2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[RnNames]{Extracting imported and top-level names in scope}
7 #include "HsVersions.h"
15 import CmdLineOpts ( opt_SourceUnchanged, opt_NoImplicitPrelude )
16 import HsSyn ( HsModule(..), HsDecl(..), FixityDecl(..), Fixity, Fake, InPat, IE(..), HsTyVar,
17 TyDecl, ClassDecl, InstDecl, DefaultDecl, ImportDecl(..), HsBinds, IfaceSig,
20 import HsImpExp ( ieName )
21 import RdrHsSyn ( RdrNameHsDecl(..), RdrName(..), RdrNameIE(..), SYN_IE(RdrNameImportDecl),
22 SYN_IE(RdrNameHsModule), SYN_IE(RdrNameFixityDecl),
25 import RnHsSyn ( RenamedHsModule(..), RenamedFixityDecl(..) )
26 import RnIfaces ( getInterfaceExports, getDeclBinders, checkUpToDate, recordSlurp )
31 import UniqFM ( UniqFM, emptyUFM, addListToUFM_C, lookupUFM )
32 import Bag ( Bag, bagToList )
33 import Maybes ( maybeToBool, expectJust )
36 import Outputable ( Outputable(..), PprStyle(..) )
37 import Util ( panic, pprTrace, assertPanic )
42 %************************************************************************
44 \subsection{Get global names}
46 %************************************************************************
49 getGlobalNames :: RdrNameHsModule
50 -> RnMG (Maybe (ExportEnv, RnEnv, NameSet))
51 -- Nothing <=> no need to recompile
52 -- The NameSet is the set of names that are
53 -- either locally defined,
54 -- or explicitly imported
56 getGlobalNames m@(HsModule this_mod _ exports imports _ _ mod_loc)
57 = fixRn (\ ~(rec_exp_fn, _) ->
59 -- PROCESS LOCAL DECLS
60 -- Do these *first* so that the correct provenance gets
61 -- into the global name cache.
62 importsFromLocalDecls rec_exp_fn m `thenRn` \ (local_rn_env, local_mod_avails, local_avails) ->
64 -- PROCESS IMPORT DECLS
65 mapAndUnzip3Rn importsFromImportDecl all_imports
66 `thenRn` \ (imp_rn_envs, imp_avails_s, explicit_imports_s) ->
68 -- CHECK FOR EARLY EXIT
69 checkEarlyExit this_mod `thenRn` \ early_exit ->
71 returnRn (junk_exp_fn, Nothing)
75 -- We put the local env second, so that a local provenance
76 -- "wins", even if a module imports itself.
77 foldlRn plusRnEnv emptyRnEnv imp_rn_envs `thenRn` \ imp_rn_env ->
78 plusRnEnv imp_rn_env local_rn_env `thenRn` \ rn_env ->
80 export_avails :: ExportAvails
81 export_avails = foldr plusExportAvails local_mod_avails imp_avails_s
83 explicit_names :: NameSet -- locally defined or explicitly imported
84 explicit_names = foldr add_on emptyNameSet (local_avails : explicit_imports_s)
85 add_on avails names = foldr (unionNameSets . mkNameSet . availNames) names avails
88 -- PROCESS EXPORT LISTS
89 exportsFromAvail this_mod exports export_avails rn_env
90 `thenRn` \ (export_fn, export_env) ->
92 -- RECORD THAT LOCALLY DEFINED THINGS ARE AVAILABLE
93 mapRn (recordSlurp Nothing Compulsory) local_avails `thenRn_`
95 returnRn (export_fn, Just (export_env, rn_env, explicit_names))
96 ) `thenRn` \ (_, result) ->
99 junk_exp_fn = error "RnNames:export_fn"
101 all_imports = prel_imports ++ imports
103 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
104 -- because the former doesn't even look at Prelude.hi for instance declarations,
105 -- whereas the latter does.
106 prel_imports | this_mod == pRELUDE ||
107 explicit_prelude_import ||
108 opt_NoImplicitPrelude
111 | otherwise = [ImportDecl pRELUDE
112 False {- Not qualified -}
113 False {- Not source imported -}
114 Nothing {- No "as" -}
115 Nothing {- No import list -}
118 explicit_prelude_import
119 = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ])
124 = checkErrsRn `thenRn` \ no_errs_so_far ->
125 if not no_errs_so_far then
126 -- Found errors already, so exit now
129 traceRn (text "Considering whether compilation is required...") `thenRn_`
130 (if not opt_SourceUnchanged then
131 -- Source code changed and no errors yet... carry on
132 traceRn (nest 4 (text "source file changed")) `thenRn_`
135 -- Unchanged source, and no errors yet; see if usage info
136 -- up to date, and exit if so
138 ) `thenRn` \ up_to_date ->
139 traceRn (text "Hence, compilation" <+>
140 text (if up_to_date then "IS NOT" else "IS") <+>
141 text "required") `thenRn_`
147 importsFromImportDecl :: RdrNameImportDecl
148 -> RnMG (RnEnv, ExportAvails, [AvailInfo])
150 importsFromImportDecl (ImportDecl mod qual_only as_source as_mod import_spec loc)
152 getInterfaceExports mod as_source `thenRn` \ (avails, fixities) ->
153 filterImports mod import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
155 filtered_avails' = map set_avail_prov filtered_avails
156 fixities' = [ (occ,(fixity,provenance)) | (occ,fixity) <- fixities ]
159 True -- Want qualified names
160 (not qual_only) -- Maybe want unqualified names
162 (ExportEnv filtered_avails' fixities')
164 `thenRn` \ (rn_env, mod_avails) ->
165 returnRn (rn_env, mod_avails, explicits)
167 set_avail_prov NotAvailable = NotAvailable
168 set_avail_prov (Avail n) = Avail (set_name_prov n)
169 set_avail_prov (AvailTC n ns) = AvailTC (set_name_prov n) (map set_name_prov ns)
170 set_name_prov name = setNameProvenance name provenance
171 provenance = Imported mod loc
176 importsFromLocalDecls rec_exp_fn (HsModule mod _ _ _ fix_decls decls _)
177 = foldlRn getLocalDeclBinders [] decls `thenRn` \ avails ->
178 mapRn fixityFromFixDecl fix_decls `thenRn` \ fixities ->
180 False -- Don't want qualified names
181 True -- Want unqualified names
182 Nothing -- No "as M" part
183 (ExportEnv avails fixities)
185 `thenRn` \ (rn_env, mod_avails) ->
186 returnRn (rn_env, mod_avails, avails)
188 newLocalName rdr_name loc
189 = newLocallyDefinedGlobalName mod (rdrNameOcc rdr_name) rec_exp_fn loc
191 getLocalDeclBinders avails (ValD binds)
192 = mapRn do_one (bagToList (collectTopBinders binds)) `thenRn` \ val_avails ->
193 returnRn (val_avails ++ avails)
195 getLocalDeclBinders avails decl
196 = getDeclBinders newLocalName decl `thenRn` \ avail ->
198 NotAvailable -> returnRn avails -- Instance decls and suchlike
199 other -> returnRn (avail : avails)
201 do_one (rdr_name, loc)
202 = newLocalName rdr_name loc `thenRn` \ name ->
203 returnRn (Avail name)
206 %************************************************************************
208 \subsection{Filtering imports}
210 %************************************************************************
212 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
213 available, and filters it through the import spec (if any).
216 filterImports :: Module
217 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hidin
218 -> [AvailInfo] -- What's available
219 -> RnMG ([AvailInfo], -- What's actually imported
220 [AvailInfo], -- What's to be hidden (the unqualified version, that is)
221 [AvailInfo]) -- What was imported explicitly
223 -- Complains if import spec mentions things that the module doesn't export
225 filterImports mod Nothing imports
226 = returnRn (imports, [], [])
228 filterImports mod (Just (want_hiding, import_items)) avails
229 = mapRn check_item import_items `thenRn` \ item_avails ->
232 returnRn (avails, item_avails, []) -- All imported; item_avails to be hidden
234 returnRn (item_avails, [], item_avails) -- Just item_avails imported; nothing to be hidden
237 import_fm :: FiniteMap OccName AvailInfo
238 import_fm = listToFM [ (nameOccName name, avail)
240 name <- availEntityNames avail]
242 check_item item@(IEModuleContents _)
243 = addErrRn (badImportItemErr mod item) `thenRn_`
244 returnRn NotAvailable
247 | not (maybeToBool maybe_in_import_avails) ||
248 (case filtered_avail of { NotAvailable -> True; other -> False })
249 = addErrRn (badImportItemErr mod item) `thenRn_`
250 returnRn NotAvailable
252 | otherwise = returnRn filtered_avail
255 maybe_in_import_avails = lookupFM import_fm (ieOcc item)
256 Just avail = maybe_in_import_avails
257 filtered_avail = filterAvail item avail
262 %************************************************************************
264 \subsection{Qualifiying imports}
266 %************************************************************************
268 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
269 of an import decl, and deals with producing an @RnEnv@ with the
270 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
271 fully fledged @Names@.
274 qualifyImports :: Module -- Imported module
275 -> Bool -- True <=> want qualified import
276 -> Bool -- True <=> want unqualified import
277 -> Maybe Module -- Optional "as M" part
278 -> ExportEnv -- What's imported
279 -> [AvailInfo] -- What's to be hidden
280 -> RnMG (RnEnv, ExportAvails)
282 qualifyImports this_mod qual_imp unqual_imp as_mod (ExportEnv avails fixities) hides
284 -- Make the name environment. Even though we're talking about a
285 -- single import module there might still be name clashes,
286 -- because it might be the module being compiled.
287 foldlRn add_avail emptyNameEnv avails `thenRn` \ name_env1 ->
289 -- Delete things that are hidden
290 name_env2 = foldl del_avail name_env1 hides
292 -- Create the fixity env
293 fixity_env = foldl (add_fixity name_env2) emptyFixityEnv fixities
295 -- Create the export-availability info
296 export_avails = mkExportAvails unqual_imp qual_mod avails
298 returnRn (RnEnv name_env2 fixity_env, export_avails)
300 qual_mod = case as_mod of
302 Just another_name -> another_name
304 add_avail env avail = foldlRn add_name env (availNames avail)
305 add_name env name = add qual_imp env (Qual qual_mod occ) `thenRn` \ env1 ->
306 add unqual_imp env1 (Unqual occ)
308 add False env rdr_name = returnRn env
309 add True env rdr_name = addOneToNameEnv env rdr_name name
310 occ = nameOccName name
312 del_avail env avail = foldl delOneFromNameEnv env rdr_names
314 rdr_names = map (Unqual . nameOccName) (availNames avail)
316 add_fixity name_env fix_env (occ_name, (fixity, provenance))
317 = add qual $ add unqual $ fix_env
319 qual = Qual qual_mod occ_name
320 unqual = Unqual occ_name
322 add rdr_name fix_env | maybeToBool (lookupFM name_env rdr_name)
323 = addOneToFixityEnv fix_env rdr_name (fixity,provenance)
328 unQualify adds an Unqual binding for every existing Qual binding.
331 unQualify :: FiniteMap RdrName elt -> FiniteMap RdrName elt
332 unQualify fm = addListToFM fm [(Unqual occ, elt) | (Qual _ occ, elt) <- fmToList fm]
335 %************************************************************************
337 \subsection{Local declarations}
339 %************************************************************************
343 fixityFromFixDecl :: RdrNameFixityDecl -> RnMG (OccName, (Fixity, Provenance))
345 fixityFromFixDecl (FixityDecl rdr_name fixity loc)
346 = returnRn (rdrNameOcc rdr_name, (fixity, LocalDef (panic "export-flag") loc))
350 %************************************************************************
352 \subsection{Export list processing
354 %************************************************************************
356 The @AvailEnv@ type is just used internally in @exportsFromAvail@.
357 When exporting we need to combine the availabilities for a particular
358 exported thing, and we also need to check for name clashes -- that
359 is: two exported things must have different @OccNames@.
362 type AvailEnv = FiniteMap OccName (RdrNameIE, AvailInfo)
363 -- The FM maps each OccName to the RdrNameIE that gave rise to it,
364 -- for error reporting, as well as to its AvailInfo
366 emptyAvailEnv = emptyFM
368 unitAvailEnv :: RdrNameIE -> AvailInfo -> AvailEnv
369 unitAvailEnv ie NotAvailable = emptyFM
370 unitAvailEnv ie (AvailTC _ []) = emptyFM
371 unitAvailEnv ie avail = unitFM (nameOccName (availName avail)) (ie,avail)
374 = mapRn (addErrRn.availClashErr) (conflictsFM bad_avail a1 a2) `thenRn_`
375 returnRn (plusFM_C plus_avail a1 a2)
377 listToAvailEnv :: RdrNameIE -> [AvailInfo] -> RnM s d AvailEnv
378 listToAvailEnv ie items
379 = foldlRn plusAvailEnv emptyAvailEnv (map (unitAvailEnv ie) items)
381 bad_avail (ie1,avail1) (ie2,avail2) = availName avail1 /= availName avail2 -- Same OccName, different Name
382 plus_avail (ie1,a1) (ie2,a2) = (ie1, a1 `plusAvail` a2)
385 Processing the export list.
387 You might think that we should record things that appear in the export list as
388 ``occurrences'' (using addOccurrenceName), but you'd be wrong. We do check (here)
389 that they are in scope, but there is no need to slurp in their actual declaration
390 (which is what addOccurrenceName forces). Indeed, doing so would big trouble when
391 compiling PrelBase, because it re-exports GHC, which includes takeMVar#, whose type
392 includes ConcBase.StateAndSynchVar#, and so on...
395 exportsFromAvail :: Module
396 -> Maybe [RdrNameIE] -- Export spec
399 -> RnMG (Name -> ExportFlag, ExportEnv)
400 -- Complains if two distinct exports have same OccName
401 -- Complains about exports items not in scope
402 exportsFromAvail this_mod Nothing export_avails rn_env
403 = exportsFromAvail this_mod (Just [IEModuleContents this_mod]) export_avails rn_env
405 exportsFromAvail this_mod (Just export_items)
406 (mod_avail_env, entity_avail_env)
407 (RnEnv name_env fixity_env)
408 = mapRn exports_from_item export_items `thenRn` \ avail_envs ->
409 foldlRn plusAvailEnv emptyAvailEnv avail_envs `thenRn` \ export_avail_env ->
411 export_avails = map snd (eltsFM export_avail_env)
412 export_fixities = mk_exported_fixities (availsToNameSet export_avails)
413 export_fn = mk_export_fn export_avails
415 returnRn (export_fn, ExportEnv export_avails export_fixities)
418 exports_from_item :: RdrNameIE -> RnMG AvailEnv
419 exports_from_item ie@(IEModuleContents mod)
420 = case lookupFM mod_avail_env mod of
421 Nothing -> failWithRn emptyAvailEnv (modExportErr mod)
422 Just avails -> listToAvailEnv ie avails
425 | not (maybeToBool maybe_in_scope)
426 = failWithRn emptyAvailEnv (unknownNameErr (ieName ie))
429 -- I can't see why this should ever happen; if the thing is in scope
430 -- at all it ought to have some availability
431 | not (maybeToBool maybe_avail)
432 = pprTrace "exportsFromAvail: curious Nothing:" (ppr PprDebug name)
433 returnRn emptyAvailEnv
437 = failWithRn emptyAvailEnv (exportItemErr ie export_avail)
439 | otherwise -- Phew! It's OK!
440 = returnRn (unitAvailEnv ie export_avail)
442 maybe_in_scope = lookupNameEnv name_env (ieName ie)
443 Just name = maybe_in_scope
444 maybe_avail = lookupUFM entity_avail_env name
445 Just avail = maybe_avail
446 export_avail = filterAvail ie avail
447 enough_avail = case export_avail of {NotAvailable -> False; other -> True}
449 -- We export a fixity iff we export a thing with the same (qualified) RdrName
450 mk_exported_fixities :: NameSet -> [(OccName, (Fixity, Provenance))]
451 mk_exported_fixities exports
452 = fmToList (foldr (perhaps_add_fixity exports)
454 (fmToList fixity_env))
456 perhaps_add_fixity :: NameSet -> (RdrName, (Fixity, Provenance))
457 -> FiniteMap OccName (Fixity,Provenance)
458 -> FiniteMap OccName (Fixity,Provenance)
459 perhaps_add_fixity exports (rdr_name, (fixity, prov)) fix_env
461 do_nothing = fix_env -- The default is to pass on the env unchanged
463 -- Step 1: check whether the rdr_name is in scope; if so find its Name
464 case lookupFM name_env rdr_name of {
465 Nothing -> do_nothing;
468 -- Step 2: check whether the fixity thing is exported
469 if not (fixity_name `elemNameSet` exports) then
473 -- Step 3: check whether we already have a fixity for the
474 -- Name's OccName in the fix_env we are building up. This can easily
475 -- happen. the original fixity_env might contain bindings for
476 -- M.a and N.a, if a was imported via M and N.
477 -- If this does happen, we expect the fixity to be the same either way.
479 occ_name = rdrNameOcc rdr_name
481 case lookupFM fix_env occ_name of {
482 Just (fixity1, prov1) -> -- Got it already
483 ASSERT( fixity == fixity1 )
487 -- Step 3: add it to the outgoing fix_env
488 addToFM fix_env occ_name (fixity,prov)
491 mk_export_fn :: [AvailInfo] -> (Name -> ExportFlag)
493 = \name -> if name `elemNameSet` exported_names
497 exported_names :: NameSet
498 exported_names = availsToNameSet avails
502 %************************************************************************
506 %************************************************************************
509 badImportItemErr mod ie sty
510 = sep [ptext SLIT("Module"), pprModule sty mod, ptext SLIT("does not export"), ppr sty ie]
513 = hsep [ ptext SLIT("Unknown module in export list: module"), ptext mod]
515 exportItemErr export_item NotAvailable sty
516 = sep [ ptext SLIT("Export item not in scope:"), ppr sty export_item ]
518 exportItemErr export_item avail sty
519 = hang (ptext SLIT("Export item not fully in scope:"))
520 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr sty export_item],
521 hsep [ptext SLIT("Available:"), ppr sty (ieOcc export_item), pprAvail sty avail]])
523 availClashErr (occ_name, ((ie1,avail1), (ie2,avail2))) sty
524 = hsep [ptext SLIT("The export items"), ppr sty ie1, ptext SLIT("and"), ppr sty ie2,
525 ptext SLIT("create conflicting exports for"), ppr sty occ_name]