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, RdrNameHsType, extractHsTyRdrTyVars )
15 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
16 mkRdrUnqual, mkRdrQual,
17 lookupRdrEnv, foldRdrEnv, rdrEnvToList, elemRdrEnv,
20 import HsTypes ( hsTyVarName, replaceTyVarName )
21 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
22 ImportReason(..), GlobalRdrEnv, GlobalRdrElt(..), AvailEnv,
23 AvailInfo, Avails, GenAvailInfo(..), NameSupply(..),
25 Deprecations(..), lookupDeprec,
30 getSrcLoc, nameIsLocalOrFrom,
31 mkLocalName, mkGlobalName,
32 mkIPName, nameOccName, nameModule_maybe,
37 import OccName ( OccName, occNameUserString, occNameFlavour )
38 import Module ( ModuleName, moduleName, mkVanillaModule,
39 mkSysModuleNameFS, moduleNameFS, WhereFrom(..) )
40 import PrelNames ( mkUnboundName,
42 mAIN_Name, pREL_MAIN_Name,
43 ioTyConName, intTyConName,
44 boolTyConName, funTyConName,
45 unpackCStringName, unpackCStringFoldrName, unpackCStringUtf8Name,
46 eqStringName, printName,
47 bindIOName, returnIOName, failIOName
49 import TysWiredIn ( unitTyCon ) -- A little odd
52 import SrcLoc ( SrcLoc, noSrcLoc )
54 import ListSetOps ( removeDups, equivClasses )
55 import Util ( sortLt )
56 import BasicTypes ( mapIPName )
58 import UniqFM ( lookupWithDefaultUFM )
59 import Maybe ( mapMaybe )
61 import FastString ( FastString )
64 %*********************************************************
66 \subsection{Making new names}
68 %*********************************************************
71 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
72 -- newTopBinder puts into the cache the binder with the
73 -- module information set correctly. When the decl is later renamed,
74 -- the binding site will thereby get the correct module.
75 -- There maybe occurrences that don't have the correct Module, but
76 -- by the typechecker will propagate the binding definition to all
77 -- the occurrences, so that doesn't matter
79 newTopBinder mod rdr_name loc
80 = -- First check the cache
82 -- There should never be a qualified name in a binding position (except in instance decls)
83 -- The parser doesn't check this because the same parser parses instance decls
84 (if isQual rdr_name then
85 qualNameErr (text "In its declaration") (rdr_name,loc)
90 getNameSupplyRn `thenRn` \ name_supply ->
92 occ = rdrNameOcc rdr_name
93 key = (moduleName mod, occ)
94 cache = nsNames name_supply
96 case lookupFM cache key of
98 -- A hit in the cache! We are at the binding site of the name, and
99 -- this is the moment when we know all about
100 -- a) the Name's host Module (in particular, which
101 -- package it comes from)
102 -- b) its defining SrcLoc
103 -- So we update this info
106 new_name = setNameModuleAndLoc name mod loc
107 new_cache = addToFM cache key new_name
109 setNameSupplyRn (name_supply {nsNames = new_cache}) `thenRn_`
110 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
113 -- Miss in the cache!
114 -- Build a completely new Name, and put it in the cache
115 -- Even for locally-defined names we use implicitImportProvenance;
116 -- updateProvenances will set it to rights
118 (us', us1) = splitUniqSupply (nsUniqs name_supply)
119 uniq = uniqFromSupply us1
120 new_name = mkGlobalName uniq mod occ loc
121 new_cache = addToFM cache key new_name
123 setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
124 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
128 newGlobalName :: ModuleName -> OccName -> RnM d Name
129 -- Used for *occurrences*. We make a place-holder Name, really just
130 -- to agree on its unique, which gets overwritten when we read in
131 -- the binding occurence later (newTopBinder)
132 -- The place-holder Name doesn't have the right SrcLoc, and its
133 -- Module won't have the right Package either.
135 -- (We have to pass a ModuleName, not a Module, because we may be
136 -- simply looking at an occurrence M.x in an interface file.)
138 -- This means that a renamed program may have incorrect info
139 -- on implicitly-imported occurrences, but the correct info on the
140 -- *binding* declaration. It's the type checker that propagates the
141 -- correct information to all the occurrences.
142 -- Since implicitly-imported names never occur in error messages,
143 -- it doesn't matter that we get the correct info in place till later,
144 -- (but since it affects DLL-ery it does matter that we get it right
146 newGlobalName mod_name occ
147 = getNameSupplyRn `thenRn` \ name_supply ->
149 key = (mod_name, occ)
150 cache = nsNames name_supply
152 case lookupFM cache key of
153 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
156 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
157 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
160 (us', us1) = splitUniqSupply (nsUniqs name_supply)
161 uniq = uniqFromSupply us1
162 mod = mkVanillaModule mod_name
163 name = mkGlobalName uniq mod occ noSrcLoc
164 new_cache = addToFM cache key name
166 newIPName rdr_name_ip
167 = getNameSupplyRn `thenRn` \ name_supply ->
169 ipcache = nsIPs name_supply
171 case lookupFM ipcache key of
172 Just name_ip -> returnRn name_ip
173 Nothing -> setNameSupplyRn new_ns `thenRn_`
176 (us', us1) = splitUniqSupply (nsUniqs name_supply)
177 uniq = uniqFromSupply us1
178 name_ip = mapIPName mk_name rdr_name_ip
179 mk_name rdr_name = mkIPName uniq (rdrNameOcc rdr_name)
180 new_ipcache = addToFM ipcache key name_ip
181 new_ns = name_supply {nsUniqs = us', nsIPs = new_ipcache}
183 key = rdr_name_ip -- Ensures that ?x and %x get distinct Names
186 %*********************************************************
188 \subsection{Looking up names}
190 %*********************************************************
192 Looking up a name in the RnEnv.
195 lookupBndrRn rdr_name
196 = getLocalNameEnv `thenRn` \ local_env ->
197 case lookupRdrEnv local_env rdr_name of
198 Just name -> returnRn name
199 Nothing -> lookupTopBndrRn rdr_name
201 lookupTopBndrRn rdr_name
202 -- Look up a top-level local binder. We may be looking up an unqualified 'f',
203 -- and there may be several imported 'f's too, which must not confuse us.
204 -- So we have to filter out the non-local ones.
205 -- A separate function (importsFromLocalDecls) reports duplicate top level
206 -- decls, so here it's safe just to choose an arbitrary one.
209 -- This is here just to catch the PrelBase defn of (say) [] and similar
210 -- The parser reads the special syntax and returns an Orig RdrName
211 -- But the global_env contains only Qual RdrNames, so we won't
212 -- find it there; instead just get the name via the Orig route
213 = lookupOrigName rdr_name
216 = getModeRn `thenRn` \ mode ->
217 if isInterfaceMode mode
218 then lookupIfaceName rdr_name
220 getModuleRn `thenRn` \ mod ->
221 getGlobalNameEnv `thenRn` \ global_env ->
222 case lookup_local mod global_env rdr_name of
223 Just name -> returnRn name
224 Nothing -> failWithRn (mkUnboundName rdr_name)
225 (unknownNameErr rdr_name)
227 lookup_local mod global_env rdr_name
228 = case lookupRdrEnv global_env rdr_name of
230 Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
235 -- lookupSigOccRn is used for type signatures and pragmas
241 -- It's clear that the 'f' in the signature must refer to A.f
242 -- The Haskell98 report does not stipulate this, but it will!
243 -- So we must treat the 'f' in the signature in the same way
244 -- as the binding occurrence of 'f', using lookupBndrRn
245 lookupSigOccRn :: RdrName -> RnMS Name
246 lookupSigOccRn = lookupBndrRn
248 -- lookupInstDeclBndr is used for the binders in an
249 -- instance declaration. Here we use the class name to
252 lookupInstDeclBndr :: Name -> RdrName -> RnMS Name
253 -- We use the selector name as the binder
254 lookupInstDeclBndr cls_name rdr_name
255 | isOrig rdr_name -- Occurs in derived instances, where we just
256 -- refer diectly to the right method
257 = lookupOrigName rdr_name
260 = getGlobalAvails `thenRn` \ avail_env ->
261 case lookupNameEnv avail_env cls_name of
262 -- The class itself isn't in scope, so cls_name is unboundName
263 -- e.g. import Prelude hiding( Ord )
264 -- instance Ord T where ...
265 -- The program is wrong, but that should not cause a crash.
266 Nothing -> returnRn (mkUnboundName rdr_name)
267 Just (AvailTC _ ns) -> case [n | n <- ns, nameOccName n == occ] of
268 (n:ns)-> ASSERT( null ns ) returnRn n
269 [] -> failWithRn (mkUnboundName rdr_name)
270 (unknownNameErr rdr_name)
271 other -> pprPanic "lookupInstDeclBndr" (ppr cls_name)
273 occ = rdrNameOcc rdr_name
275 -- lookupOccRn looks up an occurrence of a RdrName
276 lookupOccRn :: RdrName -> RnMS Name
278 = getLocalNameEnv `thenRn` \ local_env ->
279 case lookupRdrEnv local_env rdr_name of
280 Just name -> returnRn name
281 Nothing -> lookupGlobalOccRn rdr_name
283 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
284 -- environment. It's used only for
285 -- record field names
286 -- class op names in class and instance decls
288 lookupGlobalOccRn rdr_name
289 = getModeRn `thenRn` \ mode ->
290 if (isInterfaceMode mode)
291 then lookupIfaceName rdr_name
294 getGlobalNameEnv `thenRn` \ global_env ->
296 SourceMode -> lookupSrcName global_env rdr_name
299 | not (isQual rdr_name) ->
300 lookupSrcName global_env rdr_name
302 -- We allow qualified names on the command line to refer to
303 -- *any* name exported by any module in scope, just as if
304 -- there was an "import qualified M" declaration for every
307 -- First look up the name in the normal environment. If
308 -- it isn't there, we manufacture a new occurrence of an
311 case lookupRdrEnv global_env rdr_name of
312 Just _ -> lookupSrcName global_env rdr_name
313 Nothing -> lookupQualifiedName rdr_name
315 -- a qualified name on the command line can refer to any module at all: we
316 -- try to load the interface if we don't already have it.
317 lookupQualifiedName :: RdrName -> RnM d Name
318 lookupQualifiedName rdr_name
320 mod = rdrNameModule rdr_name
321 occ = rdrNameOcc rdr_name
323 loadInterface (ppr rdr_name) mod ImportByUser `thenRn` \ iface ->
324 case [ name | (_,avails) <- mi_exports iface,
326 name <- availNames avail,
327 nameOccName name == occ ] of
328 (n:ns) -> ASSERT (null ns) returnRn n
329 _ -> failWithRn (mkUnboundName rdr_name) (unknownNameErr rdr_name)
331 lookupSrcName :: GlobalRdrEnv -> RdrName -> RnM d Name
332 -- NB: passed GlobalEnv explicitly, not necessarily in RnMS monad
333 lookupSrcName global_env rdr_name
334 | isOrig rdr_name -- Can occur in source code too
335 = lookupOrigName rdr_name
338 = case lookupRdrEnv global_env rdr_name of
339 Just [GRE name _ Nothing] -> returnRn name
340 Just [GRE name _ (Just deprec)] -> warnDeprec name deprec `thenRn_`
342 Just stuff@(GRE name _ _ : _) -> addNameClashErrRn rdr_name stuff `thenRn_`
344 Nothing -> failWithRn (mkUnboundName rdr_name)
345 (unknownNameErr rdr_name)
347 lookupOrigName :: RdrName -> RnM d Name
348 lookupOrigName rdr_name
349 = ASSERT( isOrig rdr_name )
350 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
352 lookupIfaceUnqual :: RdrName -> RnM d Name
353 lookupIfaceUnqual rdr_name
354 = ASSERT( isUnqual rdr_name )
355 -- An Unqual is allowed; interface files contain
356 -- unqualified names for locally-defined things, such as
357 -- constructors of a data type.
358 getModuleRn `thenRn ` \ mod ->
359 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
361 lookupIfaceName :: RdrName -> RnM d Name
362 lookupIfaceName rdr_name
363 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
364 | otherwise = lookupOrigName rdr_name
367 @lookupOrigName@ takes an RdrName representing an {\em original}
368 name, and adds it to the occurrence pool so that it'll be loaded
369 later. This is used when language constructs (such as monad
370 comprehensions, overloaded literals, or deriving clauses) require some
371 stuff to be loaded that isn't explicitly mentioned in the code.
373 This doesn't apply in interface mode, where everything is explicit,
374 but we don't check for this case: it does no harm to record an
375 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
376 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
377 calls it at all I think).
379 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
382 lookupOrigNames :: [RdrName] -> RnM d NameSet
383 lookupOrigNames rdr_names
384 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
385 returnRn (mkNameSet names)
388 lookupSysBinder is used for the "system binders" of a type, class, or
389 instance decl. It ensures that the module is set correctly in the
390 name cache, and sets the provenance on the returned name too. The
391 returned name will end up actually in the type, class, or instance.
394 lookupSysBinder rdr_name
395 = ASSERT( isUnqual rdr_name )
396 getModuleRn `thenRn` \ mod ->
397 getSrcLocRn `thenRn` \ loc ->
398 newTopBinder mod rdr_name loc
402 %*********************************************************
404 \subsection{Implicit free vars and sugar names}
406 %*********************************************************
408 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
409 mentioned explicitly, but which might be needed by the type checker.
412 getImplicitStmtFVs -- Compiling a statement
413 = returnRn (mkFVs [printName, bindIOName, returnIOName, failIOName]
414 `plusFV` ubiquitousNames)
415 -- These are all needed implicitly when compiling a statement
416 -- See TcModule.tc_stmts
418 getImplicitModuleFVs mod_name decls -- Compiling a module
419 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
420 returnRn (deriving_names `plusFV` implicit_main `plusFV` ubiquitousNames)
422 -- Add occurrences for IO or PrimIO
423 implicit_main | mod_name == mAIN_Name
424 || mod_name == pREL_MAIN_Name = unitFV ioTyConName
425 | otherwise = emptyFVs
427 -- deriv_classes is now a list of HsTypes, so a "normal" one
428 -- appears as a (HsClassP c []). The non-normal ones for the new
429 -- newtype-deriving extension, and they don't require any
430 -- implicit names, so we can silently filter them out.
431 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
432 HsClassP cls [] <- deriv_classes,
433 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
435 -- ubiquitous_names are loaded regardless, because
436 -- they are needed in virtually every program
438 = mkFVs [unpackCStringName, unpackCStringFoldrName,
439 unpackCStringUtf8Name, eqStringName]
440 -- Virtually every program has error messages in it somewhere
443 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
444 -- Add occurrences for very frequently used types.
445 -- (e.g. we don't want to be bothered with making funTyCon a
446 -- free var at every function application!)
449 %************************************************************************
451 \subsection{Re-bindable desugaring names}
453 %************************************************************************
455 Haskell 98 says that when you say "3" you get the "fromInteger" from the
456 Standard Prelude, regardless of what is in scope. However, to experiment
457 with having a language that is less coupled to the standard prelude, we're
458 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
459 happens to be in scope. Then you can
461 import MyPrelude as Prelude
462 to get the desired effect.
464 At the moment this just happens for
465 * fromInteger, fromRational on literals (in expressions and patterns)
466 * negate (in expressions)
467 * minus (arising from n+k patterns)
469 We store the relevant Name in the HsSyn tree, in
470 * HsIntegral/HsFractional
473 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
474 fromRationalName etc), but the renamer changes this to the appropriate user
475 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
478 lookupSyntaxName :: Name -- The standard name
479 -> RnMS Name -- Possibly a non-standard name
480 lookupSyntaxName std_name
481 = doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
482 if not no_prelude then
483 returnRn std_name -- Normal case
486 rdr_name = mkRdrUnqual (nameOccName std_name)
487 -- Get the similarly named thing from the local environment
493 %*********************************************************
497 %*********************************************************
500 newLocalsRn :: [(RdrName,SrcLoc)]
502 newLocalsRn rdr_names_w_loc
503 = getNameSupplyRn `thenRn` \ name_supply ->
505 (us', us1) = splitUniqSupply (nsUniqs name_supply)
506 uniqs = uniqsFromSupply us1
507 names = [ mkLocalName uniq (rdrNameOcc rdr_name) loc
508 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
511 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
515 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
516 -> [(RdrName,SrcLoc)]
517 -> ([Name] -> RnMS a)
519 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
520 = getModeRn `thenRn` \ mode ->
521 getLocalNameEnv `thenRn` \ local_env ->
522 getGlobalNameEnv `thenRn` \ global_env ->
524 -- Check for duplicate names
525 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
527 -- Warn about shadowing, but only in source modules
529 check_shadow (rdr_name,loc)
530 | rdr_name `elemRdrEnv` local_env
531 || rdr_name `elemRdrEnv` global_env
532 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
538 SourceMode -> ifOptRn Opt_WarnNameShadowing $
539 mapRn_ check_shadow rdr_names_w_loc
543 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
545 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
547 setLocalNameEnv new_local_env (enclosed_scope names)
549 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
550 -- A specialised variant when renaming stuff from interface
551 -- files (of which there is a lot)
553 -- * no checks for shadowing
555 -- * deal with free vars
556 bindCoreLocalRn rdr_name enclosed_scope
557 = getSrcLocRn `thenRn` \ loc ->
558 getLocalNameEnv `thenRn` \ name_env ->
559 getNameSupplyRn `thenRn` \ name_supply ->
561 (us', us1) = splitUniqSupply (nsUniqs name_supply)
562 uniq = uniqFromSupply us1
563 name = mkLocalName uniq (rdrNameOcc rdr_name) loc
565 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
567 new_name_env = extendRdrEnv name_env rdr_name name
569 setLocalNameEnv new_name_env (enclosed_scope name)
571 bindCoreLocalsRn [] thing_inside = thing_inside []
572 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
573 bindCoreLocalsRn bs $ \ names' ->
574 thing_inside (name':names')
576 bindLocalNames names enclosed_scope
577 = getLocalNameEnv `thenRn` \ name_env ->
578 setLocalNameEnv (extendLocalRdrEnv name_env names)
581 bindLocalNamesFV names enclosed_scope
582 = bindLocalNames names $
583 enclosed_scope `thenRn` \ (thing, fvs) ->
584 returnRn (thing, delListFromNameSet fvs names)
587 -------------------------------------
588 bindLocalRn doc rdr_name enclosed_scope
589 = getSrcLocRn `thenRn` \ loc ->
590 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
594 bindLocalsRn doc rdr_names enclosed_scope
595 = getSrcLocRn `thenRn` \ loc ->
596 bindLocatedLocalsRn doc
597 (rdr_names `zip` repeat loc)
600 -- binLocalsFVRn is the same as bindLocalsRn
601 -- except that it deals with free vars
602 bindLocalsFVRn doc rdr_names enclosed_scope
603 = bindLocalsRn doc rdr_names $ \ names ->
604 enclosed_scope names `thenRn` \ (thing, fvs) ->
605 returnRn (thing, delListFromNameSet fvs names)
607 -------------------------------------
608 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
609 -- This tiresome function is used only in rnSourceDecl on InstDecl
610 extendTyVarEnvFVRn tyvars enclosed_scope
611 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
612 returnRn (thing, delListFromNameSet fvs tyvars)
614 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
615 -> ([HsTyVarBndr Name] -> RnMS a)
617 bindTyVarsRn doc_str tyvar_names enclosed_scope
618 = getSrcLocRn `thenRn` \ loc ->
620 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
622 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
623 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
625 bindPatSigTyVars :: [RdrNameHsType]
626 -> RnMS (a, FreeVars)
627 -> RnMS (a, FreeVars)
628 -- Find the type variables in the pattern type
629 -- signatures that must be brought into scope
631 bindPatSigTyVars tys enclosed_scope
632 = getLocalNameEnv `thenRn` \ name_env ->
633 getSrcLocRn `thenRn` \ loc ->
635 forall_tyvars = nub [ tv | ty <- tys,
636 tv <- extractHsTyRdrTyVars ty,
637 not (tv `elemFM` name_env)
639 -- The 'nub' is important. For example:
640 -- f (x :: t) (y :: t) = ....
641 -- We don't want to complain about binding t twice!
643 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
644 doc_sig = text "In a pattern type-signature"
646 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
647 enclosed_scope `thenRn` \ (thing, fvs) ->
648 returnRn (thing, delListFromNameSet fvs names)
651 -------------------------------------
652 checkDupOrQualNames, checkDupNames :: SDoc
653 -> [(RdrName, SrcLoc)]
655 -- Works in any variant of the renamer monad
657 checkDupOrQualNames doc_str rdr_names_w_loc
658 = -- Check for use of qualified names
659 mapRn_ (qualNameErr doc_str) quals `thenRn_`
660 checkDupNames doc_str rdr_names_w_loc
662 quals = filter (isQual . fst) rdr_names_w_loc
664 checkDupNames doc_str rdr_names_w_loc
665 = -- Check for duplicated names in a binding group
666 mapRn_ (dupNamesErr doc_str) dups
668 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
672 %************************************************************************
674 \subsection{GlobalRdrEnv}
676 %************************************************************************
679 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
680 -> Bool -- True <=> want unqualified import
681 -> (Name -> Provenance)
682 -> Avails -- Whats imported
686 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
689 -- Make the name environment. We're talking about a
690 -- single module here, so there must be no name clashes.
691 -- In practice there only ever will be if it's the module
694 -- Add qualified names for the things that are available
695 -- (Qualified names are always imported)
696 gbl_env1 = foldl add_avail emptyRdrEnv avails
698 -- Add unqualified names
699 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
700 | otherwise = gbl_env1
702 add_unqual env (qual_name, elts)
703 = foldl add_one env elts
705 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
706 unqual_name = unqualifyRdrName qual_name
707 -- The qualified import should only have added one
708 -- binding for each qualified name! But if there's an error in
709 -- the module (multiple bindings for the same name) we may get
710 -- duplicates. So the simple thing is to do the fold.
712 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
713 add_avail env avail = foldl add_name env (availNames avail)
715 add_name env name -- Add qualified name only
716 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
718 occ = nameOccName name
719 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
723 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
724 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
726 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
727 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
729 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
730 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
732 combine_globals :: [GlobalRdrElt] -- Old
733 -> [GlobalRdrElt] -- New
735 combine_globals ns_old ns_new -- ns_new is often short
736 = foldr add ns_old ns_new
738 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
741 choose n m | n `beats` m = n
744 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
746 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
747 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
748 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
751 We treat two bindings of a locally-defined name as a duplicate,
752 because they might be two separate, local defns and we want to report
753 and error for that, {\em not} eliminate a duplicate.
755 On the other hand, if you import the same name from two different
756 import statements, we {\em do} want to eliminate the duplicate, not report
759 If a module imports itself then there might be a local defn and an imported
760 defn of the same name; in this case the names will compare as equal, but
761 will still have different provenances.
764 @unQualInScope@ returns a function that takes a @Name@ and tells whether
765 its unqualified name is in scope. This is put as a boolean flag in
766 the @Name@'s provenance to guide whether or not to print the name qualified
770 unQualInScope :: GlobalRdrEnv -> Name -> Bool
771 -- True if 'f' is in scope, and has only one binding,
772 -- and the thing it is bound to is the name we are looking for
773 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
775 -- This fn is only efficient if the shared
776 -- partial application is used a lot.
778 = (`elemNameSet` unqual_names)
780 unqual_names :: NameSet
781 unqual_names = foldRdrEnv add emptyNameSet env
782 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
783 add _ _ unquals = unquals
787 %************************************************************************
791 %************************************************************************
794 plusAvail (Avail n1) (Avail n2) = Avail n1
795 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
798 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
801 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
802 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
804 unitAvailEnv :: AvailInfo -> AvailEnv
805 unitAvailEnv a = unitNameEnv (availName a) a
807 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
808 plusAvailEnv = plusNameEnv_C plusAvail
810 availEnvElts = nameEnvElts
812 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
813 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
815 availsToNameSet :: [AvailInfo] -> NameSet
816 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
818 availName :: GenAvailInfo name -> name
819 availName (Avail n) = n
820 availName (AvailTC n _) = n
822 availNames :: GenAvailInfo name -> [name]
823 availNames (Avail n) = [n]
824 availNames (AvailTC n ns) = ns
826 -------------------------------------
827 filterAvail :: RdrNameIE -- Wanted
828 -> AvailInfo -- Available
829 -> Maybe AvailInfo -- Resulting available;
830 -- Nothing if (any of the) wanted stuff isn't there
832 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
833 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
834 | otherwise = Nothing
836 is_wanted name = nameOccName name `elem` wanted_occs
837 sub_names_ok = all (`elem` avail_occs) wanted_occs
838 avail_occs = map nameOccName ns
839 wanted_occs = map rdrNameOcc (want:wants)
841 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
844 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
846 filterAvail (IEVar _) avail@(Avail n) = Just avail
847 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
849 wanted n = nameOccName n == occ
851 -- The second equation happens if we import a class op, thus
853 -- where op is a class operation
855 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
856 -- We don't complain even if the IE says T(..), but
857 -- no constrs/class ops of T are available
858 -- Instead that's caught with a warning by the caller
860 filterAvail ie avail = Nothing
862 -------------------------------------
863 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
864 -- Group by module and sort by occurrence
865 -- This keeps the list in canonical order
866 groupAvails this_mod avails
867 = [ (mkSysModuleNameFS fs, sortLt lt avails)
868 | (fs,avails) <- fmToList groupFM
871 groupFM :: FiniteMap FastString Avails
872 -- Deliberately use the FastString so we
873 -- get a canonical ordering
874 groupFM = foldl add emptyFM avails
876 add env avail = addToFM_C combine env mod_fs [avail']
878 mod_fs = moduleNameFS (moduleName avail_mod)
879 avail_mod = case nameModule_maybe (availName avail) of
882 combine old _ = avail':old
883 avail' = sortAvail avail
885 a1 `lt` a2 = occ1 < occ2
887 occ1 = nameOccName (availName a1)
888 occ2 = nameOccName (availName a2)
890 sortAvail :: AvailInfo -> AvailInfo
891 -- Sort the sub-names into canonical order.
892 -- The canonical order has the "main name" at the beginning
893 -- (if it's there at all)
894 sortAvail (Avail n) = Avail n
895 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
896 | otherwise = AvailTC n ( sortLt lt ns)
898 n1 `lt` n2 = nameOccName n1 < nameOccName n2
902 pruneAvails :: (Name -> Bool) -- Keep if this is True
905 pruneAvails keep avails
906 = mapMaybe del avails
908 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
909 del (Avail n) | keep n = Just (Avail n)
910 | otherwise = Nothing
911 del (AvailTC n ns) | null ns' = Nothing
912 | otherwise = Just (AvailTC n ns')
917 %************************************************************************
919 \subsection{Free variable manipulation}
921 %************************************************************************
925 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
927 (ys, fvs_s) = unzip stuff
929 returnRn (ys, plusFVs fvs_s)
933 %************************************************************************
935 \subsection{Envt utility functions}
937 %************************************************************************
940 warnUnusedModules :: [ModuleName] -> RnM d ()
941 warnUnusedModules mods
942 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
944 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
945 text "is imported, but nothing from it is used",
946 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
949 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
950 warnUnusedImports names
951 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
953 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
954 warnUnusedLocalBinds names
955 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
957 warnUnusedMatches names
958 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
960 -------------------------
962 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
963 warnUnusedBinds names
964 = mapRn_ warnUnusedGroup groups
966 -- Group by provenance
967 groups = equivClasses cmp names
968 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
971 -------------------------
973 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
974 warnUnusedGroup names
975 | null filtered_names = returnRn ()
976 | not is_local = returnRn ()
978 = pushSrcLocRn def_loc $
980 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
982 filtered_names = filter reportable names
983 (name1, prov1) = head filtered_names
984 (is_local, def_loc, msg)
986 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
988 NonLocalDef (UserImport mod loc _)
989 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
991 reportable (name,_) = case occNameUserString (nameOccName name) of
994 -- Haskell 98 encourages compilers to suppress warnings about
995 -- unused names in a pattern if they start with "_".
999 addNameClashErrRn rdr_name (np1:nps)
1000 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1001 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1003 msg1 = ptext SLIT("either") <+> mk_ref np1
1004 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1005 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1007 shadowedNameWarn shadow
1008 = hsep [ptext SLIT("This binding for"),
1009 quotes (ppr shadow),
1010 ptext SLIT("shadows an existing binding")]
1013 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1015 flavour = occNameFlavour (rdrNameOcc name)
1017 qualNameErr descriptor (name,loc)
1018 = pushSrcLocRn loc $
1019 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1022 dupNamesErr descriptor ((name,loc) : dup_things)
1023 = pushSrcLocRn loc $
1024 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1028 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1030 = ifOptRn Opt_WarnDeprecations $
1031 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1032 quotes (ppr name) <+> text "is deprecated:",