2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, importsFromLocalDecls,
10 getLocalDeclBinders, extendRdrEnvRn,
11 reportUnusedNames, reportDeprecations
14 #include "HsVersions.h"
16 import DynFlags ( DynFlag(..), GhcMode(..), DynFlags(..) )
17 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
18 ForeignDecl(..), HsGroup(..), HsValBinds(..),
19 Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
20 instDeclATs, isIdxTyDecl,
23 import RnHsDoc ( rnHsDoc )
24 import IfaceEnv ( ifaceExportNames )
25 import LoadIface ( loadSrcInterface )
26 import TcRnMonad hiding (LIE)
33 import OccName ( srcDataName, pprNonVarNameSpace,
35 OccEnv, mkOccEnv, mkOccEnv_C, lookupOccEnv,
36 emptyOccEnv, extendOccEnv )
37 import HscTypes ( GenAvailInfo(..), AvailInfo, availNames, availName,
38 HomePackageTable, PackageIfaceTable,
39 mkPrintUnqualified, availsToNameSet,
40 Deprecs(..), ModIface(..), Dependencies(..),
41 lookupIfaceByModule, ExternalPackageState(..)
43 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, Parent(..),
44 GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
45 emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
46 extendGlobalRdrEnv, lookupGlobalRdrEnv, lookupGRE_Name,
47 Provenance(..), ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..),
48 importSpecLoc, importSpecModule, isLocalGRE, pprNameProvenance,
49 unQualSpecOK, qualSpecOK )
52 import SrcLoc ( Located(..), mkGeneralSrcSpan, getLoc,
53 unLoc, noLoc, srcLocSpan, SrcSpan )
56 import BasicTypes ( DeprecTxt )
57 import DriverPhases ( isHsBoot )
60 import Data.List ( partition, concatMap, (\\) )
61 import IO ( openFile, IOMode(..) )
67 %************************************************************************
71 %************************************************************************
74 rnImports :: [LImportDecl RdrName]
75 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails)
78 -- PROCESS IMPORT DECLS
79 -- Do the non {- SOURCE -} ones first, so that we get a helpful
80 -- warning for {- SOURCE -} ones that are unnecessary
81 = do this_mod <- getModule
82 implicit_prelude <- doptM Opt_ImplicitPrelude
83 let all_imports = mk_prel_imports this_mod implicit_prelude ++ imports
84 (source, ordinary) = partition is_source_import all_imports
85 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
87 stuff1 <- mapM (rnImportDecl this_mod) ordinary
88 stuff2 <- mapM (rnImportDecl this_mod) source
89 let (decls, rdr_env, imp_avails) = combine (stuff1 ++ stuff2)
90 return (decls, rdr_env, imp_avails)
93 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
94 -- because the former doesn't even look at Prelude.hi for instance
95 -- declarations, whereas the latter does.
96 mk_prel_imports this_mod implicit_prelude
98 || explicit_prelude_import
99 || not implicit_prelude
101 | otherwise = [preludeImportDecl]
102 explicit_prelude_import
103 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
104 unLoc mod == pRELUDE_NAME ]
106 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails)]
107 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails)
108 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails)
109 where plus (decl, gbl_env1, imp_avails1)
110 (decls, gbl_env2, imp_avails2)
112 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
113 imp_avails1 `plusImportAvails` imp_avails2)
115 preludeImportDecl :: LImportDecl RdrName
118 ImportDecl (L loc pRELUDE_NAME)
119 False {- Not a boot interface -}
120 False {- Not qualified -}
121 Nothing {- No "as" -}
122 Nothing {- No import list -}
124 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
128 rnImportDecl :: Module
129 -> LImportDecl RdrName
130 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails)
132 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot
133 qual_only as_mod imp_details))
137 -- If there's an error in loadInterface, (e.g. interface
138 -- file not found) we get lots of spurious errors from 'filterImports'
140 imp_mod_name = unLoc loc_imp_mod_name
141 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
143 iface <- loadSrcInterface doc imp_mod_name want_boot
145 -- Compiler sanity check: if the import didn't say
146 -- {-# SOURCE #-} we should not get a hi-boot file
147 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
149 -- Issue a user warning for a redundant {- SOURCE -} import
150 -- NB that we arrange to read all the ordinary imports before
151 -- any of the {- SOURCE -} imports
152 warnIf (want_boot && not (mi_boot iface))
153 (warnRedundantSourceImport imp_mod_name)
156 imp_mod = mi_module iface
157 deprecs = mi_deprecs iface
158 is_orph = mi_orphan iface
159 has_finsts = mi_finsts iface
162 filtered_exports = filter not_this_mod (mi_exports iface)
163 not_this_mod (mod,_) = mod /= this_mod
164 -- If the module exports anything defined in this module, just
165 -- ignore it. Reason: otherwise it looks as if there are two
166 -- local definition sites for the thing, and an error gets
167 -- reported. Easiest thing is just to filter them out up
168 -- front. This situation only arises if a module imports
169 -- itself, or another module that imported it. (Necessarily,
170 -- this invoves a loop.)
172 -- Tiresome consequence: if you say
177 -- module B( AType ) where
178 -- import {-# SOURCE #-} A( AType )
180 -- then you'll get a 'B does not export AType' message. Oh well.
182 qual_mod_name = case as_mod of
183 Nothing -> imp_mod_name
184 Just another_name -> another_name
185 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
186 is_dloc = loc, is_as = qual_mod_name }
189 -- Get the total exports from this module
190 total_avails <- ifaceExportNames filtered_exports
192 -- filter the imports according to the import declaration
193 (new_imp_details, gbl_env) <-
194 filterImports2 iface imp_spec imp_details total_avails
199 -- Compute new transitive dependencies
201 orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) )
202 imp_mod : dep_orphs deps
203 | otherwise = dep_orphs deps
205 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
206 imp_mod : dep_finsts deps
207 | otherwise = dep_finsts deps
209 pkg = modulePackageId (mi_module iface)
211 (dependent_mods, dependent_pkgs)
212 | pkg == thisPackage dflags =
213 -- Imported module is from the home package
214 -- Take its dependent modules and add imp_mod itself
215 -- Take its dependent packages unchanged
217 -- NB: (dep_mods deps) might include a hi-boot file
218 -- for the module being compiled, CM. Do *not* filter
219 -- this out (as we used to), because when we've
220 -- finished dealing with the direct imports we want to
221 -- know if any of them depended on CM.hi-boot, in
222 -- which case we should do the hi-boot consistency
223 -- check. See LoadIface.loadHiBootInterface
224 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
227 -- Imported module is from another package
228 -- Dump the dependent modules
229 -- Add the package imp_mod comes from to the dependent packages
230 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
231 ([], pkg : dep_pkgs deps)
233 -- True <=> import M ()
234 import_all = case imp_details of
235 Just (is_hiding, ls) -> not is_hiding && null ls
238 imports = ImportAvails {
239 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
242 imp_dep_mods = mkModDeps dependent_mods,
243 imp_dep_pkgs = dependent_pkgs
246 -- Complain if we import a deprecated module
247 ifOptM Opt_WarnDeprecations (
249 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
253 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name want_boot
254 qual_only as_mod new_imp_details)
256 returnM (new_imp_decl, gbl_env, imports)
259 warnRedundantSourceImport mod_name
260 = ptext SLIT("Unnecessary {-# SOURCE #-} in the import of module")
261 <+> quotes (ppr mod_name)
265 %************************************************************************
267 importsFromLocalDecls
269 %************************************************************************
271 From the top-level declarations of this module produce
272 * the lexical environment
274 created by its bindings.
276 Complain about duplicate bindings
279 importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv
280 importsFromLocalDecls group
281 = do { gbl_env <- getGblEnv
283 ; avails <- getLocalDeclBinders gbl_env group
285 ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) avails
287 ; traceRn (text "local avails: " <> ppr avails)
289 ; returnM (gbl_env { tcg_rdr_env = rdr_env' })
292 extendRdrEnvRn :: GlobalRdrEnv -> [AvailInfo] -> RnM GlobalRdrEnv
293 -- Add the new locally-bound names one by one, checking for duplicates as
294 -- we do so. Remember that in Template Haskell the duplicates
295 -- might *already be* in the GlobalRdrEnv from higher up the module
296 extendRdrEnvRn rdr_env avails
297 = foldlM add_local rdr_env (gresFromAvails LocalDef avails)
299 add_local rdr_env gre
300 | gres <- lookupGlobalRdrEnv rdr_env (nameOccName (gre_name gre))
301 , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns
302 = do { addDupDeclErr (gre_name dup_gre) (gre_name gre)
305 = return (extendGlobalRdrEnv rdr_env gre)
308 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
309 used for source code.
311 *** See "THE NAMING STORY" in HsDecls ****
313 Instances of indexed types
314 ~~~~~~~~~~~~~~~~~~~~~~~~~~
315 Indexed data/newtype instances contain data constructors that we need to
316 collect, too. Moreover, we need to descend into the data/newtypes instances
317 of associated families.
319 We need to be careful with the handling of the type constructor of each type
320 instance as the family constructor is already defined, and we want to avoid
321 raising a duplicate declaration error. So, we make a new name for it, but
322 don't return it in the 'AvailInfo'.
325 getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [AvailInfo]
326 getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs,
327 hs_tyclds = tycl_decls,
328 hs_instds = inst_decls,
329 hs_fords = foreign_decls })
330 = do { tc_names_s <- mappM new_tc tycl_decls
331 ; at_names_s <- mappM inst_ats inst_decls
332 ; val_names <- mappM new_simple val_bndrs
333 ; return (val_names ++ tc_names_s ++ concat at_names_s) }
335 mod = tcg_mod gbl_env
336 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
337 val_bndrs | is_hs_boot = sig_hs_bndrs
338 | otherwise = for_hs_bndrs ++ val_hs_bndrs
339 -- In a hs-boot file, the value binders come from the
340 -- *signatures*, and there should be no foreign binders
342 new_simple rdr_name = do
343 nm <- newTopSrcBinder mod rdr_name
346 sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs]
347 val_hs_bndrs = collectHsBindLocatedBinders val_decls
348 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
351 | isIdxTyDecl (unLoc tc_decl)
352 = do { main_name <- lookupFamInstDeclBndr mod main_rdr
353 ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs
354 ; return (AvailTC main_name sub_names) }
355 -- main_name is not bound here!
357 = do { main_name <- newTopSrcBinder mod main_rdr
358 ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs
359 ; return (AvailTC main_name (main_name : sub_names)) }
361 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
364 = mappM new_tc (instDeclATs (unLoc inst_decl))
366 getLocalDeclBinders _ _ = panic "getLocalDeclBinders" -- ValBindsOut can't happen
370 %************************************************************************
372 \subsection{Filtering imports}
374 %************************************************************************
376 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
377 available, and filters it through the import spec (if any).
380 filterImports :: ModIface
381 -> ImpDeclSpec -- The span for the entire import decl
382 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
383 -> [AvailInfo] -- What's available
384 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
385 GlobalRdrEnv) -- Same again, but in GRE form
387 filterImports iface decl_spec Nothing all_avails
388 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
390 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
393 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
394 = do -- check for errors, convert RdrNames to Names
395 opt_indexedtypes <- doptM Opt_IndexedTypes
396 items1 <- mapM (lookup_lie opt_indexedtypes) import_items
398 let items2 :: [(LIE Name, AvailInfo)]
399 items2 = concat items1
400 -- NB the AvailInfo may have duplicates, and several items
401 -- for the same parent; e.g N(x) and N(y)
403 names = availsToNameSet (map snd items2)
404 keep n = not (n `elemNameSet` names)
405 pruned_avails = filterAvails keep all_avails
406 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
408 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
409 | otherwise = concatMap (gresFromIE decl_spec) items2
411 traceRn (ppr $ all_avails)
412 traceRn (ppr $ occ_env)
413 traceRn (ppr $ items2)
414 traceRn (ppr $ mkGlobalRdrEnv gres)
416 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
418 -- This environment is how we map names mentioned in the import
419 -- list to the actual Name they correspond to, and the name family
420 -- that the Name belongs to (the AvailInfo). The situation is
421 -- complicated by associated families, which introduce a three-level
422 -- hierachy, where class = grand parent, assoc family = parent, and
423 -- data constructors = children. The occ_env entries for associated
424 -- families needs to capture all this information; hence, we have the
425 -- third component of the environment that gives the class name (=
426 -- grand parent) in case of associated families.
428 -- This env will have entries for data constructors too,
429 -- they won't make any difference because naked entities like T
430 -- in an import list map to TcOccs, not VarOccs.
431 occ_env :: OccEnv (Name, -- the name
432 AvailInfo, -- the export item providing the name
433 Maybe Name) -- the parent of associated types
434 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
435 | a <- all_avails, n <- availNames a]
437 -- we know that (1) there are at most entries for one name, (2) their
438 -- first component is identical, (3) they are for tys/cls, and (4) one
439 -- entry has the name in its parent position (the other doesn't)
440 combine (name, AvailTC p1 subs1, Nothing)
441 (_ , AvailTC p2 subs2, Nothing)
443 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
445 (name, AvailTC name subs, Just parent)
447 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
448 lookup_lie opt_indexedtypes (L loc ieRdr)
450 stuff <- setSrcSpan loc $
451 case lookup_ie opt_indexedtypes ieRdr of
452 Failed err -> addErr err >> return []
453 Succeeded a -> return a
454 checkDodgyImport stuff
455 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
457 -- Warn when importing T(..) if T was exported abstractly
458 checkDodgyImport stuff
459 | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff
460 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
461 -- NB. use the RdrName for reporting the warning
465 -- For each import item, we convert its RdrNames to Names,
466 -- and at the same time construct an AvailInfo corresponding
467 -- to what is actually imported by this item.
468 -- Returns Nothing on error.
469 -- We return a list here, because in the case of an import
470 -- item like C, if we are hiding, then C refers to *both* a
471 -- type/class and a data constructor. Moreover, when we import
472 -- data constructors of an associated family, we need separate
473 -- AvailInfos for the data constructors and the family (as they have
474 -- different parents). See the discussion at occ_env.
475 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
476 lookup_ie opt_indexedtypes ie
477 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
479 lookup_name rdrName =
480 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
486 (name, avail, _) <- lookup_name n
487 return [(IEVar name, trimAvail avail name)]
490 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
492 -- non-associated ty/cls
493 Nothing -> return [(IEThingAll name, avail)]
495 Just parent -> return [(IEThingAll name,
496 AvailTC name2 (subs \\ [name])),
497 (IEThingAll name, AvailTC parent [name])]
500 | want_hiding -- hiding ( C )
501 -- Here the 'C' can be a data constructor
502 -- *or* a type/class, or even both
503 -> let tc_name = lookup_name tc
504 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
506 case catMaybeErr [ tc_name, dc_name ] of
508 names -> return [mkIEThingAbs name | name <- names]
510 -> do nameAvail <- lookup_name tc
511 return [mkIEThingAbs nameAvail]
513 IEThingWith tc ns -> do
514 (name, AvailTC name2 subnames, mb_parent) <- lookup_name tc
516 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
517 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
518 children <- if any isNothing mb_children
520 else return (catMaybes mb_children)
521 -- check for proper import of indexed types
522 when (not opt_indexedtypes && any isTyConName children) $
523 Failed (typeItemErr (head . filter isTyConName $ children)
524 (text "in import list"))
526 -- non-associated ty/cls
527 Nothing -> return [(IEThingWith name children,
528 AvailTC name (name:children))]
530 Just parent -> return [(IEThingWith name children,
531 AvailTC name children),
532 (IEThingWith name children,
533 AvailTC parent [name])]
535 _other -> Failed illegalImportItemErr
536 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
540 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
541 mkIEThingAbs (n, av, Just parent) = (IEThingAbs n, AvailTC parent [n])
544 catMaybeErr :: [MaybeErr err a] -> [a]
545 catMaybeErr ms = [ a | Succeeded a <- ms ]
549 filterImports2 :: ModIface
550 -> ImpDeclSpec -- The span for the entire import decl
551 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
552 -> [AvailInfo] -- What's available
553 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
554 GlobalRdrEnv) -- Same again, but in GRE form
556 filterImports2 iface decl_spec Nothing all_avails
557 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
559 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
562 filterImports2 iface decl_spec (Just (want_hiding, import_items)) all_avails
563 = do -- check for errors, convert RdrNames to Names
564 opt_indexedtypes <- doptM Opt_IndexedTypes
565 items1 <- mapM (lookup_lie opt_indexedtypes) import_items
567 let items2 :: [(LIE Name, AvailInfo)]
568 items2 = concat items1
569 -- NB the AvailInfo may have duplicates, and several items
570 -- for the same parent; e.g N(x) and N(y)
572 names = availsToNameSet (map snd items2)
573 keep n = not (n `elemNameSet` names)
574 pruned_avails = filterAvails keep all_avails
575 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
577 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
578 | otherwise = concatMap (gresFromIE decl_spec) items2
580 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
582 -- This environment is how we map names mentioned in the import
583 -- list to the actual Name they correspond to, and the family
584 -- that the Name belongs to (an AvailInfo).
586 -- This env will have entries for data constructors too,
587 -- they won't make any difference because naked entities like T
588 -- in an import list map to TcOccs, not VarOccs.
589 occ_env :: OccEnv (Name,AvailInfo)
590 occ_env = mkOccEnv [ (nameOccName n, (n,a))
591 | a <- all_avails, n <- availNames a ]
593 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
594 lookup_lie opt_indexedtypes (L loc ieRdr)
596 stuff <- setSrcSpan loc $
597 case lookup_ie opt_indexedtypes ieRdr of
598 Failed err -> addErr err >> return []
599 Succeeded a -> return a
600 checkDodgyImport stuff
601 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
603 -- Warn when importing T(..) if T was exported abstractly
604 checkDodgyImport stuff
605 | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff
606 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
607 -- NB. use the RdrName for reporting the warning
611 -- For each import item, we convert its RdrNames to Names,
612 -- and at the same time construct an AvailInfo corresponding
613 -- to what is actually imported by this item.
614 -- Returns Nothing on error.
615 -- We return a list here, because in the case of an import
616 -- item like C, if we are hiding, then C refers to *both* a
617 -- type/class and a data constructor.
618 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
619 lookup_ie opt_indexedtypes ie
620 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
622 lookup_name rdrName =
623 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
629 (name,avail) <- lookup_name n
630 return [(IEVar name, trimAvail avail name)]
633 (name,avail) <- lookup_name tc
634 return [(IEThingAll name, avail)]
637 | want_hiding -- hiding ( C )
638 -- Here the 'C' can be a data constructor
639 -- *or* a type/class, or even both
640 -> let tc_name = lookup_name tc
641 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
643 case catMaybeErr [ tc_name, dc_name ] of
645 names -> return [ (IEThingAbs n, trimAvail av n)
648 -> do (name,avail) <- lookup_name tc
649 return [(IEThingAbs name, AvailTC name [name])]
651 IEThingWith n ns -> do
652 (name,avail) <- lookup_name n
654 AvailTC nm subnames | nm == name -> do
655 let env = mkOccEnv [ (nameOccName s, s)
657 let mb_children = map (lookupOccEnv env . rdrNameOcc) ns
659 if any isNothing mb_children
661 else return (catMaybes mb_children)
662 -- check for proper import of indexed types
663 when (not opt_indexedtypes && any isTyConName children) $
664 Failed (typeItemErr (head . filter isTyConName
666 (text "in import list"))
667 return [(IEThingWith name children, AvailTC name (name:children))]
671 _other -> Failed illegalImportItemErr
672 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
676 %************************************************************************
680 %************************************************************************
683 -- | make a 'GlobalRdrEnv' where all the elements point to the same
684 -- import declaration (useful for "hiding" imports, or imports with
686 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
687 gresFromAvails prov avails
688 = concatMap (gresFromAvail (const prov)) avails
690 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
691 gresFromAvail prov_fn avail
692 = [ GRE {gre_name = n,
693 gre_par = availParent n avail,
694 gre_prov = prov_fn n}
695 | n <- availNames avail ]
697 greAvail :: GlobalRdrElt -> AvailInfo
698 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
700 mkUnitAvail :: Name -> Parent -> AvailInfo
701 mkUnitAvail me (ParentIs p) = AvailTC p [me]
702 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
703 | otherwise = Avail me
705 plusAvail (Avail n1) (Avail n2) = Avail n1
706 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
707 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
709 availParent :: Name -> AvailInfo -> Parent
710 availParent n (Avail _) = NoParent
711 availParent n (AvailTC m ms) | n==m = NoParent
712 | otherwise = ParentIs m
714 trimAvail :: AvailInfo -> Name -> AvailInfo
715 trimAvail (Avail n) m = Avail n
716 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
718 -- | filters 'AvailInfo's by the given predicate
719 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
720 filterAvails keep avails = foldr (filterAvail keep) [] avails
722 -- | filters an 'AvailInfo' by the given predicate
723 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
724 filterAvail keep ie rest =
726 Avail n | keep n -> ie : rest
729 let left = filter keep ns in
730 if null left then rest else AvailTC tc left : rest
732 -- | Given an import/export spec, construct the appropriate 'GlobalRdrElt's.
733 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
734 gresFromIE decl_spec (L loc ie, avail)
735 = gresFromAvail prov_fn avail
737 is_explicit = case ie of
738 IEThingAll name -> \n -> n==name
740 prov_fn name = Imported [imp_spec]
742 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
743 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
745 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
746 mkChildEnv gres = foldr add emptyNameEnv gres
748 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
749 add other_gre env = env
751 findChildren :: NameEnv [Name] -> Name -> [Name]
752 findChildren env n = lookupNameEnv env n `orElse` []
755 ---------------------------------------
758 All this AvailEnv stuff is hardly used; only in a very small
759 part of RnNames. Todo: remove?
760 ---------------------------------------
763 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
765 emptyAvailEnv :: AvailEnv
766 emptyAvailEnv = emptyNameEnv
768 unitAvailEnv :: AvailInfo -> AvailEnv
769 unitAvailEnv a = unitNameEnv (availName a) a
771 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
772 plusAvailEnv = plusNameEnv_C plusAvail
774 availEnvElts :: AvailEnv -> [AvailInfo]
775 availEnvElts = nameEnvElts
777 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
778 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
780 mkAvailEnv :: [AvailInfo] -> AvailEnv
781 -- 'avails' may have several items with the same availName
782 -- E.g import Ix( Ix(..), index )
783 -- will give Ix(Ix,index,range) and Ix(index)
784 -- We want to combine these; addAvail does that
785 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
787 -- | combines 'AvailInfo's from the same family
788 nubAvails :: [AvailInfo] -> [AvailInfo]
789 nubAvails avails = nameEnvElts (mkAvailEnv avails)
793 %************************************************************************
795 \subsection{Export list processing}
797 %************************************************************************
799 Processing the export list.
801 You might think that we should record things that appear in the export
802 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
803 wrong. We do check (here) that they are in scope, but there is no
804 need to slurp in their actual declaration (which is what
805 @addOccurrenceName@ forces).
807 Indeed, doing so would big trouble when compiling @PrelBase@, because
808 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
809 @ConcBase.StateAndSynchVar#@, and so on...
812 type ExportAccum -- The type of the accumulating parameter of
813 -- the main worker function in rnExports
814 = ([LIE Name], -- Export items with Names
815 ExportOccMap, -- Tracks exported occurrence names
816 [AvailInfo]) -- The accumulated exported stuff
819 emptyExportAccum = ([], emptyOccEnv, [])
821 type ExportOccMap = OccEnv (Name, IE RdrName)
822 -- Tracks what a particular exported OccName
823 -- in an export list refers to, and which item
824 -- it came from. It's illegal to export two distinct things
825 -- that have the same occurrence name
827 rnExports :: Bool -- False => no 'module M(..) where' header at all
828 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
829 -> RnM (Maybe [LIE Name], [AvailInfo])
831 -- Complains if two distinct exports have same OccName
832 -- Warns about identical exports.
833 -- Complains about exports items not in scope
835 rnExports explicit_mod exports
836 = do TcGblEnv { tcg_mod = this_mod,
837 tcg_rdr_env = rdr_env,
838 tcg_imports = imports } <- getGblEnv
840 -- If the module header is omitted altogether, then behave
841 -- as if the user had written "module Main(main) where..."
842 -- EXCEPT in interactive mode, when we behave as if he had
843 -- written "module Main where ..."
844 -- Reason: don't want to complain about 'main' not in scope
845 -- in interactive mode
846 ghc_mode <- getGhcMode
851 | ghc_mode == Interactive
854 -> do mainName <- lookupGlobalOccRn main_RDR_Unqual
855 return (Just ([noLoc (IEVar main_RDR_Unqual)]))
856 -- ToDo: the 'noLoc' here is unhelpful if 'main' turns
857 -- out to be out of scope
859 (exp_spec, avails) <- exports_from_avail real_exports rdr_env imports this_mod
861 return (exp_spec, nubAvails avails) -- Combine families
863 exports_from_avail :: Maybe [LIE RdrName]
864 -- Nothing => no explicit export list
868 -> RnM (Maybe [LIE Name], [AvailInfo])
870 exports_from_avail Nothing rdr_env imports this_mod
871 = -- The same as (module M) where M is the current module name,
872 -- so that's how we handle it.
874 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
877 return (Nothing, avails)
879 exports_from_avail (Just rdr_items) rdr_env imports this_mod
880 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
881 return (Just ie_names, exports)
883 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
884 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
886 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
887 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
889 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
890 exports_from_item acc@(ie_names, occs, exports)
891 (L loc ie@(IEModuleContents mod))
892 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
893 , mod `elem` earlier_mods -- Duplicate export of M
894 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
895 warnIf warn_dup_exports (dupModuleExport mod) ;
899 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
900 ; let gres = filter (isModuleExported implicit_prelude mod)
901 (globalRdrEnvElts rdr_env)
903 ; warnIf (null gres) (nullModuleExport mod)
905 ; occs' <- check_occs ie occs (map gre_name gres)
906 -- This check_occs not only finds conflicts
907 -- between this item and others, but also
908 -- internally within this item. That is, if
909 -- 'M.x' is in scope in several ways, we'll have
910 -- several members of mod_avails with the same
912 ; return (L loc (IEModuleContents mod) : ie_names,
913 occs', map greAvail gres ++ exports) }
915 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
917 = do new_ie <- lookup_doc_ie ie
918 return (L loc new_ie : lie_names, occs, exports)
921 = do (new_ie, avail) <- lookup_ie ie
922 if isUnboundName (ieName new_ie)
923 then return acc -- Avoid error cascade
926 occs' <- check_occs ie occs (availNames avail)
928 return (L loc new_ie : lie_names, occs', avail : exports)
931 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
932 lookup_ie (IEVar rdr)
933 = do gre <- lookupGreRn rdr
934 return (IEVar (gre_name gre), greAvail gre)
936 lookup_ie (IEThingAbs rdr)
937 = do name <- lookupGlobalOccRn rdr
938 return (IEThingAbs name, AvailTC name [name])
940 lookup_ie ie@(IEThingAll rdr)
941 = do name <- lookupGlobalOccRn rdr
942 let kids = findChildren kids_env name
944 (if (isTyConName name) then addWarn (dodgyExportWarn name)
945 -- This occurs when you export T(..), but
946 -- only import T abstractly, or T is a synonym.
947 else addErr (exportItemErr ie))
949 return (IEThingAll name, AvailTC name (name:kids))
951 lookup_ie ie@(IEThingWith rdr sub_rdrs)
952 = do name <- lookupGlobalOccRn rdr
953 if isUnboundName name
954 then return (IEThingWith name [], AvailTC name [name])
956 let env = mkOccEnv [ (nameOccName s, s)
957 | s <- findChildren kids_env name ]
958 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
959 if any isNothing mb_names
960 then do addErr (exportItemErr ie)
961 return (IEThingWith name [], AvailTC name [name])
962 else do let names = catMaybes mb_names
963 optIdxTypes <- doptM Opt_IndexedTypes
964 when (not optIdxTypes && any isTyConName names) $
965 addErr (typeItemErr ( head
968 (text "in export list"))
969 return (IEThingWith name names, AvailTC name (name:names))
971 lookup_ie ie = panic "lookup_ie" -- Other cases covered earlier
974 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
975 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
976 return (IEGroup lev rn_doc)
977 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
978 return (IEDoc rn_doc)
979 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
980 lookup_doc_ie ie = panic "lookup_doc_ie" -- Other cases covered earlier
983 isDoc (IEDoc _) = True
984 isDoc (IEDocNamed _) = True
985 isDoc (IEGroup _ _) = True
988 -------------------------------
989 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
990 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
991 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
992 | implicit_prelude && isBuiltInSyntax name = False
993 -- Optimisation: filter out names for built-in syntax
994 -- They just clutter up the environment (esp tuples), and the parser
995 -- will generate Exact RdrNames for them, so the cluttered
996 -- envt is no use. To avoid doing this filter all the time,
997 -- we use -fno-implicit-prelude as a clue that the filter is
998 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
1000 -- It's worth doing because it makes the environment smaller for
1001 -- every module that imports the Prelude
1004 LocalDef -> moduleName (nameModule name) == mod
1005 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
1007 -------------------------------
1008 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
1009 check_occs ie occs names
1010 = foldlM check occs names
1013 = case lookupOccEnv occs name_occ of
1014 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
1017 | name == name' -- Duplicate export
1018 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
1019 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
1022 | otherwise -- Same occ name but different names: an error
1023 -> do { global_env <- getGlobalRdrEnv ;
1024 addErr (exportClashErr global_env name' name ie' ie) ;
1027 name_occ = nameOccName name
1030 %*********************************************************
1034 %*********************************************************
1037 reportDeprecations :: DynFlags -> TcGblEnv -> RnM ()
1038 reportDeprecations dflags tcg_env
1039 = ifOptM Opt_WarnDeprecations $
1040 do { (eps,hpt) <- getEpsAndHpt
1041 -- By this time, typechecking is complete,
1042 -- so the PIT is fully populated
1043 ; mapM_ (check hpt (eps_PIT eps)) all_gres }
1045 used_names = allUses (tcg_dus tcg_env)
1046 -- Report on all deprecated uses; hence allUses
1047 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
1049 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
1050 | name `elemNameSet` used_names
1051 , Just deprec_txt <- lookupDeprec dflags hpt pit gre
1052 = addWarnAt (importSpecLoc imp_spec)
1053 (sep [ptext SLIT("Deprecated use of") <+>
1054 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
1056 (parens imp_msg) <> colon,
1059 name_mod = nameModule name
1060 imp_mod = importSpecModule imp_spec
1061 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
1062 extra | imp_mod == moduleName name_mod = empty
1063 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
1065 check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
1066 -- The Imported pattern-match: don't deprecate locally defined names
1067 -- For a start, we may be exporting a deprecated thing
1068 -- Also we may use a deprecated thing in the defn of another
1069 -- deprecated things. We may even use a deprecated thing in
1070 -- the defn of a non-deprecated thing, when changing a module's
1073 lookupDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1074 -> GlobalRdrElt -> Maybe DeprecTxt
1075 lookupDeprec dflags hpt pit gre
1076 = case lookupIfaceByModule dflags hpt pit (nameModule name) of
1077 Just iface -> mi_dep_fn iface name `seqMaybe` -- Bleat if the thing, *or
1079 ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd
1082 | isWiredInName name -> Nothing
1083 -- We have not necessarily loaded the .hi file for a
1084 -- wired-in name (yet), although we *could*.
1085 -- And we never deprecate them
1087 | otherwise -> pprPanic "lookupDeprec" (ppr name)
1088 -- By now all the interfaces should have been loaded
1093 %*********************************************************
1097 %*********************************************************
1100 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1101 -> TcGblEnv -> RnM ()
1102 reportUnusedNames export_decls gbl_env
1103 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1104 ; warnUnusedTopBinds unused_locals
1105 ; warnUnusedModules unused_imp_mods
1106 ; warnUnusedImports unused_imports
1107 ; warnDuplicateImports defined_and_used
1108 ; printMinimalImports minimal_imports }
1110 used_names :: NameSet
1111 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1112 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1115 -- Collect the defined names from the in-scope environment
1116 defined_names :: [GlobalRdrElt]
1117 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1119 -- Note that defined_and_used, defined_but_not_used
1120 -- are both [GRE]; that's why we need defined_and_used
1121 -- rather than just used_names
1122 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1123 (defined_and_used, defined_but_not_used)
1124 = partition (gre_is_used used_names) defined_names
1126 kids_env = mkChildEnv defined_names
1127 -- This is done in mkExports too; duplicated work
1129 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1130 gre_is_used used_names (GRE {gre_name = name})
1131 = name `elemNameSet` used_names
1132 || any (`elemNameSet` used_names) (findChildren kids_env name)
1133 -- A use of C implies a use of T,
1134 -- if C was brought into scope by T(..) or T(C)
1136 -- Filter out the ones that are
1137 -- (a) defined in this module, and
1138 -- (b) not defined by a 'deriving' clause
1139 -- The latter have an Internal Name, so we can filter them out easily
1140 unused_locals :: [GlobalRdrElt]
1141 unused_locals = filter is_unused_local defined_but_not_used
1142 is_unused_local :: GlobalRdrElt -> Bool
1143 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1145 unused_imports :: [GlobalRdrElt]
1146 unused_imports = filter unused_imp defined_but_not_used
1147 unused_imp (GRE {gre_prov = Imported imp_specs})
1148 = not (all (module_unused . importSpecModule) imp_specs)
1149 && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs]
1150 -- Don't complain about unused imports if we've already said the
1151 -- entire import is unused
1152 unused_imp other = False
1154 -- To figure out the minimal set of imports, start with the things
1155 -- that are in scope (i.e. in gbl_env). Then just combine them
1156 -- into a bunch of avails, so they are properly grouped
1158 -- BUG WARNING: this does not deal properly with qualified imports!
1159 minimal_imports :: FiniteMap ModuleName AvailEnv
1160 minimal_imports0 = foldr add_expall emptyFM expall_mods
1161 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
1162 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
1163 -- The last line makes sure that we retain all direct imports
1164 -- even if we import nothing explicitly.
1165 -- It's not necessarily redundant to import such modules. Consider
1169 -- The import M() is not *necessarily* redundant, even if
1170 -- we suck in no instance decls from M (e.g. it contains
1171 -- no instance decls, or This contains no code). It may be
1172 -- that we import M solely to ensure that M's orphan instance
1173 -- decls (or those in its imports) are visible to people who
1174 -- import This. Sigh.
1175 -- There's really no good way to detect this, so the error message
1176 -- in RnEnv.warnUnusedModules is weakened instead
1178 -- We've carefully preserved the provenance so that we can
1179 -- construct minimal imports that import the name by (one of)
1180 -- the same route(s) as the programmer originally did.
1181 add_name gre@(GRE {gre_prov = Imported (imp_spec:_)}) acc
1182 = addToFM_C plusAvailEnv acc
1183 (importSpecModule imp_spec) (unitAvailEnv (greAvail gre))
1184 add_name gre acc = acc -- Local
1186 -- Modules mentioned as 'module M' in the export list
1187 expall_mods = case export_decls of
1189 Just es -> [m | L _ (IEModuleContents m) <- es]
1191 -- This is really bogus. The idea is that if we see 'module M' in
1192 -- the export list we must retain the import decls that drive it
1193 -- If we aren't careful we might see
1194 -- module A( module M ) where
1197 -- and suppose that N exports everything that M does. Then we
1198 -- must not drop the import of M even though N brings it all into
1201 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
1203 -- The reason that add_expall is bogus is that it doesn't take
1204 -- qualified imports into account. But it's an improvement.
1205 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
1207 add_inst_mod (mod,_,_) acc
1208 | mod_name `elemFM` acc = acc -- We import something already
1209 | otherwise = addToFM acc mod_name emptyAvailEnv
1211 mod_name = moduleName mod
1212 -- Add an empty collection of imports for a module
1213 -- from which we have sucked only instance decls
1215 imports = tcg_imports gbl_env
1217 direct_import_mods :: [(Module, Bool, SrcSpan)]
1218 -- See the type of the imp_mods for this triple
1219 direct_import_mods = moduleEnvElts (imp_mods imports)
1221 -- unused_imp_mods are the directly-imported modules
1222 -- that are not mentioned in minimal_imports1
1223 -- [Note: not 'minimal_imports', because that includes directly-imported
1224 -- modules even if we use nothing from them; see notes above]
1226 -- BUG WARNING: does not deal correctly with multiple imports of the same module
1227 -- becuase direct_import_mods has only one entry per module
1228 unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods,
1229 let mod_name = moduleName mod,
1230 not (mod_name `elemFM` minimal_imports1),
1233 -- The not no_imp part is not to complain about
1234 -- import M (), which is an idiom for importing
1235 -- instance declarations
1237 module_unused :: ModuleName -> Bool
1238 module_unused mod = any (((==) mod) . fst) unused_imp_mods
1240 ---------------------
1241 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
1242 -- Given the GREs for names that are used, figure out which imports
1243 -- could be omitted without changing the top-level environment.
1245 -- NB: Given import Foo( T )
1246 -- import qualified Foo
1247 -- we do not report a duplicate import, even though Foo.T is brought
1248 -- into scope by both, because there's nothing you can *omit* without
1249 -- changing the top-level environment. So we complain only if it's
1250 -- explicitly named in both imports or neither.
1252 -- Furthermore, we complain about Foo.T only if
1253 -- there is no complaint about (unqualified) T
1255 warnDuplicateImports gres
1256 = ifOptM Opt_WarnUnusedImports $
1257 sequenceM_ [ warn name pr
1258 -- The 'head' picks the first offending group
1259 -- for this particular name
1260 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
1261 , pr <- redundants imps ]
1263 warn name (red_imp, cov_imp)
1264 = addWarnAt (importSpecLoc red_imp)
1265 (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name,
1266 ptext SLIT("It is also") <+> ppr cov_imp])
1268 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
1269 | otherwise = ppr occ
1270 occ = nameOccName name
1271 red_decl = is_decl red_imp
1273 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
1274 -- The returned pair is (redundant-import, covering-import)
1276 = [ (red_imp, cov_imp)
1278 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1280 -- "red_imp" is a putative redundant import
1281 -- "cov_imp" potentially covers it
1282 -- This test decides whether red_imp could be dropped
1284 -- NOTE: currently the test does not warn about
1287 -- even if the same underlying 'x' is involved, because dropping
1288 -- either import would change the qualified names in scope (M.x, N.x)
1289 -- But if the qualified names aren't used, the import is indeed redundant
1290 -- Sadly we don't know that. Oh well.
1291 covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item })
1292 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1293 | red_loc == cov_loc
1294 = False -- Ignore diagonal elements
1295 | not (is_as red_decl == is_as cov_decl)
1296 = False -- They bring into scope different qualified names
1297 | not (is_qual red_decl) && is_qual cov_decl
1298 = False -- Covering one doesn't bring unqualified name into scope
1300 = not cov_selective -- Redundant one is selective and covering one isn't
1301 || red_later -- Both are explicit; tie-break using red_later
1303 = not cov_selective -- Neither import is selective
1304 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1305 && red_later -- Tie-break
1307 red_loc = importSpecLoc red_imp
1308 cov_loc = importSpecLoc cov_imp
1309 red_later = red_loc > cov_loc
1310 cov_selective = selectiveImpItem cov_item
1311 red_selective = selectiveImpItem red_item
1313 selectiveImpItem :: ImpItemSpec -> Bool
1314 selectiveImpItem ImpAll = False
1315 selectiveImpItem (ImpSome {}) = True
1317 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1318 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1320 printMinimalImports imps
1321 = ifOptM Opt_D_dump_minimal_imports $ do {
1323 mod_ies <- mappM to_ies (fmToList imps) ;
1324 this_mod <- getModule ;
1325 rdr_env <- getGlobalRdrEnv ;
1326 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
1327 printForUser h (mkPrintUnqualified rdr_env)
1328 (vcat (map ppr_mod_ie mod_ies)) })
1331 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1332 ppr_mod_ie (mod_name, ies)
1333 | mod_name == moduleName pRELUDE
1335 | null ies -- Nothing except instances comes from here
1336 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
1338 = ptext SLIT("import") <+> ppr mod_name <>
1339 parens (fsep (punctuate comma (map ppr ies)))
1341 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1344 to_ie :: AvailInfo -> RnM (IE Name)
1345 -- The main trick here is that if we're importing all the constructors
1346 -- we want to say "T(..)", but if we're importing only a subset we want
1347 -- to say "T(A,B,C)". So we have to find out what the module exports.
1348 to_ie (Avail n) = returnM (IEVar n)
1349 to_ie (AvailTC n [m]) = ASSERT( n==m )
1350 returnM (IEThingAbs n)
1351 to_ie (AvailTC n ns)
1352 = loadSrcInterface doc n_mod False `thenM` \ iface ->
1353 case [xs | (m,as) <- mi_exports iface,
1354 moduleName m == n_mod,
1356 x == nameOccName n] of
1357 [xs] | all_used xs -> returnM (IEThingAll n)
1358 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
1359 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1362 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1363 doc = text "Compute minimal imports from" <+> ppr n
1364 n_mod = moduleName (nameModule n)
1368 %************************************************************************
1372 %************************************************************************
1375 badImportItemErr iface decl_spec ie
1376 = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
1377 ptext SLIT("does not export"), quotes (ppr ie)]
1379 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
1382 illegalImportItemErr = ptext SLIT("Illegal import item")
1384 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
1385 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
1388 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
1389 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
1390 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
1392 exportItemErr export_item
1393 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
1394 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
1396 typeItemErr name wherestr
1397 = sep [ ptext SLIT("Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1398 ptext SLIT("Use -findexed-types to enable this extension") ]
1400 exportClashErr global_env name1 name2 ie1 ie2
1401 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
1402 , ppr_export ie1 name1
1403 , ppr_export ie2 name2 ]
1405 occ = nameOccName name1
1406 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
1407 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1409 -- get_gre finds a GRE for the Name, so that we can show its provenance
1411 = case lookupGRE_Name global_env name of
1413 [] -> pprPanic "exportClashErr" (ppr name)
1415 addDupDeclErr :: Name -> Name -> TcRn ()
1416 addDupDeclErr name_a name_b
1417 = addErrAt (srcLocSpan loc2) $
1418 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
1419 ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]]
1421 loc2 = nameSrcLoc name2
1422 (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a)
1423 | otherwise = (name_a,name_b)
1424 -- Report the error at the later location
1426 dupExportWarn occ_name ie1 ie2
1427 = hsep [quotes (ppr occ_name),
1428 ptext SLIT("is exported by"), quotes (ppr ie1),
1429 ptext SLIT("and"), quotes (ppr ie2)]
1432 = hsep [ptext SLIT("Duplicate"),
1433 quotes (ptext SLIT("Module") <+> ppr mod),
1434 ptext SLIT("in export list")]
1436 nullModuleExport mod
1437 = ptext SLIT("The export item `module") <+> ppr mod <> ptext SLIT("' exports nothing")
1439 moduleDeprec mod txt
1440 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),