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,
17 import HsSyn ( HsModule(..), ImportDecl(..), HsDecl(..), TyClDecl(..),
19 ForeignDecl(..), ForKind(..), isDynamic,
20 FixitySig(..), Sig(..),
23 import RdrHsSyn ( RdrName(..), RdrNameIE, RdrNameImportDecl,
24 RdrNameHsModule, RdrNameHsDecl,
27 import RnIfaces ( getInterfaceExports, getDeclBinders, getImportedFixities,
28 recordSlurp, checkUpToDate, loadHomeInterface
30 import BasicTypes ( IfaceFlavour(..) )
36 import UniqFM ( lookupUFM )
37 import Bag ( bagToList )
38 import Maybes ( maybeToBool )
40 import SrcLoc ( SrcLoc )
41 import NameSet ( elemNameSet, emptyNameSet )
43 import Unique ( getUnique )
44 import Util ( removeDups, equivClassesByUniq )
50 %************************************************************************
52 \subsection{Get global names}
54 %************************************************************************
57 getGlobalNames :: RdrNameHsModule
58 -> RnMG (Maybe (ExportEnv,
60 NameEnv AvailInfo -- Maps a name to its parent AvailInfo
61 -- Just for in-scope things only
63 -- Nothing => no need to recompile
65 getGlobalNames (HsModule this_mod _ exports imports decls mod_loc)
66 = -- These two fix-loops are to get the right
67 -- provenance information into a Name
68 fixRn (\ ~(rec_exp_fn, _) ->
70 fixRn (\ ~(rec_rn_env, _) ->
72 rec_unqual_fn :: Name -> Bool -- Is this chap in scope unqualified?
73 rec_unqual_fn = mkPrintUnqualFn rec_rn_env
75 -- PROCESS LOCAL DECLS
76 -- Do these *first* so that the correct provenance gets
77 -- into the global name cache.
78 importsFromLocalDecls this_mod rec_exp_fn decls `thenRn` \ (local_gbl_env, local_mod_avails) ->
80 -- PROCESS IMPORT DECLS
81 mapAndUnzipRn (importsFromImportDecl this_mod rec_unqual_fn)
82 all_imports `thenRn` \ (imp_gbl_envs, imp_avails_s) ->
85 -- We put the local env second, so that a local provenance
86 -- "wins", even if a module imports itself.
88 gbl_env :: GlobalRdrEnv
89 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv imp_gbl_envs
90 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
92 export_avails :: ExportAvails
93 export_avails = foldr plusExportAvails local_mod_avails imp_avails_s
95 returnRn (gbl_env, export_avails)
96 ) `thenRn` \ (gbl_env, export_avails) ->
99 -- We can't go for an early exit before this because we have to check
100 -- for name clashes. Consider:
102 -- module A where module B where
106 -- Suppose I've compiled everything up, and then I add a
107 -- new definition to module B, that defines "f".
109 -- Then I must detect the name clash in A before going for an early
110 -- exit. The early-exit code checks what's actually needed from B
111 -- to compile A, and of course that doesn't include B.f. That's
112 -- why we wait till after the plusRnEnv stuff to do the early-exit.
113 checkEarlyExit this_mod `thenRn` \ up_to_date ->
115 returnRn (junk_exp_fn, Nothing)
119 fixitiesFromLocalDecls gbl_env decls `thenRn` \ local_fixity_env ->
120 getImportedFixities `thenRn` \ imp_fixity_env ->
122 fixity_env = imp_fixity_env `plusNameEnv` local_fixity_env
123 rn_env = RnEnv gbl_env fixity_env
124 (_, global_avail_env) = export_avails
126 traceRn (text "fixity env" <+> vcat (map ppr (nameEnvElts fixity_env))) `thenRn_`
128 -- PROCESS EXPORT LISTS
129 exportsFromAvail this_mod exports export_avails rn_env `thenRn` \ (export_fn, export_env) ->
132 returnRn (export_fn, Just (export_env, rn_env, global_avail_env))
133 ) `thenRn` \ (_, result) ->
136 junk_exp_fn = error "RnNames:export_fn"
138 all_imports = prel_imports ++ imports
140 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
141 -- because the former doesn't even look at Prelude.hi for instance declarations,
142 -- whereas the latter does.
143 prel_imports | this_mod == pRELUDE ||
144 explicit_prelude_import ||
145 opt_NoImplicitPrelude
148 | otherwise = [ImportDecl pRELUDE
149 False {- Not qualified -}
150 HiFile {- Not source imported -}
151 Nothing {- No "as" -}
152 Nothing {- No import list -}
155 explicit_prelude_import
156 = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ])
161 = checkErrsRn `thenRn` \ no_errs_so_far ->
162 if not no_errs_so_far then
163 -- Found errors already, so exit now
167 traceRn (text "Considering whether compilation is required...") `thenRn_`
168 if not opt_SourceUnchanged then
169 -- Source code changed and no errors yet... carry on
170 traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_`
174 -- Unchanged source, and no errors yet; see if usage info
175 -- up to date, and exit if so
176 checkUpToDate mod `thenRn` \ up_to_date ->
177 putDocRn (text "Compilation" <+>
178 text (if up_to_date then "IS NOT" else "IS") <+>
179 text "required") `thenRn_`
184 importsFromImportDecl :: Module -- The module being compiled
185 -> (Name -> Bool) -- True => print unqualified
187 -> RnMG (GlobalRdrEnv,
190 importsFromImportDecl this_mod rec_unqual_fn (ImportDecl imp_mod qual_only as_source as_mod import_spec iloc)
191 = pushSrcLocRn iloc $
192 getInterfaceExports imp_mod as_source `thenRn` \ avails ->
195 -- If there's an error in getInterfaceExports, (e.g. interface
196 -- file not found) we get lots of spurious errors from 'filterImports'
197 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod)
200 filterImports imp_mod import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
202 -- Load all the home modules for the things being
203 -- bought into scope. This makes sure their fixities
204 -- are loaded before we grab the FixityEnv from Ifaces
206 home_modules = [name | avail <- filtered_avails,
207 -- Doesn't take account of hiding, but that doesn't matter
209 -- Drop NotAvailables.
210 -- Happens if filterAvail finds something missing
212 NotAvailable -> False
215 let name = availName avail,
216 not (isLocallyDefined name || nameModule name == imp_mod)
217 -- Don't try to load the module being compiled
218 -- (this can happen in mutual-recursion situations)
219 -- or from the module being imported (it's already loaded)
222 same_module n1 n2 = nameModule n1 == nameModule n2
223 load n = loadHomeInterface (doc_str n) n
224 doc_str n = ptext SLIT("Need fixities from") <+> ppr (nameModule n) <+> parens (ppr n)
226 mapRn load (nubBy same_module home_modules) `thenRn_`
228 -- We 'improve' the provenance by setting
229 -- (a) the import-reason field, so that the Name says how it came into scope
230 -- including whether it's explicitly imported
231 -- (b) the print-unqualified field
232 -- But don't fiddle with wired-in things or we get in a twist
234 improve_prov name | isWiredInName name = name
235 | otherwise = setNameProvenance name (mk_new_prov name)
237 is_explicit name = name `elemNameSet` explicits
238 mk_new_prov name = NonLocalDef (UserImport imp_mod iloc (is_explicit name))
242 qualifyImports imp_mod
243 (not qual_only) -- Maybe want unqualified names
245 filtered_avails improve_prov `thenRn` \ (rdr_name_env, mod_avails) ->
247 returnRn (rdr_name_env, mod_avails)
252 importsFromLocalDecls mod rec_exp_fn decls
253 = mapRn (getLocalDeclBinders newLocalName) decls `thenRn` \ avails_s ->
256 avails = concat avails_s
258 all_names :: [Name] -- All the defns; no dups eliminated
259 all_names = [name | avail <- avails, name <- availNames avail]
262 dups = filter non_singleton (equivClassesByUniq getUnique all_names)
264 non_singleton (x1:x2:xs) = True
265 non_singleton other = False
267 -- Check for duplicate definitions
268 mapRn (addErrRn . dupDeclErr) dups `thenRn_`
270 -- Record that locally-defined things are available
271 mapRn (recordSlurp Nothing Compulsory) avails `thenRn_`
273 -- Build the environment
275 True -- Want unqualified names
282 newLocalName rdr_name loc = newLocallyDefinedGlobalName mod (rdrNameOcc rdr_name)
285 getLocalDeclBinders :: (RdrName -> SrcLoc -> RnMG Name) -- New-name function
288 getLocalDeclBinders new_name (ValD binds)
289 = mapRn do_one (bagToList (collectTopBinders binds))
291 do_one (rdr_name, loc) = new_name rdr_name loc `thenRn` \ name ->
292 returnRn (Avail name)
294 -- foreign declarations
295 getLocalDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
296 | binds_haskell_name kind dyn
297 = new_name nm loc `thenRn` \ name ->
298 returnRn [Avail name]
303 getLocalDeclBinders new_name decl
304 = getDeclBinders new_name decl `thenRn` \ avail ->
306 NotAvailable -> returnRn [] -- Instance decls and suchlike
307 other -> returnRn [avail]
309 binds_haskell_name (FoImport _) _ = True
310 binds_haskell_name FoLabel _ = True
311 binds_haskell_name FoExport ext_nm = isDynamic ext_nm
313 fixitiesFromLocalDecls :: GlobalRdrEnv -> [RdrNameHsDecl] -> RnMG FixityEnv
314 fixitiesFromLocalDecls gbl_env decls
315 = foldlRn getFixities emptyNameEnv decls
317 getFixities :: FixityEnv -> RdrNameHsDecl -> RnMG FixityEnv
318 getFixities acc (FixD fix)
321 getFixities acc (TyClD (ClassDecl _ _ _ sigs _ _ _ _ _))
322 = foldlRn fix_decl acc [sig | FixSig sig <- sigs]
323 -- Get fixities from class decl sigs too
325 getFixities acc other_decl
328 fix_decl acc (FixitySig rdr_name fixity loc)
329 = -- Check for fixity decl for something not declared
330 case lookupRdrEnv gbl_env rdr_name of {
331 Nothing -> pushSrcLocRn loc $
332 addWarnRn (unusedFixityDecl rdr_name fixity) `thenRn_`
336 -- Check for duplicate fixity decl
337 case lookupNameEnv acc name of {
338 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc') `thenRn_`
342 Nothing -> returnRn (addToNameEnv acc name (FixitySig name fixity loc))
346 %************************************************************************
348 \subsection{Filtering imports}
350 %************************************************************************
352 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
353 available, and filters it through the import spec (if any).
356 filterImports :: Module -- The module being imported
357 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
358 -> [AvailInfo] -- What's available
359 -> RnMG ([AvailInfo], -- What's actually imported
360 [AvailInfo], -- What's to be hidden (the unqualified version, that is)
361 NameSet) -- What was imported explicitly
363 -- Complains if import spec mentions things that the module doesn't export
364 -- Warns/informs if import spec contains duplicates.
365 filterImports mod Nothing imports
366 = returnRn (imports, [], emptyNameSet)
368 filterImports mod (Just (want_hiding, import_items)) avails
369 = mapRn check_item import_items `thenRn` \ item_avails ->
372 -- All imported; item_avails to be hidden
373 returnRn (avails, item_avails, emptyNameSet)
375 -- Just item_avails imported; nothing to be hidden
376 returnRn (item_avails, [], availsToNameSet item_avails)
379 import_fm :: FiniteMap OccName AvailInfo
380 import_fm = listToFM [ (nameOccName name, avail)
382 name <- availNames avail]
383 -- Even though availNames returns data constructors too,
384 -- they won't make any difference because naked entities like T
385 -- in an import list map to TCOccs, not VarOccs.
387 check_item item@(IEModuleContents _)
388 = addErrRn (badImportItemErr mod item) `thenRn_`
389 returnRn NotAvailable
392 | not (maybeToBool maybe_in_import_avails) ||
393 (case filtered_avail of { NotAvailable -> True; other -> False })
394 = addErrRn (badImportItemErr mod item) `thenRn_`
395 returnRn NotAvailable
397 | dodgy_import = addWarnRn (dodgyImportWarn mod item) `thenRn_`
398 returnRn filtered_avail
400 | otherwise = returnRn filtered_avail
403 maybe_in_import_avails = lookupFM import_fm (ieOcc item)
404 Just avail = maybe_in_import_avails
405 filtered_avail = filterAvail item avail
406 dodgy_import = case (item, avail) of
407 (IEThingAll _, AvailTC _ [n]) -> True
408 -- This occurs when you import T(..), but
409 -- only export T abstractly. The single [n]
410 -- in the AvailTC is the type or class itself
418 %************************************************************************
420 \subsection{Qualifiying imports}
422 %************************************************************************
424 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
425 of an import decl, and deals with producing an @RnEnv@ with the
426 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
427 fully fledged @Names@.
430 qualifyImports :: Module -- Imported module
431 -> Bool -- True <=> want unqualified import
432 -> Maybe Module -- Optional "as M" part
433 -> [AvailInfo] -- What's to be hidden
434 -> Avails -- Whats imported and how
435 -> (Name -> Name) -- Improves the provenance on imported things
436 -> RnMG (GlobalRdrEnv, ExportAvails)
437 -- NB: the Names in ExportAvails don't have the improve-provenance
438 -- function applied to them
439 -- We could fix that, but I don't think it matters
441 qualifyImports this_mod unqual_imp as_mod hides
444 -- Make the name environment. We're talking about a
445 -- single module here, so there must be no name clashes.
446 -- In practice there only ever will be if it's the module
449 -- Add the things that are available
450 name_env1 = foldl add_avail emptyRdrEnv avails
452 -- Delete things that are hidden
453 name_env2 = foldl del_avail name_env1 hides
455 -- Create the export-availability info
456 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
458 returnRn (name_env2, export_avails)
461 qual_mod = case as_mod of
463 Just another_name -> another_name
465 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
466 add_avail env avail = foldl add_name env (availNames avail)
472 env1 = addOneToGlobalRdrEnv env (Qual qual_mod occ err_hif) better_name
473 env2 = addOneToGlobalRdrEnv env1 (Unqual occ) better_name
474 occ = nameOccName name
475 better_name = improve_prov name
477 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
479 rdr_names = map (Unqual . nameOccName) (availNames avail)
481 err_hif = error "qualifyImports: hif" -- Not needed in key to mapping
485 %************************************************************************
487 \subsection{Export list processing
489 %************************************************************************
491 Processing the export list.
493 You might think that we should record things that appear in the export list as
494 ``occurrences'' (using addOccurrenceName), but you'd be wrong. We do check (here)
495 that they are in scope, but there is no need to slurp in their actual declaration
496 (which is what addOccurrenceName forces). Indeed, doing so would big trouble when
497 compiling PrelBase, because it re-exports GHC, which includes takeMVar#, whose type
498 includes ConcBase.StateAndSynchVar#, and so on...
501 type ExportAccum -- The type of the accumulating parameter of
502 -- the main worker function in exportsFromAvail
503 = ([Module], -- 'module M's seen so far
504 ExportOccMap, -- Tracks exported occurrence names
505 NameEnv AvailInfo) -- The accumulated exported stuff, kept in an env
506 -- so we can common-up related AvailInfos
508 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
509 -- Tracks what a particular exported OccName
510 -- in an export list refers to, and which item
511 -- it came from. It's illegal to export two distinct things
512 -- that have the same occurrence name
515 exportsFromAvail :: Module
516 -> Maybe [RdrNameIE] -- Export spec
519 -> RnMG (Name -> ExportFlag, ExportEnv)
520 -- Complains if two distinct exports have same OccName
521 -- Warns about identical exports.
522 -- Complains about exports items not in scope
523 exportsFromAvail this_mod Nothing export_avails rn_env
524 = exportsFromAvail this_mod (Just [IEModuleContents this_mod]) export_avails rn_env
526 exportsFromAvail this_mod (Just export_items)
527 (mod_avail_env, entity_avail_env)
528 (RnEnv global_name_env fixity_env)
529 = foldlRn exports_from_item
530 ([], emptyFM, emptyNameEnv) export_items `thenRn` \ (_, _, export_avail_map) ->
532 export_avails :: [AvailInfo]
533 export_avails = nameEnvElts export_avail_map
535 export_names :: NameSet
536 export_names = availsToNameSet export_avails
538 -- Export only those fixities that are for names that are
539 -- (a) defined in this module
541 export_fixities :: [(Name,Fixity)]
542 export_fixities = [ (name,fixity)
543 | FixitySig name fixity _ <- nameEnvElts fixity_env,
544 name `elemNameSet` export_names,
545 isLocallyDefined name
548 export_fn :: Name -> ExportFlag
549 export_fn = mk_export_fn export_names
551 returnRn (export_fn, ExportEnv export_avails export_fixities)
554 exports_from_item :: ExportAccum -> RdrNameIE -> RnMG ExportAccum
556 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
557 | mod `elem` mods -- Duplicate export of M
558 = warnCheckRn opt_WarnDuplicateExports
559 (dupModuleExport mod) `thenRn_`
563 = case lookupFM mod_avail_env mod of
564 Nothing -> failWithRn acc (modExportErr mod)
565 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails `thenRn` \ occs' ->
567 avails' = foldl add_avail avails mod_avails
569 returnRn (mod:mods, occs', avails')
571 exports_from_item acc@(mods, occs, avails) ie
572 | not (maybeToBool maybe_in_scope)
573 = failWithRn acc (unknownNameErr (ieName ie))
575 | not (null dup_names)
576 = addNameClashErrRn rdr_name (name:dup_names) `thenRn_`
580 -- I can't see why this should ever happen; if the thing is in scope
581 -- at all it ought to have some availability
582 | not (maybeToBool maybe_avail)
583 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
588 = failWithRn acc (exportItemErr ie export_avail)
590 | otherwise -- Phew! It's OK! Now to check the occurrence stuff!
591 = check_occs ie occs export_avail `thenRn` \ occs' ->
592 returnRn (mods, occs', add_avail avails export_avail)
596 maybe_in_scope = lookupFM global_name_env rdr_name
597 Just (name:dup_names) = maybe_in_scope
598 maybe_avail = lookupUFM entity_avail_env name
599 Just avail = maybe_avail
600 export_avail = filterAvail ie avail
601 enough_avail = case export_avail of {NotAvailable -> False; other -> True}
603 add_avail avails avail = addToNameEnv_C plusAvail avails (availName avail) avail
605 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
606 check_occs ie occs avail
607 = foldlRn check occs (availNames avail)
610 = case lookupFM occs name_occ of
611 Nothing -> returnRn (addToFM occs name_occ (name, ie))
613 | name == name' -> -- Duplicate export
614 warnCheckRn opt_WarnDuplicateExports
615 (dupExportWarn name_occ ie ie') `thenRn_`
618 | otherwise -> -- Same occ name but different names: an error
619 failWithRn occs (exportClashErr name_occ ie ie')
621 name_occ = nameOccName name
623 mk_export_fn :: NameSet -> (Name -> ExportFlag)
624 mk_export_fn exported_names
625 = \name -> if name `elemNameSet` exported_names
630 %************************************************************************
634 %************************************************************************
637 badImportItemErr mod ie
638 = sep [ptext SLIT("Module"), quotes (pprModule mod),
639 ptext SLIT("does not export"), quotes (ppr ie)]
641 dodgyImportWarn mod (IEThingAll tc)
642 = sep [ptext SLIT("Module") <+> quotes (pprModule mod) <+> ptext SLIT("exports") <+> quotes (ppr tc),
643 ptext SLIT("with no constructors/class operations;"),
644 ptext SLIT("yet it is imported with a (..)")]
647 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModule mod)]
649 exportItemErr export_item NotAvailable
650 = sep [ ptext SLIT("Export item not in scope:"), quotes (ppr export_item)]
652 exportItemErr export_item avail
653 = hang (ptext SLIT("Export item not fully in scope:"))
654 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr export_item],
655 hsep [ptext SLIT("Available:"), ppr (ieOcc export_item), pprAvail avail]])
657 exportClashErr occ_name ie1 ie2
658 = hsep [ptext SLIT("The export items"), quotes (ppr ie1), ptext SLIT("and"), quotes (ppr ie2),
659 ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
662 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
663 nest 4 (vcat (map pp (n:ns)))]
665 pp n = pprProvenance (getNameProvenance n)
667 dupExportWarn occ_name ie1 ie2
668 = hsep [quotes (ppr occ_name),
669 ptext SLIT("is exported by"), quotes (ppr ie1),
670 ptext SLIT("and"), quotes (ppr ie2)]
673 = hsep [ptext SLIT("Duplicate"),
674 quotes (ptext SLIT("Module") <+> pprModule mod),
675 ptext SLIT("in export list")]
677 unusedFixityDecl rdr_name fixity
678 = hsep [ptext SLIT("Unused fixity declaration for"), quotes (ppr rdr_name)]
680 dupFixityDecl rdr_name loc1 loc2
681 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
682 ptext SLIT("at ") <+> ppr loc1,
683 ptext SLIT("and") <+> ppr loc2]