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(..),
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, nameOccName, nameEnvElts )
34 import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv,
35 GenAvailInfo(..), AvailInfo, Avails, AvailEnv )
36 import RdrName ( RdrName, rdrNameOcc, setRdrNameOcc )
37 import OccName ( setOccNameSpace, dataName )
38 import NameSet ( elemNameSet, emptyNameSet )
40 import Maybes ( maybeToBool, catMaybes, mapMaybe )
41 import UniqFM ( emptyUFM, listToUFM )
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 $
127 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails_by_module) ->
129 if null avails_by_module then
130 -- If there's an error in getInterfaceExports, (e.g. interface
131 -- file not found) we get lots of spurious errors from 'filterImports'
132 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
137 avails = [ avail | (mod_name, avails) <- avails_by_module,
138 mod_name /= this_mod_name,
140 -- If the module exports anything defined in this module, just ignore it.
141 -- Reason: otherwise it looks as if there are two local definition sites
142 -- for the thing, and an error gets reported. Easiest thing is just to
143 -- filter them out up front. This situation only arises if a module
144 -- imports itself, or another module that imported it. (Necessarily,
145 -- this invoves a loop.)
147 -- Tiresome consequence: if you say
152 -- module B( AType ) where
153 -- import {-# SOURCE #-} A( AType )
155 -- then you'll get a 'B does not export AType' message. Oh well.
158 filterImports imp_mod_name from import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
161 unqual_imp = not qual_only -- Maybe want unqualified names
162 qual_mod = case as_mod of
163 Nothing -> imp_mod_name
164 Just another_name -> another_name
166 mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
167 gbl_env = mkGlobalRdrEnv qual_mod unqual_imp True hides mk_prov filtered_avails
168 exports = mkExportAvails qual_mod unqual_imp gbl_env filtered_avails
170 returnRn (gbl_env, exports)
175 importsFromLocalDecls this_mod decls
176 = mapRn (getLocalDeclBinders this_mod) decls `thenRn` \ avails_s ->
177 -- The avails that are returned don't include the "system" names
179 avails = concat avails_s
181 all_names :: [Name] -- All the defns; no dups eliminated
182 all_names = [name | avail <- avails, name <- availNames avail]
185 (_, dups) = removeDups compare all_names
187 -- Check for duplicate definitions
188 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
191 -- Record that locally-defined things are available
192 recordLocalSlurps (availsToNameSet avails) `thenRn_`
194 mod_name = moduleName this_mod
195 unqual_imp = True -- Want unqualified names
196 mk_prov n = LocalDef -- Provenance is local
197 hides = [] -- Hide nothing
198 gbl_env = mkGlobalRdrEnv mod_name unqual_imp True hides mk_prov avails
199 exports = mkExportAvails mod_name unqual_imp gbl_env avails
201 returnRn (gbl_env, exports)
203 ---------------------------
204 getLocalDeclBinders :: Module -> RdrNameHsDecl -> RnMG [AvailInfo]
205 getLocalDeclBinders mod (TyClD tycl_decl)
206 = -- For type and class decls, we generate Global names, with
207 -- no export indicator. They need to be global because they get
208 -- permanently bound into the TyCons and Classes. They don't need
209 -- an export indicator because they are all implicitly exported.
210 getTyClDeclBinders mod tycl_decl `thenRn` \ (avail, sys_names) ->
212 -- Record that the system names are available
213 recordLocalSlurps (mkNameSet sys_names) `thenRn_`
216 getLocalDeclBinders mod (ValD binds)
217 = mapRn new (bagToList (collectTopBinders binds)) `thenRn` \ avails ->
220 new (rdr_name, loc) = newTopBinder mod rdr_name loc `thenRn` \ name ->
221 returnRn (Avail name)
223 getLocalDeclBinders mod (ForD (ForeignDecl nm kind _ ext_nm _ loc))
224 | binds_haskell_name kind
225 = newTopBinder mod nm loc `thenRn` \ name ->
226 returnRn [Avail name]
228 | otherwise -- a foreign export
231 binds_haskell_name (FoImport _) = True
232 binds_haskell_name FoLabel = True
233 binds_haskell_name FoExport = isDynamicExtName ext_nm
235 getLocalDeclBinders mod (FixD _) = returnRn []
236 getLocalDeclBinders mod (DeprecD _) = returnRn []
237 getLocalDeclBinders mod (DefD _) = returnRn []
238 getLocalDeclBinders mod (InstD _) = returnRn []
239 getLocalDeclBinders mod (RuleD _) = returnRn []
243 %************************************************************************
245 \subsection{Filtering imports}
247 %************************************************************************
249 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
250 available, and filters it through the import spec (if any).
253 filterImports :: ModuleName -- The module being imported
254 -> WhereFrom -- Tells whether it's a {-# SOURCE #-} import
255 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
256 -> [AvailInfo] -- What's available
257 -> RnMG ([AvailInfo], -- What's actually imported
258 [AvailInfo], -- What's to be hidden
259 -- (the unqualified version, that is)
260 -- (We need to return both the above sets, because
261 -- the qualified version is never hidden; so we can't
262 -- implement hiding by reducing what's imported.)
263 NameSet) -- What was imported explicitly
265 -- Complains if import spec mentions things that the module doesn't export
266 -- Warns/informs if import spec contains duplicates.
267 filterImports mod from Nothing imports
268 = returnRn (imports, [], emptyNameSet)
270 filterImports mod from (Just (want_hiding, import_items)) total_avails
271 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
273 (item_avails, explicits_s) = unzip avails_w_explicits
274 explicits = foldl addListToNameSet emptyNameSet explicits_s
278 -- All imported; item_avails to be hidden
279 returnRn (total_avails, item_avails, emptyNameSet)
281 -- Just item_avails imported; nothing to be hidden
282 returnRn (item_avails, [], explicits)
284 import_fm :: FiniteMap OccName AvailInfo
285 import_fm = listToFM [ (nameOccName name, avail)
286 | avail <- total_avails,
287 name <- availNames avail]
288 -- Even though availNames returns data constructors too,
289 -- they won't make any difference because naked entities like T
290 -- in an import list map to TcOccs, not VarOccs.
292 bale_out item = addErrRn (badImportItemErr mod from item) `thenRn_`
295 get_item item@(IEModuleContents _) = bale_out item
297 get_item item@(IEThingAll _)
298 = case check_item item of
299 Nothing -> bale_out item
300 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
301 -- only export T abstractly. The single [n]
302 -- in the AvailTC is the type or class itself
303 addWarnRn (dodgyImportWarn mod item) `thenRn_`
304 returnRn [(avail, [availName avail])]
305 Just avail -> returnRn [(avail, [availName avail])]
307 get_item item@(IEThingAbs n)
308 | want_hiding -- hiding( C )
309 -- Here the 'C' can be a data constructor *or* a type/class
310 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
312 avails -> returnRn [(a, []) | a <- avails]
313 -- The 'explicits' list is irrelevant when hiding
315 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
318 = case check_item item of
319 Nothing -> bale_out item
320 Just avail -> returnRn [(avail, availNames avail)]
323 | not (maybeToBool maybe_in_import_avails) ||
324 not (maybeToBool maybe_filtered_avail)
328 = Just filtered_avail
331 wanted_occ = rdrNameOcc (ieName item)
332 maybe_in_import_avails = lookupFM import_fm wanted_occ
334 Just avail = maybe_in_import_avails
335 maybe_filtered_avail = filterAvail item avail
336 Just filtered_avail = maybe_filtered_avail
341 %************************************************************************
343 \subsection{Qualifiying imports}
345 %************************************************************************
348 mkEmptyExportAvails :: ModuleName -> ExportAvails
349 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
351 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
352 mkExportAvails mod_name unqual_imp gbl_env avails
353 = (mod_avail_env, entity_avail_env)
355 mod_avail_env = unitFM mod_name unqual_avails
357 -- unqual_avails is the Avails that are visible in *unqualfied* form
358 -- (1.4 Report, Section 5.1.1)
360 -- import T hiding( f )
361 -- we delete f from avails
363 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
364 | otherwise = mapMaybe prune avails
366 prune (Avail n) | unqual_in_scope n = Just (Avail n)
367 prune (Avail n) | otherwise = Nothing
368 prune (AvailTC n ns) | null uqs = Nothing
369 | otherwise = Just (AvailTC n uqs)
371 uqs = filter unqual_in_scope ns
373 unqual_in_scope n = unQualInScope gbl_env n
375 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
376 name <- availNames avail]
378 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
379 plusExportAvails (m1, e1) (m2, e2)
380 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
381 -- ToDo: wasteful: we do this once for each constructor!
385 %************************************************************************
387 \subsection{Export list processing}
389 %************************************************************************
391 Processing the export list.
393 You might think that we should record things that appear in the export list
394 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
395 We do check (here) that they are in scope,
396 but there is no need to slurp in their actual declaration
397 (which is what @addOccurrenceName@ forces).
399 Indeed, doing so would big trouble when
400 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
401 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
404 type ExportAccum -- The type of the accumulating parameter of
405 -- the main worker function in exportsFromAvail
406 = ([ModuleName], -- 'module M's seen so far
407 ExportOccMap, -- Tracks exported occurrence names
408 AvailEnv) -- The accumulated exported stuff, kept in an env
409 -- so we can common-up related AvailInfos
411 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
412 -- Tracks what a particular exported OccName
413 -- in an export list refers to, and which item
414 -- it came from. It's illegal to export two distinct things
415 -- that have the same occurrence name
418 exportsFromAvail :: ModuleName
419 -> Maybe [RdrNameIE] -- Export spec
423 -- Complains if two distinct exports have same OccName
424 -- Warns about identical exports.
425 -- Complains about exports items not in scope
426 exportsFromAvail this_mod Nothing export_avails global_name_env
427 = exportsFromAvail this_mod true_exports export_avails global_name_env
429 true_exports = Just $ if this_mod == mAIN_Name
430 then [IEVar main_RDR_Unqual]
431 -- export Main.main *only* unless otherwise specified,
432 else [IEModuleContents this_mod]
433 -- but for all other modules export everything.
435 exportsFromAvail this_mod (Just export_items)
436 (mod_avail_env, entity_avail_env)
438 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
439 foldlRn (exports_from_item warn_dup_exports)
440 ([], emptyFM, emptyAvailEnv) export_items
441 `thenRn` \ (_, _, export_avail_map) ->
443 export_avails :: [AvailInfo]
444 export_avails = nameEnvElts export_avail_map
446 returnRn export_avails
449 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
451 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
452 | mod `elem` mods -- Duplicate export of M
453 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
457 = case lookupFM mod_avail_env mod of
458 Nothing -> failWithRn acc (modExportErr mod)
459 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
462 avails' = foldl addAvail avails mod_avails
464 returnRn (mod:mods, occs', avails')
466 exports_from_item warn_dups acc@(mods, occs, avails) ie
467 = lookupSrcName global_name_env (ieName ie) `thenRn` \ name ->
469 -- See what's available in the current environment
470 case lookupUFM entity_avail_env name of {
471 Nothing -> -- Presumably this happens because lookupSrcName didn't find
472 -- the name and returned an unboundName, which won't be in
473 -- the entity_avail_env, of course
474 WARN( not (isUnboundName name), ppr name )
479 -- Filter out the bits we want
480 case filterAvail ie avail of {
481 Nothing -> -- Not enough availability
482 failWithRn acc (exportItemErr ie) ;
486 -- Phew! It's OK! Now to check the occurrence stuff!
487 warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
488 check_occs ie occs export_avail `thenRn` \ occs' ->
489 returnRn (mods, occs', addAvail avails export_avail)
494 ok_item (IEThingAll _) (AvailTC _ [n]) = False
495 -- This occurs when you import T(..), but
496 -- only export T abstractly. The single [n]
497 -- in the AvailTC is the type or class itself
500 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
501 check_occs ie occs avail
502 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
503 foldlRn (check warn_dup_exports) occs (availNames avail)
505 check warn_dup occs name
506 = case lookupFM occs name_occ of
507 Nothing -> returnRn (addToFM occs name_occ (name, ie))
509 | name == name' -> -- Duplicate export
511 (dupExportWarn name_occ ie ie')
512 `thenRn_` returnRn occs
514 | otherwise -> -- Same occ name but different names: an error
515 failWithRn occs (exportClashErr name_occ ie ie')
517 name_occ = nameOccName name
520 %************************************************************************
524 %************************************************************************
527 badImportItemErr mod from ie
528 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
529 ptext SLIT("does not export"), quotes (ppr ie)]
531 source_import = case from of
532 ImportByUserSource -> ptext SLIT("(hi-boot interface)")
535 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
536 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
538 dodgyMsg kind item@(IEThingAll tc)
539 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
540 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
541 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
544 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
546 exportItemErr export_item
547 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
548 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
550 exportClashErr occ_name ie1 ie2
551 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
552 ,ptext SLIT("and"), quotes (ppr ie2)
553 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
556 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
557 nest 4 (vcat (map ppr sorted_locs))]
559 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
560 occ'ed_before a b = LT == compare a b
562 dupExportWarn occ_name ie1 ie2
563 = hsep [quotes (ppr occ_name),
564 ptext SLIT("is exported by"), quotes (ppr ie1),
565 ptext SLIT("and"), quotes (ppr ie2)]
568 = hsep [ptext SLIT("Duplicate"),
569 quotes (ptext SLIT("Module") <+> ppr mod),
570 ptext SLIT("in export list")]