2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnEnv]{Environment manipulation for the renamer monad}
7 module RnEnv where -- Export everything
9 #include "HsVersions.h"
11 import {-# SOURCE #-} RnHiFiles
13 import FlattenInfo ( namesNeededForFlattening )
15 import RdrHsSyn ( RdrNameIE, RdrNameHsType, extractHsTyRdrTyVars )
16 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
17 mkRdrUnqual, mkRdrQual,
18 lookupRdrEnv, foldRdrEnv, rdrEnvToList, elemRdrEnv,
21 import HsTypes ( hsTyVarName, replaceTyVarName )
22 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
23 ImportReason(..), GlobalRdrEnv, GlobalRdrElt(..), AvailEnv,
24 AvailInfo, Avails, GenAvailInfo(..), NameSupply(..),
25 ModIface(..), GhciMode(..),
26 Deprecations(..), lookupDeprec,
31 getSrcLoc, nameIsLocalOrFrom,
32 mkInternalName, mkExternalName,
33 mkIPName, nameOccName, nameModule_maybe,
38 import OccName ( OccName, occNameUserString, occNameFlavour )
39 import Module ( ModuleName, moduleName, mkVanillaModule,
40 mkSysModuleNameFS, moduleNameFS, WhereFrom(..) )
41 import PrelNames ( mkUnboundName,
43 mAIN_Name, main_RDR_Unqual,
44 runMainName, intTyConName,
45 boolTyConName, funTyConName,
46 unpackCStringName, unpackCStringFoldrName, unpackCStringUtf8Name,
47 eqStringName, printName,
48 bindIOName, returnIOName, failIOName
50 import TysWiredIn ( unitTyCon ) -- A little odd
53 import SrcLoc ( SrcLoc, noSrcLoc )
55 import ListSetOps ( removeDups, equivClasses )
56 import Util ( sortLt )
57 import BasicTypes ( mapIPName )
59 import UniqFM ( lookupWithDefaultUFM )
60 import Maybe ( mapMaybe )
62 import FastString ( FastString )
65 %*********************************************************
67 \subsection{Making new names}
69 %*********************************************************
72 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
73 -- newTopBinder puts into the cache the binder with the
74 -- module information set correctly. When the decl is later renamed,
75 -- the binding site will thereby get the correct module.
76 -- There maybe occurrences that don't have the correct Module, but
77 -- by the typechecker will propagate the binding definition to all
78 -- the occurrences, so that doesn't matter
80 newTopBinder mod rdr_name loc
81 = -- First check the cache
83 -- There should never be a qualified name in a binding position (except in instance decls)
84 -- The parser doesn't check this because the same parser parses instance decls
85 (if isQual rdr_name then
86 qualNameErr (text "In its declaration") (rdr_name,loc)
91 getNameSupplyRn `thenRn` \ name_supply ->
93 occ = rdrNameOcc rdr_name
94 key = (moduleName mod, occ)
95 cache = nsNames name_supply
97 case lookupFM cache key of
99 -- A hit in the cache! We are at the binding site of the name, and
100 -- this is the moment when we know all about
101 -- a) the Name's host Module (in particular, which
102 -- package it comes from)
103 -- b) its defining SrcLoc
104 -- So we update this info
107 new_name = setNameModuleAndLoc name mod loc
108 new_cache = addToFM cache key new_name
110 setNameSupplyRn (name_supply {nsNames = new_cache}) `thenRn_`
111 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
114 -- Miss in the cache!
115 -- Build a completely new Name, and put it in the cache
116 -- Even for locally-defined names we use implicitImportProvenance;
117 -- updateProvenances will set it to rights
119 (us', us1) = splitUniqSupply (nsUniqs name_supply)
120 uniq = uniqFromSupply us1
121 new_name = mkExternalName uniq mod occ loc
122 new_cache = addToFM cache key new_name
124 setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
125 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
129 newGlobalName :: ModuleName -> OccName -> RnM d Name
130 -- Used for *occurrences*. We make a place-holder Name, really just
131 -- to agree on its unique, which gets overwritten when we read in
132 -- the binding occurence later (newTopBinder)
133 -- The place-holder Name doesn't have the right SrcLoc, and its
134 -- Module won't have the right Package either.
136 -- (We have to pass a ModuleName, not a Module, because we may be
137 -- simply looking at an occurrence M.x in an interface file.)
139 -- This means that a renamed program may have incorrect info
140 -- on implicitly-imported occurrences, but the correct info on the
141 -- *binding* declaration. It's the type checker that propagates the
142 -- correct information to all the occurrences.
143 -- Since implicitly-imported names never occur in error messages,
144 -- it doesn't matter that we get the correct info in place till later,
145 -- (but since it affects DLL-ery it does matter that we get it right
147 newGlobalName mod_name occ
148 = getNameSupplyRn `thenRn` \ name_supply ->
150 key = (mod_name, occ)
151 cache = nsNames name_supply
153 case lookupFM cache key of
154 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
157 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
158 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
161 (us', us1) = splitUniqSupply (nsUniqs name_supply)
162 uniq = uniqFromSupply us1
163 mod = mkVanillaModule mod_name
164 name = mkExternalName uniq mod occ noSrcLoc
165 new_cache = addToFM cache key name
167 newIPName rdr_name_ip
168 = getNameSupplyRn `thenRn` \ name_supply ->
170 ipcache = nsIPs name_supply
172 case lookupFM ipcache key of
173 Just name_ip -> returnRn name_ip
174 Nothing -> setNameSupplyRn new_ns `thenRn_`
177 (us', us1) = splitUniqSupply (nsUniqs name_supply)
178 uniq = uniqFromSupply us1
179 name_ip = mapIPName mk_name rdr_name_ip
180 mk_name rdr_name = mkIPName uniq (rdrNameOcc rdr_name)
181 new_ipcache = addToFM ipcache key name_ip
182 new_ns = name_supply {nsUniqs = us', nsIPs = new_ipcache}
184 key = rdr_name_ip -- Ensures that ?x and %x get distinct Names
187 %*********************************************************
189 \subsection{Looking up names}
191 %*********************************************************
193 Looking up a name in the RnEnv.
196 lookupBndrRn rdr_name
197 = getLocalNameEnv `thenRn` \ local_env ->
198 case lookupRdrEnv local_env rdr_name of
199 Just name -> returnRn name
200 Nothing -> lookupTopBndrRn rdr_name
202 lookupTopBndrRn rdr_name
203 -- Look up a top-level local binder. We may be looking up an unqualified 'f',
204 -- and there may be several imported 'f's too, which must not confuse us.
205 -- So we have to filter out the non-local ones.
206 -- A separate function (importsFromLocalDecls) reports duplicate top level
207 -- decls, so here it's safe just to choose an arbitrary one.
210 -- This is here just to catch the PrelBase defn of (say) [] and similar
211 -- The parser reads the special syntax and returns an Orig RdrName
212 -- But the global_env contains only Qual RdrNames, so we won't
213 -- find it there; instead just get the name via the Orig route
214 = lookupOrigName rdr_name
217 = getModeRn `thenRn` \ mode ->
218 if isInterfaceMode mode
219 then lookupIfaceName rdr_name
221 getModuleRn `thenRn` \ mod ->
222 getGlobalNameEnv `thenRn` \ global_env ->
223 case lookup_local mod global_env rdr_name of
224 Just name -> returnRn name
225 Nothing -> failWithRn (mkUnboundName rdr_name)
226 (unknownNameErr rdr_name)
228 lookup_local mod global_env rdr_name
229 = case lookupRdrEnv global_env rdr_name of
231 Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
236 -- lookupSigOccRn is used for type signatures and pragmas
242 -- It's clear that the 'f' in the signature must refer to A.f
243 -- The Haskell98 report does not stipulate this, but it will!
244 -- So we must treat the 'f' in the signature in the same way
245 -- as the binding occurrence of 'f', using lookupBndrRn
246 lookupSigOccRn :: RdrName -> RnMS Name
247 lookupSigOccRn = lookupBndrRn
249 -- lookupInstDeclBndr is used for the binders in an
250 -- instance declaration. Here we use the class name to
253 lookupInstDeclBndr :: Name -> RdrName -> RnMS Name
254 -- We use the selector name as the binder
255 lookupInstDeclBndr cls_name rdr_name
256 | isOrig rdr_name -- Occurs in derived instances, where we just
257 -- refer diectly to the right method
258 = lookupOrigName rdr_name
261 = getGlobalAvails `thenRn` \ avail_env ->
262 case lookupNameEnv avail_env cls_name of
263 -- The class itself isn't in scope, so cls_name is unboundName
264 -- e.g. import Prelude hiding( Ord )
265 -- instance Ord T where ...
266 -- The program is wrong, but that should not cause a crash.
267 Nothing -> returnRn (mkUnboundName rdr_name)
268 Just (AvailTC _ ns) -> case [n | n <- ns, nameOccName n == occ] of
269 (n:ns)-> ASSERT( null ns ) returnRn n
270 [] -> failWithRn (mkUnboundName rdr_name)
271 (unknownNameErr rdr_name)
272 other -> pprPanic "lookupInstDeclBndr" (ppr cls_name)
274 occ = rdrNameOcc rdr_name
276 -- lookupOccRn looks up an occurrence of a RdrName
277 lookupOccRn :: RdrName -> RnMS Name
279 = getLocalNameEnv `thenRn` \ local_env ->
280 case lookupRdrEnv local_env rdr_name of
281 Just name -> returnRn name
282 Nothing -> lookupGlobalOccRn rdr_name
284 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
285 -- environment. It's used only for
286 -- record field names
287 -- class op names in class and instance decls
289 lookupGlobalOccRn rdr_name
290 = getModeRn `thenRn` \ mode ->
291 if (isInterfaceMode mode)
292 then lookupIfaceName rdr_name
295 getGlobalNameEnv `thenRn` \ global_env ->
297 SourceMode -> lookupSrcName global_env rdr_name
300 | not (isQual rdr_name) ->
301 lookupSrcName global_env rdr_name
303 -- We allow qualified names on the command line to refer to
304 -- *any* name exported by any module in scope, just as if
305 -- there was an "import qualified M" declaration for every
308 -- First look up the name in the normal environment. If
309 -- it isn't there, we manufacture a new occurrence of an
312 case lookupRdrEnv global_env rdr_name of
313 Just _ -> lookupSrcName global_env rdr_name
314 Nothing -> lookupQualifiedName rdr_name
316 -- a qualified name on the command line can refer to any module at all: we
317 -- try to load the interface if we don't already have it.
318 lookupQualifiedName :: RdrName -> RnM d Name
319 lookupQualifiedName rdr_name
321 mod = rdrNameModule rdr_name
322 occ = rdrNameOcc rdr_name
324 loadInterface (ppr rdr_name) mod ImportByUser `thenRn` \ iface ->
325 case [ name | (_,avails) <- mi_exports iface,
327 name <- availNames avail,
328 nameOccName name == occ ] of
329 (n:ns) -> ASSERT (null ns) returnRn n
330 _ -> failWithRn (mkUnboundName rdr_name) (unknownNameErr rdr_name)
332 lookupSrcName :: GlobalRdrEnv -> RdrName -> RnM d Name
333 -- NB: passed GlobalEnv explicitly, not necessarily in RnMS monad
334 lookupSrcName global_env rdr_name
335 | isOrig rdr_name -- Can occur in source code too
336 = lookupOrigName rdr_name
339 = case lookupRdrEnv global_env rdr_name of
340 Just [GRE name _ Nothing] -> returnRn name
341 Just [GRE name _ (Just deprec)] -> warnDeprec name deprec `thenRn_`
343 Just stuff@(GRE name _ _ : _) -> addNameClashErrRn rdr_name stuff `thenRn_`
345 Nothing -> failWithRn (mkUnboundName rdr_name)
346 (unknownNameErr rdr_name)
348 lookupOrigName :: RdrName -> RnM d Name
349 lookupOrigName rdr_name
350 = ASSERT( isOrig rdr_name )
351 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
353 lookupIfaceUnqual :: RdrName -> RnM d Name
354 lookupIfaceUnqual rdr_name
355 = ASSERT( isUnqual rdr_name )
356 -- An Unqual is allowed; interface files contain
357 -- unqualified names for locally-defined things, such as
358 -- constructors of a data type.
359 getModuleRn `thenRn ` \ mod ->
360 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
362 lookupIfaceName :: RdrName -> RnM d Name
363 lookupIfaceName rdr_name
364 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
365 | otherwise = lookupOrigName rdr_name
368 @lookupOrigName@ takes an RdrName representing an {\em original}
369 name, and adds it to the occurrence pool so that it'll be loaded
370 later. This is used when language constructs (such as monad
371 comprehensions, overloaded literals, or deriving clauses) require some
372 stuff to be loaded that isn't explicitly mentioned in the code.
374 This doesn't apply in interface mode, where everything is explicit,
375 but we don't check for this case: it does no harm to record an
376 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
377 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
378 calls it at all I think).
380 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
383 lookupOrigNames :: [RdrName] -> RnM d NameSet
384 lookupOrigNames rdr_names
385 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
386 returnRn (mkNameSet names)
389 lookupSysBinder is used for the "system binders" of a type, class, or
390 instance decl. It ensures that the module is set correctly in the
391 name cache, and sets the provenance on the returned name too. The
392 returned name will end up actually in the type, class, or instance.
395 lookupSysBinder rdr_name
396 = ASSERT( isUnqual rdr_name )
397 getModuleRn `thenRn` \ mod ->
398 getSrcLocRn `thenRn` \ loc ->
399 newTopBinder mod rdr_name loc
403 %*********************************************************
405 \subsection{Implicit free vars and sugar names}
407 %*********************************************************
409 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
410 mentioned explicitly, but which might be needed by the type checker.
413 getImplicitStmtFVs -- Compiling a statement
414 = returnRn (mkFVs [printName, bindIOName, returnIOName, failIOName]
415 `plusFV` ubiquitousNames)
416 -- These are all needed implicitly when compiling a statement
417 -- See TcModule.tc_stmts
419 getImplicitModuleFVs decls -- Compiling a module
420 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
421 returnRn (deriving_names `plusFV` ubiquitousNames)
423 -- deriv_classes is now a list of HsTypes, so a "normal" one
424 -- appears as a (HsClassP c []). The non-normal ones for the new
425 -- newtype-deriving extension, and they don't require any
426 -- implicit names, so we can silently filter them out.
427 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
428 HsClassP cls [] <- deriv_classes,
429 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
431 -- ubiquitous_names are loaded regardless, because
432 -- they are needed in virtually every program
434 = mkFVs [unpackCStringName, unpackCStringFoldrName,
435 unpackCStringUtf8Name, eqStringName]
436 -- Virtually every program has error messages in it somewhere
439 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
440 -- Add occurrences for very frequently used types.
441 -- (e.g. we don't want to be bothered with making funTyCon a
442 -- free var at every function application!)
444 namesNeededForFlattening
445 -- this will be empty unless flattening is activated
447 checkMain ghci_mode mod_name gbl_env
448 -- LOOKUP main IF WE'RE IN MODULE Main
449 -- The main point of this is to drag in the declaration for 'main',
450 -- its in another module, and for the Prelude function 'runMain',
451 -- so that the type checker will find them
453 -- We have to return the main_name separately, because it's a
454 -- bona fide 'use', and should be recorded as such, but the others
456 | mod_name /= mAIN_Name
457 = returnRn (Nothing, emptyFVs, emptyFVs)
459 | not (main_RDR_Unqual `elemRdrEnv` gbl_env)
460 = complain_no_main `thenRn_`
461 returnRn (Nothing, emptyFVs, emptyFVs)
464 = lookupSrcName gbl_env main_RDR_Unqual `thenRn` \ main_name ->
465 returnRn (Just main_name, unitFV main_name, unitFV runMainName)
468 complain_no_main | ghci_mode == Interactive = addWarnRn noMainMsg
469 | otherwise = addErrRn noMainMsg
470 -- In interactive mode, only warn about the absence of main
473 %************************************************************************
475 \subsection{Re-bindable desugaring names}
477 %************************************************************************
479 Haskell 98 says that when you say "3" you get the "fromInteger" from the
480 Standard Prelude, regardless of what is in scope. However, to experiment
481 with having a language that is less coupled to the standard prelude, we're
482 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
483 happens to be in scope. Then you can
485 import MyPrelude as Prelude
486 to get the desired effect.
488 At the moment this just happens for
489 * fromInteger, fromRational on literals (in expressions and patterns)
490 * negate (in expressions)
491 * minus (arising from n+k patterns)
493 We store the relevant Name in the HsSyn tree, in
494 * HsIntegral/HsFractional
497 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
498 fromRationalName etc), but the renamer changes this to the appropriate user
499 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
502 lookupSyntaxName :: Name -- The standard name
503 -> RnMS Name -- Possibly a non-standard name
504 lookupSyntaxName std_name
505 = doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
506 if not no_prelude then
507 returnRn std_name -- Normal case
510 rdr_name = mkRdrUnqual (nameOccName std_name)
511 -- Get the similarly named thing from the local environment
517 %*********************************************************
521 %*********************************************************
524 newLocalsRn :: [(RdrName,SrcLoc)]
526 newLocalsRn rdr_names_w_loc
527 = getNameSupplyRn `thenRn` \ name_supply ->
529 (us', us1) = splitUniqSupply (nsUniqs name_supply)
530 uniqs = uniqsFromSupply us1
531 names = [ mkInternalName uniq (rdrNameOcc rdr_name) loc
532 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
535 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
539 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
540 -> [(RdrName,SrcLoc)]
541 -> ([Name] -> RnMS a)
543 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
544 = getModeRn `thenRn` \ mode ->
545 getLocalNameEnv `thenRn` \ local_env ->
546 getGlobalNameEnv `thenRn` \ global_env ->
548 -- Check for duplicate names
549 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
551 -- Warn about shadowing, but only in source modules
553 check_shadow (rdr_name,loc)
554 | rdr_name `elemRdrEnv` local_env
555 || rdr_name `elemRdrEnv` global_env
556 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
562 SourceMode -> ifOptRn Opt_WarnNameShadowing $
563 mapRn_ check_shadow rdr_names_w_loc
567 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
569 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
571 setLocalNameEnv new_local_env (enclosed_scope names)
573 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
574 -- A specialised variant when renaming stuff from interface
575 -- files (of which there is a lot)
577 -- * no checks for shadowing
579 -- * deal with free vars
580 bindCoreLocalRn rdr_name enclosed_scope
581 = getSrcLocRn `thenRn` \ loc ->
582 getLocalNameEnv `thenRn` \ name_env ->
583 getNameSupplyRn `thenRn` \ name_supply ->
585 (us', us1) = splitUniqSupply (nsUniqs name_supply)
586 uniq = uniqFromSupply us1
587 name = mkInternalName uniq (rdrNameOcc rdr_name) loc
589 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
591 new_name_env = extendRdrEnv name_env rdr_name name
593 setLocalNameEnv new_name_env (enclosed_scope name)
595 bindCoreLocalsRn [] thing_inside = thing_inside []
596 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
597 bindCoreLocalsRn bs $ \ names' ->
598 thing_inside (name':names')
600 bindLocalNames names enclosed_scope
601 = getLocalNameEnv `thenRn` \ name_env ->
602 setLocalNameEnv (extendLocalRdrEnv name_env names)
605 bindLocalNamesFV names enclosed_scope
606 = bindLocalNames names $
607 enclosed_scope `thenRn` \ (thing, fvs) ->
608 returnRn (thing, delListFromNameSet fvs names)
611 -------------------------------------
612 bindLocalRn doc rdr_name enclosed_scope
613 = getSrcLocRn `thenRn` \ loc ->
614 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
618 bindLocalsRn doc rdr_names enclosed_scope
619 = getSrcLocRn `thenRn` \ loc ->
620 bindLocatedLocalsRn doc
621 (rdr_names `zip` repeat loc)
624 -- binLocalsFVRn is the same as bindLocalsRn
625 -- except that it deals with free vars
626 bindLocalsFVRn doc rdr_names enclosed_scope
627 = bindLocalsRn doc rdr_names $ \ names ->
628 enclosed_scope names `thenRn` \ (thing, fvs) ->
629 returnRn (thing, delListFromNameSet fvs names)
631 -------------------------------------
632 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
633 -- This tiresome function is used only in rnSourceDecl on InstDecl
634 extendTyVarEnvFVRn tyvars enclosed_scope
635 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
636 returnRn (thing, delListFromNameSet fvs tyvars)
638 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
639 -> ([HsTyVarBndr Name] -> RnMS a)
641 bindTyVarsRn doc_str tyvar_names enclosed_scope
642 = getSrcLocRn `thenRn` \ loc ->
644 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
646 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
647 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
649 bindPatSigTyVars :: [RdrNameHsType]
650 -> RnMS (a, FreeVars)
651 -> RnMS (a, FreeVars)
652 -- Find the type variables in the pattern type
653 -- signatures that must be brought into scope
655 bindPatSigTyVars tys enclosed_scope
656 = getLocalNameEnv `thenRn` \ name_env ->
657 getSrcLocRn `thenRn` \ loc ->
659 forall_tyvars = nub [ tv | ty <- tys,
660 tv <- extractHsTyRdrTyVars ty,
661 not (tv `elemFM` name_env)
663 -- The 'nub' is important. For example:
664 -- f (x :: t) (y :: t) = ....
665 -- We don't want to complain about binding t twice!
667 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
668 doc_sig = text "In a pattern type-signature"
670 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
671 enclosed_scope `thenRn` \ (thing, fvs) ->
672 returnRn (thing, delListFromNameSet fvs names)
675 -------------------------------------
676 checkDupOrQualNames, checkDupNames :: SDoc
677 -> [(RdrName, SrcLoc)]
679 -- Works in any variant of the renamer monad
681 checkDupOrQualNames doc_str rdr_names_w_loc
682 = -- Check for use of qualified names
683 mapRn_ (qualNameErr doc_str) quals `thenRn_`
684 checkDupNames doc_str rdr_names_w_loc
686 quals = filter (isQual . fst) rdr_names_w_loc
688 checkDupNames doc_str rdr_names_w_loc
689 = -- Check for duplicated names in a binding group
690 mapRn_ (dupNamesErr doc_str) dups
692 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
696 %************************************************************************
698 \subsection{GlobalRdrEnv}
700 %************************************************************************
703 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
704 -> Bool -- True <=> want unqualified import
705 -> (Name -> Provenance)
706 -> Avails -- Whats imported
710 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
713 -- Make the name environment. We're talking about a
714 -- single module here, so there must be no name clashes.
715 -- In practice there only ever will be if it's the module
718 -- Add qualified names for the things that are available
719 -- (Qualified names are always imported)
720 gbl_env1 = foldl add_avail emptyRdrEnv avails
722 -- Add unqualified names
723 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
724 | otherwise = gbl_env1
726 add_unqual env (qual_name, elts)
727 = foldl add_one env elts
729 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
730 unqual_name = unqualifyRdrName qual_name
731 -- The qualified import should only have added one
732 -- binding for each qualified name! But if there's an error in
733 -- the module (multiple bindings for the same name) we may get
734 -- duplicates. So the simple thing is to do the fold.
736 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
737 add_avail env avail = foldl add_name env (availNames avail)
739 add_name env name -- Add qualified name only
740 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
742 occ = nameOccName name
743 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
747 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
748 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
750 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
751 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
753 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
754 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
756 combine_globals :: [GlobalRdrElt] -- Old
757 -> [GlobalRdrElt] -- New
759 combine_globals ns_old ns_new -- ns_new is often short
760 = foldr add ns_old ns_new
762 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
765 choose n m | n `beats` m = n
768 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
770 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
771 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
772 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
775 We treat two bindings of a locally-defined name as a duplicate,
776 because they might be two separate, local defns and we want to report
777 and error for that, {\em not} eliminate a duplicate.
779 On the other hand, if you import the same name from two different
780 import statements, we {\em do} want to eliminate the duplicate, not report
783 If a module imports itself then there might be a local defn and an imported
784 defn of the same name; in this case the names will compare as equal, but
785 will still have different provenances.
788 @unQualInScope@ returns a function that takes a @Name@ and tells whether
789 its unqualified name is in scope. This is put as a boolean flag in
790 the @Name@'s provenance to guide whether or not to print the name qualified
794 unQualInScope :: GlobalRdrEnv -> Name -> Bool
795 -- True if 'f' is in scope, and has only one binding,
796 -- and the thing it is bound to is the name we are looking for
797 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
799 -- This fn is only efficient if the shared
800 -- partial application is used a lot.
802 = (`elemNameSet` unqual_names)
804 unqual_names :: NameSet
805 unqual_names = foldRdrEnv add emptyNameSet env
806 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
807 add _ _ unquals = unquals
811 %************************************************************************
815 %************************************************************************
818 plusAvail (Avail n1) (Avail n2) = Avail n1
819 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
822 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
825 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
826 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
828 unitAvailEnv :: AvailInfo -> AvailEnv
829 unitAvailEnv a = unitNameEnv (availName a) a
831 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
832 plusAvailEnv = plusNameEnv_C plusAvail
834 availEnvElts = nameEnvElts
836 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
837 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
839 availsToNameSet :: [AvailInfo] -> NameSet
840 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
842 availName :: GenAvailInfo name -> name
843 availName (Avail n) = n
844 availName (AvailTC n _) = n
846 availNames :: GenAvailInfo name -> [name]
847 availNames (Avail n) = [n]
848 availNames (AvailTC n ns) = ns
850 -------------------------------------
851 filterAvail :: RdrNameIE -- Wanted
852 -> AvailInfo -- Available
853 -> Maybe AvailInfo -- Resulting available;
854 -- Nothing if (any of the) wanted stuff isn't there
856 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
857 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
858 | otherwise = Nothing
860 is_wanted name = nameOccName name `elem` wanted_occs
861 sub_names_ok = all (`elem` avail_occs) wanted_occs
862 avail_occs = map nameOccName ns
863 wanted_occs = map rdrNameOcc (want:wants)
865 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
868 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
870 filterAvail (IEVar _) avail@(Avail n) = Just avail
871 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
873 wanted n = nameOccName n == occ
875 -- The second equation happens if we import a class op, thus
877 -- where op is a class operation
879 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
880 -- We don't complain even if the IE says T(..), but
881 -- no constrs/class ops of T are available
882 -- Instead that's caught with a warning by the caller
884 filterAvail ie avail = Nothing
886 -------------------------------------
887 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
888 -- Group by module and sort by occurrence
889 -- This keeps the list in canonical order
890 groupAvails this_mod avails
891 = [ (mkSysModuleNameFS fs, sortLt lt avails)
892 | (fs,avails) <- fmToList groupFM
895 groupFM :: FiniteMap FastString Avails
896 -- Deliberately use the FastString so we
897 -- get a canonical ordering
898 groupFM = foldl add emptyFM avails
900 add env avail = addToFM_C combine env mod_fs [avail']
902 mod_fs = moduleNameFS (moduleName avail_mod)
903 avail_mod = case nameModule_maybe (availName avail) of
906 combine old _ = avail':old
907 avail' = sortAvail avail
909 a1 `lt` a2 = occ1 < occ2
911 occ1 = nameOccName (availName a1)
912 occ2 = nameOccName (availName a2)
914 sortAvail :: AvailInfo -> AvailInfo
915 -- Sort the sub-names into canonical order.
916 -- The canonical order has the "main name" at the beginning
917 -- (if it's there at all)
918 sortAvail (Avail n) = Avail n
919 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
920 | otherwise = AvailTC n ( sortLt lt ns)
922 n1 `lt` n2 = nameOccName n1 < nameOccName n2
926 pruneAvails :: (Name -> Bool) -- Keep if this is True
929 pruneAvails keep avails
930 = mapMaybe del avails
932 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
933 del (Avail n) | keep n = Just (Avail n)
934 | otherwise = Nothing
935 del (AvailTC n ns) | null ns' = Nothing
936 | otherwise = Just (AvailTC n ns')
941 %************************************************************************
943 \subsection{Free variable manipulation}
945 %************************************************************************
949 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
951 (ys, fvs_s) = unzip stuff
953 returnRn (ys, plusFVs fvs_s)
957 %************************************************************************
959 \subsection{Envt utility functions}
961 %************************************************************************
964 warnUnusedModules :: [ModuleName] -> RnM d ()
965 warnUnusedModules mods
966 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
968 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
969 text "is imported, but nothing from it is used",
970 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
973 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
974 warnUnusedImports names
975 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
977 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
978 warnUnusedLocalBinds names
979 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
981 warnUnusedMatches names
982 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
984 -------------------------
986 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
987 warnUnusedBinds names
988 = mapRn_ warnUnusedGroup groups
990 -- Group by provenance
991 groups = equivClasses cmp names
992 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
995 -------------------------
997 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
998 warnUnusedGroup names
999 | null filtered_names = returnRn ()
1000 | not is_local = returnRn ()
1002 = pushSrcLocRn def_loc $
1004 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
1006 filtered_names = filter reportable names
1007 (name1, prov1) = head filtered_names
1008 (is_local, def_loc, msg)
1010 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
1012 NonLocalDef (UserImport mod loc _)
1013 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
1015 reportable (name,_) = case occNameUserString (nameOccName name) of
1018 -- Haskell 98 encourages compilers to suppress warnings about
1019 -- unused names in a pattern if they start with "_".
1023 addNameClashErrRn rdr_name (np1:nps)
1024 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1025 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1027 msg1 = ptext SLIT("either") <+> mk_ref np1
1028 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1029 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1031 shadowedNameWarn shadow
1032 = hsep [ptext SLIT("This binding for"),
1033 quotes (ppr shadow),
1034 ptext SLIT("shadows an existing binding")]
1036 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1039 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1041 flavour = occNameFlavour (rdrNameOcc name)
1043 qualNameErr descriptor (name,loc)
1044 = pushSrcLocRn loc $
1045 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1048 dupNamesErr descriptor ((name,loc) : dup_things)
1049 = pushSrcLocRn loc $
1050 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1054 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1056 = ifOptRn Opt_WarnDeprecations $
1057 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1058 quotes (ppr name) <+> text "is deprecated:",