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
14 import RdrHsSyn ( RdrNameIE )
15 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
16 mkRdrUnqual, mkRdrQual, lookupRdrEnv, foldRdrEnv, rdrEnvToList,
19 import HsTypes ( hsTyVarName, replaceTyVarName )
20 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
21 ImportReason(..), GlobalRdrEnv, GlobalRdrElt(..), AvailEnv,
22 AvailInfo, Avails, GenAvailInfo(..), NameSupply(..),
24 Deprecations(..), lookupDeprec,
29 getSrcLoc, nameIsLocalOrFrom,
30 mkLocalName, mkGlobalName,
31 mkIPName, nameOccName, nameModule_maybe,
36 import OccName ( OccName, occNameUserString, occNameFlavour )
37 import Module ( ModuleName, moduleName, mkVanillaModule,
38 mkSysModuleNameFS, moduleNameFS, WhereFrom(..) )
39 import PrelNames ( mkUnboundName,
41 mAIN_Name, pREL_MAIN_Name,
42 ioTyConName, intTyConName,
43 boolTyConName, funTyConName,
44 unpackCStringName, unpackCStringFoldrName, unpackCStringUtf8Name,
45 eqStringName, printName,
46 bindIOName, returnIOName, failIOName
48 import TysWiredIn ( unitTyCon ) -- A little odd
51 import SrcLoc ( SrcLoc, noSrcLoc )
53 import ListSetOps ( removeDups, equivClasses )
54 import Util ( sortLt )
56 import UniqFM ( lookupWithDefaultUFM )
57 import Maybes ( orElse )
59 import FastString ( FastString )
62 %*********************************************************
64 \subsection{Making new names}
66 %*********************************************************
69 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
70 -- newTopBinder puts into the cache the binder with the
71 -- module information set correctly. When the decl is later renamed,
72 -- the binding site will thereby get the correct module.
73 -- There maybe occurrences that don't have the correct Module, but
74 -- by the typechecker will propagate the binding definition to all
75 -- the occurrences, so that doesn't matter
77 newTopBinder mod rdr_name loc
78 = -- First check the cache
80 -- There should never be a qualified name in a binding position (except in instance decls)
81 -- The parser doesn't check this because the same parser parses instance decls
82 (if isQual rdr_name then
83 qualNameErr (text "its declaration") (rdr_name,loc)
88 getNameSupplyRn `thenRn` \ name_supply ->
90 occ = rdrNameOcc rdr_name
91 key = (moduleName mod, occ)
92 cache = nsNames name_supply
94 case lookupFM cache key of
96 -- A hit in the cache! We are at the binding site of the name, and
97 -- this is the moment when we know all about
98 -- a) the Name's host Module (in particular, which
99 -- package it comes from)
100 -- b) its defining SrcLoc
101 -- So we update this info
104 new_name = setNameModuleAndLoc name mod loc
105 new_cache = addToFM cache key new_name
107 setNameSupplyRn (name_supply {nsNames = new_cache}) `thenRn_`
108 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
111 -- Miss in the cache!
112 -- Build a completely new Name, and put it in the cache
113 -- Even for locally-defined names we use implicitImportProvenance;
114 -- updateProvenances will set it to rights
116 (us', us1) = splitUniqSupply (nsUniqs name_supply)
117 uniq = uniqFromSupply us1
118 new_name = mkGlobalName uniq mod occ loc
119 new_cache = addToFM cache key new_name
121 setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
122 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
126 newGlobalName :: ModuleName -> OccName -> RnM d Name
127 -- Used for *occurrences*. We make a place-holder Name, really just
128 -- to agree on its unique, which gets overwritten when we read in
129 -- the binding occurence later (newTopBinder)
130 -- The place-holder Name doesn't have the right SrcLoc, and its
131 -- Module won't have the right Package either.
133 -- (We have to pass a ModuleName, not a Module, because we may be
134 -- simply looking at an occurrence M.x in an interface file.)
136 -- This means that a renamed program may have incorrect info
137 -- on implicitly-imported occurrences, but the correct info on the
138 -- *binding* declaration. It's the type checker that propagates the
139 -- correct information to all the occurrences.
140 -- Since implicitly-imported names never occur in error messages,
141 -- it doesn't matter that we get the correct info in place till later,
142 -- (but since it affects DLL-ery it does matter that we get it right
144 newGlobalName mod_name occ
145 = getNameSupplyRn `thenRn` \ name_supply ->
147 key = (mod_name, occ)
148 cache = nsNames name_supply
150 case lookupFM cache key of
151 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
154 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
155 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
158 (us', us1) = splitUniqSupply (nsUniqs name_supply)
159 uniq = uniqFromSupply us1
160 mod = mkVanillaModule mod_name
161 name = mkGlobalName uniq mod occ noSrcLoc
162 new_cache = addToFM cache key name
165 = getNameSupplyRn `thenRn` \ name_supply ->
167 ipcache = nsIPs name_supply
169 case lookupFM ipcache key of
170 Just name -> returnRn name
171 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsIPs = new_ipcache}) `thenRn_`
174 (us', us1) = splitUniqSupply (nsUniqs name_supply)
175 uniq = uniqFromSupply us1
176 name = mkIPName uniq key
177 new_ipcache = addToFM ipcache key name
178 where key = (rdrNameOcc rdr_name)
181 %*********************************************************
183 \subsection{Looking up names}
185 %*********************************************************
187 Looking up a name in the RnEnv.
190 lookupBndrRn rdr_name
191 = getLocalNameEnv `thenRn` \ local_env ->
192 case lookupRdrEnv local_env rdr_name of
193 Just name -> returnRn name
194 Nothing -> lookupTopBndrRn rdr_name
196 lookupTopBndrRn rdr_name
197 -- Look up a top-level local binder. We may be looking up an unqualified 'f',
198 -- and there may be several imported 'f's too, which must not confuse us.
199 -- So we have to filter out the non-local ones.
200 -- A separate function (importsFromLocalDecls) reports duplicate top level
201 -- decls, so here it's safe just to choose an arbitrary one.
204 -- This is here just to catch the PrelBase defn of (say) [] and similar
205 -- The parser reads the special syntax and returns an Orig RdrName
206 -- But the global_env contains only Qual RdrNames, so we won't
207 -- find it there; instead just get the name via the Orig route
208 = lookupOrigName rdr_name
211 = getModeRn `thenRn` \ mode ->
212 if isInterfaceMode mode
213 then lookupIfaceName rdr_name
215 getModuleRn `thenRn` \ mod ->
216 getGlobalNameEnv `thenRn` \ global_env ->
217 case lookup_local mod global_env rdr_name of
218 Just name -> returnRn name
219 Nothing -> failWithRn (mkUnboundName rdr_name)
220 (unknownNameErr rdr_name)
222 lookup_local mod global_env rdr_name
223 = case lookupRdrEnv global_env rdr_name of
225 Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
230 -- lookupSigOccRn is used for type signatures and pragmas
236 -- It's clear that the 'f' in the signature must refer to A.f
237 -- The Haskell98 report does not stipulate this, but it will!
238 -- So we must treat the 'f' in the signature in the same way
239 -- as the binding occurrence of 'f', using lookupBndrRn
240 lookupSigOccRn :: RdrName -> RnMS Name
241 lookupSigOccRn = lookupBndrRn
243 -- lookupOccRn looks up an occurrence of a RdrName
244 lookupOccRn :: RdrName -> RnMS Name
246 = getLocalNameEnv `thenRn` \ local_env ->
247 case lookupRdrEnv local_env rdr_name of
248 Just name -> returnRn name
249 Nothing -> lookupGlobalOccRn rdr_name
251 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
252 -- environment. It's used only for
253 -- record field names
254 -- class op names in class and instance decls
256 lookupGlobalOccRn rdr_name
257 = getModeRn `thenRn` \ mode ->
258 if (isInterfaceMode mode)
259 then lookupIfaceName rdr_name
262 getGlobalNameEnv `thenRn` \ global_env ->
264 SourceMode -> lookupSrcName global_env rdr_name
267 | not (isQual rdr_name) ->
268 lookupSrcName global_env rdr_name
270 -- We allow qualified names on the command line to refer to
271 -- *any* name exported by any module in scope, just as if
272 -- there was an "import qualified M" declaration for every
275 -- First look up the name in the normal environment. If
276 -- it isn't there, we manufacture a new occurrence of an
279 case lookupRdrEnv global_env rdr_name of
280 Just _ -> lookupSrcName global_env rdr_name
281 Nothing -> lookupQualifiedName rdr_name
283 -- a qualified name on the command line can refer to any module at all: we
284 -- try to load the interface if we don't already have it.
285 lookupQualifiedName :: RdrName -> RnM d Name
286 lookupQualifiedName rdr_name
288 mod = rdrNameModule rdr_name
289 occ = rdrNameOcc rdr_name
291 loadInterface (ppr rdr_name) mod ImportByUser `thenRn` \ iface ->
292 case [ name | (_,avails) <- mi_exports iface,
294 name <- availNames avail,
295 nameOccName name == occ ] of
296 (n:ns) -> ASSERT (null ns) returnRn n
297 _ -> failWithRn (mkUnboundName rdr_name) (unknownNameErr rdr_name)
299 lookupSrcName :: GlobalRdrEnv -> RdrName -> RnM d Name
300 -- NB: passed GlobalEnv explicitly, not necessarily in RnMS monad
301 lookupSrcName global_env rdr_name
302 | isOrig rdr_name -- Can occur in source code too
303 = lookupOrigName rdr_name
306 = case lookupRdrEnv global_env rdr_name of
307 Just [GRE name _ Nothing] -> returnRn name
308 Just [GRE name _ (Just deprec)] -> warnDeprec name deprec `thenRn_`
310 Just stuff@(GRE name _ _ : _) -> addNameClashErrRn rdr_name stuff `thenRn_`
312 Nothing -> failWithRn (mkUnboundName rdr_name)
313 (unknownNameErr rdr_name)
315 lookupOrigName :: RdrName -> RnM d Name
316 lookupOrigName rdr_name
317 = ASSERT( isOrig rdr_name )
318 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
320 lookupIfaceUnqual :: RdrName -> RnM d Name
321 lookupIfaceUnqual rdr_name
322 = ASSERT( isUnqual rdr_name )
323 -- An Unqual is allowed; interface files contain
324 -- unqualified names for locally-defined things, such as
325 -- constructors of a data type.
326 getModuleRn `thenRn ` \ mod ->
327 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
329 lookupIfaceName :: RdrName -> RnM d Name
330 lookupIfaceName rdr_name
331 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
332 | otherwise = lookupOrigName rdr_name
335 @lookupOrigName@ takes an RdrName representing an {\em original}
336 name, and adds it to the occurrence pool so that it'll be loaded
337 later. This is used when language constructs (such as monad
338 comprehensions, overloaded literals, or deriving clauses) require some
339 stuff to be loaded that isn't explicitly mentioned in the code.
341 This doesn't apply in interface mode, where everything is explicit,
342 but we don't check for this case: it does no harm to record an
343 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
344 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
345 calls it at all I think).
347 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
350 lookupOrigNames :: [RdrName] -> RnM d NameSet
351 lookupOrigNames rdr_names
352 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
353 returnRn (mkNameSet names)
356 lookupSysBinder is used for the "system binders" of a type, class, or
357 instance decl. It ensures that the module is set correctly in the
358 name cache, and sets the provenance on the returned name too. The
359 returned name will end up actually in the type, class, or instance.
362 lookupSysBinder rdr_name
363 = ASSERT( isUnqual rdr_name )
364 getModuleRn `thenRn` \ mod ->
365 getSrcLocRn `thenRn` \ loc ->
366 newTopBinder mod rdr_name loc
370 %*********************************************************
372 \subsection{Implicit free vars and sugar names}
374 %*********************************************************
376 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
377 mentioned explicitly, but which might be needed by the type checker.
380 getImplicitStmtFVs -- Compiling a statement
381 = returnRn (mkFVs [printName, bindIOName, returnIOName, failIOName]
382 `plusFV` ubiquitousNames)
383 -- These are all needed implicitly when compiling a statement
384 -- See TcModule.tc_stmts
386 getImplicitModuleFVs mod_name decls -- Compiling a module
387 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
388 returnRn (deriving_names `plusFV` implicit_main `plusFV` ubiquitousNames)
390 -- Add occurrences for IO or PrimIO
391 implicit_main | mod_name == mAIN_Name
392 || mod_name == pREL_MAIN_Name = unitFV ioTyConName
393 | otherwise = emptyFVs
395 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
396 cls <- deriv_classes,
397 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
399 -- ubiquitous_names are loaded regardless, because
400 -- they are needed in virtually every program
402 = mkFVs [unpackCStringName, unpackCStringFoldrName,
403 unpackCStringUtf8Name, eqStringName]
404 -- Virtually every program has error messages in it somewhere
407 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
408 -- Add occurrences for very frequently used types.
409 -- (e.g. we don't want to be bothered with making funTyCon a
410 -- free var at every function application!)
413 %************************************************************************
415 \subsection{Re-bindable desugaring names}
417 %************************************************************************
419 Haskell 98 says that when you say "3" you get the "fromInteger" from the
420 Standard Prelude, regardless of what is in scope. However, to experiment
421 with having a language that is less coupled to the standard prelude, we're
422 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
423 happens to be in scope. Then you can
425 import MyPrelude as Prelude
426 to get the desired effect.
428 At the moment this just happens for
429 * fromInteger, fromRational on literals (in expressions and patterns)
430 * negate (in expressions)
431 * minus (arising from n+k patterns)
433 We store the relevant Name in the HsSyn tree, in
434 * HsIntegral/HsFractional
437 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
438 fromRationalName etc), but the renamer changes this to the appropriate user
439 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
442 lookupSyntaxName :: Name -- The standard name
443 -> RnMS Name -- Possibly a non-standard name
444 lookupSyntaxName std_name
445 = doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
446 if not no_prelude then
447 returnRn std_name -- Normal case
450 rdr_name = mkRdrUnqual (nameOccName std_name)
451 -- Get the similarly named thing from the local environment
457 %*********************************************************
461 %*********************************************************
464 newLocalsRn :: [(RdrName,SrcLoc)]
466 newLocalsRn rdr_names_w_loc
467 = getNameSupplyRn `thenRn` \ name_supply ->
469 (us', us1) = splitUniqSupply (nsUniqs name_supply)
470 uniqs = uniqsFromSupply us1
471 names = [ mkLocalName uniq (rdrNameOcc rdr_name) loc
472 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
475 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
479 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
480 -> [(RdrName,SrcLoc)]
481 -> ([Name] -> RnMS a)
483 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
484 = getModeRn `thenRn` \ mode ->
485 getLocalNameEnv `thenRn` \ name_env ->
487 -- Check for duplicate names
488 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
490 -- Warn about shadowing, but only in source modules
492 SourceMode -> ifOptRn Opt_WarnNameShadowing $
493 mapRn_ (check_shadow name_env) rdr_names_w_loc
497 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
499 new_local_env = addListToRdrEnv name_env (map fst rdr_names_w_loc `zip` names)
501 setLocalNameEnv new_local_env (enclosed_scope names)
504 check_shadow name_env (rdr_name,loc)
505 = case lookupRdrEnv name_env rdr_name of
506 Nothing -> returnRn ()
507 Just name -> pushSrcLocRn loc $
508 addWarnRn (shadowedNameWarn rdr_name)
510 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
511 -- A specialised variant when renaming stuff from interface
512 -- files (of which there is a lot)
514 -- * no checks for shadowing
516 -- * deal with free vars
517 bindCoreLocalRn rdr_name enclosed_scope
518 = getSrcLocRn `thenRn` \ loc ->
519 getLocalNameEnv `thenRn` \ name_env ->
520 getNameSupplyRn `thenRn` \ name_supply ->
522 (us', us1) = splitUniqSupply (nsUniqs name_supply)
523 uniq = uniqFromSupply us1
524 name = mkLocalName uniq (rdrNameOcc rdr_name) loc
526 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
528 new_name_env = extendRdrEnv name_env rdr_name name
530 setLocalNameEnv new_name_env (enclosed_scope name)
532 bindCoreLocalsRn [] thing_inside = thing_inside []
533 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
534 bindCoreLocalsRn bs $ \ names' ->
535 thing_inside (name':names')
537 bindLocalNames names enclosed_scope
538 = getLocalNameEnv `thenRn` \ name_env ->
539 setLocalNameEnv (extendLocalRdrEnv name_env names)
542 bindLocalNamesFV names enclosed_scope
543 = bindLocalNames names $
544 enclosed_scope `thenRn` \ (thing, fvs) ->
545 returnRn (thing, delListFromNameSet fvs names)
548 -------------------------------------
549 bindLocalRn doc rdr_name enclosed_scope
550 = getSrcLocRn `thenRn` \ loc ->
551 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
555 bindLocalsRn doc rdr_names enclosed_scope
556 = getSrcLocRn `thenRn` \ loc ->
557 bindLocatedLocalsRn doc
558 (rdr_names `zip` repeat loc)
561 -- binLocalsFVRn is the same as bindLocalsRn
562 -- except that it deals with free vars
563 bindLocalsFVRn doc rdr_names enclosed_scope
564 = bindLocalsRn doc rdr_names $ \ names ->
565 enclosed_scope names `thenRn` \ (thing, fvs) ->
566 returnRn (thing, delListFromNameSet fvs names)
568 -------------------------------------
569 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
570 -- This tiresome function is used only in rnSourceDecl on InstDecl
571 extendTyVarEnvFVRn tyvars enclosed_scope
572 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
573 returnRn (thing, delListFromNameSet fvs tyvars)
575 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
576 -> ([HsTyVarBndr Name] -> RnMS a)
578 bindTyVarsRn doc_str tyvar_names enclosed_scope
579 = bindTyVars2Rn doc_str tyvar_names $ \ names tyvars ->
580 enclosed_scope tyvars
582 -- Gruesome name: return Names as well as HsTyVars
583 bindTyVars2Rn :: SDoc -> [HsTyVarBndr RdrName]
584 -> ([Name] -> [HsTyVarBndr Name] -> RnMS a)
586 bindTyVars2Rn doc_str tyvar_names enclosed_scope
587 = getSrcLocRn `thenRn` \ loc ->
589 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
591 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
592 enclosed_scope names (zipWith replaceTyVarName tyvar_names names)
594 bindTyVarsFVRn :: SDoc -> [HsTyVarBndr RdrName]
595 -> ([HsTyVarBndr Name] -> RnMS (a, FreeVars))
596 -> RnMS (a, FreeVars)
597 bindTyVarsFVRn doc_str rdr_names enclosed_scope
598 = bindTyVars2Rn doc_str rdr_names $ \ names tyvars ->
599 enclosed_scope tyvars `thenRn` \ (thing, fvs) ->
600 returnRn (thing, delListFromNameSet fvs names)
602 bindTyVarsFV2Rn :: SDoc -> [HsTyVarBndr RdrName]
603 -> ([Name] -> [HsTyVarBndr Name] -> RnMS (a, FreeVars))
604 -> RnMS (a, FreeVars)
605 bindTyVarsFV2Rn doc_str rdr_names enclosed_scope
606 = bindTyVars2Rn doc_str rdr_names $ \ names tyvars ->
607 enclosed_scope names tyvars `thenRn` \ (thing, fvs) ->
608 returnRn (thing, delListFromNameSet fvs names)
610 bindNakedTyVarsFVRn :: SDoc -> [RdrName]
611 -> ([Name] -> RnMS (a, FreeVars))
612 -> RnMS (a, FreeVars)
613 bindNakedTyVarsFVRn doc_str tyvar_names enclosed_scope
614 = getSrcLocRn `thenRn` \ loc ->
616 located_tyvars = [(tv, loc) | tv <- tyvar_names]
618 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
619 enclosed_scope names `thenRn` \ (thing, fvs) ->
620 returnRn (thing, delListFromNameSet fvs names)
623 -------------------------------------
624 checkDupOrQualNames, checkDupNames :: SDoc
625 -> [(RdrName, SrcLoc)]
627 -- Works in any variant of the renamer monad
629 checkDupOrQualNames doc_str rdr_names_w_loc
630 = -- Check for use of qualified names
631 mapRn_ (qualNameErr doc_str) quals `thenRn_`
632 checkDupNames doc_str rdr_names_w_loc
634 quals = filter (isQual . fst) rdr_names_w_loc
636 checkDupNames doc_str rdr_names_w_loc
637 = -- Check for duplicated names in a binding group
638 mapRn_ (dupNamesErr doc_str) dups
640 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
644 %************************************************************************
646 \subsection{GlobalRdrEnv}
648 %************************************************************************
651 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
652 -> Bool -- True <=> want unqualified import
653 -> (Name -> Provenance)
654 -> Avails -- Whats imported
655 -> Avails -- What's to be hidden
656 -- I.e. import (imports - hides)
660 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails hides deprecs
663 -- Make the name environment. We're talking about a
664 -- single module here, so there must be no name clashes.
665 -- In practice there only ever will be if it's the module
668 -- Add qualified names for the things that are available
669 -- (Qualified names are always imported)
670 gbl_env1 = foldl add_avail emptyRdrEnv avails
672 -- Delete (qualified names of) things that are hidden
673 gbl_env2 = foldl del_avail gbl_env1 hides
675 -- Add unqualified names
676 gbl_env3 | unqual_imp = foldl add_unqual gbl_env2 (rdrEnvToList gbl_env2)
677 | otherwise = gbl_env2
679 add_unqual env (qual_name, elts)
680 = foldl add_one env elts
682 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
683 unqual_name = unqualifyRdrName qual_name
684 -- The qualified import should only have added one
685 -- binding for each qualified name! But if there's an error in
686 -- the module (multiple bindings for the same name) we may get
687 -- duplicates. So the simple thing is to do the fold.
690 = foldl delOneFromGlobalRdrEnv env rdr_names
692 rdr_names = map (mkRdrQual this_mod . nameOccName)
696 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
697 add_avail env avail = foldl add_name env (availNames avail)
699 add_name env name -- Add qualified name only
700 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
702 occ = nameOccName name
703 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
705 mkIfaceGlobalRdrEnv :: [(ModuleName,Avails)] -> GlobalRdrEnv
706 -- Used to construct a GlobalRdrEnv for an interface that we've
707 -- read from a .hi file. We can't construct the original top-level
708 -- environment because we don't have enough info, but we compromise
709 -- by making an environment from its exports
710 mkIfaceGlobalRdrEnv m_avails
711 = foldl add emptyRdrEnv m_avails
713 add env (mod,avails) = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True
714 (\n -> LocalDef) avails [] NoDeprecs)
715 -- The NoDeprecs is a bit of a hack I suppose
719 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
720 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
722 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
723 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
725 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
726 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
728 combine_globals :: [GlobalRdrElt] -- Old
729 -> [GlobalRdrElt] -- New
731 combine_globals ns_old ns_new -- ns_new is often short
732 = foldr add ns_old ns_new
734 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
737 choose n m | n `beats` m = n
740 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
742 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
743 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
744 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
747 We treat two bindings of a locally-defined name as a duplicate,
748 because they might be two separate, local defns and we want to report
749 and error for that, {\em not} eliminate a duplicate.
751 On the other hand, if you import the same name from two different
752 import statements, we {\em do} want to eliminate the duplicate, not report
755 If a module imports itself then there might be a local defn and an imported
756 defn of the same name; in this case the names will compare as equal, but
757 will still have different provenances.
760 @unQualInScope@ returns a function that takes a @Name@ and tells whether
761 its unqualified name is in scope. This is put as a boolean flag in
762 the @Name@'s provenance to guide whether or not to print the name qualified
766 unQualInScope :: GlobalRdrEnv -> Name -> Bool
767 -- True if 'f' is in scope, and has only one binding
768 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
770 = (`elemNameSet` unqual_names)
772 unqual_names :: NameSet
773 unqual_names = foldRdrEnv add emptyNameSet env
774 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
775 add _ _ unquals = unquals
779 %************************************************************************
783 %************************************************************************
786 plusAvail (Avail n1) (Avail n2) = Avail n1
787 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
790 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
793 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
794 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
796 emptyAvailEnv = emptyNameEnv
797 unitAvailEnv :: AvailInfo -> AvailEnv
798 unitAvailEnv a = unitNameEnv (availName a) a
800 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
801 plusAvailEnv = plusNameEnv_C plusAvail
803 availEnvElts = nameEnvElts
805 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
806 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
808 availsToNameSet :: [AvailInfo] -> NameSet
809 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
811 availName :: GenAvailInfo name -> name
812 availName (Avail n) = n
813 availName (AvailTC n _) = n
815 availNames :: GenAvailInfo name -> [name]
816 availNames (Avail n) = [n]
817 availNames (AvailTC n ns) = ns
819 -------------------------------------
820 filterAvail :: RdrNameIE -- Wanted
821 -> AvailInfo -- Available
822 -> Maybe AvailInfo -- Resulting available;
823 -- Nothing if (any of the) wanted stuff isn't there
825 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
826 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
827 | otherwise = Nothing
829 is_wanted name = nameOccName name `elem` wanted_occs
830 sub_names_ok = all (`elem` avail_occs) wanted_occs
831 avail_occs = map nameOccName ns
832 wanted_occs = map rdrNameOcc (want:wants)
834 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
837 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
839 filterAvail (IEVar _) avail@(Avail n) = Just avail
840 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
842 wanted n = nameOccName n == occ
844 -- The second equation happens if we import a class op, thus
846 -- where op is a class operation
848 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
849 -- We don't complain even if the IE says T(..), but
850 -- no constrs/class ops of T are available
851 -- Instead that's caught with a warning by the caller
853 filterAvail ie avail = Nothing
855 -------------------------------------
856 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
857 -- Group by module and sort by occurrence
858 -- This keeps the list in canonical order
859 groupAvails this_mod avails
860 = [ (mkSysModuleNameFS fs, sortLt lt avails)
861 | (fs,avails) <- fmToList groupFM
864 groupFM :: FiniteMap FastString Avails
865 -- Deliberately use the FastString so we
866 -- get a canonical ordering
867 groupFM = foldl add emptyFM avails
869 add env avail = addToFM_C combine env mod_fs [avail']
871 mod_fs = moduleNameFS (moduleName avail_mod)
872 avail_mod = case nameModule_maybe (availName avail) of
875 combine old _ = avail':old
876 avail' = sortAvail avail
878 a1 `lt` a2 = occ1 < occ2
880 occ1 = nameOccName (availName a1)
881 occ2 = nameOccName (availName a2)
883 sortAvail :: AvailInfo -> AvailInfo
884 -- Sort the sub-names into canonical order.
885 -- The canonical order has the "main name" at the beginning
886 -- (if it's there at all)
887 sortAvail (Avail n) = Avail n
888 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
889 | otherwise = AvailTC n ( sortLt lt ns)
891 n1 `lt` n2 = nameOccName n1 < nameOccName n2
895 %************************************************************************
897 \subsection{Free variable manipulation}
899 %************************************************************************
903 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
905 (ys, fvs_s) = unzip stuff
907 returnRn (ys, plusFVs fvs_s)
911 %************************************************************************
913 \subsection{Envt utility functions}
915 %************************************************************************
918 warnUnusedModules :: [ModuleName] -> RnM d ()
919 warnUnusedModules mods
920 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
922 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
923 text "is imported, but nothing from it is used",
924 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
927 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
928 warnUnusedImports names
929 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
931 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
932 warnUnusedLocalBinds names
933 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
935 warnUnusedMatches names
936 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
938 -------------------------
940 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
941 warnUnusedBinds names
942 = mapRn_ warnUnusedGroup groups
944 -- Group by provenance
945 groups = equivClasses cmp names
946 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
949 -------------------------
951 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
952 warnUnusedGroup names
953 | null filtered_names = returnRn ()
954 | not is_local = returnRn ()
956 = pushSrcLocRn def_loc $
958 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
960 filtered_names = filter reportable names
961 (name1, prov1) = head filtered_names
962 (is_local, def_loc, msg)
964 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
966 NonLocalDef (UserImport mod loc _)
967 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
969 reportable (name,_) = case occNameUserString (nameOccName name) of
972 -- Haskell 98 encourages compilers to suppress warnings about
973 -- unused names in a pattern if they start with "_".
977 addNameClashErrRn rdr_name (np1:nps)
978 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
979 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
981 msg1 = ptext SLIT("either") <+> mk_ref np1
982 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
983 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
985 shadowedNameWarn shadow
986 = hsep [ptext SLIT("This binding for"),
988 ptext SLIT("shadows an existing binding")]
991 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
993 flavour = occNameFlavour (rdrNameOcc name)
995 qualNameErr descriptor (name,loc)
997 addErrRn (hsep [ ptext SLIT("Invalid use of qualified name"),
1002 dupNamesErr descriptor ((name,loc) : dup_things)
1003 = pushSrcLocRn loc $
1004 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1008 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1010 = ifOptRn Opt_WarnDeprecations $
1011 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1012 quotes (ppr name) <+> text "is deprecated:",