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 from 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 -> WhereFrom -- Tells whether it's a {-# SOURCE #-} import
281 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
282 -> [AvailInfo] -- What's available
283 -> RnMG ([AvailInfo], -- What's actually imported
284 [AvailInfo], -- What's to be hidden
285 -- (the unqualified version, that is)
286 -- (We need to return both the above sets, because
287 -- the qualified version is never hidden; so we can't
288 -- implement hiding by reducing what's imported.)
289 NameSet) -- What was imported explicitly
291 -- Complains if import spec mentions things that the module doesn't export
292 -- Warns/informs if import spec contains duplicates.
293 filterImports mod from Nothing imports
294 = returnRn (imports, [], emptyNameSet)
296 filterImports mod from (Just (want_hiding, import_items)) total_avails
297 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
299 (item_avails, explicits_s) = unzip avails_w_explicits
300 explicits = foldl addListToNameSet emptyNameSet explicits_s
304 -- All imported; item_avails to be hidden
305 returnRn (total_avails, item_avails, emptyNameSet)
307 -- Just item_avails imported; nothing to be hidden
308 returnRn (item_avails, [], explicits)
310 import_fm :: FiniteMap OccName AvailInfo
311 import_fm = listToFM [ (nameOccName name, avail)
312 | avail <- total_avails,
313 name <- availNames avail]
314 -- Even though availNames returns data constructors too,
315 -- they won't make any difference because naked entities like T
316 -- in an import list map to TcOccs, not VarOccs.
318 bale_out item = addErrRn (badImportItemErr mod from item) `thenRn_`
321 get_item item@(IEModuleContents _) = bale_out item
323 get_item item@(IEThingAll _)
324 = case check_item item of
325 Nothing -> bale_out item
326 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
327 -- only export T abstractly. The single [n]
328 -- in the AvailTC is the type or class itself
329 addWarnRn (dodgyImportWarn mod item) `thenRn_`
330 returnRn [(avail, [availName avail])]
331 Just avail -> returnRn [(avail, [availName avail])]
333 get_item item@(IEThingAbs n)
334 | want_hiding -- hiding( C )
335 -- Here the 'C' can be a data constructor *or* a type/class
336 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
338 avails -> returnRn [(a, []) | a <- avails]
339 -- The 'explicits' list is irrelevant when hiding
341 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
344 = case check_item item of
345 Nothing -> bale_out item
346 Just avail -> returnRn [(avail, availNames avail)]
349 | not (maybeToBool maybe_in_import_avails) ||
350 not (maybeToBool maybe_filtered_avail)
354 = Just filtered_avail
357 wanted_occ = rdrNameOcc (ieName item)
358 maybe_in_import_avails = lookupFM import_fm wanted_occ
360 Just avail = maybe_in_import_avails
361 maybe_filtered_avail = filterAvail item avail
362 Just filtered_avail = maybe_filtered_avail
367 %************************************************************************
369 \subsection{Qualifiying imports}
371 %************************************************************************
373 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
374 of an import decl, and deals with producing an @RnEnv@ with the
375 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
376 fully fledged @Names@.
379 qualifyImports :: ModuleName -- Imported module
380 -> Bool -- True <=> want unqualified import
381 -> Maybe ModuleName -- Optional "as M" part
382 -> [AvailInfo] -- What's to be hidden
383 -> (Name -> Provenance)
384 -> Avails -- Whats imported and how
385 -> RnMG (GlobalRdrEnv, ExportAvails)
387 qualifyImports this_mod unqual_imp as_mod hides mk_provenance avails
389 -- Make the name environment. We're talking about a
390 -- single module here, so there must be no name clashes.
391 -- In practice there only ever will be if it's the module
394 -- Add the things that are available
395 name_env1 = foldl add_avail emptyRdrEnv avails
397 -- Delete things that are hidden
398 name_env2 = foldl del_avail name_env1 hides
400 -- Create the export-availability info
401 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
403 returnRn (name_env2, export_avails)
406 qual_mod = case as_mod of
408 Just another_name -> another_name
410 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
411 add_avail env avail = foldl add_name env (availNames avail)
417 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) (name,prov)
418 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) (name,prov)
419 occ = nameOccName name
420 prov = mk_provenance name
422 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
424 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
427 mkEmptyExportAvails :: ModuleName -> ExportAvails
428 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
430 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
431 mkExportAvails mod_name unqual_imp name_env avails
432 = (mod_avail_env, entity_avail_env)
434 mod_avail_env = unitFM mod_name unqual_avails
436 -- unqual_avails is the Avails that are visible in *unqualfied* form
437 -- (1.4 Report, Section 5.1.1)
439 -- import T hiding( f )
440 -- we delete f from avails
442 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
443 | otherwise = mapMaybe prune avails
445 prune (Avail n) | unqual_in_scope n = Just (Avail n)
446 prune (Avail n) | otherwise = Nothing
447 prune (AvailTC n ns) | null uqs = Nothing
448 | otherwise = Just (AvailTC n uqs)
450 uqs = filter unqual_in_scope ns
452 unqual_in_scope n = unQualInScope name_env n
454 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
455 name <- availNames avail]
457 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
458 plusExportAvails (m1, e1) (m2, e2)
459 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
460 -- ToDo: wasteful: we do this once for each constructor!
464 %************************************************************************
466 \subsection{Export list processing}
468 %************************************************************************
470 Processing the export list.
472 You might think that we should record things that appear in the export list
473 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
474 We do check (here) that they are in scope,
475 but there is no need to slurp in their actual declaration
476 (which is what @addOccurrenceName@ forces).
478 Indeed, doing so would big trouble when
479 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
480 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
483 type ExportAccum -- The type of the accumulating parameter of
484 -- the main worker function in exportsFromAvail
485 = ([ModuleName], -- 'module M's seen so far
486 ExportOccMap, -- Tracks exported occurrence names
487 AvailEnv) -- The accumulated exported stuff, kept in an env
488 -- so we can common-up related AvailInfos
490 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
491 -- Tracks what a particular exported OccName
492 -- in an export list refers to, and which item
493 -- it came from. It's illegal to export two distinct things
494 -- that have the same occurrence name
497 exportsFromAvail :: ModuleName
498 -> Maybe [RdrNameIE] -- Export spec
502 -- Complains if two distinct exports have same OccName
503 -- Warns about identical exports.
504 -- Complains about exports items not in scope
505 exportsFromAvail this_mod Nothing export_avails global_name_env
506 = exportsFromAvail this_mod true_exports export_avails global_name_env
508 true_exports = Just $ if this_mod == mAIN_Name
509 then [IEVar main_RDR]
510 -- export Main.main *only* unless otherwise specified,
511 else [IEModuleContents this_mod]
512 -- but for all other modules export everything.
514 exportsFromAvail this_mod (Just export_items)
515 (mod_avail_env, entity_avail_env)
517 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
518 foldlRn (exports_from_item warn_dup_exports)
519 ([], emptyFM, emptyAvailEnv) export_items
520 `thenRn` \ (_, _, export_avail_map) ->
522 export_avails :: [AvailInfo]
523 export_avails = nameEnvElts export_avail_map
525 returnRn export_avails
528 exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum
530 exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod)
531 | mod `elem` mods -- Duplicate export of M
532 = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_`
536 = case lookupFM mod_avail_env mod of
537 Nothing -> failWithRn acc (modExportErr mod)
538 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
541 avails' = foldl addAvail avails mod_avails
543 returnRn (mod:mods, occs', avails')
545 exports_from_item warn_dups acc@(mods, occs, avails) ie
546 = lookupSrcName global_name_env (ieName ie) `thenRn` \ name ->
548 -- See what's available in the current environment
549 case lookupUFM entity_avail_env name of {
550 Nothing -> -- I can't see why this should ever happen; if the thing
551 -- is in scope at all it ought to have some availability
552 pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
557 -- Filter out the bits we want
558 case filterAvail ie avail of {
559 Nothing -> -- Not enough availability
560 failWithRn acc (exportItemErr ie) ;
564 -- Phew! It's OK! Now to check the occurrence stuff!
565 warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
566 check_occs ie occs export_avail `thenRn` \ occs' ->
567 returnRn (mods, occs', addAvail avails export_avail)
572 ok_item (IEThingAll _) (AvailTC _ [n]) = False
573 -- This occurs when you import T(..), but
574 -- only export T abstractly. The single [n]
575 -- in the AvailTC is the type or class itself
578 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
579 check_occs ie occs avail
580 = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports ->
581 foldlRn (check warn_dup_exports) occs (availNames avail)
583 check warn_dup occs name
584 = case lookupFM occs name_occ of
585 Nothing -> returnRn (addToFM occs name_occ (name, ie))
587 | name == name' -> -- Duplicate export
589 (dupExportWarn name_occ ie ie')
590 `thenRn_` returnRn occs
592 | otherwise -> -- Same occ name but different names: an error
593 failWithRn occs (exportClashErr name_occ ie ie')
595 name_occ = nameOccName name
597 mk_export_fn :: NameSet -> (Name -> Bool) -- True => exported
598 mk_export_fn exported_names = \name -> name `elemNameSet` exported_names
601 %************************************************************************
605 %************************************************************************
608 badImportItemErr mod from ie
609 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
610 ptext SLIT("does not export"), quotes (ppr ie)]
612 source_import = case from of
613 ImportByUserSource -> ptext SLIT("(hi-boot interface)")
616 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
617 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
619 dodgyMsg kind item@(IEThingAll tc)
620 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
621 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
622 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
625 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
627 exportItemErr export_item
628 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
629 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
631 exportClashErr occ_name ie1 ie2
632 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
633 ,ptext SLIT("and"), quotes (ppr ie2)
634 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
637 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
638 nest 4 (vcat (map ppr sorted_locs))]
640 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
641 occ'ed_before a b = LT == compare a b
643 dupExportWarn occ_name ie1 ie2
644 = hsep [quotes (ppr occ_name),
645 ptext SLIT("is exported by"), quotes (ppr ie1),
646 ptext SLIT("and"), quotes (ppr ie2)]
649 = hsep [ptext SLIT("Duplicate"),
650 quotes (ptext SLIT("Module") <+> ppr mod),
651 ptext SLIT("in export list")]