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 ( opt_NoImplicitPrelude, opt_WarnDuplicateExports, opt_SourceUnchanged )
15 import HsSyn ( HsModule(..), HsDecl(..), IE(..), ieName, ImportDecl(..),
18 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl,
19 RdrNameHsModule, RdrNameHsDecl
21 import RnIfaces ( getInterfaceExports, getDeclBinders,
22 recordLocalSlurps, checkModUsage, findAndReadIface, outOfDate
28 import PrelNames ( pRELUDE_Name, mAIN_Name, main_RDR )
29 import UniqFM ( lookupUFM )
30 import Bag ( bagToList )
31 import Module ( ModuleName, mkThisModule, pprModuleName, WhereFrom(..) )
33 import Name ( Name, ExportFlag(..), ImportReason(..), Provenance(..),
35 nameOccName, getSrcLoc, pprProvenance, getNameProvenance,
38 import RdrName ( RdrName, rdrNameOcc, setRdrNameOcc, mkRdrQual, mkRdrUnqual, isQual, isUnqual )
39 import OccName ( setOccNameSpace, dataName )
40 import NameSet ( elemNameSet, emptyNameSet )
42 import Maybes ( maybeToBool, catMaybes, mapMaybe )
43 import UniqFM ( emptyUFM, listToUFM )
44 import Util ( removeDups, sortLt )
45 import List ( partition )
50 %************************************************************************
52 \subsection{Get global names}
54 %************************************************************************
57 getGlobalNames :: RdrNameHsModule
58 -> RnMG (Maybe (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
63 Maybe ParsedIface -- The old interface file, if any
65 -- Nothing => no need to recompile
67 getGlobalNames (HsModule this_mod _ exports imports decls _ mod_loc)
68 = -- These two fix-loops are to get the right
69 -- provenance information into a Name
70 fixRn ( \ ~(Just (rec_gbl_env, _, rec_export_avails, _, _)) ->
73 rec_unqual_fn :: Name -> Bool -- Is this chap in scope unqualified?
74 rec_unqual_fn = unQualInScope rec_gbl_env
76 rec_exp_fn :: Name -> ExportFlag
77 rec_exp_fn = mk_export_fn (availsToNameSet rec_export_avails)
80 -- PROCESS LOCAL DECLS
81 -- Do these *first* so that the correct provenance gets
82 -- into the global name cache.
83 importsFromLocalDecls this_mod rec_exp_fn decls
84 `thenRn` \ (local_gbl_env, local_mod_avails) ->
86 -- PROCESS IMPORT DECLS
87 -- Do the non {- SOURCE -} ones first, so that we get a helpful
88 -- warning for {- SOURCE -} ones that are unnecessary
90 (source, ordinary) = partition is_source_import all_imports
91 is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True
92 is_source_import other = False
94 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) ordinary
95 `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
96 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) source
97 `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
100 -- We put the local env second, so that a local provenance
101 -- "wins", even if a module imports itself.
103 gbl_env :: GlobalRdrEnv
104 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
105 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
107 all_avails :: ExportAvails
108 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
109 (_, global_avail_env) = all_avails
112 -- TRY FOR EARLY EXIT
113 -- We can't go for an early exit before this because we have to check
114 -- for name clashes. Consider:
116 -- module A where module B where
120 -- Suppose I've compiled everything up, and then I add a
121 -- new definition to module B, that defines "f".
123 -- Then I must detect the name clash in A before going for an early
124 -- exit. The early-exit code checks what's actually needed from B
125 -- to compile A, and of course that doesn't include B.f. That's
126 -- why we wait till after the plusEnv stuff to do the early-exit.
128 -- Check For eacly exit
129 checkErrsRn `thenRn` \ no_errs_so_far ->
130 if not no_errs_so_far then
131 -- Found errors already, so exit now
134 checkEarlyExit this_mod `thenRn` \ (up_to_date, old_iface) ->
136 -- Interface files are sufficiently unchanged
137 putDocRn (text "Compilation IS NOT required") `thenRn_`
141 -- RECORD BETTER PROVENANCES IN THE CACHE
142 -- The names in the envirnoment have better provenances (e.g. imported on line x)
143 -- than the names in the name cache. We update the latter now, so that we
144 -- we start renaming declarations we'll get the good names
145 -- The isQual is because the qualified name is always in scope
146 updateProvenances (concat [names | (rdr_name, names) <- rdrEnvToList gbl_env,
147 isQual rdr_name]) `thenRn_`
149 -- PROCESS EXPORT LISTS
150 exportsFromAvail this_mod exports all_avails gbl_env `thenRn` \ export_avails ->
154 returnRn (Just (gbl_env, local_gbl_env, export_avails, global_avail_env, old_iface))
157 all_imports = prel_imports ++ imports
159 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
160 -- because the former doesn't even look at Prelude.hi for instance declarations,
161 -- whereas the latter does.
162 prel_imports | this_mod == pRELUDE_Name ||
163 explicit_prelude_import ||
164 opt_NoImplicitPrelude
167 | otherwise = [ImportDecl pRELUDE_Name
169 False {- Not qualified -}
170 Nothing {- No "as" -}
171 Nothing {- No import list -}
174 explicit_prelude_import
175 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
179 checkEarlyExit mod_name
180 = traceRn (text "Considering whether compilation is required...") `thenRn_`
182 -- Read the old interface file, if any, for the module being compiled
183 findAndReadIface doc_str mod_name False {- Not hi-boot -} `thenRn` \ maybe_iface ->
185 -- CHECK WHETHER WE HAVE IT ALREADY
187 Left err -> -- Old interface file not found, so we'd better bail out
188 traceRn (vcat [ptext SLIT("No old interface file for") <+> pprModuleName mod_name,
190 returnRn (outOfDate, Nothing)
193 | not opt_SourceUnchanged
194 -> -- Source code changed
195 traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_`
196 returnRn (False, Just iface)
199 -> -- Source code unchanged and no errors yet... carry on
200 checkModUsage (pi_usages iface) `thenRn` \ up_to_date ->
201 returnRn (up_to_date, Just iface)
203 -- Only look in current directory, with suffix .hi
204 doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
208 importsFromImportDecl :: (Name -> Bool) -- OK to omit qualifier
210 -> RnMG (GlobalRdrEnv,
213 importsFromImportDecl is_unqual (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
214 = pushSrcLocRn iloc $
215 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails) ->
218 -- If there's an error in getInterfaceExports, (e.g. interface
219 -- file not found) we get lots of spurious errors from 'filterImports'
220 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
223 filterImports imp_mod_name import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
225 qualifyImports imp_mod_name
226 (not qual_only) -- Maybe want unqualified names
228 (improveAvails imp_mod iloc explicits
229 is_unqual filtered_avails)
232 improveAvails imp_mod iloc explicits is_unqual avails
233 -- We 'improve' the provenance by setting
234 -- (a) the import-reason field, so that the Name says how it came into scope
235 -- including whether it's explicitly imported
236 -- (b) the print-unqualified field
237 = map improve_avail avails
239 improve_avail (Avail n) = Avail (improve n)
240 improve_avail (AvailTC n ns) = AvailTC (improve n) (map improve ns)
242 improve name = setNameProvenance name
243 (NonLocalDef (UserImport imp_mod iloc (is_explicit name))
245 is_explicit name = name `elemNameSet` explicits
250 importsFromLocalDecls mod_name rec_exp_fn decls
251 = mapRn (getLocalDeclBinders mod rec_exp_fn) decls `thenRn` \ avails_s ->
254 avails = concat avails_s
256 all_names :: [Name] -- All the defns; no dups eliminated
257 all_names = [name | avail <- avails, name <- availNames avail]
260 (_, dups) = removeDups compare all_names
262 -- Check for duplicate definitions
263 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
265 -- Record that locally-defined things are available
266 recordLocalSlurps avails `thenRn_`
268 -- Build the environment
269 qualifyImports mod_name
270 True -- Want unqualified names
276 mod = mkThisModule mod_name
278 getLocalDeclBinders :: Module -> (Name -> ExportFlag)
279 -> RdrNameHsDecl -> RnMG Avails
280 getLocalDeclBinders mod rec_exp_fn (ValD binds)
281 = mapRn do_one (bagToList (collectTopBinders binds))
283 do_one (rdr_name, loc) = newLocalName mod rec_exp_fn rdr_name loc `thenRn` \ name ->
284 returnRn (Avail name)
286 getLocalDeclBinders mod rec_exp_fn decl
287 = getDeclBinders (newLocalName mod rec_exp_fn) decl `thenRn` \ maybe_avail ->
289 Nothing -> returnRn [] -- Instance decls and suchlike
290 Just avail -> returnRn [avail]
292 newLocalName mod rec_exp_fn rdr_name loc
293 = check_unqual rdr_name loc `thenRn_`
294 newTopBinder mod (rdrNameOcc rdr_name) `thenRn` \ name ->
295 returnRn (setNameProvenance name (LocalDef loc (rec_exp_fn name)))
297 -- There should never be a qualified name in a binding position (except in instance decls)
298 -- The parser doesn't check this because the same parser parses instance decls
299 check_unqual rdr_name loc
300 | isUnqual rdr_name = returnRn ()
301 | otherwise = qualNameErr (text "the binding for" <+> quotes (ppr rdr_name))
306 %************************************************************************
308 \subsection{Filtering imports}
310 %************************************************************************
312 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
313 available, and filters it through the import spec (if any).
316 filterImports :: ModuleName -- The module being imported
317 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
318 -> [AvailInfo] -- What's available
319 -> RnMG ([AvailInfo], -- What's actually imported
320 [AvailInfo], -- What's to be hidden
321 -- (the unqualified version, that is)
322 -- (We need to return both the above sets, because
323 -- the qualified version is never hidden; so we can't
324 -- implement hiding by reducing what's imported.)
325 NameSet) -- What was imported explicitly
327 -- Complains if import spec mentions things that the module doesn't export
328 -- Warns/informs if import spec contains duplicates.
329 filterImports mod Nothing imports
330 = returnRn (imports, [], emptyNameSet)
332 filterImports mod (Just (want_hiding, import_items)) avails
333 = flatMapRn get_item import_items `thenRn` \ avails_w_explicits ->
335 (item_avails, explicits_s) = unzip avails_w_explicits
336 explicits = foldl addListToNameSet emptyNameSet explicits_s
340 -- All imported; item_avails to be hidden
341 returnRn (avails, item_avails, emptyNameSet)
343 -- Just item_avails imported; nothing to be hidden
344 returnRn (item_avails, [], explicits)
346 import_fm :: FiniteMap OccName AvailInfo
347 import_fm = listToFM [ (nameOccName name, avail)
349 name <- availNames avail]
350 -- Even though availNames returns data constructors too,
351 -- they won't make any difference because naked entities like T
352 -- in an import list map to TcOccs, not VarOccs.
354 bale_out item = addErrRn (badImportItemErr mod item) `thenRn_`
357 get_item item@(IEModuleContents _) = bale_out item
359 get_item item@(IEThingAll _)
360 = case check_item item of
361 Nothing -> bale_out item
362 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
363 -- only export T abstractly. The single [n]
364 -- in the AvailTC is the type or class itself
365 addWarnRn (dodgyImportWarn mod item) `thenRn_`
366 returnRn [(avail, [availName avail])]
367 Just avail -> returnRn [(avail, [availName avail])]
369 get_item item@(IEThingAbs n)
370 | want_hiding -- hiding( C )
371 -- Here the 'C' can be a data constructor *or* a type/class
372 = case catMaybes [check_item item, check_item (IEThingAbs data_n)] of
374 avails -> returnRn [(a, []) | a <- avails]
375 -- The 'explicits' list is irrelevant when hiding
377 data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName)
380 = case check_item item of
381 Nothing -> bale_out item
382 Just avail -> returnRn [(avail, availNames avail)]
385 | not (maybeToBool maybe_in_import_avails) ||
386 not (maybeToBool maybe_filtered_avail)
390 = Just filtered_avail
393 wanted_occ = rdrNameOcc (ieName item)
394 maybe_in_import_avails = lookupFM import_fm wanted_occ
396 Just avail = maybe_in_import_avails
397 maybe_filtered_avail = filterAvail item avail
398 Just filtered_avail = maybe_filtered_avail
403 %************************************************************************
405 \subsection{Qualifiying imports}
407 %************************************************************************
409 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
410 of an import decl, and deals with producing an @RnEnv@ with the
411 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
412 fully fledged @Names@.
415 qualifyImports :: ModuleName -- Imported module
416 -> Bool -- True <=> want unqualified import
417 -> Maybe ModuleName -- Optional "as M" part
418 -> [AvailInfo] -- What's to be hidden
419 -> Avails -- Whats imported and how
420 -> RnMG (GlobalRdrEnv, ExportAvails)
422 qualifyImports this_mod unqual_imp as_mod hides avails
424 -- Make the name environment. We're talking about a
425 -- single module here, so there must be no name clashes.
426 -- In practice there only ever will be if it's the module
429 -- Add the things that are available
430 name_env1 = foldl add_avail emptyRdrEnv avails
432 -- Delete things that are hidden
433 name_env2 = foldl del_avail name_env1 hides
435 -- Create the export-availability info
436 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
438 returnRn (name_env2, export_avails)
441 qual_mod = case as_mod of
443 Just another_name -> another_name
445 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
446 add_avail env avail = foldl add_name env (availNames avail)
452 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) name
453 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) name
454 occ = nameOccName name
456 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
458 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
461 mkEmptyExportAvails :: ModuleName -> ExportAvails
462 mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyUFM)
464 mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails
465 mkExportAvails mod_name unqual_imp name_env avails
466 = (mod_avail_env, entity_avail_env)
468 mod_avail_env = unitFM mod_name unqual_avails
470 -- unqual_avails is the Avails that are visible in *unqualfied* form
471 -- (1.4 Report, Section 5.1.1)
473 -- import T hiding( f )
474 -- we delete f from avails
476 unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports
477 | otherwise = mapMaybe prune avails
479 prune (Avail n) | unqual_in_scope n = Just (Avail n)
480 prune (Avail n) | otherwise = Nothing
481 prune (AvailTC n ns) | null uqs = Nothing
482 | otherwise = Just (AvailTC n uqs)
484 uqs = filter unqual_in_scope ns
486 unqual_in_scope n = unQualInScope name_env n
488 entity_avail_env = listToUFM [ (name,avail) | avail <- avails,
489 name <- availNames avail]
491 plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails
492 plusExportAvails (m1, e1) (m2, e2)
493 = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2)
494 -- ToDo: wasteful: we do this once for each constructor!
498 %************************************************************************
500 \subsection{Export list processing}
502 %************************************************************************
504 Processing the export list.
506 You might think that we should record things that appear in the export list
507 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
508 We do check (here) that they are in scope,
509 but there is no need to slurp in their actual declaration
510 (which is what @addOccurrenceName@ forces).
512 Indeed, doing so would big trouble when
513 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
514 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
517 type ExportAccum -- The type of the accumulating parameter of
518 -- the main worker function in exportsFromAvail
519 = ([ModuleName], -- 'module M's seen so far
520 ExportOccMap, -- Tracks exported occurrence names
521 AvailEnv) -- The accumulated exported stuff, kept in an env
522 -- so we can common-up related AvailInfos
524 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
525 -- Tracks what a particular exported OccName
526 -- in an export list refers to, and which item
527 -- it came from. It's illegal to export two distinct things
528 -- that have the same occurrence name
531 exportsFromAvail :: ModuleName
532 -> Maybe [RdrNameIE] -- Export spec
536 -- Complains if two distinct exports have same OccName
537 -- Warns about identical exports.
538 -- Complains about exports items not in scope
539 exportsFromAvail this_mod Nothing export_avails global_name_env
540 = exportsFromAvail this_mod true_exports export_avails global_name_env
542 true_exports = Just $ if this_mod == mAIN_Name
543 then [IEVar main_RDR]
544 -- export Main.main *only* unless otherwise specified,
545 else [IEModuleContents this_mod]
546 -- but for all other modules export everything.
548 exportsFromAvail this_mod (Just export_items)
549 (mod_avail_env, entity_avail_env)
551 = foldlRn exports_from_item
552 ([], emptyFM, emptyAvailEnv) export_items `thenRn` \ (_, _, export_avail_map) ->
554 export_avails :: [AvailInfo]
555 export_avails = nameEnvElts export_avail_map
557 returnRn export_avails
560 exports_from_item :: ExportAccum -> RdrNameIE -> RnMG ExportAccum
562 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
563 | mod `elem` mods -- Duplicate export of M
564 = warnCheckRn opt_WarnDuplicateExports
565 (dupModuleExport mod) `thenRn_`
569 = case lookupFM mod_avail_env mod of
570 Nothing -> failWithRn acc (modExportErr mod)
571 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
574 avails' = foldl addAvail avails mod_avails
576 returnRn (mod:mods, occs', avails')
578 exports_from_item acc@(mods, occs, avails) ie
579 | not (maybeToBool maybe_in_scope)
580 = failWithRn acc (unknownNameErr (ieName ie))
582 | not (null dup_names)
583 = addNameClashErrRn rdr_name (name:dup_names) `thenRn_`
587 -- I can't see why this should ever happen; if the thing is in scope
588 -- at all it ought to have some availability
589 | not (maybeToBool maybe_avail)
590 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
595 = failWithRn acc (exportItemErr ie)
597 | otherwise -- Phew! It's OK! Now to check the occurrence stuff!
600 = warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_`
601 check_occs ie occs export_avail `thenRn` \ occs' ->
602 returnRn (mods, occs', addAvail avails export_avail)
606 maybe_in_scope = lookupFM global_name_env rdr_name
607 Just (name:dup_names) = maybe_in_scope
608 maybe_avail = lookupUFM entity_avail_env name
609 Just avail = maybe_avail
610 maybe_export_avail = filterAvail ie avail
611 enough_avail = maybeToBool maybe_export_avail
612 Just export_avail = maybe_export_avail
614 ok_item (IEThingAll _) (AvailTC _ [n]) = False
615 -- This occurs when you import T(..), but
616 -- only export T abstractly. The single [n]
617 -- in the AvailTC is the type or class itself
620 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
621 check_occs ie occs avail
622 = foldlRn check occs (availNames avail)
625 = case lookupFM occs name_occ of
626 Nothing -> returnRn (addToFM occs name_occ (name, ie))
628 | name == name' -> -- Duplicate export
629 warnCheckRn opt_WarnDuplicateExports
630 (dupExportWarn name_occ ie ie')
631 `thenRn_` returnRn occs
633 | otherwise -> -- Same occ name but different names: an error
634 failWithRn occs (exportClashErr name_occ ie ie')
636 name_occ = nameOccName name
638 mk_export_fn :: NameSet -> (Name -> ExportFlag)
639 mk_export_fn exported_names
640 = \name -> if name `elemNameSet` exported_names
645 %************************************************************************
649 %************************************************************************
652 badImportItemErr mod ie
653 = sep [ptext SLIT("Module"), quotes (pprModuleName mod),
654 ptext SLIT("does not export"), quotes (ppr ie)]
656 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
657 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
659 dodgyMsg kind item@(IEThingAll tc)
660 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
661 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
662 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
665 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModuleName mod)]
667 exportItemErr export_item
668 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
669 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
671 exportClashErr occ_name ie1 ie2
672 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
673 ,ptext SLIT("and"), quotes (ppr ie2)
674 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
677 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
678 nest 4 (vcat (map pp sorted_ns))]
680 sorted_ns = sortLt occ'ed_before (n:ns)
682 occ'ed_before a b = LT == compare (getSrcLoc a) (getSrcLoc b)
684 pp n = pprProvenance (getNameProvenance n)
686 dupExportWarn occ_name ie1 ie2
687 = hsep [quotes (ppr occ_name),
688 ptext SLIT("is exported by"), quotes (ppr ie1),
689 ptext SLIT("and"), quotes (ppr ie2)]
692 = hsep [ptext SLIT("Duplicate"),
693 quotes (ptext SLIT("Module") <+> pprModuleName mod),
694 ptext SLIT("in export list")]