnv) -- The accumulated exported stuff, kept in an env
487 -- so we can common-up related AvailInfos
489 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
490 -- Tracks what a particular exported OccName
491 -- in an export list refers to, and which item
492 -- it came from. It's illegal to export two distinct things
493 -- that have the same occurrence name
496 exportsFromAvail :: ModuleName
497 -> Maybe [RdrNameIE] -- Export spec
501 -- Complains if two distinct exports have same OccName
502 -- Warns about identical exports.
503 -- Complains about exports items not in scope
504 exportsFromAvail this_mod Nothing export_avails global_name_env
505 = exportsFromAvail this_mod true_exports export_avails global_name_env
507 true_exports = Just $ if this_mod == mAIN_Name
508 then [IEVar main_RDR]
509 -- export Main.main *only* unless otherwise specified,
510 else [IEModuleContents this_mod]
511 -- but for all other modules export everything.
513 exportsFromAvail this_mod (Just export_items)
514 (mod_avail_env, entity_avail_env)
516 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
517 foldlRn (exports_from_item warn_dup_exports)
518 ([], emptyFM, emptyAvailEnv) export_items
519 `thenRn` \ (_, _, export_avail_map) ->
521 export_avails :: [AvailInfo]
522 export_avails = nameEnvElts export_avail_map
524 returnRn export_avails
527 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
529 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
530 | mod `elem` mods -- Duplicate export of M
531 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
535 = case lookupFM mod_avail_env mod of
536 Nothing -> failWithRn acc (modExportErr mod)
537 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
540 avails' = foldl addAvail avails mod_avails
542 returnRn (mod:mods, occs', avails')
544 exports_from_item warn_dups acc@(mods, occs, avails) ie
545 = lookupSrcName global_name_env (ieName ie) `thenRn` \ name ->
547 -- See what's available in the current environment
548 case lookupUFM entity_avail_env name of {
549 Nothing -> -- I can't see why this should ever happen; if the thing
550 -- is in scope at all it ought to have some availability
551 pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
556 -- Filter out the bits we want
557 case filterAvail ie avail of {
558 Nothing -> -- Not enough availability
559 failWithRn acc (exportItemErr ie) ;
563 -- Phew! It's OK! Now to check the occurrence stuff!
564 warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
565 check_occs ie occs export_avail `thenRn` \ occs' ->
566 returnRn (mods, occs', addAvail avails export_avail)
571 ok_item (IEThingAll _) (AvailTC _ [n]) = False
572 -- This occurs when you import T(..), but
573 -- only export T abstractly. The single [n]
574 -- in the AvailTC is the type or class itself
577 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
578 check_occs ie occs avail
579 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
580 foldlRn (check warn_dup_exports) occs (availNames avail)
582 check warn_dup occs name
583 = case lookupFM occs name_occ of
584 Nothing -> returnRn (addToFM occs name_occ (name, ie))
586 | name == name' -> -- Duplicate export
588 (dupExportWarn name_occ ie ie')
589 `thenRn_` returnRn occs
591 | otherwise -> -- Same occ name but different names: an error
592 failWithRn occs (exportClashErr name_occ ie ie')
594 name_occ = nameOccName name
596 mk_export_fn :: NameSet -> (Name -> Bool) -- True => exported
597 mk_export_fn exported_names = \name -> name `elemNameSet` exported_names
600 %************************************************************************
604 %************************************************************************
607 badImportItemErr mod ie
608 = sep [ptext SLIT("Module"), quotes (ppr mod),
609 ptext SLIT("does not export"), quotes (ppr ie)]
611 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
612 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
614 dodgyMsg kind item@(IEThingAll tc)
615 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
616 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
617 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
620 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
622 exportItemErr export_item
623 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
624 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
626 exportClashErr occ_name ie1 ie2
627 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
628 ,ptext SLIT("and"), quotes (ppr ie2)
629 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
632 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
633 nest 4 (vcat (map ppr sorted_locs))]
635 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
636 occ'ed_before a b = LT == compare a b
638 dupExportWarn occ_name ie1 ie2
639 = hsep [quotes (ppr occ_name),
640 ptext SLIT("is exported by"), quotes (ppr ie1),
641 ptext SLIT("and"), quotes (ppr ie2)]
644 = hsep [ptext SLIT("Duplicate"),
645 quotes (ptext SLIT("Module") <+> ppr mod),
646 ptext SLIT("in export list")]