2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-2006
4 \section[RnEnv]{Environment manipulation for the renamer monad}
8 newTopSrcBinder, lookupFamInstDeclBndr,
9 lookupLocatedTopBndrRn, lookupTopBndrRn,
10 lookupLocatedOccRn, lookupOccRn,
11 lookupLocatedGlobalOccRn, lookupGlobalOccRn,
12 lookupLocalDataTcNames, lookupSrcOcc_maybe,
14 lookupFixityRn, lookupTyFixityRn,
15 lookupInstDeclBndr, lookupRecordBndr, lookupConstructorFields,
16 lookupSyntaxName, lookupSyntaxTable, lookupImportedName,
17 lookupGreRn, lookupGreLocalRn, lookupGreRn_maybe,
20 newLocalsRn, newIPNameRn,
21 bindLocalNames, bindLocalNamesFV,
22 MiniFixityEnv, emptyFsEnv, extendFsEnv, lookupFsEnv,
23 bindLocalNamesFV_WithFixities,
24 bindLocatedLocalsFV, bindLocatedLocalsRn,
25 bindSigTyVarsFV, bindPatSigTyVars, bindPatSigTyVarsFV,
26 bindTyVarsRn, extendTyVarEnvFVRn,
28 checkDupRdrNames, checkDupNames, checkShadowedNames,
29 checkDupAndShadowedRdrNames,
31 warnUnusedMatches, warnUnusedModules, warnUnusedImports,
32 warnUnusedTopBinds, warnUnusedLocalBinds,
33 dataTcOccs, unknownNameErr, perhapsForallMsg
36 #include "HsVersions.h"
38 import LoadIface ( loadInterfaceForName, loadSrcInterface )
39 import IfaceEnv ( lookupOrig, newGlobalBinder, newIPName )
41 import RdrHsSyn ( extractHsTyRdrTyVars )
43 import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity)
44 import TcEnv ( tcLookupDataCon, tcLookupField, isBrackStage )
46 import Id ( isRecordSelector )
47 import Name ( Name, nameIsLocalOrFrom, mkInternalName, isWiredInName,
48 nameSrcLoc, nameSrcSpan, nameOccName, nameModule, isExternalName )
52 import DataCon ( dataConFieldLabels )
54 import Module ( Module, ModuleName )
55 import PrelNames ( mkUnboundName, rOOT_MAIN, iNTERACTIVE,
56 consDataConKey, hasKey, forall_tv_RDR )
58 import BasicTypes ( IPName, mapIPName, Fixity )
59 import ErrUtils ( Message )
64 import ListSetOps ( removeDups )
73 thenM :: Monad a => a b -> (b -> a c) -> a c
76 thenM_ :: Monad a => a b -> a c -> a c
79 returnM :: Monad m => a -> m a
82 mappM :: (Monad m) => (a -> m b) -> [a] -> m [b]
85 mappM_ :: (Monad m) => (a -> m b) -> [a] -> m ()
88 checkM :: Monad m => Bool -> m () -> m ()
92 %*********************************************************
96 %*********************************************************
99 newTopSrcBinder :: Module -> Located RdrName -> RnM Name
100 newTopSrcBinder this_mod (L loc rdr_name)
101 | Just name <- isExact_maybe rdr_name
102 = -- This is here to catch
103 -- (a) Exact-name binders created by Template Haskell
104 -- (b) The PrelBase defn of (say) [] and similar, for which
105 -- the parser reads the special syntax and returns an Exact RdrName
106 -- We are at a binding site for the name, so check first that it
107 -- the current module is the correct one; otherwise GHC can get
108 -- very confused indeed. This test rejects code like
109 -- data T = (,) Int Int
110 -- unless we are in GHC.Tup
111 ASSERT2( isExternalName name, ppr name )
112 do { checkM (this_mod == nameModule name)
113 (addErrAt loc (badOrigBinding rdr_name))
117 | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name
118 = do { checkM (rdr_mod == this_mod || rdr_mod == rOOT_MAIN)
119 (addErrAt loc (badOrigBinding rdr_name))
120 -- When reading External Core we get Orig names as binders,
121 -- but they should agree with the module gotten from the monad
123 -- We can get built-in syntax showing up here too, sadly. If you type
125 -- the constructor is parsed as a type, and then RdrHsSyn.tyConToDataCon
126 -- uses setRdrNameSpace to make it into a data constructors. At that point
127 -- the nice Exact name for the TyCon gets swizzled to an Orig name.
128 -- Hence the badOrigBinding error message.
130 -- Except for the ":Main.main = ..." definition inserted into
131 -- the Main module; ugh!
133 -- Because of this latter case, we call newGlobalBinder with a module from
134 -- the RdrName, not from the environment. In principle, it'd be fine to
135 -- have an arbitrary mixture of external core definitions in a single module,
136 -- (apart from module-initialisation issues, perhaps).
137 ; newGlobalBinder rdr_mod rdr_occ loc }
138 --TODO, should pass the whole span
141 = do { checkM (not (isQual rdr_name))
142 (addErrAt loc (badQualBndrErr rdr_name))
143 -- Binders should not be qualified; if they are, and with a different
144 -- module name, we we get a confusing "M.T is not in scope" error later
147 ; if isBrackStage stage then
148 -- We are inside a TH bracket, so make an *Internal* name
149 -- See Note [Top-level Names in Template Haskell decl quotes] in RnNames
150 do { uniq <- newUnique
151 ; return (mkInternalName uniq (rdrNameOcc rdr_name) loc) }
154 newGlobalBinder this_mod (rdrNameOcc rdr_name) loc }
157 %*********************************************************
159 Source code occurrences
161 %*********************************************************
163 Looking up a name in the RnEnv.
166 lookupTopBndrRn :: RdrName -> RnM Name
167 lookupTopBndrRn n = do nopt <- lookupTopBndrRn_maybe n
170 Nothing -> do traceRn $ text "lookupTopBndrRn"
173 lookupLocatedTopBndrRn :: Located RdrName -> RnM (Located Name)
174 lookupLocatedTopBndrRn = wrapLocM lookupTopBndrRn
176 lookupTopBndrRn_maybe :: RdrName -> RnM (Maybe Name)
177 -- Look up a top-level source-code binder. We may be looking up an unqualified 'f',
178 -- and there may be several imported 'f's too, which must not confuse us.
179 -- For example, this is OK:
181 -- infix 9 f -- The 'f' here does not need to be qualified
182 -- f x = x -- Nor here, of course
183 -- So we have to filter out the non-local ones.
185 -- A separate function (importsFromLocalDecls) reports duplicate top level
186 -- decls, so here it's safe just to choose an arbitrary one.
188 -- There should never be a qualified name in a binding position in Haskell,
189 -- but there can be if we have read in an external-Core file.
190 -- The Haskell parser checks for the illegal qualified name in Haskell
191 -- source files, so we don't need to do so here.
193 lookupTopBndrRn_maybe rdr_name
194 | Just name <- isExact_maybe rdr_name
195 = returnM (Just name)
197 | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name
198 -- This deals with the case of derived bindings, where
199 -- we don't bother to call newTopSrcBinder first
200 -- We assume there is no "parent" name
201 = do { loc <- getSrcSpanM
202 ; n <- newGlobalBinder rdr_mod rdr_occ loc
206 = do { mb_gre <- lookupGreLocalRn rdr_name
208 Nothing -> returnM Nothing
209 Just gre -> returnM (Just $ gre_name gre) }
212 -----------------------------------------------
213 lookupInstDeclBndr :: Name -> Located RdrName -> RnM (Located Name)
214 -- This is called on the method name on the left-hand side of an
215 -- instance declaration binding. eg. instance Functor T where
217 -- ^^^^ called on this
218 -- Regardless of how many unqualified fmaps are in scope, we want
219 -- the one that comes from the Functor class.
221 -- Furthermore, note that we take no account of whether the
222 -- name is only in scope qualified. I.e. even if method op is
223 -- in scope as M.op, we still allow plain 'op' on the LHS of
225 lookupInstDeclBndr cls rdr = lookup_located_sub_bndr is_op doc rdr
227 doc = ptext (sLit "method of class") <+> quotes (ppr cls)
228 is_op (GRE {gre_par = ParentIs n}) = n == cls
231 -----------------------------------------------
232 lookupRecordBndr :: Maybe (Located Name) -> Located RdrName -> RnM (Located Name)
233 -- Used for record construction and pattern matching
234 -- When the -XDisambiguateRecordFields flag is on, take account of the
235 -- constructor name to disambiguate which field to use; it's just the
236 -- same as for instance decls
238 -- NB: Consider this:
239 -- module Foo where { data R = R { fld :: Int } }
240 -- module Odd where { import Foo; fld x = x { fld = 3 } }
241 -- Arguably this should work, because the reference to 'fld' is
242 -- unambiguous because there is only one field id 'fld' in scope.
243 -- But currently it's rejected.
244 lookupRecordBndr Nothing rdr_name
245 = lookupLocatedGlobalOccRn rdr_name
246 lookupRecordBndr (Just (L _ data_con)) rdr_name
247 = do { flag_on <- doptM Opt_DisambiguateRecordFields
249 then lookupLocatedGlobalOccRn rdr_name
251 fields <- lookupConstructorFields data_con
252 ; let is_field gre = gre_name gre `elem` fields
253 ; lookup_located_sub_bndr is_field doc rdr_name
256 doc = ptext (sLit "field of constructor") <+> quotes (ppr data_con)
259 lookupConstructorFields :: Name -> RnM [Name]
260 -- Look up the fields of a given constructor
261 -- * For constructors from this module, use the record field env,
262 -- which is itself gathered from the (as yet un-typechecked)
265 -- * For constructors from imported modules, use the *type* environment
266 -- since imported modles are already compiled, the info is conveniently
269 lookupConstructorFields con_name
270 = do { this_mod <- getModule
271 ; if nameIsLocalOrFrom this_mod con_name then
272 do { RecFields field_env _ <- getRecFieldEnv
273 ; return (lookupNameEnv field_env con_name `orElse` []) }
275 do { con <- tcLookupDataCon con_name
276 ; return (dataConFieldLabels con) } }
278 -----------------------------------------------
279 lookup_located_sub_bndr :: (GlobalRdrElt -> Bool)
280 -> SDoc -> Located RdrName
281 -> RnM (Located Name)
282 lookup_located_sub_bndr is_good doc rdr_name
283 = wrapLocM (lookup_sub_bndr is_good doc) rdr_name
285 lookup_sub_bndr :: (GlobalRdrElt -> Bool) -> SDoc -> RdrName -> RnM Name
286 lookup_sub_bndr is_good doc rdr_name
287 | isUnqual rdr_name -- Find all the things the rdr-name maps to
288 = do { -- and pick the one with the right parent name
289 ; env <- getGlobalRdrEnv
290 ; case filter is_good (lookupGlobalRdrEnv env (rdrNameOcc rdr_name)) of
291 -- NB: lookupGlobalRdrEnv, not lookupGRE_RdrName!
292 -- The latter does pickGREs, but we want to allow 'x'
293 -- even if only 'M.x' is in scope
294 [gre] -> return (gre_name gre)
295 [] -> do { addErr (unknownSubordinateErr doc rdr_name)
296 ; traceRn (text "RnEnv.lookup_sub_bndr" <+> ppr rdr_name)
297 ; return (mkUnboundName rdr_name) }
298 gres -> do { addNameClashErrRn rdr_name gres
299 ; return (gre_name (head gres)) }
302 | otherwise -- Occurs in derived instances, where we just
303 -- refer directly to the right method
304 = ASSERT2( not (isQual rdr_name), ppr rdr_name )
305 -- NB: qualified names are rejected by the parser
306 lookupImportedName rdr_name
308 newIPNameRn :: IPName RdrName -> TcRnIf m n (IPName Name)
309 newIPNameRn ip_rdr = newIPName (mapIPName rdrNameOcc ip_rdr)
311 -- Looking up family names in type instances is a subtle affair. The family
312 -- may be imported, in which case we need to lookup the occurence of a global
313 -- name. Alternatively, the family may be in the same binding group (and in
314 -- fact in a declaration processed later), and we need to create a new top
317 -- So, also this is strictly speaking an occurence, we cannot raise an error
318 -- message yet for instances without a family declaration. This will happen
319 -- during renaming the type instance declaration in RnSource.rnTyClDecl.
321 lookupFamInstDeclBndr :: Module -> Located RdrName -> RnM Name
322 lookupFamInstDeclBndr mod lrdr_name@(L _ rdr_name)
323 = do { mb_gre <- lookupGreRn_maybe rdr_name
325 Just gre -> returnM (gre_name gre)
326 Nothing -> newTopSrcBinder mod lrdr_name }
328 --------------------------------------------------
330 --------------------------------------------------
332 getLookupOccRn :: RnM (Name -> Maybe Name)
334 = getLocalRdrEnv `thenM` \ local_env ->
335 return (lookupLocalRdrOcc local_env . nameOccName)
337 lookupLocatedOccRn :: Located RdrName -> RnM (Located Name)
338 lookupLocatedOccRn = wrapLocM lookupOccRn
340 -- lookupOccRn looks up an occurrence of a RdrName
341 lookupOccRn :: RdrName -> RnM Name
343 = getLocalRdrEnv `thenM` \ local_env ->
344 case lookupLocalRdrEnv local_env rdr_name of
345 Just name -> returnM name
346 Nothing -> lookupGlobalOccRn rdr_name
348 lookupLocatedGlobalOccRn :: Located RdrName -> RnM (Located Name)
349 lookupLocatedGlobalOccRn = wrapLocM lookupGlobalOccRn
351 lookupGlobalOccRn :: RdrName -> RnM Name
352 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
353 -- environment. It's called directly only for
354 -- record field names
355 -- class op names in class and instance decls
356 -- names in export lists
358 lookupGlobalOccRn rdr_name
359 | not (isSrcRdrName rdr_name)
360 = lookupImportedName rdr_name
364 -- First look up the name in the normal environment.
365 mb_gre <- lookupGreRn_maybe rdr_name
367 Just gre -> returnM (gre_name gre) ;
370 -- We allow qualified names on the command line to refer to
371 -- *any* name exported by any module in scope, just as if
372 -- there was an "import qualified M" declaration for every
374 allow_qual <- doptM Opt_ImplicitImportQualified
376 -- This test is not expensive,
377 -- and only happens for failed lookups
378 if isQual rdr_name && allow_qual && mod == iNTERACTIVE
379 then lookupQualifiedName rdr_name
380 else unboundName rdr_name
383 lookupImportedName :: RdrName -> TcRnIf m n Name
384 -- Lookup the occurrence of an imported name
385 -- The RdrName is *always* qualified or Exact
386 -- Treat it as an original name, and conjure up the Name
387 -- Usually it's Exact or Orig, but it can be Qual if it
388 -- comes from an hi-boot file. (This minor infelicity is
389 -- just to reduce duplication in the parser.)
390 lookupImportedName rdr_name
391 | Just n <- isExact_maybe rdr_name
392 -- This happens in derived code
395 -- Always Orig, even when reading a .hi-boot file
396 | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name
397 = lookupOrig rdr_mod rdr_occ
400 = pprPanic "RnEnv.lookupImportedName" (ppr rdr_name)
402 unboundName :: RdrName -> RnM Name
404 = do { addErr (unknownNameErr rdr_name)
405 ; env <- getGlobalRdrEnv;
406 ; traceRn (vcat [unknownNameErr rdr_name,
407 ptext (sLit "Global envt is:"),
408 nest 3 (pprGlobalRdrEnv env)])
409 ; returnM (mkUnboundName rdr_name) }
411 --------------------------------------------------
412 -- Lookup in the Global RdrEnv of the module
413 --------------------------------------------------
415 lookupSrcOcc_maybe :: RdrName -> RnM (Maybe Name)
416 -- No filter function; does not report an error on failure
417 lookupSrcOcc_maybe rdr_name
418 = do { mb_gre <- lookupGreRn_maybe rdr_name
420 Nothing -> returnM Nothing
421 Just gre -> returnM (Just (gre_name gre)) }
423 -------------------------
424 lookupGreRn_maybe :: RdrName -> RnM (Maybe GlobalRdrElt)
425 -- Just look up the RdrName in the GlobalRdrEnv
426 lookupGreRn_maybe rdr_name
427 = lookupGreRn_help rdr_name (lookupGRE_RdrName rdr_name)
429 lookupGreRn :: RdrName -> RnM GlobalRdrElt
430 -- If not found, add error message, and return a fake GRE
432 = do { mb_gre <- lookupGreRn_maybe rdr_name
434 Just gre -> return gre ;
436 { traceRn $ text "lookupGreRn"
437 ; name <- unboundName rdr_name
438 ; return (GRE { gre_name = name, gre_par = NoParent,
439 gre_prov = LocalDef }) }}}
441 lookupGreLocalRn :: RdrName -> RnM (Maybe GlobalRdrElt)
442 -- Similar, but restricted to locally-defined things
443 lookupGreLocalRn rdr_name
444 = lookupGreRn_help rdr_name lookup_fn
446 lookup_fn env = filter isLocalGRE (lookupGRE_RdrName rdr_name env)
448 lookupGreRn_help :: RdrName -- Only used in error message
449 -> (GlobalRdrEnv -> [GlobalRdrElt]) -- Lookup function
450 -> RnM (Maybe GlobalRdrElt)
451 -- Checks for exactly one match; reports deprecations
452 -- Returns Nothing, without error, if too few
453 lookupGreRn_help rdr_name lookup
454 = do { env <- getGlobalRdrEnv
456 [] -> returnM Nothing
457 [gre] -> returnM (Just gre)
458 gres -> do { addNameClashErrRn rdr_name gres
459 ; returnM (Just (head gres)) } }
461 ------------------------------
463 ------------------------------
465 -- A qualified name on the command line can refer to any module at all: we
466 -- try to load the interface if we don't already have it.
467 lookupQualifiedName :: RdrName -> RnM Name
468 lookupQualifiedName rdr_name
469 | Just (mod,occ) <- isQual_maybe rdr_name
470 -- Note: we want to behave as we would for a source file import here,
471 -- and respect hiddenness of modules/packages, hence loadSrcInterface.
472 = loadSrcInterface doc mod False Nothing `thenM` \ iface ->
475 (mod,avails) <- mi_exports iface,
477 name <- availNames avail,
479 ((mod,occ):ns) -> ASSERT (null ns)
481 _ -> unboundName rdr_name
484 = pprPanic "RnEnv.lookupQualifiedName" (ppr rdr_name)
486 doc = ptext (sLit "Need to find") <+> ppr rdr_name
489 lookupSigOccRn is used for type signatures and pragmas
495 It's clear that the 'f' in the signature must refer to A.f
496 The Haskell98 report does not stipulate this, but it will!
497 So we must treat the 'f' in the signature in the same way
498 as the binding occurrence of 'f', using lookupBndrRn
500 However, consider this case:
504 We don't want to say 'f' is out of scope; instead, we want to
505 return the imported 'f', so that later on the reanamer will
506 correctly report "misplaced type sig".
509 lookupSigOccRn :: Maybe NameSet -- Just ns => source file; these are the binders
511 -- Nothing => hs-boot file; signatures without
512 -- binders are expected
514 -> Located RdrName -> RnM (Located Name)
515 lookupSigOccRn mb_bound_names sig
516 = wrapLocM $ \ rdr_name ->
517 do { mb_name <- lookupBindGroupOcc mb_bound_names (hsSigDoc sig) rdr_name
519 Left err -> do { addErr err; return (mkUnboundName rdr_name) }
520 Right name -> return name }
522 lookupBindGroupOcc :: Maybe NameSet -- Just ns => source file; these are the binders
524 -- Nothing => hs-boot file; signatures without
525 -- binders are expected
527 -> RdrName -> RnM (Either Message Name)
528 -- Looks up the RdrName, expecting it to resolve to one of the
529 -- bound names passed in. If not, return an appropriate error message
530 lookupBindGroupOcc mb_bound_names what rdr_name
531 = do { local_env <- getLocalRdrEnv
532 ; case lookupLocalRdrEnv local_env rdr_name of
533 Just n -> check_local_name n
534 Nothing -> do -- Not defined in a nested scope
536 { env <- getGlobalRdrEnv
537 ; let gres = lookupGlobalRdrEnv env (rdrNameOcc rdr_name)
538 ; case (filter isLocalGRE gres) of
539 (gre:_) -> check_local_name (gre_name gre)
540 -- If there is more than one local GRE for the
541 -- same OccName, that will be reported separately
542 [] | null gres -> bale_out_with empty
543 | otherwise -> bale_out_with import_msg
546 check_local_name name -- The name is in scope, and not imported
547 = case mb_bound_names of
548 Just bound_names | not (name `elemNameSet` bound_names)
549 -> bale_out_with local_msg
550 _other -> return (Right name)
553 = return (Left (sep [ ptext (sLit "The") <+> what
554 <+> ptext (sLit "for") <+> quotes (ppr rdr_name)
555 , nest 2 $ ptext (sLit "lacks an accompanying binding")]
558 local_msg = parens $ ptext (sLit "The") <+> what <+> ptext (sLit "must be given where")
559 <+> quotes (ppr rdr_name) <+> ptext (sLit "is declared")
561 import_msg = parens $ ptext (sLit "You cannot give a") <+> what
562 <+> ptext (sLit "for an imported value")
565 lookupLocalDataTcNames :: NameSet -> SDoc -> RdrName -> RnM [Name]
566 -- GHC extension: look up both the tycon and data con
567 -- for con-like things
568 -- Complain if neither is in scope
569 lookupLocalDataTcNames bound_names what rdr_name
570 | Just n <- isExact_maybe rdr_name
571 -- Special case for (:), which doesn't get into the GlobalRdrEnv
572 = return [n] -- For this we don't need to try the tycon too
574 = do { mb_gres <- mapM (lookupBindGroupOcc (Just bound_names) what)
575 (dataTcOccs rdr_name)
576 ; let (errs, names) = splitEithers mb_gres
577 ; when (null names) (addErr (head errs)) -- Bleat about one only
580 dataTcOccs :: RdrName -> [RdrName]
581 -- If the input is a data constructor, return both it and a type
582 -- constructor. This is useful when we aren't sure which we are
585 | Just n <- isExact_maybe rdr_name -- Ghastly special case
586 , n `hasKey` consDataConKey = [rdr_name] -- see note below
587 | isDataOcc occ = [rdr_name, rdr_name_tc]
588 | otherwise = [rdr_name]
590 occ = rdrNameOcc rdr_name
591 rdr_name_tc = setRdrNameSpace rdr_name tcName
593 -- If the user typed "[]" or "(,,)", we'll generate an Exact RdrName,
594 -- and setRdrNameSpace generates an Orig, which is fine
595 -- But it's not fine for (:), because there *is* no corresponding type
596 -- constructor. If we generate an Orig tycon for GHC.Base.(:), it'll
597 -- appear to be in scope (because Orig's simply allocate a new name-cache
598 -- entry) and then we get an error when we use dataTcOccs in
599 -- TcRnDriver.tcRnGetInfo. Large sigh.
603 %*********************************************************
607 %*********************************************************
610 --------------------------------
611 type FastStringEnv a = UniqFM a -- Keyed by FastString
614 emptyFsEnv :: FastStringEnv a
615 lookupFsEnv :: FastStringEnv a -> FastString -> Maybe a
616 extendFsEnv :: FastStringEnv a -> FastString -> a -> FastStringEnv a
618 emptyFsEnv = emptyUFM
619 lookupFsEnv = lookupUFM
620 extendFsEnv = addToUFM
622 --------------------------------
623 type MiniFixityEnv = FastStringEnv (Located Fixity)
624 -- Mini fixity env for the names we're about
625 -- to bind, in a single binding group
627 -- It is keyed by the *FastString*, not the *OccName*, because
628 -- the single fixity decl infix 3 T
629 -- affects both the data constructor T and the type constrctor T
631 -- We keep the location so that if we find
632 -- a duplicate, we can report it sensibly
634 --------------------------------
635 -- Used for nested fixity decls to bind names along with their fixities.
636 -- the fixities are given as a UFM from an OccName's FastString to a fixity decl
637 -- Also check for unused binders
638 bindLocalNamesFV_WithFixities :: [Name]
640 -> RnM (a, FreeVars) -> RnM (a, FreeVars)
641 bindLocalNamesFV_WithFixities names fixities thing_inside
642 = bindLocalNamesFV names $
643 extendFixityEnv boundFixities $
646 -- find the names that have fixity decls
647 boundFixities = foldr
649 -- check whether this name has a fixity decl
650 case lookupFsEnv fixities (occNameFS (nameOccName name)) of
651 Just (L _ fix) -> (name, FixItem (nameOccName name) fix) : acc
652 Nothing -> acc) [] names
653 -- bind the names; extend the fixity env; do the thing inside
656 --------------------------------
657 lookupFixity is a bit strange.
659 * Nested local fixity decls are put in the local fixity env, which we
660 find with getFixtyEnv
662 * Imported fixities are found in the HIT or PIT
664 * Top-level fixity decls in this module may be for Names that are
665 either Global (constructors, class operations)
666 or Local/Exported (everything else)
667 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
668 We put them all in the local fixity environment
671 lookupFixityRn :: Name -> RnM Fixity
673 = getModule `thenM` \ this_mod ->
674 if nameIsLocalOrFrom this_mod name
675 then do -- It's defined in this module
676 local_fix_env <- getFixityEnv
677 traceRn (text "lookupFixityRn: looking up name in local environment:" <+>
678 vcat [ppr name, ppr local_fix_env])
679 return $ lookupFixity local_fix_env name
680 else -- It's imported
681 -- For imported names, we have to get their fixities by doing a
682 -- loadInterfaceForName, and consulting the Ifaces that comes back
683 -- from that, because the interface file for the Name might not
684 -- have been loaded yet. Why not? Suppose you import module A,
685 -- which exports a function 'f', thus;
686 -- module CurrentModule where
688 -- module A( f ) where
690 -- Then B isn't loaded right away (after all, it's possible that
691 -- nothing from B will be used). When we come across a use of
692 -- 'f', we need to know its fixity, and it's then, and only
693 -- then, that we load B.hi. That is what's happening here.
695 -- loadInterfaceForName will find B.hi even if B is a hidden module,
696 -- and that's what we want.
697 loadInterfaceForName doc name `thenM` \ iface -> do {
698 traceRn (text "lookupFixityRn: looking up name in iface cache and found:" <+>
699 vcat [ppr name, ppr $ mi_fix_fn iface (nameOccName name)]);
700 returnM (mi_fix_fn iface (nameOccName name))
703 doc = ptext (sLit "Checking fixity for") <+> ppr name
706 lookupTyFixityRn :: Located Name -> RnM Fixity
707 lookupTyFixityRn (L _ n) = lookupFixityRn n
711 %************************************************************************
714 Dealing with rebindable syntax is driven by the
715 Opt_NoImplicitPrelude dynamic flag.
717 In "deriving" code we don't want to use rebindable syntax
718 so we switch off the flag locally
721 %************************************************************************
723 Haskell 98 says that when you say "3" you get the "fromInteger" from the
724 Standard Prelude, regardless of what is in scope. However, to experiment
725 with having a language that is less coupled to the standard prelude, we're
726 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
727 happens to be in scope. Then you can
729 import MyPrelude as Prelude
730 to get the desired effect.
732 At the moment this just happens for
733 * fromInteger, fromRational on literals (in expressions and patterns)
734 * negate (in expressions)
735 * minus (arising from n+k patterns)
738 We store the relevant Name in the HsSyn tree, in
739 * HsIntegral/HsFractional/HsIsString
743 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
744 fromRationalName etc), but the renamer changes this to the appropriate user
745 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
747 We treat the orignal (standard) names as free-vars too, because the type checker
748 checks the type of the user thing against the type of the standard thing.
751 lookupSyntaxName :: Name -- The standard name
752 -> RnM (SyntaxExpr Name, FreeVars) -- Possibly a non-standard name
753 lookupSyntaxName std_name
754 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
755 if implicit_prelude then normal_case
757 -- Get the similarly named thing from the local environment
758 lookupOccRn (mkRdrUnqual (nameOccName std_name)) `thenM` \ usr_name ->
759 returnM (HsVar usr_name, unitFV usr_name)
761 normal_case = returnM (HsVar std_name, emptyFVs)
763 lookupSyntaxTable :: [Name] -- Standard names
764 -> RnM (SyntaxTable Name, FreeVars) -- See comments with HsExpr.ReboundNames
765 lookupSyntaxTable std_names
766 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
767 if implicit_prelude then normal_case
769 -- Get the similarly named thing from the local environment
770 mappM (lookupOccRn . mkRdrUnqual . nameOccName) std_names `thenM` \ usr_names ->
772 returnM (std_names `zip` map HsVar usr_names, mkFVs usr_names)
774 normal_case = returnM (std_names `zip` map HsVar std_names, emptyFVs)
778 %*********************************************************
782 %*********************************************************
785 newLocalsRn :: [Located RdrName] -> RnM [Name]
786 newLocalsRn rdr_names_w_loc
787 = newUniqueSupply `thenM` \ us ->
788 returnM (zipWith mk rdr_names_w_loc (uniqsFromSupply us))
790 mk (L loc rdr_name) uniq
791 | Just name <- isExact_maybe rdr_name = name
792 -- This happens in code generated by Template Haskell
793 | otherwise = ASSERT2( isUnqual rdr_name, ppr rdr_name )
794 -- We only bind unqualified names here
795 -- lookupRdrEnv doesn't even attempt to look up a qualified RdrName
796 mkInternalName uniq (rdrNameOcc rdr_name) loc
798 ---------------------
799 checkDupAndShadowedRdrNames :: SDoc -> [Located RdrName] -> RnM ()
800 checkDupAndShadowedRdrNames doc loc_rdr_names
801 = do { checkDupRdrNames doc loc_rdr_names
803 ; checkShadowedNames doc envs
804 [(loc,rdrNameOcc rdr) | L loc rdr <- loc_rdr_names] }
806 ---------------------
807 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
811 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
812 = checkDupAndShadowedRdrNames doc_str rdr_names_w_loc `thenM_`
814 -- Make fresh Names and extend the environment
815 newLocalsRn rdr_names_w_loc `thenM` \names ->
816 bindLocalNames names (enclosed_scope names)
818 bindLocalNames :: [Name] -> RnM a -> RnM a
819 bindLocalNames names enclosed_scope
820 = getLocalRdrEnv `thenM` \ name_env ->
821 setLocalRdrEnv (extendLocalRdrEnv name_env names)
824 bindLocalNamesFV :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
825 bindLocalNamesFV names enclosed_scope
826 = do { (result, fvs) <- bindLocalNames names enclosed_scope
827 ; returnM (result, delListFromNameSet fvs names) }
830 -------------------------------------
831 -- binLocalsFVRn is the same as bindLocalsRn
832 -- except that it deals with free vars
833 bindLocatedLocalsFV :: SDoc -> [Located RdrName]
834 -> ([Name] -> RnM (a,FreeVars)) -> RnM (a, FreeVars)
835 bindLocatedLocalsFV doc rdr_names enclosed_scope
836 = bindLocatedLocalsRn doc rdr_names $ \ names ->
837 enclosed_scope names `thenM` \ (thing, fvs) ->
838 returnM (thing, delListFromNameSet fvs names)
840 -------------------------------------
841 bindTyVarsRn :: SDoc -> [LHsTyVarBndr RdrName]
842 -> ([LHsTyVarBndr Name] -> RnM a)
844 -- Haskell-98 binding of type variables; e.g. within a data type decl
845 bindTyVarsRn doc_str tyvar_names enclosed_scope
847 located_tyvars = hsLTyVarLocNames tyvar_names
849 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
850 enclosed_scope (zipWith replace tyvar_names names)
852 replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2)
854 bindPatSigTyVars :: [LHsType RdrName] -> ([Name] -> RnM a) -> RnM a
855 -- Find the type variables in the pattern type
856 -- signatures that must be brought into scope
857 bindPatSigTyVars tys thing_inside
858 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
859 ; if not scoped_tyvars then
862 do { name_env <- getLocalRdrEnv
863 ; let locd_tvs = [ tv | ty <- tys
864 , tv <- extractHsTyRdrTyVars ty
865 , not (unLoc tv `elemLocalRdrEnv` name_env) ]
866 nubbed_tvs = nubBy eqLocated locd_tvs
867 -- The 'nub' is important. For example:
868 -- f (x :: t) (y :: t) = ....
869 -- We don't want to complain about binding t twice!
871 ; bindLocatedLocalsRn doc_sig nubbed_tvs thing_inside }}
873 doc_sig = text "In a pattern type-signature"
875 bindPatSigTyVarsFV :: [LHsType RdrName]
878 bindPatSigTyVarsFV tys thing_inside
879 = bindPatSigTyVars tys $ \ tvs ->
880 thing_inside `thenM` \ (result,fvs) ->
881 returnM (result, fvs `delListFromNameSet` tvs)
883 bindSigTyVarsFV :: [Name]
886 bindSigTyVarsFV tvs thing_inside
887 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
888 ; if not scoped_tyvars then
891 bindLocalNamesFV tvs thing_inside }
893 extendTyVarEnvFVRn :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
894 -- This function is used only in rnSourceDecl on InstDecl
895 extendTyVarEnvFVRn tyvars thing_inside = bindLocalNamesFV tyvars thing_inside
897 -------------------------------------
898 checkDupRdrNames :: SDoc
901 checkDupRdrNames doc_str rdr_names_w_loc
902 = -- Check for duplicated names in a binding group
903 mappM_ (dupNamesErr getLoc doc_str) dups
905 (_, dups) = removeDups (\n1 n2 -> unLoc n1 `compare` unLoc n2) rdr_names_w_loc
907 checkDupNames :: SDoc
910 checkDupNames doc_str names
911 = -- Check for duplicated names in a binding group
912 mappM_ (dupNamesErr nameSrcSpan doc_str) dups
914 (_, dups) = removeDups (\n1 n2 -> nameOccName n1 `compare` nameOccName n2) names
916 -------------------------------------
917 checkShadowedNames :: SDoc -> (GlobalRdrEnv, LocalRdrEnv) -> [(SrcSpan,OccName)] -> RnM ()
918 checkShadowedNames doc_str (global_env,local_env) loc_rdr_names
919 = ifOptM Opt_WarnNameShadowing $
920 do { traceRn (text "shadow" <+> ppr loc_rdr_names)
921 ; mappM_ check_shadow loc_rdr_names }
923 check_shadow (loc, occ)
924 | Just n <- mb_local = complain [ptext (sLit "bound at") <+> ppr (nameSrcLoc n)]
925 | otherwise = do { gres' <- filterM is_shadowed_gre gres
926 ; complain (map pprNameProvenance gres') }
928 complain [] = return ()
929 complain pp_locs = addWarnAt loc (shadowedNameWarn doc_str occ pp_locs)
930 mb_local = lookupLocalRdrOcc local_env occ
931 gres = lookupGRE_RdrName (mkRdrUnqual occ) global_env
932 -- Make an Unqualified RdrName and look that up, so that
933 -- we don't find any GREs that are in scope qualified-only
935 is_shadowed_gre :: GlobalRdrElt -> RnM Bool
936 -- Returns False for record selectors that are shadowed, when
937 -- punning or wild-cards are on (cf Trac #2723)
938 is_shadowed_gre gre@(GRE { gre_par = ParentIs _ })
939 = do { dflags <- getDOpts
940 ; if (dopt Opt_RecordPuns dflags || dopt Opt_RecordWildCards dflags)
941 then do { is_fld <- is_rec_fld gre; return (not is_fld) }
943 is_shadowed_gre _other = return True
945 is_rec_fld gre -- Return True for record selector ids
946 | isLocalGRE gre = do { RecFields _ fld_set <- getRecFieldEnv
947 ; return (gre_name gre `elemNameSet` fld_set) }
948 | otherwise = do { sel_id <- tcLookupField (gre_name gre)
949 ; return (isRecordSelector sel_id) }
953 %************************************************************************
955 \subsection{Free variable manipulation}
957 %************************************************************************
961 mapFvRn :: (a -> RnM (b, FreeVars)) -> [a] -> RnM ([b], FreeVars)
962 mapFvRn f xs = do stuff <- mappM f xs
964 (ys, fvs_s) -> returnM (ys, plusFVs fvs_s)
966 -- because some of the rename functions are CPSed:
967 -- maps the function across the list from left to right;
968 -- collects all the free vars into one set
969 mapFvRnCPS :: (a -> (b -> RnM c) -> RnM c)
970 -> [a] -> ([b] -> RnM c) -> RnM c
972 mapFvRnCPS _ [] cont = cont []
973 mapFvRnCPS f (x:xs) cont = f x $ \ x' ->
974 mapFvRnCPS f xs $ \ xs' ->
979 %************************************************************************
981 \subsection{Envt utility functions}
983 %************************************************************************
986 warnUnusedModules :: [(ModuleName,SrcSpan)] -> RnM ()
987 warnUnusedModules mods
988 = ifOptM Opt_WarnUnusedImports (mappM_ bleat mods)
990 bleat (mod,loc) = addWarnAt loc (mk_warn mod)
991 mk_warn m = vcat [ptext (sLit "Module") <+> quotes (ppr m)
992 <+> text "is imported, but nothing from it is used,",
993 nest 2 (ptext (sLit "except perhaps instances visible in")
995 ptext (sLit "To suppress this warning, use:")
996 <+> ptext (sLit "import") <+> ppr m <> parens empty ]
999 warnUnusedImports, warnUnusedTopBinds :: [GlobalRdrElt] -> RnM ()
1000 warnUnusedImports gres = ifOptM Opt_WarnUnusedImports (warnUnusedGREs gres)
1001 warnUnusedTopBinds gres = ifOptM Opt_WarnUnusedBinds (warnUnusedGREs gres)
1003 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> FreeVars -> RnM ()
1004 warnUnusedLocalBinds = check_unused Opt_WarnUnusedBinds
1005 warnUnusedMatches = check_unused Opt_WarnUnusedMatches
1007 check_unused :: DynFlag -> [Name] -> FreeVars -> RnM ()
1008 check_unused flag bound_names used_names
1009 = ifOptM flag (warnUnusedLocals (filterOut (`elemNameSet` used_names) bound_names))
1011 -------------------------
1013 warnUnusedGREs :: [GlobalRdrElt] -> RnM ()
1015 = warnUnusedBinds [(n,p) | GRE {gre_name = n, gre_prov = p} <- gres]
1017 warnUnusedLocals :: [Name] -> RnM ()
1018 warnUnusedLocals names
1019 = warnUnusedBinds [(n,LocalDef) | n<-names]
1021 warnUnusedBinds :: [(Name,Provenance)] -> RnM ()
1022 warnUnusedBinds names = mappM_ warnUnusedName (filter reportable names)
1023 where reportable (name,_)
1024 | isWiredInName name = False -- Don't report unused wired-in names
1025 -- Otherwise we get a zillion warnings
1027 | otherwise = reportIfUnused (nameOccName name)
1029 -------------------------
1031 warnUnusedName :: (Name, Provenance) -> RnM ()
1032 warnUnusedName (name, LocalDef)
1033 = addUnusedWarning name (nameSrcSpan name)
1034 (ptext (sLit "Defined but not used"))
1036 warnUnusedName (name, Imported is)
1039 warn spec = addUnusedWarning name span msg
1041 span = importSpecLoc spec
1042 pp_mod = quotes (ppr (importSpecModule spec))
1043 msg = ptext (sLit "Imported from") <+> pp_mod <+> ptext (sLit "but not used")
1045 addUnusedWarning :: Name -> SrcSpan -> SDoc -> RnM ()
1046 addUnusedWarning name span msg
1049 nest 2 $ pprNonVarNameSpace (occNameSpace (nameOccName name))
1050 <+> quotes (ppr name)]
1054 addNameClashErrRn :: RdrName -> [GlobalRdrElt] -> RnM ()
1055 addNameClashErrRn rdr_name names
1056 = addErr (vcat [ptext (sLit "Ambiguous occurrence") <+> quotes (ppr rdr_name),
1057 ptext (sLit "It could refer to") <+> vcat (msg1 : msgs)])
1060 msg1 = ptext (sLit "either") <+> mk_ref np1
1061 msgs = [ptext (sLit " or") <+> mk_ref np | np <- nps]
1062 mk_ref gre = quotes (ppr (gre_name gre)) <> comma <+> pprNameProvenance gre
1064 shadowedNameWarn :: SDoc -> OccName -> [SDoc] -> SDoc
1065 shadowedNameWarn doc occ shadowed_locs
1066 = sep [ptext (sLit "This binding for") <+> quotes (ppr occ)
1067 <+> ptext (sLit "shadows the existing binding") <> plural shadowed_locs,
1068 nest 2 (vcat shadowed_locs)]
1071 unknownNameErr :: RdrName -> SDoc
1072 unknownNameErr rdr_name
1073 = vcat [ hang (ptext (sLit "Not in scope:"))
1074 2 (pprNonVarNameSpace (occNameSpace (rdrNameOcc rdr_name))
1075 <+> quotes (ppr rdr_name))
1078 extra | rdr_name == forall_tv_RDR = perhapsForallMsg
1081 perhapsForallMsg :: SDoc
1083 = vcat [ ptext (sLit "Perhaps you intended to use -XRankNTypes or similar flag")
1084 , ptext (sLit "to enable explicit-forall syntax: forall <tvs>. <type>")]
1086 unknownSubordinateErr :: SDoc -> RdrName -> SDoc
1087 unknownSubordinateErr doc op -- Doc is "method of class" or
1088 -- "field of constructor"
1089 = quotes (ppr op) <+> ptext (sLit "is not a (visible)") <+> doc
1091 badOrigBinding :: RdrName -> SDoc
1093 = ptext (sLit "Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
1094 -- The rdrNameOcc is because we don't want to print Prelude.(,)
1096 dupNamesErr :: Outputable n => (n -> SrcSpan) -> SDoc -> [n] -> RnM ()
1097 dupNamesErr get_loc descriptor names
1098 = addErrAt big_loc $
1099 vcat [ptext (sLit "Conflicting definitions for") <+> quotes (ppr (head names)),
1100 locations, descriptor]
1102 locs = map get_loc names
1103 big_loc = foldr1 combineSrcSpans locs
1104 one_line = isOneLineSpan big_loc
1105 locations | one_line = empty
1106 | otherwise = ptext (sLit "Bound at:") <+>
1107 vcat (map ppr (sortLe (<=) locs))
1109 badQualBndrErr :: RdrName -> SDoc
1110 badQualBndrErr rdr_name
1111 = ptext (sLit "Qualified name in binding position:") <+> ppr rdr_name