2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnEnv]{Environment manipulation for the renamer monad}
9 lookupLocatedBndrRn, lookupBndrRn,
10 lookupLocatedTopBndrRn, lookupTopBndrRn,
11 lookupLocatedOccRn, lookupOccRn,
12 lookupLocatedGlobalOccRn, lookupGlobalOccRn,
13 lookupLocalDataTcNames, lookupSrcOcc_maybe,
14 lookupFixityRn, lookupLocatedSigOccRn,
15 lookupLocatedInstDeclBndr,
16 lookupSyntaxName, lookupSyntaxTable, lookupImportedName,
18 newLocalsRn, newIPNameRn,
19 bindLocalNames, bindLocalNamesFV,
20 bindLocatedLocalsFV, bindLocatedLocalsRn,
21 bindSigTyVarsFV, bindPatSigTyVars, bindPatSigTyVarsFV,
22 bindTyVarsRn, extendTyVarEnvFVRn,
25 checkDupNames, mapFvRn,
26 warnUnusedMatches, warnUnusedModules, warnUnusedImports,
27 warnUnusedTopBinds, warnUnusedLocalBinds,
28 dataTcOccs, unknownNameErr,
31 #include "HsVersions.h"
33 import LoadIface ( loadHomeInterface, loadSrcInterface )
34 import IfaceEnv ( lookupOrig, newGlobalBinder, newIPName )
35 import HsSyn ( FixitySig(..), HsExpr(..), SyntaxExpr, SyntaxTable,
36 HsType(..), HsExplicitForAll(..), LHsTyVarBndr, LHsType,
37 LSig, Sig(..), Fixity, hsLTyVarName, hsLTyVarLocNames, replaceTyVarName )
38 import RdrHsSyn ( extractHsTyRdrTyVars )
39 import RdrName ( RdrName, rdrNameModule, isQual, isUnqual, isOrig,
40 mkRdrUnqual, setRdrNameSpace, rdrNameOcc,
41 pprGlobalRdrEnv, lookupGRE_RdrName,
42 isExact_maybe, isSrcRdrName,
43 GlobalRdrElt(..), GlobalRdrEnv, lookupGlobalRdrEnv,
44 isLocalGRE, extendLocalRdrEnv, elemLocalRdrEnv, lookupLocalRdrEnv,
45 Provenance(..), pprNameProvenance,
46 importSpecLoc, importSpecModule
48 import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity )
50 import Name ( Name, nameIsLocalOrFrom, mkInternalName,
51 nameSrcLoc, nameOccName, nameModule, nameParent, isExternalName )
53 import OccName ( tcName, isDataOcc, occNameFlavour, reportIfUnused )
54 import Module ( Module )
55 import PrelNames ( mkUnboundName, rOOT_MAIN, iNTERACTIVE, consDataConKey, hasKey )
57 import BasicTypes ( IPName, mapIPName )
58 import SrcLoc ( SrcSpan, srcSpanStart, Located(..), eqLocated, unLoc,
59 srcLocSpan, getLoc, combineSrcSpans, srcSpanStartLine, srcSpanEndLine )
61 import Util ( sortLe )
62 import ListSetOps ( removeDups )
67 %*********************************************************
71 %*********************************************************
74 newTopSrcBinder :: Module -> Maybe Name -> Located RdrName -> RnM Name
75 newTopSrcBinder this_mod mb_parent (L loc rdr_name)
76 | Just name <- isExact_maybe rdr_name
77 = -- This is here to catch
78 -- (a) Exact-name binders created by Template Haskell
79 -- (b) The PrelBase defn of (say) [] and similar, for which
80 -- the parser reads the special syntax and returns an Exact RdrName
81 -- We are at a binding site for the name, so check first that it
82 -- the current module is the correct one; otherwise GHC can get
83 -- very confused indeed. This test rejects code like
84 -- data T = (,) Int Int
85 -- unless we are in GHC.Tup
86 ASSERT2( isExternalName name, ppr name )
87 do checkErr (this_mod == nameModule name)
88 (badOrigBinding rdr_name)
93 = do checkErr (rdr_mod == this_mod || rdr_mod == rOOT_MAIN)
94 (badOrigBinding rdr_name)
95 -- When reading External Core we get Orig names as binders,
96 -- but they should agree with the module gotten from the monad
98 -- We can get built-in syntax showing up here too, sadly. If you type
100 -- the constructor is parsed as a type, and then RdrHsSyn.tyConToDataCon
101 -- uses setRdrNameSpace to make it into a data constructors. At that point
102 -- the nice Exact name for the TyCon gets swizzled to an Orig name.
103 -- Hence the badOrigBinding error message.
105 -- Except for the ":Main.main = ..." definition inserted into
106 -- the Main module; ugh!
108 -- Because of this latter case, we call newGlobalBinder with a module from
109 -- the RdrName, not from the environment. In principle, it'd be fine to
110 -- have an arbitrary mixture of external core definitions in a single module,
111 -- (apart from module-initialisation issues, perhaps).
112 newGlobalBinder rdr_mod (rdrNameOcc rdr_name) mb_parent
113 (srcSpanStart loc) --TODO, should pass the whole span
116 = newGlobalBinder this_mod (rdrNameOcc rdr_name) mb_parent (srcSpanStart loc)
118 rdr_mod = rdrNameModule rdr_name
121 %*********************************************************
123 Source code occurrences
125 %*********************************************************
127 Looking up a name in the RnEnv.
130 lookupLocatedBndrRn :: Located RdrName -> RnM (Located Name)
131 lookupLocatedBndrRn = wrapLocM lookupBndrRn
133 lookupBndrRn :: RdrName -> RnM Name
134 -- NOTE: assumes that the SrcSpan of the binder has already been setSrcSpan'd
135 lookupBndrRn rdr_name
136 = getLocalRdrEnv `thenM` \ local_env ->
137 case lookupLocalRdrEnv local_env rdr_name of
138 Just name -> returnM name
139 Nothing -> lookupTopBndrRn rdr_name
141 lookupLocatedTopBndrRn :: Located RdrName -> RnM (Located Name)
142 lookupLocatedTopBndrRn = wrapLocM lookupTopBndrRn
144 lookupTopBndrRn :: RdrName -> RnM Name
145 -- Look up a top-level source-code binder. We may be looking up an unqualified 'f',
146 -- and there may be several imported 'f's too, which must not confuse us.
147 -- For example, this is OK:
149 -- infix 9 f -- The 'f' here does not need to be qualified
150 -- f x = x -- Nor here, of course
151 -- So we have to filter out the non-local ones.
153 -- A separate function (importsFromLocalDecls) reports duplicate top level
154 -- decls, so here it's safe just to choose an arbitrary one.
156 -- There should never be a qualified name in a binding position in Haskell,
157 -- but there can be if we have read in an external-Core file.
158 -- The Haskell parser checks for the illegal qualified name in Haskell
159 -- source files, so we don't need to do so here.
161 lookupTopBndrRn rdr_name
162 | Just name <- isExact_maybe rdr_name
166 -- This deals with the case of derived bindings, where
167 -- we don't bother to call newTopSrcBinder first
168 -- We assume there is no "parent" name
169 = do { loc <- getSrcSpanM
170 ; newGlobalBinder (rdrNameModule rdr_name)
171 (rdrNameOcc rdr_name) Nothing (srcSpanStart loc) }
174 = do { mb_gre <- lookupGreLocalRn rdr_name
176 Nothing -> unboundName rdr_name
177 Just gre -> returnM (gre_name gre) }
179 -- lookupLocatedSigOccRn is used for type signatures and pragmas
185 -- It's clear that the 'f' in the signature must refer to A.f
186 -- The Haskell98 report does not stipulate this, but it will!
187 -- So we must treat the 'f' in the signature in the same way
188 -- as the binding occurrence of 'f', using lookupBndrRn
189 lookupLocatedSigOccRn :: Located RdrName -> RnM (Located Name)
190 lookupLocatedSigOccRn = lookupLocatedBndrRn
192 -- lookupInstDeclBndr is used for the binders in an
193 -- instance declaration. Here we use the class name to
196 lookupLocatedInstDeclBndr :: Name -> Located RdrName -> RnM (Located Name)
197 lookupLocatedInstDeclBndr cls = wrapLocM (lookupInstDeclBndr cls)
199 lookupInstDeclBndr :: Name -> RdrName -> RnM Name
200 lookupInstDeclBndr cls_name rdr_name
201 | isUnqual rdr_name -- Find all the things the rdr-name maps to
202 = do { -- and pick the one with the right parent name
203 let { is_op gre = cls_name == nameParent (gre_name gre)
204 ; occ = rdrNameOcc rdr_name
205 ; lookup_fn env = filter is_op (lookupGlobalRdrEnv env occ) }
206 ; mb_gre <- lookupGreRn_help rdr_name lookup_fn
208 Just gre -> return (gre_name gre)
209 Nothing -> do { addErr (unknownInstBndrErr cls_name rdr_name)
210 ; return (mkUnboundName rdr_name) } }
212 | otherwise -- Occurs in derived instances, where we just
213 -- refer directly to the right method
214 = ASSERT2( not (isQual rdr_name), ppr rdr_name )
215 -- NB: qualified names are rejected by the parser
216 lookupImportedName rdr_name
218 newIPNameRn :: IPName RdrName -> TcRnIf m n (IPName Name)
219 newIPNameRn ip_rdr = newIPName (mapIPName rdrNameOcc ip_rdr)
221 --------------------------------------------------
223 --------------------------------------------------
225 lookupLocatedOccRn :: Located RdrName -> RnM (Located Name)
226 lookupLocatedOccRn = wrapLocM lookupOccRn
228 -- lookupOccRn looks up an occurrence of a RdrName
229 lookupOccRn :: RdrName -> RnM Name
231 = getLocalRdrEnv `thenM` \ local_env ->
232 case lookupLocalRdrEnv local_env rdr_name of
233 Just name -> returnM name
234 Nothing -> lookupGlobalOccRn rdr_name
236 lookupLocatedGlobalOccRn :: Located RdrName -> RnM (Located Name)
237 lookupLocatedGlobalOccRn = wrapLocM lookupGlobalOccRn
239 lookupGlobalOccRn :: RdrName -> RnM Name
240 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
241 -- environment. It's used only for
242 -- record field names
243 -- class op names in class and instance decls
245 lookupGlobalOccRn rdr_name
246 | not (isSrcRdrName rdr_name)
247 = lookupImportedName rdr_name
250 = -- First look up the name in the normal environment.
251 lookupGreRn rdr_name `thenM` \ mb_gre ->
253 Just gre -> returnM (gre_name gre) ;
256 -- We allow qualified names on the command line to refer to
257 -- *any* name exported by any module in scope, just as if
258 -- there was an "import qualified M" declaration for every
260 getModule `thenM` \ mod ->
261 if isQual rdr_name && mod == iNTERACTIVE then
262 -- This test is not expensive,
263 lookupQualifiedName rdr_name -- and only happens for failed lookups
265 unboundName rdr_name }
267 lookupImportedName :: RdrName -> TcRnIf m n Name
268 -- Lookup the occurrence of an imported name
269 -- The RdrName is *always* qualified or Exact
270 -- Treat it as an original name, and conjure up the Name
271 -- Usually it's Exact or Orig, but it can be Qual if it
272 -- comes from an hi-boot file. (This minor infelicity is
273 -- just to reduce duplication in the parser.)
274 lookupImportedName rdr_name
275 | Just n <- isExact_maybe rdr_name
276 -- This happens in derived code
279 | otherwise -- Always Orig, even when reading a .hi-boot file
280 = ASSERT( not (isUnqual rdr_name) )
281 lookupOrig (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
283 unboundName :: RdrName -> RnM Name
285 = do { addErr (unknownNameErr rdr_name)
286 ; env <- getGlobalRdrEnv;
287 ; traceRn (vcat [unknownNameErr rdr_name,
288 ptext SLIT("Global envt is:"),
289 nest 3 (pprGlobalRdrEnv env)])
290 ; returnM (mkUnboundName rdr_name) }
292 --------------------------------------------------
293 -- Lookup in the Global RdrEnv of the module
294 --------------------------------------------------
296 lookupSrcOcc_maybe :: RdrName -> RnM (Maybe Name)
297 -- No filter function; does not report an error on failure
298 lookupSrcOcc_maybe rdr_name
299 = do { mb_gre <- lookupGreRn rdr_name
301 Nothing -> returnM Nothing
302 Just gre -> returnM (Just (gre_name gre)) }
304 -------------------------
305 lookupGreRn :: RdrName -> RnM (Maybe GlobalRdrElt)
306 -- Just look up the RdrName in the GlobalRdrEnv
308 = lookupGreRn_help rdr_name (lookupGRE_RdrName rdr_name)
310 lookupGreLocalRn :: RdrName -> RnM (Maybe GlobalRdrElt)
311 -- Similar, but restricted to locally-defined things
312 lookupGreLocalRn rdr_name
313 = lookupGreRn_help rdr_name lookup_fn
315 lookup_fn env = filter isLocalGRE (lookupGRE_RdrName rdr_name env)
317 lookupGreRn_help :: RdrName -- Only used in error message
318 -> (GlobalRdrEnv -> [GlobalRdrElt]) -- Lookup function
319 -> RnM (Maybe GlobalRdrElt)
320 -- Checks for exactly one match; reports deprecations
321 -- Returns Nothing, without error, if too few
322 lookupGreRn_help rdr_name lookup
323 = do { env <- getGlobalRdrEnv
325 [] -> returnM Nothing
326 [gre] -> returnM (Just gre)
327 gres -> do { addNameClashErrRn rdr_name gres
328 ; returnM (Just (head gres)) } }
330 ------------------------------
332 ------------------------------
334 -- A qualified name on the command line can refer to any module at all: we
335 -- try to load the interface if we don't already have it.
336 lookupQualifiedName :: RdrName -> RnM Name
337 lookupQualifiedName rdr_name
339 mod = rdrNameModule rdr_name
340 occ = rdrNameOcc rdr_name
342 -- Note: we want to behave as we would for a source file import here,
343 -- and respect hiddenness of modules/packages, hence loadSrcInterface.
344 loadSrcInterface doc mod False `thenM` \ iface ->
347 (mod,avails) <- mi_exports iface,
349 name <- availNames avail,
351 ((mod,occ):ns) -> ASSERT (null ns)
353 _ -> unboundName rdr_name
355 doc = ptext SLIT("Need to find") <+> ppr rdr_name
358 %*********************************************************
362 %*********************************************************
365 lookupLocalDataTcNames :: RdrName -> RnM [Name]
366 -- GHC extension: look up both the tycon and data con
367 -- for con-like things
368 -- Complain if neither is in scope
369 lookupLocalDataTcNames rdr_name
370 | Just n <- isExact_maybe rdr_name
371 -- Special case for (:), which doesn't get into the GlobalRdrEnv
372 = return [n] -- For this we don't need to try the tycon too
374 = do { mb_gres <- mapM lookupGreLocalRn (dataTcOccs rdr_name)
375 ; case [gre_name gre | Just gre <- mb_gres] of
376 [] -> do { addErr (unknownNameErr rdr_name)
378 names -> return names
381 --------------------------------
382 bindLocalFixities :: [FixitySig RdrName] -> RnM a -> RnM a
383 -- Used for nested fixity decls
384 -- No need to worry about type constructors here,
385 -- Should check for duplicates but we don't
386 bindLocalFixities fixes thing_inside
387 | null fixes = thing_inside
388 | otherwise = mappM rn_sig fixes `thenM` \ new_bit ->
389 extendFixityEnv new_bit thing_inside
391 rn_sig (FixitySig lv@(L loc v) fix)
392 = addLocM lookupBndrRn lv `thenM` \ new_v ->
393 returnM (new_v, (FixItem (rdrNameOcc v) fix loc))
396 --------------------------------
397 lookupFixity is a bit strange.
399 * Nested local fixity decls are put in the local fixity env, which we
400 find with getFixtyEnv
402 * Imported fixities are found in the HIT or PIT
404 * Top-level fixity decls in this module may be for Names that are
405 either Global (constructors, class operations)
406 or Local/Exported (everything else)
407 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
408 We put them all in the local fixity environment
411 lookupFixityRn :: Name -> RnM Fixity
413 = getModule `thenM` \ this_mod ->
414 if nameIsLocalOrFrom this_mod name
415 then -- It's defined in this module
416 getFixityEnv `thenM` \ local_fix_env ->
417 traceRn (text "lookupFixityRn" <+> (ppr name $$ ppr local_fix_env)) `thenM_`
418 returnM (lookupFixity local_fix_env name)
420 else -- It's imported
421 -- For imported names, we have to get their fixities by doing a
422 -- loadHomeInterface, and consulting the Ifaces that comes back
423 -- from that, because the interface file for the Name might not
424 -- have been loaded yet. Why not? Suppose you import module A,
425 -- which exports a function 'f', thus;
426 -- module CurrentModule where
428 -- module A( f ) where
430 -- Then B isn't loaded right away (after all, it's possible that
431 -- nothing from B will be used). When we come across a use of
432 -- 'f', we need to know its fixity, and it's then, and only
433 -- then, that we load B.hi. That is what's happening here.
435 -- loadHomeInterface will find B.hi even if B is a hidden module,
436 -- and that's what we want.
437 loadHomeInterface doc name `thenM` \ iface ->
438 returnM (mi_fix_fn iface (nameOccName name))
440 doc = ptext SLIT("Checking fixity for") <+> ppr name
442 dataTcOccs :: RdrName -> [RdrName]
443 -- If the input is a data constructor, return both it and a type
444 -- constructor. This is useful when we aren't sure which we are
447 | Just n <- isExact_maybe rdr_name -- Ghastly special case
448 , n `hasKey` consDataConKey = [rdr_name] -- see note below
449 | isDataOcc occ = [rdr_name_tc, rdr_name]
450 | otherwise = [rdr_name]
452 occ = rdrNameOcc rdr_name
453 rdr_name_tc = setRdrNameSpace rdr_name tcName
455 -- If the user typed "[]" or "(,,)", we'll generate an Exact RdrName,
456 -- and setRdrNameSpace generates an Orig, which is fine
457 -- But it's not fine for (:), because there *is* no corresponding type
458 -- constructor. If we generate an Orig tycon for GHC.Base.(:), it'll
459 -- appear to be in scope (because Orig's simply allocate a new name-cache
460 -- entry) and then we get an error when we use dataTcOccs in
461 -- TcRnDriver.tcRnGetInfo. Large sigh.
464 %************************************************************************
467 Dealing with rebindable syntax is driven by the
468 Opt_NoImplicitPrelude dynamic flag.
470 In "deriving" code we don't want to use rebindable syntax
471 so we switch off the flag locally
474 %************************************************************************
476 Haskell 98 says that when you say "3" you get the "fromInteger" from the
477 Standard Prelude, regardless of what is in scope. However, to experiment
478 with having a language that is less coupled to the standard prelude, we're
479 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
480 happens to be in scope. Then you can
482 import MyPrelude as Prelude
483 to get the desired effect.
485 At the moment this just happens for
486 * fromInteger, fromRational on literals (in expressions and patterns)
487 * negate (in expressions)
488 * minus (arising from n+k patterns)
491 We store the relevant Name in the HsSyn tree, in
492 * HsIntegral/HsFractional
496 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
497 fromRationalName etc), but the renamer changes this to the appropriate user
498 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
500 We treat the orignal (standard) names as free-vars too, because the type checker
501 checks the type of the user thing against the type of the standard thing.
504 lookupSyntaxName :: Name -- The standard name
505 -> RnM (SyntaxExpr Name, FreeVars) -- Possibly a non-standard name
506 lookupSyntaxName std_name
507 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
508 if implicit_prelude then normal_case
510 -- Get the similarly named thing from the local environment
511 lookupOccRn (mkRdrUnqual (nameOccName std_name)) `thenM` \ usr_name ->
512 returnM (HsVar usr_name, unitFV usr_name)
514 normal_case = returnM (HsVar std_name, emptyFVs)
516 lookupSyntaxTable :: [Name] -- Standard names
517 -> RnM (SyntaxTable Name, FreeVars) -- See comments with HsExpr.ReboundNames
518 lookupSyntaxTable std_names
519 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
520 if implicit_prelude then normal_case
522 -- Get the similarly named thing from the local environment
523 mappM (lookupOccRn . mkRdrUnqual . nameOccName) std_names `thenM` \ usr_names ->
525 returnM (std_names `zip` map HsVar usr_names, mkFVs usr_names)
527 normal_case = returnM (std_names `zip` map HsVar std_names, emptyFVs)
531 %*********************************************************
535 %*********************************************************
538 newLocalsRn :: [Located RdrName] -> RnM [Name]
539 newLocalsRn rdr_names_w_loc
540 = newUniqueSupply `thenM` \ us ->
541 returnM (zipWith mk rdr_names_w_loc (uniqsFromSupply us))
543 mk (L loc rdr_name) uniq
544 | Just name <- isExact_maybe rdr_name = name
545 -- This happens in code generated by Template Haskell
546 | otherwise = ASSERT2( isUnqual rdr_name, ppr rdr_name )
547 -- We only bind unqualified names here
548 -- lookupRdrEnv doesn't even attempt to look up a qualified RdrName
549 mkInternalName uniq (rdrNameOcc rdr_name) (srcSpanStart loc)
551 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
555 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
556 = -- Check for duplicate names
557 checkDupNames doc_str rdr_names_w_loc `thenM_`
559 -- Warn about shadowing, but only in source modules
560 ifOptM Opt_WarnNameShadowing
561 (checkShadowing doc_str rdr_names_w_loc) `thenM_`
563 -- Make fresh Names and extend the environment
564 newLocalsRn rdr_names_w_loc `thenM` \ names ->
565 getLocalRdrEnv `thenM` \ local_env ->
566 setLocalRdrEnv (extendLocalRdrEnv local_env names)
567 (enclosed_scope names)
570 bindLocalNames :: [Name] -> RnM a -> RnM a
571 bindLocalNames names enclosed_scope
572 = getLocalRdrEnv `thenM` \ name_env ->
573 setLocalRdrEnv (extendLocalRdrEnv name_env names)
576 bindLocalNamesFV :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
577 bindLocalNamesFV names enclosed_scope
578 = do { (result, fvs) <- bindLocalNames names enclosed_scope
579 ; returnM (result, delListFromNameSet fvs names) }
582 -------------------------------------
583 -- binLocalsFVRn is the same as bindLocalsRn
584 -- except that it deals with free vars
585 bindLocatedLocalsFV :: SDoc -> [Located RdrName] -> ([Name] -> RnM (a,FreeVars))
587 bindLocatedLocalsFV doc rdr_names enclosed_scope
588 = bindLocatedLocalsRn doc rdr_names $ \ names ->
589 enclosed_scope names `thenM` \ (thing, fvs) ->
590 returnM (thing, delListFromNameSet fvs names)
592 -------------------------------------
593 bindTyVarsRn :: SDoc -> [LHsTyVarBndr RdrName]
594 -> ([LHsTyVarBndr Name] -> RnM a)
596 -- Haskell-98 binding of type variables; e.g. within a data type decl
597 bindTyVarsRn doc_str tyvar_names enclosed_scope
599 located_tyvars = hsLTyVarLocNames tyvar_names
601 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
602 enclosed_scope (zipWith replace tyvar_names names)
604 replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2)
606 bindPatSigTyVars :: [LHsType RdrName] -> ([Name] -> RnM a) -> RnM a
607 -- Find the type variables in the pattern type
608 -- signatures that must be brought into scope
609 bindPatSigTyVars tys thing_inside
610 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
611 ; if not scoped_tyvars then
614 do { name_env <- getLocalRdrEnv
615 ; let locd_tvs = [ tv | ty <- tys
616 , tv <- extractHsTyRdrTyVars ty
617 , not (unLoc tv `elemLocalRdrEnv` name_env) ]
618 nubbed_tvs = nubBy eqLocated locd_tvs
619 -- The 'nub' is important. For example:
620 -- f (x :: t) (y :: t) = ....
621 -- We don't want to complain about binding t twice!
623 ; bindLocatedLocalsRn doc_sig nubbed_tvs thing_inside }}
625 doc_sig = text "In a pattern type-signature"
627 bindPatSigTyVarsFV :: [LHsType RdrName]
630 bindPatSigTyVarsFV tys thing_inside
631 = bindPatSigTyVars tys $ \ tvs ->
632 thing_inside `thenM` \ (result,fvs) ->
633 returnM (result, fvs `delListFromNameSet` tvs)
635 bindSigTyVarsFV :: [LSig Name]
638 -- Bind the top-level forall'd type variables in the sigs.
641 -- The 'a' scopes over the rhs
643 -- NB: there'll usually be just one (for a function binding)
644 -- but if there are many, one may shadow the rest; too bad!
645 -- e.g x :: [a] -> [a]
648 -- In e, 'a' will be in scope, and it'll be the one from 'y'!
649 bindSigTyVarsFV sigs thing_inside
650 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
651 ; if not scoped_tyvars then
654 bindLocalNamesFV tvs thing_inside }
656 tvs = [ hsLTyVarName ltv
657 | L _ (Sig _ (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs, ltv <- ltvs ]
658 -- Note the pattern-match on "Explicit"; we only bind
659 -- type variables from signatures with an explicit top-level for-all
662 extendTyVarEnvFVRn :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
663 -- This function is used only in rnSourceDecl on InstDecl
664 extendTyVarEnvFVRn tyvars thing_inside = bindLocalNamesFV tyvars thing_inside
666 -------------------------------------
667 checkDupNames :: SDoc
670 checkDupNames doc_str rdr_names_w_loc
671 = -- Check for duplicated names in a binding group
672 mappM_ (dupNamesErr doc_str) dups
674 (_, dups) = removeDups (\n1 n2 -> unLoc n1 `compare` unLoc n2) rdr_names_w_loc
676 -------------------------------------
677 checkShadowing doc_str loc_rdr_names
678 = getLocalRdrEnv `thenM` \ local_env ->
679 getGlobalRdrEnv `thenM` \ global_env ->
681 check_shadow (L loc rdr_name)
682 | rdr_name `elemLocalRdrEnv` local_env
683 || not (null (lookupGRE_RdrName rdr_name global_env ))
684 = setSrcSpan loc $ addWarn (shadowedNameWarn doc_str rdr_name)
685 | otherwise = returnM ()
687 mappM_ check_shadow loc_rdr_names
691 %************************************************************************
693 \subsection{Free variable manipulation}
695 %************************************************************************
699 mapFvRn f xs = mappM f xs `thenM` \ stuff ->
701 (ys, fvs_s) = unzip stuff
703 returnM (ys, plusFVs fvs_s)
707 %************************************************************************
709 \subsection{Envt utility functions}
711 %************************************************************************
714 warnUnusedModules :: [(Module,SrcSpan)] -> RnM ()
715 warnUnusedModules mods
716 = ifOptM Opt_WarnUnusedImports (mappM_ bleat mods)
718 bleat (mod,loc) = setSrcSpan loc $ addWarn (mk_warn mod)
719 mk_warn m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
720 text "is imported, but nothing from it is used",
721 parens (ptext SLIT("except perhaps instances visible in") <+>
724 warnUnusedImports, warnUnusedTopBinds :: [GlobalRdrElt] -> RnM ()
725 warnUnusedImports gres = ifOptM Opt_WarnUnusedImports (warnUnusedGREs gres)
726 warnUnusedTopBinds gres = ifOptM Opt_WarnUnusedBinds (warnUnusedGREs gres)
728 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM ()
729 warnUnusedLocalBinds names = ifOptM Opt_WarnUnusedBinds (warnUnusedLocals names)
730 warnUnusedMatches names = ifOptM Opt_WarnUnusedMatches (warnUnusedLocals names)
732 -------------------------
735 = warnUnusedBinds [(n,Just p) | GRE {gre_name = n, gre_prov = p} <- gres]
737 warnUnusedLocals names
738 = warnUnusedBinds [(n,Nothing) | n<-names]
740 warnUnusedBinds :: [(Name,Maybe Provenance)] -> RnM ()
741 warnUnusedBinds names = mappM_ warnUnusedName (filter reportable names)
742 where reportable (name,_) = reportIfUnused (nameOccName name)
744 -------------------------
746 warnUnusedName :: (Name, Maybe Provenance) -> RnM ()
747 warnUnusedName (name, prov)
750 nest 2 $ occNameFlavour (nameOccName name) <+> quotes (ppr name)]
751 -- TODO should be a proper span
753 (loc,msg) = case prov of
755 -> (importSpecLoc imp_spec, imp_from (importSpecModule imp_spec))
758 other -> (srcLocSpan (nameSrcLoc name), unused_msg)
760 unused_msg = text "Defined but not used"
761 imp_from mod = text "Imported from" <+> quotes (ppr mod) <+> text "but not used"
765 addNameClashErrRn rdr_name (np1:nps)
766 = addErr (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
767 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
769 msg1 = ptext SLIT("either") <+> mk_ref np1
770 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
771 mk_ref gre = quotes (ppr (gre_name gre)) <> comma <+> pprNameProvenance gre
773 shadowedNameWarn doc shadow
774 = hsep [ptext SLIT("This binding for"),
776 ptext SLIT("shadows an existing binding")]
779 unknownNameErr rdr_name
780 = sep [ptext SLIT("Not in scope:"),
781 nest 2 $ occNameFlavour (rdrNameOcc rdr_name) <+> quotes (ppr rdr_name)]
783 unknownInstBndrErr cls op
784 = quotes (ppr op) <+> ptext SLIT("is not a (visible) method of class") <+> quotes (ppr cls)
787 = ptext SLIT("Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
788 -- The rdrNameOcc is because we don't want to print Prelude.(,)
790 dupNamesErr :: SDoc -> [Located RdrName] -> RnM ()
791 dupNamesErr descriptor located_names
792 = setSrcSpan big_loc $
793 addErr (vcat [ptext SLIT("Conflicting definitions for") <+> quotes (ppr name1),
797 L _ name1 = head located_names
798 locs = map getLoc located_names
799 big_loc = foldr1 combineSrcSpans locs
800 one_line = srcSpanStartLine big_loc == srcSpanEndLine big_loc
801 locations | one_line = empty
802 | otherwise = ptext SLIT("Bound at:") <+>
803 vcat (map ppr (sortLe (<=) locs))