2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, getLocalNonValBinders,
9 rnExports, extendGlobalRdrEnvRn,
10 reportUnusedNames, finishWarnings,
13 #include "HsVersions.h"
17 import TcEnv ( isBrackStage )
19 import RnHsDoc ( rnHsDoc )
20 import IfaceEnv ( ifaceExportNames )
21 import LoadIface ( loadSrcInterface, loadSysInterface )
22 import TcRnMonad hiding (LIE)
24 import HeaderInfo ( mkPrelImports )
40 import Data.List ( partition, (\\), delete )
41 import qualified Data.Set as Set
48 %************************************************************************
52 %************************************************************************
55 rnImports :: [LImportDecl RdrName]
56 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
59 -- PROCESS IMPORT DECLS
60 -- Do the non {- SOURCE -} ones first, so that we get a helpful
61 -- warning for {- SOURCE -} ones that are unnecessary
62 = do this_mod <- getModule
63 implicit_prelude <- doptM Opt_ImplicitPrelude
64 let prel_imports = mkPrelImports (moduleName this_mod) implicit_prelude imports
65 (source, ordinary) = partition is_source_import imports
66 is_source_import (L _ (ImportDecl _ _ is_boot _ _ _)) = is_boot
68 ifOptM Opt_WarnImplicitPrelude (
69 when (notNull prel_imports) $ addWarn (implicitPreludeWarn)
72 stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
73 stuff2 <- mapM (rnImportDecl this_mod) source
74 let (decls, rdr_env, imp_avails,hpc_usage) = combine (stuff1 ++ stuff2)
75 return (decls, rdr_env, imp_avails,hpc_usage)
78 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)]
79 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
80 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails,False)
81 where plus (decl, gbl_env1, imp_avails1,hpc_usage1)
82 (decls, gbl_env2, imp_avails2,hpc_usage2)
84 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
85 imp_avails1 `plusImportAvails` imp_avails2,
86 hpc_usage1 || hpc_usage2)
88 rnImportDecl :: Module
89 -> LImportDecl RdrName
90 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
92 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
93 qual_only as_mod imp_details))
96 when (isJust mb_pkg) $ do
97 pkg_imports <- doptM Opt_PackageImports
98 when (not pkg_imports) $ addErr packageImportErr
100 -- If there's an error in loadInterface, (e.g. interface
101 -- file not found) we get lots of spurious errors from 'filterImports'
103 imp_mod_name = unLoc loc_imp_mod_name
104 doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
106 iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg
108 -- Compiler sanity check: if the import didn't say
109 -- {-# SOURCE #-} we should not get a hi-boot file
110 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
112 -- Issue a user warning for a redundant {- SOURCE -} import
113 -- NB that we arrange to read all the ordinary imports before
114 -- any of the {- SOURCE -} imports.
116 -- in --make and GHCi, the compilation manager checks for this,
117 -- and indeed we shouldn't do it here because the existence of
118 -- the non-boot module depends on the compilation order, which
119 -- is not deterministic. The hs-boot test can show this up.
121 warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags))
122 (warnRedundantSourceImport imp_mod_name)
125 imp_mod = mi_module iface
126 warns = mi_warns iface
127 orph_iface = mi_orphan iface
128 has_finsts = mi_finsts iface
131 filtered_exports = filter not_this_mod (mi_exports iface)
132 not_this_mod (mod,_) = mod /= this_mod
133 -- If the module exports anything defined in this module, just
134 -- ignore it. Reason: otherwise it looks as if there are two
135 -- local definition sites for the thing, and an error gets
136 -- reported. Easiest thing is just to filter them out up
137 -- front. This situation only arises if a module imports
138 -- itself, or another module that imported it. (Necessarily,
139 -- this invoves a loop.)
141 -- Tiresome consequence: if you say
146 -- module B( AType ) where
147 -- import {-# SOURCE #-} A( AType )
149 -- then you'll get a 'B does not export AType' message. Oh well.
151 qual_mod_name = case as_mod of
152 Nothing -> imp_mod_name
153 Just another_name -> another_name
154 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
155 is_dloc = loc, is_as = qual_mod_name }
158 -- Get the total exports from this module
159 total_avails <- ifaceExportNames filtered_exports
161 -- filter the imports according to the import declaration
162 (new_imp_details, gbl_env) <-
163 filterImports iface imp_spec imp_details total_avails
168 -- Compute new transitive dependencies
170 orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
171 imp_mod : dep_orphs deps
172 | otherwise = dep_orphs deps
174 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
175 imp_mod : dep_finsts deps
176 | otherwise = dep_finsts deps
178 pkg = modulePackageId (mi_module iface)
180 (dependent_mods, dependent_pkgs)
181 | pkg == thisPackage dflags =
182 -- Imported module is from the home package
183 -- Take its dependent modules and add imp_mod itself
184 -- Take its dependent packages unchanged
186 -- NB: (dep_mods deps) might include a hi-boot file
187 -- for the module being compiled, CM. Do *not* filter
188 -- this out (as we used to), because when we've
189 -- finished dealing with the direct imports we want to
190 -- know if any of them depended on CM.hi-boot, in
191 -- which case we should do the hi-boot consistency
192 -- check. See LoadIface.loadHiBootInterface
193 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
196 -- Imported module is from another package
197 -- Dump the dependent modules
198 -- Add the package imp_mod comes from to the dependent packages
199 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
200 ([], pkg : dep_pkgs deps)
202 -- True <=> import M ()
203 import_all = case imp_details of
204 Just (is_hiding, ls) -> not is_hiding && null ls
207 imports = ImportAvails {
208 imp_mods = unitModuleEnv imp_mod [(qual_mod_name, import_all, loc)],
211 imp_dep_mods = mkModDeps dependent_mods,
212 imp_dep_pkgs = dependent_pkgs
215 -- Complain if we import a deprecated module
216 ifOptM Opt_WarnWarningsDeprecations (
218 WarnAll txt -> addWarn (moduleWarn imp_mod_name txt)
222 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
223 qual_only as_mod new_imp_details)
225 return (new_imp_decl, gbl_env, imports, mi_hpc iface)
228 warnRedundantSourceImport :: ModuleName -> SDoc
229 warnRedundantSourceImport mod_name
230 = ptext (sLit "Unnecessary {-# SOURCE #-} in the import of module")
231 <+> quotes (ppr mod_name)
235 %************************************************************************
237 importsFromLocalDecls
239 %************************************************************************
241 From the top-level declarations of this module produce
242 * the lexical environment
244 created by its bindings.
246 Note [Top-level Names in Template Haskell decl quotes]
247 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
248 Consider a Template Haskell declaration quotation like this:
251 When renaming the declarations inside [d| ...|], we treat the
252 top level binders specially in two ways
254 1. We give them an Internal name, not (as usual) an External one.
255 Otherwise the NameCache gets confused by a second allocation of
256 M.f. (We used to invent a fake module ThFake to avoid this, but
257 that had other problems, notably in getting the correct answer for
258 nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module
261 2. We make them *shadow* the outer bindings. If we don't do that,
262 we'll get a complaint when extending the GlobalRdrEnv, saying that
263 there are two bindings for 'f'.
265 This shadowing applies even if the binding for 'f' is in a
266 where-clause, and hence is in the *local* RdrEnv not the *global*
269 We find out whether we are inside a [d| ... |] by testing the TH
270 stage. This is a slight hack, because the stage field was really meant for
271 the type checker, and here we are not interested in the fields of Brack,
272 hence the error thunks in thRnBrack.
275 extendGlobalRdrEnvRn :: [AvailInfo]
277 -> RnM (TcGblEnv, TcLclEnv)
278 -- Updates both the GlobalRdrEnv and the FixityEnv
279 -- We return a new TcLclEnv only becuase we might have to
280 -- delete some bindings from it;
281 -- see Note [Top-level Names in Template Haskell decl quotes]
283 extendGlobalRdrEnvRn avails new_fixities
284 = do { (gbl_env, lcl_env) <- getEnvs
286 ; let rdr_env = tcg_rdr_env gbl_env
287 fix_env = tcg_fix_env gbl_env
289 -- Delete new_occs from global and local envs
290 -- If we are in a TemplateHaskell decl bracket,
291 -- we are going to shadow them
292 -- See Note [Top-level Names in Template Haskell decl quotes]
293 shadowP = isBrackStage stage
294 new_occs = map (nameOccName . gre_name) gres
295 rdr_env1 = hideSomeUnquals rdr_env new_occs
296 lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
297 (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
298 | otherwise = (rdr_env, lcl_env)
300 rdr_env3 = foldl extendGlobalRdrEnv rdr_env2 gres
301 fix_env' = foldl extend_fix_env fix_env gres
302 (rdr_env', dups) = findLocalDupsRdrEnv rdr_env3 new_occs
304 gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
306 ; mapM_ addDupDeclErr dups
308 ; traceRn (text "extendGlobalRdrEnvRn" <+> (ppr new_fixities $$ ppr fix_env $$ ppr fix_env'))
309 ; return (gbl_env', lcl_env2) }
311 gres = gresFromAvails LocalDef avails
313 -- If there is a fixity decl for the gre, add it to the fixity env
314 extend_fix_env fix_env gre
315 | Just (L _ fi) <- lookupFsEnv new_fixities (occNameFS occ)
316 = extendNameEnv fix_env name (FixItem occ fi)
321 occ = nameOccName name
324 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
325 used for source code.
327 *** See "THE NAMING STORY" in HsDecls ****
329 Instances of type families
330 ~~~~~~~~~~~~~~~~~~~~~~~~~~
331 Family instances contain data constructors that we need to collect and we also
332 need to descend into the type instances of associated families in class
333 instances. The type constructor of a family instance is a usage occurence.
334 Hence, we don't return it as a subname in 'AvailInfo'; otherwise, we would get
335 a duplicate declaration error.
337 Note [Looking up family names in family instances]
338 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
343 type instance M.T Int = Bool
345 We might think that we can simply use 'lookupOccRn' when processing the type
346 instance to look up 'M.T'. Alas, we can't! The type family declaration is in
347 the *same* HsGroup as the type instance declaration. Hence, as we are
348 currently collecting the binders declared in that HsGroup, these binders will
349 not have been added to the global environment yet.
351 In the case of type classes, this problem does not arise, as a class instance
352 does not define any binders of it's own. So, we simply don't attempt to look
353 up the class names of class instances in 'get_local_binders' below.
355 If we don't look up class instances, can't we get away without looking up type
356 instances, too? No, we can't. Data type instances define data constructors
359 (1) collect those in 'get_local_binders' and
360 (2) we need to get their parent name in 'get_local_binders', too, to
361 produce an appropriate 'AvailTC'.
363 This parent name is exactly the family name of the type instance that is so
364 difficult to look up.
366 We solve this problem as follows:
368 (a) We process all type declarations other than type instances first.
369 (b) Then, we compute a 'GlobalRdrEnv' from the result of the first step.
370 (c) Finally, we process all type instances (both those on the toplevel and
371 those nested in class instances) and check for the family names in the
372 'GlobalRdrEnv' produced in the previous step before using 'lookupOccRn'.
375 getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
376 -- Get all the top-level binders bound the group *except*
377 -- for value bindings, which are treated separately
378 -- Specificaly we return AvailInfo for
383 -- (in hs-boot files) value signatures
385 getLocalNonValBinders group
386 = do { gbl_env <- getGblEnv
387 ; get_local_binders gbl_env group }
389 get_local_binders :: TcGblEnv -> HsGroup RdrName -> RnM [GenAvailInfo Name]
390 get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
391 hs_tyclds = tycl_decls,
392 hs_instds = inst_decls,
393 hs_fords = foreign_decls })
394 = do { -- separate out the family instance declarations
395 let (tyinst_decls1, tycl_decls_noinsts)
396 = partition (isFamInstDecl . unLoc) tycl_decls
397 tyinst_decls = tyinst_decls1 ++ instDeclATs inst_decls
399 -- process all type/class decls except family instances
400 ; tc_names <- mapM new_tc tycl_decls_noinsts
402 -- create a temporary rdr env of the type binders
403 ; let tc_gres = gresFromAvails LocalDef tc_names
404 tc_name_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv tc_gres
406 -- process all family instances
407 ; ti_names <- mapM (new_ti tc_name_env) tyinst_decls
409 -- finish off with value binder in case of a hs-boot file
410 ; val_names <- mapM new_simple val_bndrs
411 ; return (val_names ++ tc_names ++ ti_names) }
413 mod = tcg_mod gbl_env
414 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
416 for_hs_bndrs :: [Located RdrName]
417 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
419 -- In a hs-boot file, the value binders come from the
420 -- *signatures*, and there should be no foreign binders
421 val_bndrs :: [Located RdrName]
422 val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
423 | otherwise = for_hs_bndrs
425 new_simple :: Located RdrName -> RnM (GenAvailInfo Name)
426 new_simple rdr_name = do
427 nm <- newTopSrcBinder mod rdr_name
430 new_tc tc_decl -- NOT for type/data instances
431 = do { main_name <- newTopSrcBinder mod main_rdr
432 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
433 ; return (AvailTC main_name (main_name : sub_names)) }
435 (main_rdr : sub_rdrs) = hsTyClDeclBinders tc_decl
437 new_ti tc_name_env ti_decl -- ONLY for type/data instances
438 = do { main_name <- lookupFamInstDeclBndr tc_name_env main_rdr
439 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
440 ; return (AvailTC main_name sub_names) }
441 -- main_name is not bound here!
443 (main_rdr : sub_rdrs) = hsTyClDeclBinders ti_decl
445 get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
449 %************************************************************************
451 \subsection{Filtering imports}
453 %************************************************************************
455 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
456 available, and filters it through the import spec (if any).
459 filterImports :: ModIface
460 -> ImpDeclSpec -- The span for the entire import decl
461 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
462 -> [AvailInfo] -- What's available
463 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
464 GlobalRdrEnv) -- Same again, but in GRE form
465 filterImports _ decl_spec Nothing all_avails
466 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
468 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
471 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
472 = do -- check for errors, convert RdrNames to Names
473 opt_typeFamilies <- doptM Opt_TypeFamilies
474 items1 <- mapM (lookup_lie opt_typeFamilies) import_items
476 let items2 :: [(LIE Name, AvailInfo)]
477 items2 = concat items1
478 -- NB the AvailInfo may have duplicates, and several items
479 -- for the same parent; e.g N(x) and N(y)
481 names = availsToNameSet (map snd items2)
482 keep n = not (n `elemNameSet` names)
483 pruned_avails = filterAvails keep all_avails
484 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
486 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
487 | otherwise = concatMap (gresFromIE decl_spec) items2
489 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
491 -- This environment is how we map names mentioned in the import
492 -- list to the actual Name they correspond to, and the name family
493 -- that the Name belongs to (the AvailInfo). The situation is
494 -- complicated by associated families, which introduce a three-level
495 -- hierachy, where class = grand parent, assoc family = parent, and
496 -- data constructors = children. The occ_env entries for associated
497 -- families needs to capture all this information; hence, we have the
498 -- third component of the environment that gives the class name (=
499 -- grand parent) in case of associated families.
501 -- This env will have entries for data constructors too,
502 -- they won't make any difference because naked entities like T
503 -- in an import list map to TcOccs, not VarOccs.
504 occ_env :: OccEnv (Name, -- the name
505 AvailInfo, -- the export item providing the name
506 Maybe Name) -- the parent of associated types
507 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
508 | a <- all_avails, n <- availNames a]
510 -- we know that (1) there are at most entries for one name, (2) their
511 -- first component is identical, (3) they are for tys/cls, and (4) one
512 -- entry has the name in its parent position (the other doesn't)
513 combine (name, AvailTC p1 subs1, Nothing)
514 (_ , AvailTC p2 subs2, Nothing)
516 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
518 (name, AvailTC name subs, Just parent)
519 combine x y = pprPanic "filterImports/combine" (ppr x $$ ppr y)
521 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
522 lookup_lie opt_typeFamilies (L loc ieRdr)
524 stuff <- setSrcSpan loc $
525 case lookup_ie opt_typeFamilies ieRdr of
526 Failed err -> addErr err >> return []
527 Succeeded a -> return a
528 checkDodgyImport stuff
529 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
531 -- Warn when importing T(..) if T was exported abstractly
532 checkDodgyImport stuff
533 | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
534 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
535 -- NB. use the RdrName for reporting the warning
539 -- For each import item, we convert its RdrNames to Names,
540 -- and at the same time construct an AvailInfo corresponding
541 -- to what is actually imported by this item.
542 -- Returns Nothing on error.
543 -- We return a list here, because in the case of an import
544 -- item like C, if we are hiding, then C refers to *both* a
545 -- type/class and a data constructor. Moreover, when we import
546 -- data constructors of an associated family, we need separate
547 -- AvailInfos for the data constructors and the family (as they have
548 -- different parents). See the discussion at occ_env.
549 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
550 lookup_ie opt_typeFamilies ie
551 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
554 | isQual rdr = Failed (qualImportItemErr rdr)
555 | Just nm <- lookupOccEnv occ_env (rdrNameOcc rdr) = return nm
560 (name, avail, _) <- lookup_name n
561 return [(IEVar name, trimAvail avail name)]
564 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
566 -- non-associated ty/cls
567 Nothing -> return [(IEThingAll name, avail)]
569 Just parent -> return [(IEThingAll name,
570 AvailTC name2 (subs \\ [name])),
571 (IEThingAll name, AvailTC parent [name])]
574 | want_hiding -- hiding ( C )
575 -- Here the 'C' can be a data constructor
576 -- *or* a type/class, or even both
577 -> let tc_name = lookup_name tc
578 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
580 case catMaybeErr [ tc_name, dc_name ] of
582 names -> return [mkIEThingAbs name | name <- names]
584 -> do nameAvail <- lookup_name tc
585 return [mkIEThingAbs nameAvail]
587 IEThingWith tc ns -> do
588 (name, AvailTC _ subnames, mb_parent) <- lookup_name tc
590 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
591 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
592 children <- if any isNothing mb_children
594 else return (catMaybes mb_children)
595 -- check for proper import of type families
596 when (not opt_typeFamilies && any isTyConName children) $
597 Failed (typeItemErr (head . filter isTyConName $ children)
598 (text "in import list"))
600 -- non-associated ty/cls
601 Nothing -> return [(IEThingWith name children,
602 AvailTC name (name:children))]
604 Just parent -> return [(IEThingWith name children,
605 AvailTC name children),
606 (IEThingWith name children,
607 AvailTC parent [name])]
609 _other -> Failed illegalImportItemErr
610 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
614 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
615 mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n])
618 catMaybeErr :: [MaybeErr err a] -> [a]
619 catMaybeErr ms = [ a | Succeeded a <- ms ]
622 %************************************************************************
626 %************************************************************************
629 -- | make a 'GlobalRdrEnv' where all the elements point to the same
630 -- import declaration (useful for "hiding" imports, or imports with
632 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
633 gresFromAvails prov avails
634 = concatMap (gresFromAvail (const prov)) avails
636 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
637 gresFromAvail prov_fn avail
638 = [ GRE {gre_name = n,
639 gre_par = availParent n avail,
640 gre_prov = prov_fn n}
641 | n <- availNames avail ]
643 greAvail :: GlobalRdrElt -> AvailInfo
644 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
646 mkUnitAvail :: Name -> Parent -> AvailInfo
647 mkUnitAvail me (ParentIs p) = AvailTC p [me]
648 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
649 | otherwise = Avail me
651 plusAvail :: GenAvailInfo Name -> GenAvailInfo Name -> GenAvailInfo Name
652 plusAvail (Avail n1) (Avail _) = Avail n1
653 plusAvail (AvailTC _ ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
654 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
656 availParent :: Name -> AvailInfo -> Parent
657 availParent _ (Avail _) = NoParent
658 availParent n (AvailTC m _) | n == m = NoParent
659 | otherwise = ParentIs m
661 trimAvail :: AvailInfo -> Name -> AvailInfo
662 trimAvail (Avail n) _ = Avail n
663 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
665 -- | filters 'AvailInfo's by the given predicate
666 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
667 filterAvails keep avails = foldr (filterAvail keep) [] avails
669 -- | filters an 'AvailInfo' by the given predicate
670 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
671 filterAvail keep ie rest =
673 Avail n | keep n -> ie : rest
676 let left = filter keep ns in
677 if null left then rest else AvailTC tc left : rest
679 -- | Given an import\/export spec, construct the appropriate 'GlobalRdrElt's.
680 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
681 gresFromIE decl_spec (L loc ie, avail)
682 = gresFromAvail prov_fn avail
684 is_explicit = case ie of
685 IEThingAll name -> \n -> n == name
687 prov_fn name = Imported [imp_spec]
689 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
690 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
692 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
693 mkChildEnv gres = foldr add emptyNameEnv gres
695 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_Acc (:) singleton env p n
698 findChildren :: NameEnv [Name] -> Name -> [Name]
699 findChildren env n = lookupNameEnv env n `orElse` []
702 ---------------------------------------
705 All this AvailEnv stuff is hardly used; only in a very small
706 part of RnNames. Todo: remove?
707 ---------------------------------------
710 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
712 emptyAvailEnv :: AvailEnv
713 emptyAvailEnv = emptyNameEnv
716 unitAvailEnv :: AvailInfo -> AvailEnv
717 unitAvailEnv a = unitNameEnv (availName a) a
719 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
720 plusAvailEnv = plusNameEnv_C plusAvail
722 availEnvElts :: AvailEnv -> [AvailInfo]
723 availEnvElts = nameEnvElts
726 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
727 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
729 mkAvailEnv :: [AvailInfo] -> AvailEnv
730 -- 'avails' may have several items with the same availName
731 -- E.g import Ix( Ix(..), index )
732 -- will give Ix(Ix,index,range) and Ix(index)
733 -- We want to combine these; addAvail does that
734 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
736 -- After combining the avails, we need to ensure that the parent name is the
737 -- first entry in the list of subnames, if it is included at all. (Subsequent
738 -- functions rely on that.)
739 normaliseAvail :: AvailInfo -> AvailInfo
740 normaliseAvail avail@(Avail _) = avail
741 normaliseAvail (AvailTC name subs) = AvailTC name subs'
743 subs' = if name `elem` subs then name : (delete name subs) else subs
745 -- | combines 'AvailInfo's from the same family
746 nubAvails :: [AvailInfo] -> [AvailInfo]
747 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
751 %************************************************************************
753 \subsection{Export list processing}
755 %************************************************************************
757 Processing the export list.
759 You might think that we should record things that appear in the export
760 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
761 wrong. We do check (here) that they are in scope, but there is no
762 need to slurp in their actual declaration (which is what
763 @addOccurrenceName@ forces).
765 Indeed, doing so would big trouble when compiling @PrelBase@, because
766 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
767 @ConcBase.StateAndSynchVar#@, and so on...
770 type ExportAccum -- The type of the accumulating parameter of
771 -- the main worker function in rnExports
772 = ([LIE Name], -- Export items with Names
773 ExportOccMap, -- Tracks exported occurrence names
774 [AvailInfo]) -- The accumulated exported stuff
777 emptyExportAccum :: ExportAccum
778 emptyExportAccum = ([], emptyOccEnv, [])
780 type ExportOccMap = OccEnv (Name, IE RdrName)
781 -- Tracks what a particular exported OccName
782 -- in an export list refers to, and which item
783 -- it came from. It's illegal to export two distinct things
784 -- that have the same occurrence name
786 rnExports :: Bool -- False => no 'module M(..) where' header at all
787 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
791 -- Complains if two distinct exports have same OccName
792 -- Warns about identical exports.
793 -- Complains about exports items not in scope
795 rnExports explicit_mod exports
796 tcg_env@(TcGblEnv { tcg_mod = this_mod,
797 tcg_rdr_env = rdr_env,
798 tcg_imports = imports })
800 -- If the module header is omitted altogether, then behave
801 -- as if the user had written "module Main(main) where..."
802 -- EXCEPT in interactive mode, when we behave as if he had
803 -- written "module Main where ..."
804 -- Reason: don't want to complain about 'main' not in scope
805 -- in interactive mode
808 | explicit_mod = exports
809 | ghcLink dflags == LinkInMemory = Nothing
810 | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
811 -- ToDo: the 'noLoc' here is unhelpful if 'main'
812 -- turns out to be out of scope
814 ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
815 ; let final_avails = nubAvails avails -- Combine families
817 ; return (tcg_env { tcg_exports = final_avails,
818 tcg_rn_exports = case tcg_rn_exports tcg_env of
820 Just _ -> rn_exports,
821 tcg_dus = tcg_dus tcg_env `plusDU`
822 usesOnly (availsToNameSet final_avails) }) }
824 exports_from_avail :: Maybe [LIE RdrName]
825 -- Nothing => no explicit export list
829 -> RnM (Maybe [LIE Name], [AvailInfo])
831 exports_from_avail Nothing rdr_env _imports _this_mod
832 = -- The same as (module M) where M is the current module name,
833 -- so that's how we handle it.
835 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
838 return (Nothing, avails)
840 exports_from_avail (Just rdr_items) rdr_env imports this_mod
841 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
843 return (Just ie_names, exports)
845 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
846 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
848 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
849 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
851 imported_modules = [ qual_name
852 | xs <- moduleEnvElts $ imp_mods imports,
853 (qual_name, _, _) <- xs ]
855 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
856 exports_from_item acc@(ie_names, occs, exports)
857 (L loc ie@(IEModuleContents mod))
858 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
859 , mod `elem` earlier_mods -- Duplicate export of M
860 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
861 warnIf warn_dup_exports (dupModuleExport mod) ;
865 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
866 ; warnDodgyExports <- doptM Opt_WarnDodgyExports
867 ; let { exportValid = (mod `elem` imported_modules)
868 || (moduleName this_mod == mod)
869 ; gres = filter (isModuleExported implicit_prelude mod)
870 (globalRdrEnvElts rdr_env)
871 ; names = map gre_name gres
874 ; checkErr exportValid (moduleNotImported mod)
875 ; warnIf (warnDodgyExports && exportValid && null gres) (nullModuleExport mod)
877 ; addUsedRdrNames (concat [ [mkRdrQual mod occ, mkRdrUnqual occ]
878 | occ <- map nameOccName names ])
879 -- The qualified and unqualified version of all of
880 -- these names are, in effect, used by this export
882 ; occs' <- check_occs ie occs names
883 -- This check_occs not only finds conflicts
884 -- between this item and others, but also
885 -- internally within this item. That is, if
886 -- 'M.x' is in scope in several ways, we'll have
887 -- several members of mod_avails with the same
889 ; return (L loc (IEModuleContents mod) : ie_names,
890 occs', map greAvail gres ++ exports) }
892 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
894 = do new_ie <- lookup_doc_ie ie
895 return (L loc new_ie : lie_names, occs, exports)
898 = do (new_ie, avail) <- lookup_ie ie
899 if isUnboundName (ieName new_ie)
900 then return acc -- Avoid error cascade
903 occs' <- check_occs ie occs (availNames avail)
905 return (L loc new_ie : lie_names, occs', avail : exports)
908 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
909 lookup_ie (IEVar rdr)
910 = do gre <- lookupGreRn rdr
911 return (IEVar (gre_name gre), greAvail gre)
913 lookup_ie (IEThingAbs rdr)
914 = do gre <- lookupGreRn rdr
915 let name = gre_name gre
917 NoParent -> return (IEThingAbs name,
919 ParentIs p -> return (IEThingAbs name,
922 lookup_ie ie@(IEThingAll rdr)
923 = do name <- lookupGlobalOccRn rdr
924 let kids = findChildren kids_env name
925 mkKidRdrName = case isQual_maybe rdr of
926 Nothing -> mkRdrUnqual
927 Just (modName, _) -> mkRdrQual modName
928 addUsedRdrNames $ map (mkKidRdrName . nameOccName) kids
929 warnDodgyExports <- doptM Opt_WarnDodgyExports
932 then when warnDodgyExports $ addWarn (dodgyExportWarn name)
933 else -- This occurs when you export T(..), but
934 -- only import T abstractly, or T is a synonym.
935 addErr (exportItemErr ie)
937 return (IEThingAll name, AvailTC name (name:kids))
939 lookup_ie ie@(IEThingWith rdr sub_rdrs)
940 = do name <- lookupGlobalOccRn rdr
941 if isUnboundName name
942 then return (IEThingWith name [], AvailTC name [name])
944 let env = mkOccEnv [ (nameOccName s, s)
945 | s <- findChildren kids_env name ]
946 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
947 if any isNothing mb_names
948 then do addErr (exportItemErr ie)
949 return (IEThingWith name [], AvailTC name [name])
950 else do let names = catMaybes mb_names
951 optTyFam <- doptM Opt_TypeFamilies
952 when (not optTyFam && any isTyConName names) $
953 addErr (typeItemErr ( head
956 (text "in export list"))
957 return (IEThingWith name names, AvailTC name (name:names))
959 lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier
962 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
963 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
964 return (IEGroup lev rn_doc)
965 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
966 return (IEDoc rn_doc)
967 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
968 lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier
971 isDoc :: IE RdrName -> Bool
972 isDoc (IEDoc _) = True
973 isDoc (IEDocNamed _) = True
974 isDoc (IEGroup _ _) = True
977 -------------------------------
978 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
979 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
980 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
981 | implicit_prelude && isBuiltInSyntax name = False
982 -- Optimisation: filter out names for built-in syntax
983 -- They just clutter up the environment (esp tuples), and the parser
984 -- will generate Exact RdrNames for them, so the cluttered
985 -- envt is no use. To avoid doing this filter all the time,
986 -- we use -XNoImplicitPrelude as a clue that the filter is
987 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
989 -- It's worth doing because it makes the environment smaller for
990 -- every module that imports the Prelude
993 LocalDef | Just name_mod <- nameModule_maybe name
994 -> moduleName name_mod == mod
996 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
998 -------------------------------
999 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
1000 check_occs ie occs names
1001 = foldlM check occs names
1004 = case lookupOccEnv occs name_occ of
1005 Nothing -> return (extendOccEnv occs name_occ (name, ie))
1008 | name == name' -- Duplicate export
1009 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
1010 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
1013 | otherwise -- Same occ name but different names: an error
1014 -> do { global_env <- getGlobalRdrEnv ;
1015 addErr (exportClashErr global_env name' name ie' ie) ;
1018 name_occ = nameOccName name
1021 %*********************************************************
1025 %*********************************************************
1028 finishWarnings :: DynFlags -> Maybe WarningTxt
1029 -> TcGblEnv -> RnM TcGblEnv
1030 -- (a) Report usage of imports that are deprecated or have other warnings
1031 -- (b) If the whole module is warned about or deprecated, update tcg_warns
1032 -- All this happens only once per module
1033 finishWarnings dflags mod_warn tcg_env
1034 = do { (eps,hpt) <- getEpsAndHpt
1035 ; ifOptM Opt_WarnWarningsDeprecations $
1036 mapM_ (check hpt (eps_PIT eps)) all_gres
1037 -- By this time, typechecking is complete,
1038 -- so the PIT is fully populated
1040 -- Deal with a module deprecation; it overrides all existing warns
1041 ; let new_warns = case mod_warn of
1042 Just txt -> WarnAll txt
1043 Nothing -> tcg_warns tcg_env
1044 ; return (tcg_env { tcg_warns = new_warns }) }
1046 used_names = allUses (tcg_dus tcg_env)
1047 -- Report on all deprecated uses; hence allUses
1048 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
1050 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
1051 | name `elemNameSet` used_names
1052 , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
1053 = addWarnAt (importSpecLoc imp_spec)
1054 (sep [ptext (sLit "In the use of") <+>
1055 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
1057 (parens imp_msg) <> colon,
1060 name_mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1061 imp_mod = importSpecModule imp_spec
1062 imp_msg = ptext (sLit "imported from") <+> ppr imp_mod <> extra
1063 extra | imp_mod == moduleName name_mod = empty
1064 | otherwise = ptext (sLit ", but defined in") <+> ppr name_mod
1066 check _ _ _ = return () -- Local, or not used, or not deprectated
1067 -- The Imported pattern-match: don't deprecate locally defined names
1068 -- For a start, we may be exporting a deprecated thing
1069 -- Also we may use a deprecated thing in the defn of another
1070 -- deprecated things. We may even use a deprecated thing in
1071 -- the defn of a non-deprecated thing, when changing a module's
1074 lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1075 -> GlobalRdrElt -> Maybe WarningTxt
1076 -- The name is definitely imported, so look in HPT, PIT
1077 lookupImpDeprec dflags hpt pit gre
1078 = case lookupIfaceByModule dflags hpt pit mod of
1079 Just iface -> mi_warn_fn iface name `mplus` -- Bleat if the thing, *or
1081 ParentIs p -> mi_warn_fn iface p -- its parent*, is warn'd
1084 Nothing -> Nothing -- See Note [Used names with interface not loaded]
1087 mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1090 Note [Used names with interface not loaded]
1091 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1092 By now all the interfaces should have been loaded,
1093 because reportDeprecations happens after typechecking.
1094 However, it's still (just) possible to to find a used
1095 Name whose interface hasn't been loaded:
1097 a) It might be a WiredInName; in that case we may not load
1098 its interface (although we could).
1100 b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
1101 These are seen as "used" by the renamer (if -XNoImplicitPrelude)
1102 is on), but the typechecker may discard their uses
1103 if in fact the in-scope fromRational is GHC.Read.fromRational,
1104 (see tcPat.tcOverloadedLit), and the typechecker sees that the type
1105 is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
1106 In that obscure case it won't force the interface in.
1108 In both cases we simply don't permit deprecations;
1109 this is, after all, wired-in stuff.
1112 %*********************************************************
1116 %*********************************************************
1119 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1120 -> TcGblEnv -> RnM ()
1121 reportUnusedNames _export_decls gbl_env
1122 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1123 ; warnUnusedImportDecls gbl_env
1124 ; warnUnusedTopBinds unused_locals }
1126 used_names :: NameSet
1127 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1128 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1131 -- Collect the defined names from the in-scope environment
1132 defined_names :: [GlobalRdrElt]
1133 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1135 -- Note that defined_and_used, defined_but_not_used
1136 -- are both [GRE]; that's why we need defined_and_used
1137 -- rather than just used_names
1138 _defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1139 (_defined_and_used, defined_but_not_used)
1140 = partition (gre_is_used used_names) defined_names
1142 kids_env = mkChildEnv defined_names
1143 -- This is done in mkExports too; duplicated work
1145 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1146 gre_is_used used_names (GRE {gre_name = name})
1147 = name `elemNameSet` used_names
1148 || any (`elemNameSet` used_names) (findChildren kids_env name)
1149 -- A use of C implies a use of T,
1150 -- if C was brought into scope by T(..) or T(C)
1152 -- Filter out the ones that are
1153 -- (a) defined in this module, and
1154 -- (b) not defined by a 'deriving' clause
1155 -- The latter have an Internal Name, so we can filter them out easily
1156 unused_locals :: [GlobalRdrElt]
1157 unused_locals = filter is_unused_local defined_but_not_used
1158 is_unused_local :: GlobalRdrElt -> Bool
1159 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1162 %*********************************************************
1166 %*********************************************************
1168 This code finds which import declarations are unused. The
1169 specification and implementation notes are here:
1170 http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/UnusedImports
1173 type ImportDeclUsage
1174 = ( LImportDecl Name -- The import declaration
1175 , [AvailInfo] -- What *is* used (normalised)
1176 , [Name] ) -- What is imported but *not* used
1180 warnUnusedImportDecls :: TcGblEnv -> RnM ()
1181 warnUnusedImportDecls gbl_env
1182 = do { uses <- readMutVar (tcg_used_rdrnames gbl_env)
1183 ; let imports = filter explicit_import (tcg_rn_imports gbl_env)
1184 rdr_env = tcg_rdr_env gbl_env
1186 ; let usage :: [ImportDeclUsage]
1187 usage = findImportUsage imports rdr_env (Set.elems uses)
1189 ; ifOptM Opt_WarnUnusedImports $
1190 mapM_ warnUnusedImport usage
1192 ; ifOptM Opt_D_dump_minimal_imports $
1193 printMinimalImports usage }
1195 explicit_import (L loc _) = isGoodSrcSpan loc
1196 -- Filter out the implicit Prelude import
1197 -- which we do not want to bleat about
1201 findImportUsage :: [LImportDecl Name]
1204 -> [ImportDeclUsage]
1206 type ImportMap = FiniteMap SrcLoc [AvailInfo]
1207 -- The intermediate data struture records, for each import
1208 -- declaration, what stuff brought into scope by that
1209 -- declaration is actually used in the module.
1211 -- The SrcLoc is the location of the start
1212 -- of a particular 'import' declaration
1214 -- The AvailInfos are the things imported from that decl
1215 -- (just a list, not normalised)
1217 findImportUsage imports rdr_env rdrs
1218 = map unused_decl imports
1220 import_usage :: ImportMap
1221 import_usage = foldr add_rdr emptyFM rdrs
1223 unused_decl decl@(L loc (ImportDecl { ideclHiding = imps }))
1224 = (decl, nubAvails used_avails, unused_imps)
1226 used_avails = lookupFM import_usage (srcSpanStart loc) `orElse` []
1227 used_names = availsToNameSet used_avails
1229 unused_imps = case imps of
1230 Just (False, imp_ies) -> nameSetToList unused_imps
1232 imp_names = mkNameSet (concatMap (ieNames . unLoc) imp_ies)
1233 unused_imps = imp_names `minusNameSet` used_names
1235 _other -> [] -- No explicit import list => no unused-name list
1237 add_rdr :: RdrName -> ImportMap -> ImportMap
1239 = case lookupGRE_RdrName rdr rdr_env of
1240 [gre] | Imported imps <- gre_prov gre
1241 -> add_imp gre (bestImport imps) iu
1244 add_imp :: GlobalRdrElt -> ImportSpec -> ImportMap -> ImportMap
1245 add_imp gre (ImpSpec { is_decl = imp_decl_spec }) iu
1246 = addToFM_C add iu decl_loc [avail]
1248 add avails _ = avail : avails
1249 decl_loc = srcSpanStart (is_dloc imp_decl_spec)
1251 avail = case gre_par gre of
1252 ParentIs p -> AvailTC p [p,name]
1253 NoParent | isTyConName name -> AvailTC name [name]
1254 | otherwise -> Avail name
1255 -- If you use (+) from Num, then for this purpose we want
1256 -- to say that Num is used as well. That is why in the
1257 -- ParentIs case we have [p,name] in the ParentIs case
1259 bestImport :: [ImportSpec] -> ImportSpec
1261 = case partition isImpAll iss of
1262 ([], imp_somes) -> textuallyFirst imp_somes
1263 (imp_alls, _) -> textuallyFirst imp_alls
1265 textuallyFirst :: [ImportSpec] -> ImportSpec
1266 textuallyFirst iss = case sortWith (is_dloc . is_decl) iss of
1267 [] -> pprPanic "textuallyFirst" (ppr iss)
1270 isImpAll :: ImportSpec -> Bool
1271 isImpAll (ImpSpec { is_item = ImpAll }) = True
1272 isImpAll _other = False
1276 warnUnusedImport :: ImportDeclUsage -> RnM ()
1277 warnUnusedImport (L loc decl, used, unused)
1278 | Just (False,[]) <- ideclHiding decl
1279 = return () -- Do not warn for 'import M()'
1280 | null used = addWarnAt loc msg1 -- Nothing used; drop entire decl
1281 | null unused = return () -- Everything imported is used; nop
1282 | otherwise = addWarnAt loc msg2 -- Some imports are unused
1284 msg1 = vcat [pp_herald <+> quotes pp_mod <+> pp_not_used,
1285 nest 2 (ptext (sLit "except perhaps to import instances from")
1287 ptext (sLit "To import instances alone, use:")
1288 <+> ptext (sLit "import") <+> pp_mod <> parens empty ]
1289 msg2 = sep [pp_herald <+> quotes (pprWithCommas ppr unused),
1290 text "from module" <+> quotes pp_mod <+> pp_not_used]
1291 pp_herald = text "The import of"
1292 pp_mod = ppr (unLoc (ideclName decl))
1293 pp_not_used = text "is redundant"
1296 To print the minimal imports we walk over the user-supplied import
1297 decls, and simply trim their import lists. NB that
1299 * We do *not* change the 'qualified' or 'as' parts!
1301 * We do not disard a decl altogether; we might need instances
1302 from it. Instead we just trim to an empty import list
1305 printMinimalImports :: [ImportDeclUsage] -> RnM ()
1306 printMinimalImports imports_w_usage
1307 = do { imports' <- mapM mk_minimal imports_w_usage
1308 ; this_mod <- getModule
1310 do { h <- openFile (mkFilename this_mod) WriteMode
1311 ; printForUser h neverQualify (vcat (map ppr imports')) }
1312 -- The neverQualify is important. We are printing Names
1313 -- but they are in the context of an 'import' decl, and
1314 -- we never qualify things inside there
1315 -- E.g. import Blag( f, b )
1316 -- not import Blag( Blag.f, Blag.g )!
1319 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1321 mk_minimal (L l decl, used, unused)
1323 , Just (False, _) <- ideclHiding decl
1326 = do { ies <- initIfaceTcRn $ mapM to_ie used
1327 ; return (L l (decl { ideclHiding = Just (False, map (L l) ies) })) }
1329 to_ie :: AvailInfo -> IfG (IE Name)
1330 -- The main trick here is that if we're importing all the constructors
1331 -- we want to say "T(..)", but if we're importing only a subset we want
1332 -- to say "T(A,B,C)". So we have to find out what the module exports.
1333 to_ie (Avail n) = return (IEVar n)
1334 to_ie (AvailTC n [m]) = ASSERT( n==m )
1335 return (IEThingAbs n)
1336 to_ie (AvailTC n ns) = do
1337 iface <- loadSysInterface doc n_mod
1338 case [xs | (m,as) <- mi_exports iface,
1341 x == nameOccName n] of
1342 [xs] | all_used xs -> return (IEThingAll n)
1343 | otherwise -> return (IEThingWith n (filter (/= n) ns))
1344 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1347 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1348 doc = text "Compute minimal imports from" <+> ppr n
1349 n_mod = ASSERT( isExternalName n ) nameModule n
1352 %************************************************************************
1356 %************************************************************************
1359 qualImportItemErr :: RdrName -> SDoc
1360 qualImportItemErr rdr
1361 = hang (ptext (sLit "Illegal qualified name in import item:"))
1364 badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc
1365 badImportItemErr iface decl_spec ie
1366 = sep [ptext (sLit "Module"), quotes (ppr (is_mod decl_spec)), source_import,
1367 ptext (sLit "does not export"), quotes (ppr ie)]
1369 source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
1372 illegalImportItemErr :: SDoc
1373 illegalImportItemErr = ptext (sLit "Illegal import item")
1375 dodgyImportWarn :: RdrName -> SDoc
1376 dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item
1377 dodgyExportWarn :: Name -> SDoc
1378 dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item
1380 dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc
1382 = sep [ ptext (sLit "The") <+> kind <+> ptext (sLit "item") <+> quotes (ppr (IEThingAll tc))
1383 <+> ptext (sLit "suggests that"),
1384 quotes (ppr tc) <+> ptext (sLit "has (in-scope) constructors or class methods,"),
1385 ptext (sLit "but it has none") ]
1387 exportItemErr :: IE RdrName -> SDoc
1388 exportItemErr export_item
1389 = sep [ ptext (sLit "The export item") <+> quotes (ppr export_item),
1390 ptext (sLit "attempts to export constructors or class methods that are not visible here") ]
1392 typeItemErr :: Name -> SDoc -> SDoc
1393 typeItemErr name wherestr
1394 = sep [ ptext (sLit "Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1395 ptext (sLit "Use -XTypeFamilies to enable this extension") ]
1397 exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
1399 exportClashErr global_env name1 name2 ie1 ie2
1400 = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon
1401 , ppr_export ie1' name1'
1402 , ppr_export ie2' name2' ]
1404 occ = nameOccName name1
1405 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
1406 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1408 -- get_gre finds a GRE for the Name, so that we can show its provenance
1410 = case lookupGRE_Name global_env name of
1412 [] -> pprPanic "exportClashErr" (ppr name)
1413 get_loc name = nameSrcLoc $ gre_name $ get_gre name
1414 (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
1415 then (name1, ie1, name2, ie2)
1416 else (name2, ie2, name1, ie1)
1418 addDupDeclErr :: [Name] -> TcRn ()
1420 = panic "addDupDeclErr: empty list"
1421 addDupDeclErr names@(name : _)
1422 = addErrAt (getSrcSpan (last sorted_names)) $
1423 -- Report the error at the later location
1424 vcat [ptext (sLit "Multiple declarations of") <+> quotes (ppr name),
1425 ptext (sLit "Declared at:") <+> vcat (map (ppr . nameSrcLoc) sorted_names)]
1427 sorted_names = sortWith nameSrcLoc names
1429 dupExportWarn :: OccName -> IE RdrName -> IE RdrName -> SDoc
1430 dupExportWarn occ_name ie1 ie2
1431 = hsep [quotes (ppr occ_name),
1432 ptext (sLit "is exported by"), quotes (ppr ie1),
1433 ptext (sLit "and"), quotes (ppr ie2)]
1435 dupModuleExport :: ModuleName -> SDoc
1437 = hsep [ptext (sLit "Duplicate"),
1438 quotes (ptext (sLit "Module") <+> ppr mod),
1439 ptext (sLit "in export list")]
1441 moduleNotImported :: ModuleName -> SDoc
1442 moduleNotImported mod
1443 = ptext (sLit "The export item `module") <+> ppr mod <>
1444 ptext (sLit "' is not imported")
1446 nullModuleExport :: ModuleName -> SDoc
1447 nullModuleExport mod
1448 = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing")
1450 moduleWarn :: ModuleName -> WarningTxt -> SDoc
1451 moduleWarn mod (WarningTxt txt)
1452 = sep [ ptext (sLit "Module") <+> quotes (ppr mod) <> ptext (sLit ":"),
1453 nest 2 (vcat (map ppr txt)) ]
1454 moduleWarn mod (DeprecatedTxt txt)
1455 = sep [ ptext (sLit "Module") <+> quotes (ppr mod)
1456 <+> ptext (sLit "is deprecated:"),
1457 nest 2 (vcat (map ppr txt)) ]
1459 implicitPreludeWarn :: SDoc
1461 = ptext (sLit "Module `Prelude' implicitly imported")
1463 packageImportErr :: SDoc
1465 = ptext (sLit "Package-qualified imports are not enabled; use -XPackageImports")