2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 -- The above warning supression flag is a temporary kludge.
9 -- While working on this module you are encouraged to remove it and fix
10 -- any warnings in the module. See
11 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
15 rnImports, getLocalNonValBinders,
16 rnExports, extendGlobalRdrEnvRn,
17 reportUnusedNames, finishDeprecations,
20 #include "HsVersions.h"
23 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
24 ForeignDecl(..), HsGroup(..), HsValBindsLR(..),
25 Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
26 instDeclATs, isFamInstDecl,
29 import RnHsDoc ( rnHsDoc )
30 import IfaceEnv ( ifaceExportNames )
31 import LoadIface ( loadSrcInterface, loadSysInterface )
32 import TcRnMonad hiding (LIE)
48 import BasicTypes ( DeprecTxt, Fixity )
49 import DriverPhases ( isHsBoot )
53 import Data.List ( partition, concatMap, (\\), delete )
54 import IO ( openFile, IOMode(..) )
55 import Monad ( when, mplus )
60 %************************************************************************
64 %************************************************************************
67 rnImports :: [LImportDecl RdrName]
68 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
71 -- PROCESS IMPORT DECLS
72 -- Do the non {- SOURCE -} ones first, so that we get a helpful
73 -- warning for {- SOURCE -} ones that are unnecessary
74 = do this_mod <- getModule
75 implicit_prelude <- doptM Opt_ImplicitPrelude
76 let prel_imports = mkPrelImports this_mod implicit_prelude imports
77 (source, ordinary) = partition is_source_import imports
78 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
80 ifOptM Opt_WarnImplicitPrelude (
81 when (notNull prel_imports) $ addWarn (implicitPreludeWarn)
84 stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
85 stuff2 <- mapM (rnImportDecl this_mod) source
86 let (decls, rdr_env, imp_avails,hpc_usage) = combine (stuff1 ++ stuff2)
87 return (decls, rdr_env, imp_avails,hpc_usage)
90 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)]
91 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
92 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails,False)
93 where plus (decl, gbl_env1, imp_avails1,hpc_usage1)
94 (decls, gbl_env2, imp_avails2,hpc_usage2)
96 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
97 imp_avails1 `plusImportAvails` imp_avails2,
98 hpc_usage1 || hpc_usage2)
100 mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName]
101 -- Consruct the implicit declaration "import Prelude" (or not)
103 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
104 -- because the former doesn't even look at Prelude.hi for instance
105 -- declarations, whereas the latter does.
106 mkPrelImports this_mod implicit_prelude import_decls
107 | this_mod == pRELUDE
108 || explicit_prelude_import
109 || not implicit_prelude
111 | otherwise = [preludeImportDecl]
113 explicit_prelude_import
114 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- import_decls,
115 unLoc mod == pRELUDE_NAME ]
117 preludeImportDecl :: LImportDecl RdrName
120 ImportDecl (L loc pRELUDE_NAME)
121 False {- Not a boot interface -}
122 False {- Not qualified -}
123 Nothing {- No "as" -}
124 Nothing {- No import list -}
126 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
129 rnImportDecl :: Module
130 -> LImportDecl RdrName
131 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
133 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot
134 qual_only as_mod imp_details))
138 -- If there's an error in loadInterface, (e.g. interface
139 -- file not found) we get lots of spurious errors from 'filterImports'
141 imp_mod_name = unLoc loc_imp_mod_name
142 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
144 iface <- loadSrcInterface doc imp_mod_name want_boot
146 -- Compiler sanity check: if the import didn't say
147 -- {-# SOURCE #-} we should not get a hi-boot file
148 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
150 -- Issue a user warning for a redundant {- SOURCE -} import
151 -- NB that we arrange to read all the ordinary imports before
152 -- any of the {- SOURCE -} imports
153 warnIf (want_boot && not (mi_boot iface))
154 (warnRedundantSourceImport imp_mod_name)
157 imp_mod = mi_module iface
158 deprecs = mi_deprecs iface
159 orph_iface = mi_orphan iface
160 has_finsts = mi_finsts iface
163 filtered_exports = filter not_this_mod (mi_exports iface)
164 not_this_mod (mod,_) = mod /= this_mod
165 -- If the module exports anything defined in this module, just
166 -- ignore it. Reason: otherwise it looks as if there are two
167 -- local definition sites for the thing, and an error gets
168 -- reported. Easiest thing is just to filter them out up
169 -- front. This situation only arises if a module imports
170 -- itself, or another module that imported it. (Necessarily,
171 -- this invoves a loop.)
173 -- Tiresome consequence: if you say
178 -- module B( AType ) where
179 -- import {-# SOURCE #-} A( AType )
181 -- then you'll get a 'B does not export AType' message. Oh well.
183 qual_mod_name = case as_mod of
184 Nothing -> imp_mod_name
185 Just another_name -> another_name
186 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
187 is_dloc = loc, is_as = qual_mod_name }
190 -- Get the total exports from this module
191 total_avails <- ifaceExportNames filtered_exports
193 -- filter the imports according to the import declaration
194 (new_imp_details, gbl_env) <-
195 filterImports iface imp_spec imp_details total_avails
200 -- Compute new transitive dependencies
202 orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
203 imp_mod : dep_orphs deps
204 | otherwise = dep_orphs deps
206 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
207 imp_mod : dep_finsts deps
208 | otherwise = dep_finsts deps
210 pkg = modulePackageId (mi_module iface)
212 (dependent_mods, dependent_pkgs)
213 | pkg == thisPackage dflags =
214 -- Imported module is from the home package
215 -- Take its dependent modules and add imp_mod itself
216 -- Take its dependent packages unchanged
218 -- NB: (dep_mods deps) might include a hi-boot file
219 -- for the module being compiled, CM. Do *not* filter
220 -- this out (as we used to), because when we've
221 -- finished dealing with the direct imports we want to
222 -- know if any of them depended on CM.hi-boot, in
223 -- which case we should do the hi-boot consistency
224 -- check. See LoadIface.loadHiBootInterface
225 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
228 -- Imported module is from another package
229 -- Dump the dependent modules
230 -- Add the package imp_mod comes from to the dependent packages
231 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
232 ([], pkg : dep_pkgs deps)
234 -- True <=> import M ()
235 import_all = case imp_details of
236 Just (is_hiding, ls) -> not is_hiding && null ls
239 imports = ImportAvails {
240 imp_mods = unitModuleEnv imp_mod (imp_mod, [(qual_mod_name, import_all, loc)]),
243 imp_dep_mods = mkModDeps dependent_mods,
244 imp_dep_pkgs = dependent_pkgs
247 -- Complain if we import a deprecated module
248 ifOptM Opt_WarnDeprecations (
250 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
254 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name want_boot
255 qual_only as_mod new_imp_details)
257 return (new_imp_decl, gbl_env, imports, mi_hpc iface)
260 warnRedundantSourceImport mod_name
261 = ptext SLIT("Unnecessary {-# SOURCE #-} in the import of module")
262 <+> quotes (ppr mod_name)
266 %************************************************************************
268 importsFromLocalDecls
270 %************************************************************************
272 From the top-level declarations of this module produce
273 * the lexical environment
275 created by its bindings.
277 Note [Shadowing in extendRdrEnvRn]
278 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
279 Usually when etending the GlobalRdrEnv we complain if a new binding
280 duplicates an existing one. By adding the bindings one at a time,
281 this check also complains if we add two new bindings for the same name.
282 (Remember that in Template Haskell the duplicates might *already be*
283 in the GlobalRdrEnv from higher up the module.)
285 But with a Template Haskell quotation we want to *shadow*:
287 Here the inner binding for 'f' simply shadows the outer one.
288 And that applies even if the binding for 'f' is in a where-clause,
289 and hence is in the *local* RdrEnv not the *global* RdrEnv.
291 Hence the shadowP boolean passed in.
294 extendGlobalRdrEnvRn :: Bool -- Note [Shadowing in extendGlobalRdrEnvRn]
297 -> RnM (TcGblEnv, TcLclEnv)
298 -- Updates both the GlobalRdrEnv and the FixityEnv
299 -- We return a new TcLclEnv only becuase we might have to
300 -- delete some bindings from it; see Note [Shadowing in extendGlobalRdrEnvRn]
302 extendGlobalRdrEnvRn shadowP avails new_fixities
303 = do { (gbl_env, lcl_env) <- getEnvs
304 ; let rdr_env = tcg_rdr_env gbl_env
305 fix_env = tcg_fix_env gbl_env
307 -- Delete new_occs from global and local envs
308 -- We are going to shadow them
309 new_occs = map (nameOccName . gre_name) gres
310 rdr_env1 = hideSomeUnquals rdr_env new_occs
311 lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
313 -- Note [Shadowing in extendGlobalRdrEnvRn]
314 (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
315 | otherwise = (rdr_env, lcl_env)
317 ; (rdr_env', fix_env') <- foldlM extend (rdr_env2, fix_env) gres
319 ; let gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
320 ; return (gbl_env', lcl_env2) }
322 gres = gresFromAvails LocalDef avails
324 extend envs@(cur_rdr_env, cur_fix_env) gre
325 = let gres = lookupGlobalRdrEnv cur_rdr_env (nameOccName (gre_name gre))
326 in case filter isLocalGRE gres of -- Check for existing *local* defns
327 dup_gre:_ -> do { addDupDeclErr (gre_name dup_gre) (gre_name gre)
329 [] -> return (simple_extend envs gre)
331 simple_extend (rdr_env, fix_env) gre
332 = (extendGlobalRdrEnv rdr_env gre, fix_env')
334 -- If there is a fixity decl for the gre,
335 -- add it to the fixity env
337 occ = nameOccName name
338 fix_env' = case lookupOccEnv new_fixities occ of
340 Just (L _ fi) -> extendNameEnv fix_env name (FixItem occ fi)
343 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
344 used for source code.
346 *** See "THE NAMING STORY" in HsDecls ****
348 Instances of type families
349 ~~~~~~~~~~~~~~~~~~~~~~~~~~
350 Indexed data/newtype instances contain data constructors that we need to
351 collect, too. Moreover, we need to descend into the data/newtypes instances
352 of associated families.
354 We need to be careful with the handling of the type constructor of each type
355 instance as the family constructor is already defined, and we want to avoid
356 raising a duplicate declaration error. So, we make a new name for it, but
357 don't return it in the 'AvailInfo'.
360 getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
361 -- Get all the top-level binders bound the group *except*
362 -- for value bindings, which are treated separately
363 -- Specificaly we return AvailInfo for
368 -- (in hs-boot files) value signatures
370 getLocalNonValBinders group
371 = do { gbl_env <- getGblEnv
372 ; get_local_binders gbl_env group }
374 get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
375 hs_tyclds = tycl_decls,
376 hs_instds = inst_decls,
377 hs_fords = foreign_decls })
378 = do { tc_names_s <- mapM new_tc tycl_decls
379 ; at_names_s <- mapM inst_ats inst_decls
380 ; val_names <- mapM new_simple val_bndrs
381 ; return (val_names ++ tc_names_s ++ concat at_names_s) }
383 mod = tcg_mod gbl_env
384 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
386 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
388 -- In a hs-boot file, the value binders come from the
389 -- *signatures*, and there should be no foreign binders
390 val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
391 | otherwise = for_hs_bndrs
393 new_simple rdr_name = do
394 nm <- newTopSrcBinder mod rdr_name
398 | isFamInstDecl (unLoc tc_decl)
399 = do { main_name <- lookupFamInstDeclBndr mod main_rdr
400 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
401 ; return (AvailTC main_name sub_names) }
402 -- main_name is not bound here!
404 = do { main_name <- newTopSrcBinder mod main_rdr
405 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
406 ; return (AvailTC main_name (main_name : sub_names)) }
408 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
411 = mapM new_tc (instDeclATs (unLoc inst_decl))
413 getLocalDeclBinders _ _ = panic "getLocalDeclBinders" -- ValBindsOut can't happen
417 %************************************************************************
419 \subsection{Filtering imports}
421 %************************************************************************
423 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
424 available, and filters it through the import spec (if any).
427 filterImports :: ModIface
428 -> ImpDeclSpec -- The span for the entire import decl
429 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
430 -> [AvailInfo] -- What's available
431 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
432 GlobalRdrEnv) -- Same again, but in GRE form
434 filterImports iface decl_spec Nothing all_avails
435 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
437 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
440 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
441 = do -- check for errors, convert RdrNames to Names
442 opt_typeFamilies <- doptM Opt_TypeFamilies
443 items1 <- mapM (lookup_lie opt_typeFamilies) import_items
445 let items2 :: [(LIE Name, AvailInfo)]
446 items2 = concat items1
447 -- NB the AvailInfo may have duplicates, and several items
448 -- for the same parent; e.g N(x) and N(y)
450 names = availsToNameSet (map snd items2)
451 keep n = not (n `elemNameSet` names)
452 pruned_avails = filterAvails keep all_avails
453 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
455 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
456 | otherwise = concatMap (gresFromIE decl_spec) items2
458 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
460 -- This environment is how we map names mentioned in the import
461 -- list to the actual Name they correspond to, and the name family
462 -- that the Name belongs to (the AvailInfo). The situation is
463 -- complicated by associated families, which introduce a three-level
464 -- hierachy, where class = grand parent, assoc family = parent, and
465 -- data constructors = children. The occ_env entries for associated
466 -- families needs to capture all this information; hence, we have the
467 -- third component of the environment that gives the class name (=
468 -- grand parent) in case of associated families.
470 -- This env will have entries for data constructors too,
471 -- they won't make any difference because naked entities like T
472 -- in an import list map to TcOccs, not VarOccs.
473 occ_env :: OccEnv (Name, -- the name
474 AvailInfo, -- the export item providing the name
475 Maybe Name) -- the parent of associated types
476 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
477 | a <- all_avails, n <- availNames a]
479 -- we know that (1) there are at most entries for one name, (2) their
480 -- first component is identical, (3) they are for tys/cls, and (4) one
481 -- entry has the name in its parent position (the other doesn't)
482 combine (name, AvailTC p1 subs1, Nothing)
483 (_ , AvailTC p2 subs2, Nothing)
485 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
487 (name, AvailTC name subs, Just parent)
489 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
490 lookup_lie opt_typeFamilies (L loc ieRdr)
492 stuff <- setSrcSpan loc $
493 case lookup_ie opt_typeFamilies ieRdr of
494 Failed err -> addErr err >> return []
495 Succeeded a -> return a
496 checkDodgyImport stuff
497 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
499 -- Warn when importing T(..) if T was exported abstractly
500 checkDodgyImport stuff
501 | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff
502 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
503 -- NB. use the RdrName for reporting the warning
507 -- For each import item, we convert its RdrNames to Names,
508 -- and at the same time construct an AvailInfo corresponding
509 -- to what is actually imported by this item.
510 -- Returns Nothing on error.
511 -- We return a list here, because in the case of an import
512 -- item like C, if we are hiding, then C refers to *both* a
513 -- type/class and a data constructor. Moreover, when we import
514 -- data constructors of an associated family, we need separate
515 -- AvailInfos for the data constructors and the family (as they have
516 -- different parents). See the discussion at occ_env.
517 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
518 lookup_ie opt_typeFamilies ie
519 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
521 lookup_name rdrName =
522 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
528 (name, avail, _) <- lookup_name n
529 return [(IEVar name, trimAvail avail name)]
532 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
534 -- non-associated ty/cls
535 Nothing -> return [(IEThingAll name, avail)]
537 Just parent -> return [(IEThingAll name,
538 AvailTC name2 (subs \\ [name])),
539 (IEThingAll name, AvailTC parent [name])]
542 | want_hiding -- hiding ( C )
543 -- Here the 'C' can be a data constructor
544 -- *or* a type/class, or even both
545 -> let tc_name = lookup_name tc
546 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
548 case catMaybeErr [ tc_name, dc_name ] of
550 names -> return [mkIEThingAbs name | name <- names]
552 -> do nameAvail <- lookup_name tc
553 return [mkIEThingAbs nameAvail]
555 IEThingWith tc ns -> do
556 (name, AvailTC name2 subnames, mb_parent) <- lookup_name tc
558 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
559 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
560 children <- if any isNothing mb_children
562 else return (catMaybes mb_children)
563 -- check for proper import of type families
564 when (not opt_typeFamilies && any isTyConName children) $
565 Failed (typeItemErr (head . filter isTyConName $ children)
566 (text "in import list"))
568 -- non-associated ty/cls
569 Nothing -> return [(IEThingWith name children,
570 AvailTC name (name:children))]
572 Just parent -> return [(IEThingWith name children,
573 AvailTC name children),
574 (IEThingWith name children,
575 AvailTC parent [name])]
577 _other -> Failed illegalImportItemErr
578 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
582 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
583 mkIEThingAbs (n, av, Just parent) = (IEThingAbs n, AvailTC parent [n])
586 catMaybeErr :: [MaybeErr err a] -> [a]
587 catMaybeErr ms = [ a | Succeeded a <- ms ]
590 %************************************************************************
594 %************************************************************************
597 -- | make a 'GlobalRdrEnv' where all the elements point to the same
598 -- import declaration (useful for "hiding" imports, or imports with
600 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
601 gresFromAvails prov avails
602 = concatMap (gresFromAvail (const prov)) avails
604 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
605 gresFromAvail prov_fn avail
606 = [ GRE {gre_name = n,
607 gre_par = availParent n avail,
608 gre_prov = prov_fn n}
609 | n <- availNames avail ]
611 greAvail :: GlobalRdrElt -> AvailInfo
612 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
614 mkUnitAvail :: Name -> Parent -> AvailInfo
615 mkUnitAvail me (ParentIs p) = AvailTC p [me]
616 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
617 | otherwise = Avail me
619 plusAvail (Avail n1) (Avail n2) = Avail n1
620 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
621 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
623 availParent :: Name -> AvailInfo -> Parent
624 availParent n (Avail _) = NoParent
625 availParent n (AvailTC m ms) | n==m = NoParent
626 | otherwise = ParentIs m
628 trimAvail :: AvailInfo -> Name -> AvailInfo
629 trimAvail (Avail n) m = Avail n
630 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
632 -- | filters 'AvailInfo's by the given predicate
633 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
634 filterAvails keep avails = foldr (filterAvail keep) [] avails
636 -- | filters an 'AvailInfo' by the given predicate
637 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
638 filterAvail keep ie rest =
640 Avail n | keep n -> ie : rest
643 let left = filter keep ns in
644 if null left then rest else AvailTC tc left : rest
646 -- | Given an import/export spec, construct the appropriate 'GlobalRdrElt's.
647 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
648 gresFromIE decl_spec (L loc ie, avail)
649 = gresFromAvail prov_fn avail
651 is_explicit = case ie of
652 IEThingAll name -> \n -> n==name
654 prov_fn name = Imported [imp_spec]
656 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
657 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
659 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
660 mkChildEnv gres = foldr add emptyNameEnv gres
662 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
663 add other_gre env = env
665 findChildren :: NameEnv [Name] -> Name -> [Name]
666 findChildren env n = lookupNameEnv env n `orElse` []
669 ---------------------------------------
672 All this AvailEnv stuff is hardly used; only in a very small
673 part of RnNames. Todo: remove?
674 ---------------------------------------
677 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
679 emptyAvailEnv :: AvailEnv
680 emptyAvailEnv = emptyNameEnv
682 unitAvailEnv :: AvailInfo -> AvailEnv
683 unitAvailEnv a = unitNameEnv (availName a) a
685 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
686 plusAvailEnv = plusNameEnv_C plusAvail
688 availEnvElts :: AvailEnv -> [AvailInfo]
689 availEnvElts = nameEnvElts
691 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
692 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
694 mkAvailEnv :: [AvailInfo] -> AvailEnv
695 -- 'avails' may have several items with the same availName
696 -- E.g import Ix( Ix(..), index )
697 -- will give Ix(Ix,index,range) and Ix(index)
698 -- We want to combine these; addAvail does that
699 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
701 -- After combining the avails, we need to ensure that the parent name is the
702 -- first entry in the list of subnames, if it is included at all. (Subsequent
703 -- functions rely on that.)
704 normaliseAvail :: AvailInfo -> AvailInfo
705 normaliseAvail avail@(Avail _) = avail
706 normaliseAvail (AvailTC name subs) = AvailTC name subs'
708 subs' = if name `elem` subs then name : (delete name subs) else subs
710 -- | combines 'AvailInfo's from the same family
711 nubAvails :: [AvailInfo] -> [AvailInfo]
712 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
716 %************************************************************************
718 \subsection{Export list processing}
720 %************************************************************************
722 Processing the export list.
724 You might think that we should record things that appear in the export
725 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
726 wrong. We do check (here) that they are in scope, but there is no
727 need to slurp in their actual declaration (which is what
728 @addOccurrenceName@ forces).
730 Indeed, doing so would big trouble when compiling @PrelBase@, because
731 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
732 @ConcBase.StateAndSynchVar#@, and so on...
735 type ExportAccum -- The type of the accumulating parameter of
736 -- the main worker function in rnExports
737 = ([LIE Name], -- Export items with Names
738 ExportOccMap, -- Tracks exported occurrence names
739 [AvailInfo]) -- The accumulated exported stuff
742 emptyExportAccum = ([], emptyOccEnv, [])
744 type ExportOccMap = OccEnv (Name, IE RdrName)
745 -- Tracks what a particular exported OccName
746 -- in an export list refers to, and which item
747 -- it came from. It's illegal to export two distinct things
748 -- that have the same occurrence name
750 rnExports :: Bool -- False => no 'module M(..) where' header at all
751 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
755 -- Complains if two distinct exports have same OccName
756 -- Warns about identical exports.
757 -- Complains about exports items not in scope
759 rnExports explicit_mod exports
760 tcg_env@(TcGblEnv { tcg_mod = this_mod,
761 tcg_rdr_env = rdr_env,
762 tcg_imports = imports })
764 -- If the module header is omitted altogether, then behave
765 -- as if the user had written "module Main(main) where..."
766 -- EXCEPT in interactive mode, when we behave as if he had
767 -- written "module Main where ..."
768 -- Reason: don't want to complain about 'main' not in scope
769 -- in interactive mode
772 | explicit_mod = exports
773 | ghcLink dflags == LinkInMemory = Nothing
774 | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
775 -- ToDo: the 'noLoc' here is unhelpful if 'main'
776 -- turns out to be out of scope
778 ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
779 ; let final_avails = nubAvails avails -- Combine families
781 ; return (tcg_env { tcg_exports = final_avails,
782 tcg_rn_exports = case tcg_rn_exports tcg_env of
784 Just _ -> rn_exports,
785 tcg_dus = tcg_dus tcg_env `plusDU`
786 usesOnly (availsToNameSet final_avails) }) }
789 exports_from_avail :: Maybe [LIE RdrName]
790 -- Nothing => no explicit export list
794 -> RnM (Maybe [LIE Name], [AvailInfo])
796 exports_from_avail Nothing rdr_env imports this_mod
797 = -- The same as (module M) where M is the current module name,
798 -- so that's how we handle it.
800 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
803 return (Nothing, avails)
805 exports_from_avail (Just rdr_items) rdr_env imports this_mod
806 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
808 return (Just ie_names, exports)
810 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
811 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
813 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
814 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
816 imported_modules = [ qual_name
817 | (_, xs) <- moduleEnvElts $ imp_mods imports,
818 (qual_name, _, _) <- xs ]
820 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
821 exports_from_item acc@(ie_names, occs, exports)
822 (L loc ie@(IEModuleContents mod))
823 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
824 , mod `elem` earlier_mods -- Duplicate export of M
825 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
826 warnIf warn_dup_exports (dupModuleExport mod) ;
830 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
831 ; let { exportValid = (mod `elem` imported_modules)
832 || (moduleName this_mod == mod)
833 ; gres = filter (isModuleExported implicit_prelude mod)
834 (globalRdrEnvElts rdr_env)
837 ; checkErr exportValid (moduleNotImported mod)
838 ; warnIf (exportValid && null gres) (nullModuleExport mod)
840 ; occs' <- check_occs ie occs (map gre_name gres)
841 -- This check_occs not only finds conflicts
842 -- between this item and others, but also
843 -- internally within this item. That is, if
844 -- 'M.x' is in scope in several ways, we'll have
845 -- several members of mod_avails with the same
847 ; return (L loc (IEModuleContents mod) : ie_names,
848 occs', map greAvail gres ++ exports) }
850 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
852 = do new_ie <- lookup_doc_ie ie
853 return (L loc new_ie : lie_names, occs, exports)
856 = do (new_ie, avail) <- lookup_ie ie
857 if isUnboundName (ieName new_ie)
858 then return acc -- Avoid error cascade
861 occs' <- check_occs ie occs (availNames avail)
863 return (L loc new_ie : lie_names, occs', avail : exports)
866 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
867 lookup_ie (IEVar rdr)
868 = do gre <- lookupGreRn rdr
869 return (IEVar (gre_name gre), greAvail gre)
871 lookup_ie (IEThingAbs rdr)
872 = do gre <- lookupGreRn rdr
873 let name = gre_name gre
875 NoParent -> return (IEThingAbs name,
877 ParentIs p -> return (IEThingAbs name,
880 lookup_ie ie@(IEThingAll rdr)
881 = do name <- lookupGlobalOccRn rdr
882 let kids = findChildren kids_env name
884 (if (isTyConName name) then addWarn (dodgyExportWarn name)
885 -- This occurs when you export T(..), but
886 -- only import T abstractly, or T is a synonym.
887 else addErr (exportItemErr ie))
889 return (IEThingAll name, AvailTC name (name:kids))
891 lookup_ie ie@(IEThingWith rdr sub_rdrs)
892 = do name <- lookupGlobalOccRn rdr
893 if isUnboundName name
894 then return (IEThingWith name [], AvailTC name [name])
896 let env = mkOccEnv [ (nameOccName s, s)
897 | s <- findChildren kids_env name ]
898 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
899 if any isNothing mb_names
900 then do addErr (exportItemErr ie)
901 return (IEThingWith name [], AvailTC name [name])
902 else do let names = catMaybes mb_names
903 optTyFam <- doptM Opt_TypeFamilies
904 when (not optTyFam && any isTyConName names) $
905 addErr (typeItemErr ( head
908 (text "in export list"))
909 return (IEThingWith name names, AvailTC name (name:names))
911 lookup_ie ie = panic "lookup_ie" -- Other cases covered earlier
914 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
915 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
916 return (IEGroup lev rn_doc)
917 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
918 return (IEDoc rn_doc)
919 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
920 lookup_doc_ie ie = panic "lookup_doc_ie" -- Other cases covered earlier
923 isDoc (IEDoc _) = True
924 isDoc (IEDocNamed _) = True
925 isDoc (IEGroup _ _) = True
928 -------------------------------
929 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
930 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
931 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
932 | implicit_prelude && isBuiltInSyntax name = False
933 -- Optimisation: filter out names for built-in syntax
934 -- They just clutter up the environment (esp tuples), and the parser
935 -- will generate Exact RdrNames for them, so the cluttered
936 -- envt is no use. To avoid doing this filter all the time,
937 -- we use -fno-implicit-prelude as a clue that the filter is
938 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
940 -- It's worth doing because it makes the environment smaller for
941 -- every module that imports the Prelude
944 LocalDef -> moduleName (nameModule name) == mod
945 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
947 -------------------------------
948 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
949 check_occs ie occs names
950 = foldlM check occs names
953 = case lookupOccEnv occs name_occ of
954 Nothing -> return (extendOccEnv occs name_occ (name, ie))
957 | name == name' -- Duplicate export
958 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
959 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
962 | otherwise -- Same occ name but different names: an error
963 -> do { global_env <- getGlobalRdrEnv ;
964 addErr (exportClashErr global_env name' name ie' ie) ;
967 name_occ = nameOccName name
970 %*********************************************************
974 %*********************************************************
977 finishDeprecations :: DynFlags -> Maybe DeprecTxt
978 -> TcGblEnv -> RnM TcGblEnv
979 -- (a) Report usasge of deprecated imports
980 -- (b) If the whole module is deprecated, update tcg_deprecs
981 -- All this happens only once per module
982 finishDeprecations dflags mod_deprec tcg_env
983 = do { (eps,hpt) <- getEpsAndHpt
984 ; ifOptM Opt_WarnDeprecations $
985 mapM_ (check hpt (eps_PIT eps)) all_gres
986 -- By this time, typechecking is complete,
987 -- so the PIT is fully populated
989 -- Deal with a module deprecation; it overrides all existing deprecs
990 ; let new_deprecs = case mod_deprec of
991 Just txt -> DeprecAll txt
992 Nothing -> tcg_deprecs tcg_env
993 ; return (tcg_env { tcg_deprecs = new_deprecs }) }
995 used_names = allUses (tcg_dus tcg_env)
996 -- Report on all deprecated uses; hence allUses
997 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
999 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
1000 | name `elemNameSet` used_names
1001 , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
1002 = addWarnAt (importSpecLoc imp_spec)
1003 (sep [ptext SLIT("Deprecated use of") <+>
1004 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
1006 (parens imp_msg) <> colon,
1009 name_mod = nameModule name
1010 imp_mod = importSpecModule imp_spec
1011 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
1012 extra | imp_mod == moduleName name_mod = empty
1013 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
1015 check hpt pit ok_gre = return () -- Local, or not used, or not deprectated
1016 -- The Imported pattern-match: don't deprecate locally defined names
1017 -- For a start, we may be exporting a deprecated thing
1018 -- Also we may use a deprecated thing in the defn of another
1019 -- deprecated things. We may even use a deprecated thing in
1020 -- the defn of a non-deprecated thing, when changing a module's
1023 lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1024 -> GlobalRdrElt -> Maybe DeprecTxt
1025 -- The name is definitely imported, so look in HPT, PIT
1026 lookupImpDeprec dflags hpt pit gre
1027 = case lookupIfaceByModule dflags hpt pit (nameModule name) of
1028 Just iface -> mi_dep_fn iface name `mplus` -- Bleat if the thing, *or
1030 ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd
1033 Nothing -> Nothing -- See Note [Used names with interface not loaded]
1038 Note [Used names with interface not loaded]
1039 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1040 By now all the interfaces should have been loaded,
1041 because reportDeprecations happens after typechecking.
1042 However, it's still (just) possible to to find a used
1043 Name whose interface hasn't been loaded:
1045 a) It might be a WiredInName; in that case we may not load
1046 its interface (although we could).
1048 b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
1049 These are seen as "used" by the renamer (if -fno-implicit-prelude)
1050 is on), but the typechecker may discard their uses
1051 if in fact the in-scope fromRational is GHC.Read.fromRational,
1052 (see tcPat.tcOverloadedLit), and the typechecker sees that the type
1053 is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
1054 In that obscure case it won't force the interface in.
1056 In both cases we simply don't permit deprecations;
1057 this is, after all, wired-in stuff.
1060 %*********************************************************
1064 %*********************************************************
1067 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1068 -> TcGblEnv -> RnM ()
1069 reportUnusedNames export_decls gbl_env
1070 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1071 ; warnUnusedTopBinds unused_locals
1072 ; warnUnusedModules unused_imp_mods
1073 ; warnUnusedImports unused_imports
1074 ; warnDuplicateImports defined_and_used
1075 ; printMinimalImports minimal_imports }
1077 used_names :: NameSet
1078 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1079 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1082 -- Collect the defined names from the in-scope environment
1083 defined_names :: [GlobalRdrElt]
1084 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1086 -- Note that defined_and_used, defined_but_not_used
1087 -- are both [GRE]; that's why we need defined_and_used
1088 -- rather than just used_names
1089 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1090 (defined_and_used, defined_but_not_used)
1091 = partition (gre_is_used used_names) defined_names
1093 kids_env = mkChildEnv defined_names
1094 -- This is done in mkExports too; duplicated work
1096 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1097 gre_is_used used_names (GRE {gre_name = name})
1098 = name `elemNameSet` used_names
1099 || any (`elemNameSet` used_names) (findChildren kids_env name)
1100 -- A use of C implies a use of T,
1101 -- if C was brought into scope by T(..) or T(C)
1103 -- Filter out the ones that are
1104 -- (a) defined in this module, and
1105 -- (b) not defined by a 'deriving' clause
1106 -- The latter have an Internal Name, so we can filter them out easily
1107 unused_locals :: [GlobalRdrElt]
1108 unused_locals = filter is_unused_local defined_but_not_used
1109 is_unused_local :: GlobalRdrElt -> Bool
1110 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1112 unused_imports :: [GlobalRdrElt]
1113 unused_imports = mapCatMaybes unused_imp defined_but_not_used
1114 unused_imp :: GlobalRdrElt -> Maybe GlobalRdrElt -- Result has trimmed Imported provenances
1115 unused_imp gre@(GRE {gre_prov = LocalDef}) = Nothing
1116 unused_imp gre@(GRE {gre_prov = Imported imp_specs})
1117 | null trimmed_specs = Nothing
1118 | otherwise = Just (gre {gre_prov = Imported trimmed_specs})
1120 trimmed_specs = filter report_if_unused imp_specs
1122 -- To figure out the minimal set of imports, start with the things
1123 -- that are in scope (i.e. in gbl_env). Then just combine them
1124 -- into a bunch of avails, so they are properly grouped
1126 -- BUG WARNING: this does not deal properly with qualified imports!
1127 minimal_imports :: FiniteMap ModuleName AvailEnv
1128 minimal_imports0 = foldr add_expall emptyFM expall_mods
1129 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
1130 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
1131 -- The last line makes sure that we retain all direct imports
1132 -- even if we import nothing explicitly.
1133 -- It's not necessarily redundant to import such modules. Consider
1137 -- The import M() is not *necessarily* redundant, even if
1138 -- we suck in no instance decls from M (e.g. it contains
1139 -- no instance decls, or This contains no code). It may be
1140 -- that we import M solely to ensure that M's orphan instance
1141 -- decls (or those in its imports) are visible to people who
1142 -- import This. Sigh.
1143 -- There's really no good way to detect this, so the error message
1144 -- in RnEnv.warnUnusedModules is weakened instead
1146 -- We've carefully preserved the provenance so that we can
1147 -- construct minimal imports that import the name by (one of)
1148 -- the same route(s) as the programmer originally did.
1149 add_name gre@(GRE {gre_prov = Imported (imp_spec:_)}) acc
1150 = addToFM_C plusAvailEnv acc
1151 (importSpecModule imp_spec) (unitAvailEnv (greAvail gre))
1152 add_name gre acc = acc -- Local
1154 -- Modules mentioned as 'module M' in the export list
1155 expall_mods = case export_decls of
1157 Just es -> [m | L _ (IEModuleContents m) <- es]
1159 -- This is really bogus. The idea is that if we see 'module M' in
1160 -- the export list we must retain the import decls that drive it
1161 -- If we aren't careful we might see
1162 -- module A( module M ) where
1165 -- and suppose that N exports everything that M does. Then we
1166 -- must not drop the import of M even though N brings it all into
1169 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
1171 -- The reason that add_expall is bogus is that it doesn't take
1172 -- qualified imports into account. But it's an improvement.
1173 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
1175 add_inst_mod (mod, _) acc
1176 | mod_name `elemFM` acc = acc -- We import something already
1177 | otherwise = addToFM acc mod_name emptyAvailEnv
1179 mod_name = moduleName mod
1180 -- Add an empty collection of imports for a module
1181 -- from which we have sucked only instance decls
1183 imports = tcg_imports gbl_env
1185 direct_import_mods :: [(Module, [(ModuleName, Bool, SrcSpan)])]
1186 -- See the type of the imp_mods for this triple
1187 direct_import_mods = moduleEnvElts (imp_mods imports)
1189 -- unused_imp_mods are the directly-imported modules
1190 -- that are not mentioned in minimal_imports1
1191 -- [Note: not 'minimal_imports', because that includes directly-imported
1192 -- modules even if we use nothing from them; see notes above]
1194 -- BUG WARNING: this code is generally buggy
1195 unused_imp_mods :: [(ModuleName, SrcSpan)]
1196 unused_imp_mods = [(mod_name,loc)
1197 | (mod, xs) <- direct_import_mods,
1198 (_, no_imp, loc) <- xs,
1199 let mod_name = moduleName mod,
1200 not (mod_name `elemFM` minimal_imports1),
1203 -- The not no_imp part is not to complain about
1204 -- import M (), which is an idiom for importing
1205 -- instance declarations
1207 module_unused :: ModuleName -> Bool
1208 module_unused mod = any (((==) mod) . fst) unused_imp_mods
1210 report_if_unused :: ImportSpec -> Bool
1211 -- Do we want to report this as an unused import?
1212 report_if_unused (ImpSpec {is_decl = d, is_item = i})
1213 = not (module_unused (is_mod d)) -- Not if we've already said entire import is unused
1214 && isExplicitItem i -- Only if the import was explicit
1216 ---------------------
1217 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
1218 -- Given the GREs for names that are used, figure out which imports
1219 -- could be omitted without changing the top-level environment.
1221 -- NB: Given import Foo( T )
1222 -- import qualified Foo
1223 -- we do not report a duplicate import, even though Foo.T is brought
1224 -- into scope by both, because there's nothing you can *omit* without
1225 -- changing the top-level environment. So we complain only if it's
1226 -- explicitly named in both imports or neither.
1228 -- Furthermore, we complain about Foo.T only if
1229 -- there is no complaint about (unqualified) T
1231 warnDuplicateImports gres
1232 = ifOptM Opt_WarnUnusedImports $
1233 sequence_ [ warn name pr
1234 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
1235 , pr <- redundants imps ]
1237 warn name (red_imp, cov_imp)
1238 = addWarnAt (importSpecLoc red_imp)
1239 (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name,
1240 ptext SLIT("It is also") <+> ppr cov_imp])
1242 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
1243 | otherwise = ppr occ
1244 occ = nameOccName name
1245 red_decl = is_decl red_imp
1247 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
1248 -- The returned pair is (redundant-import, covering-import)
1250 = [ (red_imp, cov_imp)
1252 , isExplicitItem (is_item red_imp)
1253 -- Complain only about redundant imports
1254 -- mentioned explicitly by the user
1255 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1256 -- The 'take 1' picks the first offending group
1257 -- for this particular name
1259 -- "red_imp" is a putative redundant import
1260 -- "cov_imp" potentially covers it
1261 -- This test decides whether red_imp could be dropped
1263 -- NOTE: currently the test does not warn about
1266 -- even if the same underlying 'x' is involved, because dropping
1267 -- either import would change the qualified names in scope (M.x, N.x)
1268 -- But if the qualified names aren't used, the import is indeed redundant
1269 -- Sadly we don't know that. Oh well.
1270 covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item })
1271 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1272 | red_loc == cov_loc
1273 = False -- Ignore diagonal elements
1274 | not (is_as red_decl == is_as cov_decl)
1275 = False -- They bring into scope different qualified names
1276 | not (is_qual red_decl) && is_qual cov_decl
1277 = False -- Covering one doesn't bring unqualified name into scope
1279 = not (isExplicitItem cov_item) -- Redundant one is selective and covering one isn't
1280 || red_later -- or both are explicit; tie-break using red_later
1283 = not cov_selective -- Redundant one is selective and covering one isn't
1284 || red_later -- Both are explicit; tie-break using red_later
1286 = not cov_selective -- Neither import is selective
1287 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1288 && red_later -- Tie-break
1291 red_loc = importSpecLoc red_imp
1292 cov_loc = importSpecLoc cov_imp
1293 red_later = red_loc > cov_loc
1295 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1296 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1298 printMinimalImports imps
1299 = ifOptM Opt_D_dump_minimal_imports $ do {
1301 mod_ies <- initIfaceTcRn $ mapM to_ies (fmToList imps) ;
1302 this_mod <- getModule ;
1303 rdr_env <- getGlobalRdrEnv ;
1304 dflags <- getDOpts ;
1305 liftIO $ do h <- openFile (mkFilename this_mod) WriteMode
1306 printForUser h (mkPrintUnqualified dflags rdr_env)
1307 (vcat (map ppr_mod_ie mod_ies))
1310 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1311 ppr_mod_ie (mod_name, ies)
1312 | mod_name == moduleName pRELUDE
1314 | null ies -- Nothing except instances comes from here
1315 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
1317 = ptext SLIT("import") <+> ppr mod_name <>
1318 parens (fsep (punctuate comma (map ppr ies)))
1320 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1323 to_ie :: AvailInfo -> IfG (IE Name)
1324 -- The main trick here is that if we're importing all the constructors
1325 -- we want to say "T(..)", but if we're importing only a subset we want
1326 -- to say "T(A,B,C)". So we have to find out what the module exports.
1327 to_ie (Avail n) = return (IEVar n)
1328 to_ie (AvailTC n [m]) = ASSERT( n==m )
1329 return (IEThingAbs n)
1330 to_ie (AvailTC n ns) = do
1331 iface <- loadSysInterface doc n_mod
1332 case [xs | (m,as) <- mi_exports iface,
1335 x == nameOccName n] of
1336 [xs] | all_used xs -> return (IEThingAll n)
1337 | otherwise -> return (IEThingWith n (filter (/= n) ns))
1338 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1341 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1342 doc = text "Compute minimal imports from" <+> ppr n
1343 n_mod = nameModule n
1347 %************************************************************************
1351 %************************************************************************
1354 badImportItemErr iface decl_spec ie
1355 = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
1356 ptext SLIT("does not export"), quotes (ppr ie)]
1358 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
1361 illegalImportItemErr = ptext SLIT("Illegal import item")
1363 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
1364 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
1367 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
1368 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructors or class methods,"),
1369 ptext SLIT("but it has none") ]
1371 exportItemErr export_item
1372 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
1373 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
1375 typeItemErr name wherestr
1376 = sep [ ptext SLIT("Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1377 ptext SLIT("Use -XTypeFamilies to enable this extension") ]
1379 exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
1381 exportClashErr global_env name1 name2 ie1 ie2
1382 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
1383 , ppr_export ie1' name1'
1384 , ppr_export ie2' name2' ]
1386 occ = nameOccName name1
1387 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
1388 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1390 -- get_gre finds a GRE for the Name, so that we can show its provenance
1392 = case lookupGRE_Name global_env name of
1394 [] -> pprPanic "exportClashErr" (ppr name)
1395 get_loc name = nameSrcLoc $ gre_name $ get_gre name
1396 (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
1397 then (name1, ie1, name2, ie2)
1398 else (name2, ie2, name1, ie1)
1400 addDupDeclErr :: Name -> Name -> TcRn ()
1401 addDupDeclErr name_a name_b
1402 = addErrAt (srcLocSpan loc2) $
1403 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
1404 ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]]
1406 loc2 = nameSrcLoc name2
1407 (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a)
1408 | otherwise = (name_a,name_b)
1409 -- Report the error at the later location
1411 dupExportWarn occ_name ie1 ie2
1412 = hsep [quotes (ppr occ_name),
1413 ptext SLIT("is exported by"), quotes (ppr ie1),
1414 ptext SLIT("and"), quotes (ppr ie2)]
1417 = hsep [ptext SLIT("Duplicate"),
1418 quotes (ptext SLIT("Module") <+> ppr mod),
1419 ptext SLIT("in export list")]
1421 moduleNotImported :: ModuleName -> SDoc
1422 moduleNotImported mod
1423 = ptext SLIT("The export item `module") <+> ppr mod <>
1424 ptext SLIT("' is not imported")
1426 nullModuleExport mod
1427 = ptext SLIT("The export item `module") <+> ppr mod <> ptext SLIT("' exports nothing")
1429 moduleDeprec mod txt
1430 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),
1434 = ptext SLIT("Module `Prelude' implicitly imported")