2 % (c) The GRASP Project, Glasgow University, 1992-1998
4 \section[Rename]{Renaming and dependency analysis passes}
7 module Rename ( renameModule ) where
9 #include "HsVersions.h"
12 import HsPragmas ( DataPragmas(..) )
13 import RdrHsSyn ( RdrNameHsModule, RdrNameHsDecl, RdrNameDeprecation )
14 import RnHsSyn ( RenamedHsModule, RenamedHsDecl,
15 extractHsTyNames, extractHsCtxtTyNames
18 import CmdLineOpts ( opt_HiMap, opt_D_dump_rn_trace, opt_D_dump_minimal_imports,
19 opt_D_dump_rn, opt_D_dump_rn_stats, opt_WarnDeprecations,
23 import RnNames ( getGlobalNames )
24 import RnSource ( rnSourceDecls, rnDecl )
25 import RnIfaces ( getImportedInstDecls, importDecl, mkImportExportInfo, getInterfaceExports,
26 getImportedRules, getSlurped, removeContext,
27 loadBuiltinRules, getDeferredDecls, ImportDeclResult(..)
29 import RnEnv ( availName, availsToNameSet,
30 emptyAvailEnv, unitAvailEnv, availEnvElts, plusAvailEnv,
31 warnUnusedImports, warnUnusedLocalBinds, warnUnusedModules,
32 lookupOrigNames, unknownNameErr,
33 FreeVars, plusFVs, plusFV, unitFV, emptyFVs, isEmptyFVs, addOneFV
35 import Module ( Module, ModuleName, WhereFrom(..),
36 moduleNameUserString, mkSearchPath, moduleName, mkThisModule
38 import Name ( Name, isLocallyDefined, NamedThing(..), getSrcLoc,
39 nameOccName, nameUnique, nameModule, maybeUserImportedFrom,
40 isUserImportedExplicitlyName, isUserImportedName,
41 maybeWiredInTyConName, maybeWiredInIdName,
42 isUserExportedName, toRdrName,
43 nameEnvElts, extendNameEnv
45 import OccName ( occNameFlavour, isValOcc )
47 import TyCon ( isSynTyCon, getSynTyConDefn )
49 import TysWiredIn ( unitTyCon, intTyCon, doubleTyCon, boolTyCon )
50 import PrelRules ( builtinRules )
51 import PrelInfo ( mAIN_Name, pREL_MAIN_Name, pRELUDE_Name,
52 ioTyCon_RDR, unpackCString_RDR, unpackCStringFoldr_RDR, unpackCStringUtf8_RDR,
53 fractionalClassKeys, derivingOccurrences
55 import Type ( namesOfType, funTyCon )
56 import ErrUtils ( printErrorsAndWarnings, dumpIfSet, ghcExit )
57 import BasicTypes ( Version, initialVersion )
58 import Bag ( isEmptyBag, bagToList )
59 import FiniteMap ( FiniteMap, eltsFM, fmToList, emptyFM, lookupFM,
60 addToFM_C, elemFM, addToFM
62 import UniqSupply ( UniqSupply )
63 import UniqFM ( lookupUFM )
64 import SrcLoc ( noSrcLoc )
65 import Maybes ( maybeToBool, expectJust )
67 import IO ( openFile, IOMode(..) )
73 type RenameResult = ( Module -- This module
74 , RenamedHsModule -- Renamed module
75 , Maybe ParsedIface -- The existing interface file, if any
76 , ParsedIface -- The new interface
77 , RnNameSupply -- Final env; for renaming derivings
78 , FixityEnv -- The fixity environment; for derivings
79 , [Module]) -- Imported modules
81 renameModule :: UniqSupply -> RdrNameHsModule -> IO (Maybe RenameResult)
82 renameModule us this_mod@(HsModule mod_name vers exports imports local_decls _ loc)
83 = -- Initialise the renamer monad
85 ((maybe_rn_stuff, dump_action), rn_errs_bag, rn_warns_bag)
86 <- initRn (mkThisModule mod_name) us
87 (mkSearchPath opt_HiMap) loc
91 printErrorsAndWarnings rn_errs_bag rn_warns_bag ;
93 -- Dump any debugging output
97 if not (isEmptyBag rn_errs_bag) then
98 do { ghcExit 1 ; return Nothing }
100 return maybe_rn_stuff
105 rename :: RdrNameHsModule -> RnMG (Maybe RenameResult, IO ())
106 rename this_mod@(HsModule mod_name vers exports imports local_decls mod_deprec loc)
107 = -- FIND THE GLOBAL NAME ENVIRONMENT
108 getGlobalNames this_mod `thenRn` \ maybe_stuff ->
110 -- CHECK FOR EARLY EXIT
111 case maybe_stuff of {
112 Nothing -> -- Everything is up to date; no need to recompile further
113 rnDump [] [] `thenRn` \ dump_action ->
114 returnRn (Nothing, dump_action) ;
116 Just (gbl_env, local_gbl_env, export_avails, global_avail_env, old_iface) ->
118 -- DEAL WITH DEPRECATIONS
119 rnDeprecs local_gbl_env mod_deprec local_decls `thenRn` \ my_deprecs ->
121 -- DEAL WITH LOCAL FIXITIES
122 fixitiesFromLocalDecls local_gbl_env local_decls `thenRn` \ local_fixity_env ->
125 initRnMS gbl_env local_fixity_env SourceMode (
126 rnSourceDecls local_decls
127 ) `thenRn` \ (rn_local_decls, source_fvs) ->
129 -- SLURP IN ALL THE NEEDED DECLARATIONS
130 implicitFVs mod_name rn_local_decls `thenRn` \ implicit_fvs ->
132 -- The export_fvs make the exported names look just as if they
133 -- occurred in the source program. For the reasoning, see the
134 -- comments with RnIfaces.getImportVersions.
135 -- We only need the 'parent name' of the avail;
136 -- that's enough to suck in the declaration.
137 export_fvs = mkNameSet (map availName export_avails)
138 real_source_fvs = source_fvs `plusFV` export_fvs
140 slurp_fvs = implicit_fvs `plusFV` real_source_fvs
141 -- It's important to do the "plus" this way round, so that
142 -- when compiling the prelude, locally-defined (), Bool, etc
143 -- override the implicit ones.
145 loadBuiltinRules builtinRules `thenRn_`
146 slurpImpDecls slurp_fvs `thenRn` \ rn_imp_decls ->
148 -- EXIT IF ERRORS FOUND
149 rnDump rn_imp_decls rn_local_decls `thenRn` \ dump_action ->
150 checkErrsRn `thenRn` \ no_errs_so_far ->
151 if not no_errs_so_far then
152 -- Found errors already, so exit now
153 returnRn (Nothing, dump_action)
156 -- GENERATE THE VERSION/USAGE INFO
157 mkImportExportInfo mod_name export_avails exports `thenRn` \ (my_exports, my_usages) ->
159 -- RETURN THE RENAMED MODULE
160 getNameSupplyRn `thenRn` \ name_supply ->
161 getIfacesRn `thenRn` \ ifaces ->
163 direct_import_mods :: [Module]
164 direct_import_mods = [m | (_, _, Just (m, _, _, _, imp, _))
165 <- eltsFM (iImpModInfo ifaces), user_import imp]
167 -- *don't* just pick the forward edges. It's entirely possible
168 -- that a module is only reachable via back edges.
169 user_import ImportByUser = True
170 user_import ImportByUserSource = True
171 user_import _ = False
173 this_module = mkThisModule mod_name
175 -- Export only those fixities that are for names that are
176 -- (a) defined in this module
179 = [ FixitySig (toRdrName name) fixity loc
180 | FixitySig name fixity loc <- nameEnvElts local_fixity_env,
181 isUserExportedName name
184 new_iface = ParsedIface { pi_mod = this_module
185 , pi_vers = initialVersion
186 , pi_orphan = any isOrphanDecl rn_local_decls
187 , pi_exports = my_exports
188 , pi_usages = my_usages
189 , pi_fixity = (initialVersion, exported_fixities)
190 , pi_deprecs = my_deprecs
191 -- These ones get filled in later
192 , pi_insts = [], pi_decls = []
193 , pi_rules = (initialVersion, [])
196 renamed_module = HsModule mod_name vers
197 trashed_exports trashed_imports
198 (rn_local_decls ++ rn_imp_decls)
202 result = (this_module, renamed_module,
203 old_iface, new_iface,
204 name_supply, local_fixity_env,
208 -- REPORT UNUSED NAMES, AND DEBUG DUMP
209 reportUnusedNames mod_name direct_import_mods
210 gbl_env global_avail_env
211 export_avails source_fvs
212 rn_imp_decls `thenRn_`
214 returnRn (Just result, dump_action) }
216 trashed_exports = {-trace "rnSource:trashed_exports"-} Nothing
217 trashed_imports = {-trace "rnSource:trashed_imports"-} []
220 @implicitFVs@ forces the renamer to slurp in some things which aren't
221 mentioned explicitly, but which might be needed by the type checker.
224 implicitFVs mod_name decls
225 = lookupOrigNames implicit_occs `thenRn` \ implicit_names ->
226 returnRn (mkNameSet (map getName default_tycons) `plusFV`
229 -- Add occurrences for Int, and (), because they
230 -- are the types to which ambigious type variables may be defaulted by
231 -- the type checker; so they won't always appear explicitly.
232 -- [The () one is a GHC extension for defaulting CCall results.]
233 -- ALSO: funTyCon, since it occurs implicitly everywhere!
234 -- (we don't want to be bothered with making funTyCon a
235 -- free var at every function application!)
236 -- Double is dealt with separately in getGates
237 default_tycons = [unitTyCon, funTyCon, boolTyCon, intTyCon]
239 -- Add occurrences for IO or PrimIO
240 implicit_main | mod_name == mAIN_Name
241 || mod_name == pREL_MAIN_Name = [ioTyCon_RDR]
244 -- Now add extra "occurrences" for things that
245 -- the deriving mechanism, or defaulting, will later need in order to
247 implicit_occs = string_occs ++ foldr ((++) . get) implicit_main decls
249 -- Virtually every program has error messages in it somewhere
250 string_occs = [unpackCString_RDR, unpackCStringFoldr_RDR, unpackCStringUtf8_RDR]
252 get (TyClD (TyData _ _ _ _ _ _ (Just deriv_classes) _ _))
253 = concat (map get_deriv deriv_classes)
256 get_deriv cls = case lookupUFM derivingOccurrences cls of
262 isOrphanDecl (InstD (InstDecl inst_ty _ _ _ _))
263 = not (foldNameSet ((||) . isLocallyDefined) False (extractHsTyNames (removeContext inst_ty)))
264 -- The 'removeContext' is because of
265 -- instance Foo a => Baz T where ...
266 -- The decl is an orphan if Baz and T are both not locally defined,
267 -- even if Foo *is* locally defined
269 isOrphanDecl (RuleD (HsRule _ _ _ lhs _ _))
272 -- At the moment we just check for common LHS forms
273 -- Expand as necessary. Getting it wrong just means
274 -- more orphans than necessary
275 check (HsVar v) = not (isLocallyDefined v)
276 check (HsApp f a) = check f && check a
277 check (HsLit _) = False
278 check (OpApp l o _ r) = check l && check o && check r
279 check (NegApp e _) = check e
280 check (HsPar e) = check e
281 check (SectionL e o) = check e && check o
282 check (SectionR o e) = check e && check o
284 check other = True -- Safe fall through
286 isOrphanDecl other = False
291 dupDefaultDeclErrRn (DefaultDecl _ locn1 : dup_things)
292 = pushSrcLocRn locn1 $
295 msg = hang (ptext SLIT("Multiple default declarations"))
296 4 (vcat (map pp dup_things))
297 pp (DefaultDecl _ locn) = ptext SLIT("here was another default declaration") <+> ppr locn
301 %*********************************************************
303 \subsection{Slurping declarations}
305 %*********************************************************
308 -------------------------------------------------------
309 slurpImpDecls source_fvs
310 = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenRn_`
312 -- The current slurped-set records all local things
313 getSlurped `thenRn` \ source_binders ->
314 slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
316 -- Then get everything else
317 closeDecls decls needed `thenRn` \ decls1 ->
319 -- Finally, get any deferred data type decls
320 slurpDeferredDecls decls1 `thenRn` \ final_decls ->
324 -------------------------------------------------------
325 slurpSourceRefs :: NameSet -- Variables defined in source
326 -> FreeVars -- Variables referenced in source
327 -> RnMG ([RenamedHsDecl],
328 FreeVars) -- Un-satisfied needs
329 -- The declaration (and hence home module) of each gate has
330 -- already been loaded
332 slurpSourceRefs source_binders source_fvs
333 = go_outer [] -- Accumulating decls
334 emptyFVs -- Unsatisfied needs
335 emptyFVs -- Accumulating gates
336 (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
338 -- The outer loop repeatedly slurps the decls for the current gates
339 -- and the instance decls
341 -- The outer loop is needed because consider
342 -- instance Foo a => Baz (Maybe a) where ...
343 -- It may be that @Baz@ and @Maybe@ are used in the source module,
344 -- but not @Foo@; so we need to chase @Foo@ too.
346 -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
347 -- include actually getting in Foo's class decl
348 -- class Wib a => Foo a where ..
349 -- so that its superclasses are discovered. The point is that Wib is a gate too.
350 -- We do this for tycons too, so that we look through type synonyms.
352 go_outer decls fvs all_gates []
353 = returnRn (decls, fvs)
355 go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
356 = traceRn (text "go_outer" <+> ppr refs) `thenRn_`
357 foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
358 getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
359 rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
360 go_outer decls2 fvs2 (all_gates `plusFV` gates2)
361 (nameSetToList (gates2 `minusNameSet` all_gates))
362 -- Knock out the all_gates because even if we don't slurp any new
363 -- decls we can get some apparently-new gates from wired-in names
365 go_inner (decls, fvs, gates) wanted_name
366 = importDecl wanted_name `thenRn` \ import_result ->
367 case import_result of
368 AlreadySlurped -> returnRn (decls, fvs, gates)
369 WiredIn -> returnRn (decls, fvs, gates `plusFV` getWiredInGates wanted_name)
370 Deferred -> returnRn (decls, fvs, gates `addOneFV` wanted_name) -- It's a type constructor
372 HereItIs decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
373 returnRn (new_decl : decls,
375 gates `plusFV` getGates source_fvs new_decl)
377 rnInstDecls decls fvs gates []
378 = returnRn (decls, fvs, gates)
379 rnInstDecls decls fvs gates (d:ds)
380 = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
381 rnInstDecls (new_decl:decls)
383 (gates `plusFV` getInstDeclGates new_decl)
389 -------------------------------------------------------
390 -- closeDecls keeps going until the free-var set is empty
391 closeDecls decls needed
392 | not (isEmptyFVs needed)
393 = slurpDecls decls needed `thenRn` \ (decls1, needed1) ->
394 closeDecls decls1 needed1
397 = getImportedRules `thenRn` \ rule_decls ->
399 [] -> returnRn decls -- No new rules, so we are done
400 other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
401 closeDecls decls1 needed1
404 -------------------------------------------------------
405 -- Augment decls with any decls needed by needed.
406 -- Return also free vars of the new decls (only)
407 slurpDecls decls needed
408 = go decls emptyFVs (nameSetToList needed)
410 go decls fvs [] = returnRn (decls, fvs)
411 go decls fvs (ref:refs) = slurpDecl decls fvs ref `thenRn` \ (decls1, fvs1) ->
414 -------------------------------------------------------
415 slurpDecl decls fvs wanted_name
416 = importDecl wanted_name `thenRn` \ import_result ->
417 case import_result of
418 -- Found a declaration... rename it
419 HereItIs decl -> rnIfaceDecl decl `thenRn` \ (new_decl, fvs1) ->
420 returnRn (new_decl:decls, fvs1 `plusFV` fvs)
422 -- No declaration... (wired in thing, or deferred, or already slurped)
423 other -> returnRn (decls, fvs)
426 -------------------------------------------------------
427 rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
428 -> [(Module, RdrNameHsDecl)]
429 -> RnM d ([RenamedHsDecl], FreeVars)
430 rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
431 rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
432 rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
434 rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
438 %*********************************************************
440 \subsection{Deferred declarations}
442 %*********************************************************
444 The idea of deferred declarations is this. Suppose we have a function
449 Then we don't want to load T and all its constructors, and all
450 the types those constructors refer to, and all the types *those*
451 constructors refer to, and so on. That might mean loading many more
452 interface files than is really necessary. So we 'defer' loading T.
454 But f might be strict, and the calling convention for evaluating
455 values of type T depends on how many constructors T has, so
456 we do need to load T, but not the full details of the type T.
457 So we load the full decl for T, but only skeleton decls for A and B:
459 data T = {- 2 constructors -}
461 Whether all this is worth it is moot.
464 slurpDeferredDecls :: [RenamedHsDecl] -> RnMG [RenamedHsDecl]
465 slurpDeferredDecls decls
466 = getDeferredDecls `thenRn` \ def_decls ->
467 rnIfaceDecls decls emptyFVs (map stripDecl def_decls) `thenRn` \ (decls1, fvs) ->
468 ASSERT( isEmptyFVs fvs )
471 stripDecl (mod, TyClD (TyData dt _ tc tvs _ nconstrs _ _ loc))
472 = (mod, TyClD (TyData dt [] tc tvs [] nconstrs Nothing NoDataPragmas loc))
473 -- Nuke the context and constructors
474 -- But retain the *number* of constructors!
475 -- Also the tvs will have kinds on them.
479 %*********************************************************
481 \subsection{Extracting the `gates'}
483 %*********************************************************
485 When we import a declaration like
487 data T = T1 Wibble | T2 Wobble
489 we don't want to treat @Wibble@ and @Wobble@ as gates
490 {\em unless} @T1@, @T2@ respectively are mentioned by the user program.
491 If only @T@ is mentioned
492 we want only @T@ to be a gate;
493 that way we don't suck in useless instance
494 decls for (say) @Eq Wibble@, when they can't possibly be useful.
496 @getGates@ takes a newly imported (and renamed) decl, and the free
497 vars of the source program, and extracts from the decl the gate names.
500 getGates source_fvs (SigD (IfaceSig _ ty _ _))
501 = extractHsTyNames ty
503 getGates source_fvs (TyClD (ClassDecl ctxt cls tvs _ sigs _ _ _ _ _ _ _))
504 = (delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
506 `addOneToNameSet` cls)
507 `plusFV` maybe_double
509 get (ClassOpSig n _ ty _)
510 | n `elemNameSet` source_fvs = extractHsTyNames ty
511 | otherwise = emptyFVs
513 -- If we load any numeric class that doesn't have
514 -- Int as an instance, add Double to the gates.
515 -- This takes account of the fact that Double might be needed for
516 -- defaulting, but we don't want to load Double (and all its baggage)
517 -- if the more exotic classes aren't used at all.
518 maybe_double | nameUnique cls `elem` fractionalClassKeys
519 = unitFV (getName doubleTyCon)
523 getGates source_fvs (TyClD (TySynonym tycon tvs ty _))
524 = delListFromNameSet (extractHsTyNames ty)
526 -- A type synonym type constructor isn't a "gate" for instance decls
528 getGates source_fvs (TyClD (TyData _ ctxt tycon tvs cons _ _ _ _))
529 = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) cons)
531 `addOneToNameSet` tycon
533 get (ConDecl n _ tvs ctxt details _)
534 | n `elemNameSet` source_fvs
535 -- If the constructor is method, get fvs from all its fields
536 = delListFromNameSet (get_details details `plusFV`
537 extractHsCtxtTyNames ctxt)
539 get (ConDecl n _ tvs ctxt (RecCon fields) _)
540 -- Even if the constructor isn't mentioned, the fields
541 -- might be, as selectors. They can't mention existentially
542 -- bound tyvars (typechecker checks for that) so no need for
543 -- the deleteListFromNameSet part
544 = foldr (plusFV . get_field) emptyFVs fields
546 get other_con = emptyFVs
548 get_details (VanillaCon tys) = plusFVs (map get_bang tys)
549 get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
550 get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
551 get_details (NewCon t _) = extractHsTyNames t
553 get_field (fs,t) | any (`elemNameSet` source_fvs) fs = get_bang t
554 | otherwise = emptyFVs
556 get_bang bty = extractHsTyNames (getBangType bty)
558 getGates source_fvs other_decl = emptyFVs
561 @getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
562 rather than a declaration.
565 getWiredInGates :: Name -> FreeVars
566 getWiredInGates name -- No classes are wired in
567 | is_id = getWiredInGates_s (namesOfType (idType the_id))
568 | isSynTyCon the_tycon = getWiredInGates_s
569 (delListFromNameSet (namesOfType ty) (map getName tyvars))
570 | otherwise = unitFV name
572 maybe_wired_in_id = maybeWiredInIdName name
573 is_id = maybeToBool maybe_wired_in_id
574 maybe_wired_in_tycon = maybeWiredInTyConName name
575 Just the_id = maybe_wired_in_id
576 Just the_tycon = maybe_wired_in_tycon
577 (tyvars,ty) = getSynTyConDefn the_tycon
579 getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
583 getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
584 getInstDeclGates other = emptyFVs
588 %*********************************************************
590 \subsection{Fixities}
592 %*********************************************************
595 fixitiesFromLocalDecls :: GlobalRdrEnv -> [RdrNameHsDecl] -> RnMG FixityEnv
596 fixitiesFromLocalDecls gbl_env decls
597 = foldlRn getFixities emptyNameEnv decls `thenRn` \ env ->
598 traceRn (text "fixity env" <+> vcat (map ppr (nameEnvElts env))) `thenRn_`
601 getFixities :: FixityEnv -> RdrNameHsDecl -> RnMG FixityEnv
602 getFixities acc (FixD fix)
605 getFixities acc (TyClD (ClassDecl _ _ _ _ sigs _ _ _ _ _ _ _))
606 = foldlRn fix_decl acc [sig | FixSig sig <- sigs]
607 -- Get fixities from class decl sigs too.
608 getFixities acc other_decl
611 fix_decl acc sig@(FixitySig rdr_name fixity loc)
612 = -- Check for fixity decl for something not declared
613 case lookupRdrEnv gbl_env rdr_name of {
614 Nothing | opt_WarnUnusedBinds
615 -> pushSrcLocRn loc (addWarnRn (unusedFixityDecl rdr_name fixity))
616 `thenRn_` returnRn acc
617 | otherwise -> returnRn acc ;
621 -- Check for duplicate fixity decl
622 case lookupNameEnv acc name of {
623 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc')
624 `thenRn_` returnRn acc ;
626 Nothing -> returnRn (extendNameEnv acc name (FixitySig name fixity loc))
631 %*********************************************************
633 \subsection{Deprecations}
635 %*********************************************************
637 For deprecations, all we do is check that the names are in scope.
638 It's only imported deprecations, dealt with in RnIfaces, that we
639 gather them together.
642 rnDeprecs :: GlobalRdrEnv -> Maybe DeprecTxt
643 -> [RdrNameHsDecl] -> RnMG [RdrNameDeprecation]
644 rnDeprecs gbl_env mod_deprec decls
645 = mapRn rn_deprec deprecs `thenRn_`
646 returnRn (extra_deprec ++ deprecs)
648 deprecs = [d | DeprecD d <- decls]
649 extra_deprec = case mod_deprec of
651 Just txt -> [Deprecation (IEModuleContents undefined) txt noSrcLoc]
653 rn_deprec (Deprecation ie txt loc)
655 mapRn check (ieNames ie)
657 check n = case lookupRdrEnv gbl_env n of
658 Nothing -> addErrRn (unknownNameErr n)
659 Just _ -> returnRn ()
663 %*********************************************************
665 \subsection{Unused names}
667 %*********************************************************
670 reportUnusedNames :: ModuleName -> [Module]
671 -> GlobalRdrEnv -> AvailEnv
672 -> Avails -> NameSet -> [RenamedHsDecl]
674 reportUnusedNames mod_name direct_import_mods
676 export_avails mentioned_names
679 used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
681 -- Now, a use of C implies a use of T,
682 -- if C was brought into scope by T(..) or T(C)
683 really_used_names = used_names `unionNameSets`
684 mkNameSet [ availName parent_avail
685 | sub_name <- nameSetToList used_names
686 , isValOcc (getOccName sub_name)
688 -- Usually, every used name will appear in avail_env, but there
689 -- is one time when it doesn't: tuples and other built in syntax. When you
690 -- write (a,b) that gives rise to a *use* of "(,)", so that the
691 -- instances will get pulled in, but the tycon "(,)" isn't actually
692 -- in scope. Hence the isValOcc filter.
694 -- Also, (-x) gives rise to an implicit use of 'negate'; similarly,
695 -- 3.5 gives rise to an implcit use of :%
696 -- hence the isUserImportedName filter on the warning
699 = case lookupNameEnv avail_env sub_name of
701 Nothing -> WARN( isUserImportedName sub_name,
702 text "reportUnusedName: not in avail_env" <+>
706 , case parent_avail of { AvailTC _ _ -> True; other -> False }
709 defined_names = mkNameSet (concat (rdrEnvElts gbl_env))
710 defined_but_not_used =
711 nameSetToList (defined_names `minusNameSet` really_used_names)
713 -- Filter out the ones only defined implicitly
714 bad_locals = [n | n <- defined_but_not_used, isLocallyDefined n]
715 bad_imp_names = [n | n <- defined_but_not_used, isUserImportedExplicitlyName n,
716 not (module_unused n)]
718 deprec_used deprec_env = [ (n,txt)
719 | n <- nameSetToList mentioned_names,
720 not (isLocallyDefined n),
721 Just txt <- [lookupNameEnv deprec_env n] ]
723 -- inst_mods are directly-imported modules that
724 -- contain instance decl(s) that the renamer decided to suck in
725 -- It's not necessarily redundant to import such modules.
731 -- The import M() is not *necessarily* redundant, even if
732 -- we suck in no instance decls from M (e.g. it contains
733 -- no instance decls, or This contains no code). It may be
734 -- that we import M solely to ensure that M's orphan instance
735 -- decls (or those in its imports) are visible to people who
736 -- import This. Sigh.
737 -- There's really no good way to detect this, so the error message
738 -- in RnEnv.warnUnusedModules is weakened instead
739 inst_mods = [m | InstD (InstDecl _ _ _ (Just dfun) _) <- imported_decls,
740 let m = nameModule dfun,
741 m `elem` direct_import_mods
744 minimal_imports :: FiniteMap Module AvailEnv
745 minimal_imports0 = emptyFM
746 minimal_imports1 = foldNameSet add_name minimal_imports0 really_used_names
747 minimal_imports = foldr add_inst_mod minimal_imports1 inst_mods
749 add_name n acc = case maybeUserImportedFrom n of
751 Just m -> addToFM_C plusAvailEnv acc m
752 (unitAvailEnv (mk_avail n))
754 | m `elemFM` acc = acc -- We import something already
755 | otherwise = addToFM acc m emptyAvailEnv
756 -- Add an empty collection of imports for a module
757 -- from which we have sucked only instance decls
759 mk_avail n = case lookupNameEnv avail_env n of
760 Just (AvailTC m _) | n==m -> AvailTC n [n]
761 | otherwise -> AvailTC m [n,m]
762 Just avail -> Avail n
763 Nothing -> pprPanic "mk_avail" (ppr n)
765 -- unused_imp_mods are the directly-imported modules
766 -- that are not mentioned in minimal_imports
767 unused_imp_mods = [m | m <- direct_import_mods,
768 not (maybeToBool (lookupFM minimal_imports m)),
769 moduleName m /= pRELUDE_Name]
771 module_unused :: Name -> Bool
772 -- Name is imported from a module that's completely unused,
773 -- so don't report stuff about the name (the module covers it)
774 module_unused n = expectJust "module_unused" (maybeUserImportedFrom n)
775 `elem` unused_imp_mods
776 -- module_unused is only called if it's user-imported
778 warnUnusedModules unused_imp_mods `thenRn_`
779 warnUnusedLocalBinds bad_locals `thenRn_`
780 warnUnusedImports bad_imp_names `thenRn_`
781 printMinimalImports mod_name minimal_imports `thenRn_`
782 getIfacesRn `thenRn` \ ifaces ->
783 (if opt_WarnDeprecations
784 then mapRn_ warnDeprec (deprec_used (iDeprecs ifaces))
787 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
788 printMinimalImports mod_name imps
789 | not opt_D_dump_minimal_imports
792 = mapRn to_ies (fmToList imps) `thenRn` \ mod_ies ->
793 ioToRnM (do { h <- openFile filename WriteMode ;
794 printForUser h (vcat (map ppr_mod_ie mod_ies))
798 filename = moduleNameUserString mod_name ++ ".imports"
799 ppr_mod_ie (mod_name, ies)
800 | mod_name == pRELUDE_Name
803 = ptext SLIT("import") <+> ppr mod_name <>
804 parens (fsep (punctuate comma (map ppr ies)))
806 to_ies (mod, avail_env) = mapRn to_ie (availEnvElts avail_env) `thenRn` \ ies ->
807 returnRn (moduleName mod, ies)
809 to_ie :: AvailInfo -> RnMG (IE Name)
810 to_ie (Avail n) = returnRn (IEVar n)
811 to_ie (AvailTC n [m]) = ASSERT( n==m )
812 returnRn (IEThingAbs n)
813 to_ie (AvailTC n ns) = getInterfaceExports (moduleName (nameModule n))
814 ImportBySystem `thenRn` \ (_, avails) ->
815 case [ms | AvailTC m ms <- avails, m == n] of
816 [ms] | all (`elem` ns) ms -> returnRn (IEThingAll n)
817 | otherwise -> returnRn (IEThingWith n (filter (/= n) ns))
818 other -> pprTrace "to_ie" (ppr n <+> ppr (nameModule n) <+> ppr other) $
821 rnDump :: [RenamedHsDecl] -- Renamed imported decls
822 -> [RenamedHsDecl] -- Renamed local decls
824 rnDump imp_decls local_decls
825 | opt_D_dump_rn_trace ||
826 opt_D_dump_rn_stats ||
828 = getRnStats imp_decls `thenRn` \ stats_msg ->
830 returnRn (printErrs stats_msg >>
831 dumpIfSet opt_D_dump_rn "Renamer:"
832 (vcat (map ppr (local_decls ++ imp_decls))))
834 | otherwise = returnRn (return ())
838 %*********************************************************
840 \subsection{Statistics}
842 %*********************************************************
845 getRnStats :: [RenamedHsDecl] -> RnMG SDoc
846 getRnStats imported_decls
847 = getIfacesRn `thenRn` \ ifaces ->
849 n_mods = length [() | (_, _, Just _) <- eltsFM (iImpModInfo ifaces)]
851 decls_read = [decl | (_, avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
852 -- Data, newtype, and class decls are in the decls_fm
853 -- under multiple names; the tycon/class, and each
854 -- constructor/class op too.
855 -- The 'True' selects just the 'main' decl
856 not (isLocallyDefined (availName avail))
859 (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
860 (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
862 unslurped_insts = iInsts ifaces
863 inst_decls_unslurped = length (bagToList unslurped_insts)
864 inst_decls_read = id_sp + inst_decls_unslurped
867 [int n_mods <+> text "interfaces read",
868 hsep [ int cd_sp, text "class decls imported, out of",
869 int cd_rd, text "read"],
870 hsep [ int dd_sp, text "data decls imported, out of",
871 int dd_rd, text "read"],
872 hsep [ int nd_sp, text "newtype decls imported, out of",
873 int nd_rd, text "read"],
874 hsep [int sd_sp, text "type synonym decls imported, out of",
875 int sd_rd, text "read"],
876 hsep [int vd_sp, text "value signatures imported, out of",
877 int vd_rd, text "read"],
878 hsep [int id_sp, text "instance decls imported, out of",
879 int inst_decls_read, text "read"],
880 text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
881 [d | TyClD d <- imported_decls, isClassDecl d]),
882 text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
883 [d | TyClD d <- decls_read, isClassDecl d])]
885 returnRn (hcat [text "Renamer stats: ", stats])
895 tycl_decls = [d | TyClD d <- decls]
896 (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
898 val_decls = length [() | SigD _ <- decls]
899 inst_decls = length [() | InstD _ <- decls]
903 %************************************************************************
905 \subsection{Errors and warnings}
907 %************************************************************************
910 warnDeprec :: (Name, DeprecTxt) -> RnM d ()
911 warnDeprec (name, txt)
912 = pushSrcLocRn (getSrcLoc name) $
914 sep [ text (occNameFlavour (nameOccName name)) <+> ppr name <+>
915 text "is deprecated:", nest 4 (ppr txt) ]
918 unusedFixityDecl rdr_name fixity
919 = hsep [ptext SLIT("Unused fixity declaration for"), quotes (ppr rdr_name)]
921 dupFixityDecl rdr_name loc1 loc2
922 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
923 ptext SLIT("at ") <+> ppr loc1,
924 ptext SLIT("and") <+> ppr loc2]