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 lookupTopFixSigNames, lookupSrcOcc_maybe,
14 lookupFixityRn, lookupLocatedSigOccRn,
15 lookupLocatedInstDeclBndr,
16 lookupSyntaxName, lookupSyntaxNames, 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 ( loadSrcInterface )
34 import IfaceEnv ( lookupOrig, newGlobalBinder, newIPName )
36 import RdrHsSyn ( extractHsTyRdrTyVars )
37 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
38 mkRdrUnqual, setRdrNameSpace, rdrNameOcc,
39 pprGlobalRdrEnv, lookupGRE_RdrName,
40 isExact_maybe, isSrcRdrName,
41 GlobalRdrElt(..), GlobalRdrEnv, lookupGlobalRdrEnv,
42 isLocalGRE, extendLocalRdrEnv, elemLocalRdrEnv, lookupLocalRdrEnv,
43 Provenance(..), pprNameProvenance, ImportSpec(..)
45 import HsTypes ( replaceTyVarName )
46 import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity )
48 import Name ( Name, nameIsLocalOrFrom, mkInternalName,
49 nameSrcLoc, nameOccName, nameModule, nameParent, isExternalName )
51 import OccName ( tcName, isDataOcc, occNameFlavour, reportIfUnused )
52 import Module ( Module )
53 import PrelNames ( mkUnboundName, rOOT_MAIN, iNTERACTIVE, consDataConKey, hasKey )
55 import BasicTypes ( IPName, mapIPName )
56 import SrcLoc ( SrcSpan, srcSpanStart, Located(..), eqLocated, unLoc,
57 srcLocSpan, getLoc, combineSrcSpans, srcSpanStartLine, srcSpanEndLine )
59 import Util ( sortLe )
60 import ListSetOps ( removeDups )
63 import FastString ( FastString )
66 %*********************************************************
70 %*********************************************************
73 newTopSrcBinder :: Module -> Maybe Name -> Located RdrName -> RnM Name
74 newTopSrcBinder this_mod mb_parent (L loc rdr_name)
75 | Just name <- isExact_maybe rdr_name
76 = -- This is here to catch
77 -- (a) Exact-name binders created by Template Haskell
78 -- (b) The PrelBase defn of (say) [] and similar, for which
79 -- the parser reads the special syntax and returns an Exact RdrName
80 -- We are at a binding site for the name, so check first that it
81 -- the current module is the correct one; otherwise GHC can get
82 -- very confused indeed. This test rejects code like
83 -- data T = (,) Int Int
84 -- unless we are in GHC.Tup
85 ASSERT2( isExternalName name, ppr name )
86 do checkErr (this_mod == nameModule name)
87 (badOrigBinding rdr_name)
92 = do checkErr (rdr_mod == this_mod || rdr_mod == rOOT_MAIN)
93 (badOrigBinding rdr_name)
94 -- When reading External Core we get Orig names as binders,
95 -- but they should agree with the module gotten from the monad
97 -- We can get built-in syntax showing up here too, sadly. If you type
99 -- the constructor is parsed as a type, and then RdrHsSyn.tyConToDataCon
100 -- uses setRdrNameSpace to make it into a data constructors. At that point
101 -- the nice Exact name for the TyCon gets swizzled to an Orig name.
102 -- Hence the badOrigBinding error message.
104 -- Except for the ":Main.main = ..." definition inserted into
105 -- the Main module; ugh!
107 -- Because of this latter case, we call newGlobalBinder with a module from
108 -- the RdrName, not from the environment. In principle, it'd be fine to
109 -- have an arbitrary mixture of external core definitions in a single module,
110 -- (apart from module-initialisation issues, perhaps).
111 newGlobalBinder rdr_mod (rdrNameOcc rdr_name) mb_parent
112 (srcSpanStart loc) --TODO, should pass the whole span
115 = newGlobalBinder this_mod (rdrNameOcc rdr_name) mb_parent (srcSpanStart loc)
117 rdr_mod = rdrNameModule rdr_name
120 %*********************************************************
122 Source code occurrences
124 %*********************************************************
126 Looking up a name in the RnEnv.
129 lookupLocatedBndrRn :: Located RdrName -> RnM (Located Name)
130 lookupLocatedBndrRn = wrapLocM lookupBndrRn
132 lookupBndrRn :: RdrName -> RnM Name
133 -- NOTE: assumes that the SrcSpan of the binder has already been setSrcSpan'd
134 lookupBndrRn rdr_name
135 = getLocalRdrEnv `thenM` \ local_env ->
136 case lookupLocalRdrEnv local_env rdr_name of
137 Just name -> returnM name
138 Nothing -> lookupTopBndrRn rdr_name
140 lookupLocatedTopBndrRn :: Located RdrName -> RnM (Located Name)
141 lookupLocatedTopBndrRn = wrapLocM lookupTopBndrRn
143 lookupTopBndrRn :: RdrName -> RnM Name
144 -- Look up a top-level source-code binder. We may be looking up an unqualified 'f',
145 -- and there may be several imported 'f's too, which must not confuse us.
146 -- For example, this is OK:
148 -- infix 9 f -- The 'f' here does not need to be qualified
149 -- f x = x -- Nor here, of course
150 -- So we have to filter out the non-local ones.
152 -- A separate function (importsFromLocalDecls) reports duplicate top level
153 -- decls, so here it's safe just to choose an arbitrary one.
155 -- There should never be a qualified name in a binding position in Haskell,
156 -- but there can be if we have read in an external-Core file.
157 -- The Haskell parser checks for the illegal qualified name in Haskell
158 -- source files, so we don't need to do so here.
160 lookupTopBndrRn rdr_name
161 | Just name <- isExact_maybe rdr_name
165 -- This deals with the case of derived bindings, where
166 -- we don't bother to call newTopSrcBinder first
167 -- We assume there is no "parent" name
168 = do { loc <- getSrcSpanM
169 ; newGlobalBinder (rdrNameModule rdr_name)
170 (rdrNameOcc rdr_name) Nothing (srcSpanStart loc) }
173 = do { mb_gre <- lookupGreLocalRn rdr_name
175 Nothing -> unboundName rdr_name
176 Just gre -> returnM (gre_name gre) }
178 -- lookupLocatedSigOccRn is used for type signatures and pragmas
184 -- It's clear that the 'f' in the signature must refer to A.f
185 -- The Haskell98 report does not stipulate this, but it will!
186 -- So we must treat the 'f' in the signature in the same way
187 -- as the binding occurrence of 'f', using lookupBndrRn
188 lookupLocatedSigOccRn :: Located RdrName -> RnM (Located Name)
189 lookupLocatedSigOccRn = lookupLocatedBndrRn
191 -- lookupInstDeclBndr is used for the binders in an
192 -- instance declaration. Here we use the class name to
195 lookupLocatedInstDeclBndr :: Name -> Located RdrName -> RnM (Located Name)
196 lookupLocatedInstDeclBndr cls = wrapLocM (lookupInstDeclBndr cls)
198 lookupInstDeclBndr :: Name -> RdrName -> RnM Name
199 lookupInstDeclBndr cls_name rdr_name
200 | isUnqual rdr_name -- Find all the things the rdr-name maps to
201 = do { -- and pick the one with the right parent name
202 let { is_op gre = cls_name == nameParent (gre_name gre)
203 ; occ = rdrNameOcc rdr_name
204 ; lookup_fn env = filter is_op (lookupGlobalRdrEnv env occ) }
205 ; mb_gre <- lookupGreRn_help rdr_name lookup_fn
207 Just gre -> return (gre_name gre)
208 Nothing -> do { addErr (unknownInstBndrErr cls_name rdr_name)
209 ; return (mkUnboundName rdr_name) } }
211 | otherwise -- Occurs in derived instances, where we just
212 -- refer directly to the right method
213 = ASSERT2( not (isQual rdr_name), ppr rdr_name )
214 -- NB: qualified names are rejected by the parser
215 lookupImportedName rdr_name
217 newIPNameRn :: IPName RdrName -> TcRnIf m n (IPName Name)
218 newIPNameRn ip_rdr = newIPName (mapIPName rdrNameOcc ip_rdr)
220 --------------------------------------------------
222 --------------------------------------------------
224 lookupLocatedOccRn :: Located RdrName -> RnM (Located Name)
225 lookupLocatedOccRn = wrapLocM lookupOccRn
227 -- lookupOccRn looks up an occurrence of a RdrName
228 lookupOccRn :: RdrName -> RnM Name
230 = getLocalRdrEnv `thenM` \ local_env ->
231 case lookupLocalRdrEnv local_env rdr_name of
232 Just name -> returnM name
233 Nothing -> lookupGlobalOccRn rdr_name
235 lookupLocatedGlobalOccRn :: Located RdrName -> RnM (Located Name)
236 lookupLocatedGlobalOccRn = wrapLocM lookupGlobalOccRn
238 lookupGlobalOccRn :: RdrName -> RnM Name
239 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
240 -- environment. It's used only for
241 -- record field names
242 -- class op names in class and instance decls
244 lookupGlobalOccRn rdr_name
245 | not (isSrcRdrName rdr_name)
246 = lookupImportedName rdr_name
249 = -- First look up the name in the normal environment.
250 lookupGreRn rdr_name `thenM` \ mb_gre ->
252 Just gre -> returnM (gre_name gre) ;
255 -- We allow qualified names on the command line to refer to
256 -- *any* name exported by any module in scope, just as if
257 -- there was an "import qualified M" declaration for every
259 getModule `thenM` \ mod ->
260 if isQual rdr_name && mod == iNTERACTIVE then
261 -- This test is not expensive,
262 lookupQualifiedName rdr_name -- and only happens for failed lookups
264 unboundName rdr_name }
266 lookupImportedName :: RdrName -> TcRnIf m n Name
267 -- Lookup the occurrence of an imported name
268 -- The RdrName is *always* qualified or Exact
269 -- Treat it as an original name, and conjure up the Name
270 -- Usually it's Exact or Orig, but it can be Qual if it
271 -- comes from an hi-boot file. (This minor infelicity is
272 -- just to reduce duplication in the parser.)
273 lookupImportedName rdr_name
274 | Just n <- isExact_maybe rdr_name
275 -- This happens in derived code
278 | otherwise -- Always Orig, even when reading a .hi-boot file
279 = ASSERT( not (isUnqual rdr_name) )
280 lookupOrig (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
282 unboundName :: RdrName -> RnM Name
284 = do { addErr (unknownNameErr rdr_name)
285 ; env <- getGlobalRdrEnv;
286 ; traceRn (vcat [unknownNameErr rdr_name,
287 ptext SLIT("Global envt is:"),
288 nest 3 (pprGlobalRdrEnv env)])
289 ; returnM (mkUnboundName rdr_name) }
291 --------------------------------------------------
292 -- Lookup in the Global RdrEnv of the module
293 --------------------------------------------------
295 lookupSrcOcc_maybe :: RdrName -> RnM (Maybe Name)
296 -- No filter function; does not report an error on failure
297 lookupSrcOcc_maybe rdr_name
298 = do { mb_gre <- lookupGreRn rdr_name
300 Nothing -> returnM Nothing
301 Just gre -> returnM (Just (gre_name gre)) }
303 -------------------------
304 lookupGreRn :: RdrName -> RnM (Maybe GlobalRdrElt)
305 -- Just look up the RdrName in the GlobalRdrEnv
307 = lookupGreRn_help rdr_name (lookupGRE_RdrName rdr_name)
309 lookupGreLocalRn :: RdrName -> RnM (Maybe GlobalRdrElt)
310 -- Similar, but restricted to locally-defined things
311 lookupGreLocalRn rdr_name
312 = lookupGreRn_help rdr_name lookup_fn
314 lookup_fn env = filter isLocalGRE (lookupGRE_RdrName rdr_name env)
316 lookupGreRn_help :: RdrName -- Only used in error message
317 -> (GlobalRdrEnv -> [GlobalRdrElt]) -- Lookup function
318 -> RnM (Maybe GlobalRdrElt)
319 -- Checks for exactly one match; reports deprecations
320 -- Returns Nothing, without error, if too few
321 lookupGreRn_help rdr_name lookup
322 = do { env <- getGlobalRdrEnv
324 [] -> returnM Nothing
325 [gre] -> returnM (Just gre)
326 gres -> do { addNameClashErrRn rdr_name gres
327 ; returnM (Just (head gres)) } }
329 ------------------------------
331 ------------------------------
333 -- A qualified name on the command line can refer to any module at all: we
334 -- try to load the interface if we don't already have it.
335 lookupQualifiedName :: RdrName -> RnM Name
336 lookupQualifiedName rdr_name
338 mod = rdrNameModule rdr_name
339 occ = rdrNameOcc rdr_name
341 loadSrcInterface doc mod False `thenM` \ iface ->
344 (mod,avails) <- mi_exports iface,
346 name <- availNames avail,
348 ((mod,occ):ns) -> ASSERT (null ns)
350 _ -> unboundName rdr_name
352 doc = ptext SLIT("Need to find") <+> ppr rdr_name
355 %*********************************************************
359 %*********************************************************
362 lookupTopFixSigNames :: RdrName -> RnM [Name]
363 -- GHC extension: look up both the tycon and data con
364 -- for con-like things
365 lookupTopFixSigNames rdr_name
366 | Just n <- isExact_maybe rdr_name
367 -- Special case for (:), which doesn't get into the GlobalRdrEnv
368 = return [n] -- For this we don't need to try the tycon too
370 = do { mb_gres <- mapM lookupGreLocalRn (dataTcOccs rdr_name)
371 ; return [gre_name gre | Just gre <- mb_gres] }
373 --------------------------------
374 bindLocalFixities :: [FixitySig RdrName] -> RnM a -> RnM a
375 -- Used for nested fixity decls
376 -- No need to worry about type constructors here,
377 -- Should check for duplicates but we don't
378 bindLocalFixities fixes thing_inside
379 | null fixes = thing_inside
380 | otherwise = mappM rn_sig fixes `thenM` \ new_bit ->
381 extendFixityEnv new_bit thing_inside
383 rn_sig (FixitySig lv@(L loc v) fix)
384 = addLocM lookupBndrRn lv `thenM` \ new_v ->
385 returnM (new_v, (FixItem (rdrNameOcc v) fix loc))
388 --------------------------------
389 lookupFixity is a bit strange.
391 * Nested local fixity decls are put in the local fixity env, which we
392 find with getFixtyEnv
394 * Imported fixities are found in the HIT or PIT
396 * Top-level fixity decls in this module may be for Names that are
397 either Global (constructors, class operations)
398 or Local/Exported (everything else)
399 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
400 We put them all in the local fixity environment
403 lookupFixityRn :: Name -> RnM Fixity
405 = getModule `thenM` \ this_mod ->
406 if nameIsLocalOrFrom this_mod name
407 then -- It's defined in this module
408 getFixityEnv `thenM` \ local_fix_env ->
409 traceRn (text "lookupFixityRn" <+> (ppr name $$ ppr local_fix_env)) `thenM_`
410 returnM (lookupFixity local_fix_env name)
412 else -- It's imported
413 -- For imported names, we have to get their fixities by doing a
414 -- loadHomeInterface, and consulting the Ifaces that comes back
415 -- from that, because the interface file for the Name might not
416 -- have been loaded yet. Why not? Suppose you import module A,
417 -- which exports a function 'f', thus;
418 -- module CurrentModule where
420 -- module A( f ) where
422 -- Then B isn't loaded right away (after all, it's possible that
423 -- nothing from B will be used). When we come across a use of
424 -- 'f', we need to know its fixity, and it's then, and only
425 -- then, that we load B.hi. That is what's happening here.
426 loadSrcInterface doc name_mod False `thenM` \ iface ->
427 returnM (mi_fix_fn iface (nameOccName name))
429 doc = ptext SLIT("Checking fixity for") <+> ppr name
430 name_mod = nameModule name
432 dataTcOccs :: RdrName -> [RdrName]
433 -- If the input is a data constructor, return both it and a type
434 -- constructor. This is useful when we aren't sure which we are
437 | Just n <- isExact_maybe rdr_name -- Ghastly special case
438 , n `hasKey` consDataConKey = [rdr_name] -- see note below
439 | isDataOcc occ = [rdr_name_tc, rdr_name]
440 | otherwise = [rdr_name]
442 occ = rdrNameOcc rdr_name
443 rdr_name_tc = setRdrNameSpace rdr_name tcName
445 -- If the user typed "[]" or "(,,)", we'll generate an Exact RdrName,
446 -- and setRdrNameSpace generates an Orig, which is fine
447 -- But it's not fine for (:), because there *is* no corresponding type
448 -- constructor. If we generate an Orig tycon for GHC.Base.(:), it'll
449 -- appear to be in scope (because Orig's simply allocate a new name-cache
450 -- entry) and then we get an error when we use dataTcOccs in
451 -- TcRnDriver.tcRnGetInfo. Large sigh.
454 %************************************************************************
457 Dealing with rebindable syntax is driven by the
458 Opt_NoImplicitPrelude dynamic flag.
460 In "deriving" code we don't want to use rebindable syntax
461 so we switch off the flag locally
464 %************************************************************************
466 Haskell 98 says that when you say "3" you get the "fromInteger" from the
467 Standard Prelude, regardless of what is in scope. However, to experiment
468 with having a language that is less coupled to the standard prelude, we're
469 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
470 happens to be in scope. Then you can
472 import MyPrelude as Prelude
473 to get the desired effect.
475 At the moment this just happens for
476 * fromInteger, fromRational on literals (in expressions and patterns)
477 * negate (in expressions)
478 * minus (arising from n+k patterns)
481 We store the relevant Name in the HsSyn tree, in
482 * HsIntegral/HsFractional
486 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
487 fromRationalName etc), but the renamer changes this to the appropriate user
488 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
490 We treat the orignal (standard) names as free-vars too, because the type checker
491 checks the type of the user thing against the type of the standard thing.
494 lookupSyntaxName :: Name -- The standard name
495 -> RnM (Name, FreeVars) -- Possibly a non-standard name
496 lookupSyntaxName std_name
497 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
498 if implicit_prelude then normal_case
500 -- Get the similarly named thing from the local environment
501 lookupOccRn (mkRdrUnqual (nameOccName std_name)) `thenM` \ usr_name ->
502 returnM (usr_name, unitFV usr_name)
504 normal_case = returnM (std_name, emptyFVs)
506 lookupSyntaxNames :: [Name] -- Standard names
507 -> RnM (ReboundNames Name, FreeVars) -- See comments with HsExpr.ReboundNames
508 lookupSyntaxNames std_names
509 = doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
510 if implicit_prelude then normal_case
512 -- Get the similarly named thing from the local environment
513 mappM (lookupOccRn . mkRdrUnqual . nameOccName) std_names `thenM` \ usr_names ->
515 returnM (std_names `zip` map HsVar usr_names, mkFVs usr_names)
517 normal_case = returnM (std_names `zip` map HsVar std_names, emptyFVs)
521 %*********************************************************
525 %*********************************************************
528 newLocalsRn :: [Located RdrName] -> RnM [Name]
529 newLocalsRn rdr_names_w_loc
530 = newUniqueSupply `thenM` \ us ->
531 returnM (zipWith mk rdr_names_w_loc (uniqsFromSupply us))
533 mk (L loc rdr_name) uniq
534 | Just name <- isExact_maybe rdr_name = name
535 -- This happens in code generated by Template Haskell
536 | otherwise = ASSERT2( isUnqual rdr_name, ppr rdr_name )
537 -- We only bind unqualified names here
538 -- lookupRdrEnv doesn't even attempt to look up a qualified RdrName
539 mkInternalName uniq (rdrNameOcc rdr_name) (srcSpanStart loc)
541 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
545 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
546 = -- Check for duplicate names
547 checkDupNames doc_str rdr_names_w_loc `thenM_`
549 -- Warn about shadowing, but only in source modules
550 ifOptM Opt_WarnNameShadowing
551 (checkShadowing doc_str rdr_names_w_loc) `thenM_`
553 -- Make fresh Names and extend the environment
554 newLocalsRn rdr_names_w_loc `thenM` \ names ->
555 getLocalRdrEnv `thenM` \ local_env ->
556 setLocalRdrEnv (extendLocalRdrEnv local_env names)
557 (enclosed_scope names)
560 bindLocalNames :: [Name] -> RnM a -> RnM a
561 bindLocalNames names enclosed_scope
562 = getLocalRdrEnv `thenM` \ name_env ->
563 setLocalRdrEnv (extendLocalRdrEnv name_env names)
566 bindLocalNamesFV :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
567 bindLocalNamesFV names enclosed_scope
568 = do { (result, fvs) <- bindLocalNames names enclosed_scope
569 ; returnM (result, delListFromNameSet fvs names) }
572 -------------------------------------
573 -- binLocalsFVRn is the same as bindLocalsRn
574 -- except that it deals with free vars
575 bindLocatedLocalsFV :: SDoc -> [Located RdrName] -> ([Name] -> RnM (a,FreeVars))
577 bindLocatedLocalsFV doc rdr_names enclosed_scope
578 = bindLocatedLocalsRn doc rdr_names $ \ names ->
579 enclosed_scope names `thenM` \ (thing, fvs) ->
580 returnM (thing, delListFromNameSet fvs names)
582 -------------------------------------
583 bindTyVarsRn :: SDoc -> [LHsTyVarBndr RdrName]
584 -> ([LHsTyVarBndr Name] -> RnM a)
586 -- Haskell-98 binding of type variables; e.g. within a data type decl
587 bindTyVarsRn doc_str tyvar_names enclosed_scope
589 located_tyvars = hsLTyVarLocNames tyvar_names
591 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
592 enclosed_scope (zipWith replace tyvar_names names)
594 replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2)
596 bindPatSigTyVars :: [LHsType RdrName] -> ([Name] -> RnM a) -> RnM a
597 -- Find the type variables in the pattern type
598 -- signatures that must be brought into scope
599 bindPatSigTyVars tys thing_inside
600 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
601 ; if not scoped_tyvars then
604 do { name_env <- getLocalRdrEnv
605 ; let locd_tvs = [ tv | ty <- tys
606 , tv <- extractHsTyRdrTyVars ty
607 , not (unLoc tv `elemLocalRdrEnv` name_env) ]
608 nubbed_tvs = nubBy eqLocated locd_tvs
609 -- The 'nub' is important. For example:
610 -- f (x :: t) (y :: t) = ....
611 -- We don't want to complain about binding t twice!
613 ; bindLocatedLocalsRn doc_sig nubbed_tvs thing_inside }}
615 doc_sig = text "In a pattern type-signature"
617 bindPatSigTyVarsFV :: [LHsType RdrName]
620 bindPatSigTyVarsFV tys thing_inside
621 = bindPatSigTyVars tys $ \ tvs ->
622 thing_inside `thenM` \ (result,fvs) ->
623 returnM (result, fvs `delListFromNameSet` tvs)
625 bindSigTyVarsFV :: [LSig Name]
628 -- Bind the top-level forall'd type variables in the sigs.
631 -- The 'a' scopes over the rhs
633 -- NB: there'll usually be just one (for a function binding)
634 -- but if there are many, one may shadow the rest; too bad!
635 -- e.g x :: [a] -> [a]
638 -- In e, 'a' will be in scope, and it'll be the one from 'y'!
639 bindSigTyVarsFV sigs thing_inside
640 = do { scoped_tyvars <- doptM Opt_ScopedTypeVariables
641 ; if not scoped_tyvars then
644 bindLocalNamesFV tvs thing_inside }
646 tvs = [ hsLTyVarName ltv
647 | L _ (Sig _ (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs, ltv <- ltvs ]
648 -- Note the pattern-match on "Explicit"; we only bind
649 -- type variables from signatures with an explicit top-level for-all
652 extendTyVarEnvFVRn :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars)
653 -- This function is used only in rnSourceDecl on InstDecl
654 extendTyVarEnvFVRn tyvars thing_inside = bindLocalNamesFV tyvars thing_inside
656 -------------------------------------
657 checkDupNames :: SDoc
660 checkDupNames doc_str rdr_names_w_loc
661 = -- Check for duplicated names in a binding group
662 mappM_ (dupNamesErr doc_str) dups
664 (_, dups) = removeDups (\n1 n2 -> unLoc n1 `compare` unLoc n2) rdr_names_w_loc
666 -------------------------------------
667 checkShadowing doc_str loc_rdr_names
668 = getLocalRdrEnv `thenM` \ local_env ->
669 getGlobalRdrEnv `thenM` \ global_env ->
671 check_shadow (L loc rdr_name)
672 | rdr_name `elemLocalRdrEnv` local_env
673 || not (null (lookupGRE_RdrName rdr_name global_env ))
674 = setSrcSpan loc $ addWarn (shadowedNameWarn doc_str rdr_name)
675 | otherwise = returnM ()
677 mappM_ check_shadow loc_rdr_names
681 %************************************************************************
683 \subsection{Free variable manipulation}
685 %************************************************************************
689 mapFvRn f xs = mappM f xs `thenM` \ stuff ->
691 (ys, fvs_s) = unzip stuff
693 returnM (ys, plusFVs fvs_s)
697 %************************************************************************
699 \subsection{Envt utility functions}
701 %************************************************************************
704 warnUnusedModules :: [(Module,SrcSpan)] -> RnM ()
705 warnUnusedModules mods
706 = ifOptM Opt_WarnUnusedImports (mappM_ bleat mods)
708 bleat (mod,loc) = setSrcSpan loc $ addWarn (mk_warn mod)
709 mk_warn m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
710 text "is imported, but nothing from it is used",
711 parens (ptext SLIT("except perhaps instances visible in") <+>
714 warnUnusedImports, warnUnusedTopBinds :: [GlobalRdrElt] -> RnM ()
715 warnUnusedImports gres = ifOptM Opt_WarnUnusedImports (warnUnusedGREs gres)
716 warnUnusedTopBinds gres = ifOptM Opt_WarnUnusedBinds (warnUnusedGREs gres)
718 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM ()
719 warnUnusedLocalBinds names = ifOptM Opt_WarnUnusedBinds (warnUnusedLocals names)
720 warnUnusedMatches names = ifOptM Opt_WarnUnusedMatches (warnUnusedLocals names)
722 -------------------------
725 = warnUnusedBinds [(n,Just p) | GRE {gre_name = n, gre_prov = p} <- gres]
727 warnUnusedLocals names
728 = warnUnusedBinds [(n,Nothing) | n<-names]
730 warnUnusedBinds :: [(Name,Maybe Provenance)] -> RnM ()
731 warnUnusedBinds names = mappM_ warnUnusedName (filter reportable names)
732 where reportable (name,_) = reportIfUnused (nameOccName name)
734 -------------------------
736 warnUnusedName :: (Name, Maybe Provenance) -> RnM ()
737 warnUnusedName (name, prov)
740 nest 2 $ occNameFlavour (nameOccName name) <+> quotes (ppr name)]
741 -- TODO should be a proper span
743 (loc,msg) = case prov of
744 Just (Imported is _) ->
745 ( is_loc (head is), imp_from (is_mod imp_spec) )
749 ( srcLocSpan (nameSrcLoc name), unused_msg )
751 unused_msg = text "Defined but not used"
752 imp_from mod = text "Imported from" <+> quotes (ppr mod) <+> text "but not used"
756 addNameClashErrRn rdr_name (np1:nps)
757 = addErr (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
758 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
760 msg1 = ptext SLIT("either") <+> mk_ref np1
761 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
762 mk_ref gre = quotes (ppr (gre_name gre)) <> comma <+> pprNameProvenance gre
764 shadowedNameWarn doc shadow
765 = hsep [ptext SLIT("This binding for"),
767 ptext SLIT("shadows an existing binding")]
770 unknownNameErr rdr_name
771 = sep [ptext SLIT("Not in scope:"),
772 nest 2 $ occNameFlavour (rdrNameOcc rdr_name) <+> quotes (ppr rdr_name)]
774 unknownInstBndrErr cls op
775 = quotes (ppr op) <+> ptext SLIT("is not a (visible) method of class") <+> quotes (ppr cls)
778 = ptext SLIT("Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
779 -- The rdrNameOcc is because we don't want to print Prelude.(,)
781 dupNamesErr :: SDoc -> [Located RdrName] -> RnM ()
782 dupNamesErr descriptor located_names
783 = setSrcSpan big_loc $
784 addErr (vcat [ptext SLIT("Conflicting definitions for") <+> quotes (ppr name1),
788 L _ name1 = head located_names
789 locs = map getLoc located_names
790 big_loc = foldr1 combineSrcSpans locs
791 one_line = srcSpanStartLine big_loc == srcSpanEndLine big_loc
792 locations | one_line = empty
793 | otherwise = ptext SLIT("Bound at:") <+>
794 vcat (map ppr (sortLe (<=) locs))