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( loadInterface )
13 import FlattenInfo ( namesNeededForFlattening )
15 import RnHsSyn ( RenamedFixitySig )
16 import RdrHsSyn ( RdrNameIE, RdrNameHsType, RdrNameFixitySig, extractHsTyRdrTyVars )
17 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
18 mkRdrUnqual, mkRdrQual, setRdrNameOcc,
19 lookupRdrEnv, foldRdrEnv, rdrEnvToList, elemRdrEnv,
22 import HsTypes ( hsTyVarName, replaceTyVarName )
23 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
24 ImportReason(..), GlobalRdrEnv, GlobalRdrElt(..), AvailEnv,
25 AvailInfo, Avails, GenAvailInfo(..), NameSupply(..),
26 ModIface(..), GhciMode(..),
27 Deprecations(..), lookupDeprec,
28 extendLocalRdrEnv, lookupFixity
32 getSrcLoc, nameIsLocalOrFrom,
33 mkInternalName, mkExternalName,
34 mkIPName, nameOccName, nameModule_maybe,
35 setNameModuleAndLoc, nameModule
39 import OccName ( OccName, occNameUserString, occNameFlavour,
40 isDataSymOcc, setOccNameSpace, tcName )
41 import Module ( ModuleName, moduleName, mkVanillaModule,
42 mkSysModuleNameFS, moduleNameFS, WhereFrom(..) )
43 import PrelNames ( mkUnboundName,
45 mAIN_Name, main_RDR_Unqual,
46 runMainName, intTyConName,
47 boolTyConName, funTyConName,
48 unpackCStringName, unpackCStringFoldrName, unpackCStringUtf8Name,
49 eqStringName, printName,
50 bindIOName, returnIOName, failIOName, thenIOName
52 import TysWiredIn ( unitTyCon ) -- A little odd
55 import SrcLoc ( SrcLoc, noSrcLoc )
57 import ListSetOps ( removeDups, equivClasses )
58 import Util ( sortLt )
59 import BasicTypes ( mapIPName, defaultFixity )
61 import UniqFM ( lookupWithDefaultUFM )
62 import Maybe ( mapMaybe )
63 import Maybes ( orElse, catMaybes )
65 import FastString ( FastString )
68 %*********************************************************
70 \subsection{Making new names}
72 %*********************************************************
75 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
76 -- newTopBinder puts into the cache the binder with the
77 -- module information set correctly. When the decl is later renamed,
78 -- the binding site will thereby get the correct module.
79 -- There maybe occurrences that don't have the correct Module, but
80 -- by the typechecker will propagate the binding definition to all
81 -- the occurrences, so that doesn't matter
83 newTopBinder mod rdr_name loc
84 = -- First check the cache
86 -- There should never be a qualified name in a binding position (except in instance decls)
87 -- The parser doesn't check this because the same parser parses instance decls
88 (if isQual rdr_name then
89 qualNameErr (text "In its declaration") (rdr_name,loc)
94 getNameSupplyRn `thenRn` \ name_supply ->
96 occ = rdrNameOcc rdr_name
97 key = (moduleName mod, occ)
98 cache = nsNames name_supply
100 case lookupFM cache key of
102 -- A hit in the cache! We are at the binding site of the name, and
103 -- this is the moment when we know all about
104 -- a) the Name's host Module (in particular, which
105 -- package it comes from)
106 -- b) its defining SrcLoc
107 -- So we update this info
110 new_name = setNameModuleAndLoc name mod loc
111 new_cache = addToFM cache key new_name
113 setNameSupplyRn (name_supply {nsNames = new_cache}) `thenRn_`
114 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
117 -- Miss in the cache!
118 -- Build a completely new Name, and put it in the cache
119 -- Even for locally-defined names we use implicitImportProvenance;
120 -- updateProvenances will set it to rights
122 (us', us1) = splitUniqSupply (nsUniqs name_supply)
123 uniq = uniqFromSupply us1
124 new_name = mkExternalName uniq mod occ loc
125 new_cache = addToFM cache key new_name
127 setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
128 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
132 newGlobalName :: ModuleName -> OccName -> RnM d Name
133 -- Used for *occurrences*. We make a place-holder Name, really just
134 -- to agree on its unique, which gets overwritten when we read in
135 -- the binding occurence later (newTopBinder)
136 -- The place-holder Name doesn't have the right SrcLoc, and its
137 -- Module won't have the right Package either.
139 -- (We have to pass a ModuleName, not a Module, because we may be
140 -- simply looking at an occurrence M.x in an interface file.)
142 -- This means that a renamed program may have incorrect info
143 -- on implicitly-imported occurrences, but the correct info on the
144 -- *binding* declaration. It's the type checker that propagates the
145 -- correct information to all the occurrences.
146 -- Since implicitly-imported names never occur in error messages,
147 -- it doesn't matter that we get the correct info in place till later,
148 -- (but since it affects DLL-ery it does matter that we get it right
150 newGlobalName mod_name occ
151 = getNameSupplyRn `thenRn` \ name_supply ->
153 key = (mod_name, occ)
154 cache = nsNames name_supply
156 case lookupFM cache key of
157 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
160 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
161 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
164 (us', us1) = splitUniqSupply (nsUniqs name_supply)
165 uniq = uniqFromSupply us1
166 mod = mkVanillaModule mod_name
167 name = mkExternalName uniq mod occ noSrcLoc
168 new_cache = addToFM cache key name
170 newIPName rdr_name_ip
171 = getNameSupplyRn `thenRn` \ name_supply ->
173 ipcache = nsIPs name_supply
175 case lookupFM ipcache key of
176 Just name_ip -> returnRn name_ip
177 Nothing -> setNameSupplyRn new_ns `thenRn_`
180 (us', us1) = splitUniqSupply (nsUniqs name_supply)
181 uniq = uniqFromSupply us1
182 name_ip = mapIPName mk_name rdr_name_ip
183 mk_name rdr_name = mkIPName uniq (rdrNameOcc rdr_name)
184 new_ipcache = addToFM ipcache key name_ip
185 new_ns = name_supply {nsUniqs = us', nsIPs = new_ipcache}
187 key = rdr_name_ip -- Ensures that ?x and %x get distinct Names
190 %*********************************************************
192 \subsection{Looking up names}
194 %*********************************************************
196 Looking up a name in the RnEnv.
199 lookupBndrRn rdr_name
200 = getLocalNameEnv `thenRn` \ local_env ->
201 case lookupRdrEnv local_env rdr_name of
202 Just name -> returnRn name
203 Nothing -> lookupTopBndrRn rdr_name
205 lookupTopBndrRn rdr_name
206 -- Look up a top-level local binder. We may be looking up an unqualified 'f',
207 -- and there may be several imported 'f's too, which must not confuse us.
208 -- So we have to filter out the non-local ones.
209 -- A separate function (importsFromLocalDecls) reports duplicate top level
210 -- decls, so here it's safe just to choose an arbitrary one.
213 -- This is here just to catch the PrelBase defn of (say) [] and similar
214 -- The parser reads the special syntax and returns an Orig RdrName
215 -- But the global_env contains only Qual RdrNames, so we won't
216 -- find it there; instead just get the name via the Orig route
218 = -- This is a binding site for the name, so check first that it
219 -- the current module is the correct one; otherwise GHC can get
220 -- very confused indeed. This test rejects code like
221 -- data T = (,) Int Int
222 -- unless we are in GHC.Tup
223 getModuleRn `thenRn` \ mod ->
224 checkRn (moduleName mod == rdrNameModule rdr_name)
225 (badOrigBinding rdr_name) `thenRn_`
226 lookupOrigName rdr_name
229 = getModeRn `thenRn` \ mode ->
230 if isInterfaceMode mode
231 then lookupSysBinder rdr_name
232 -- lookupSysBinder uses the Module in the monad to set
233 -- the correct module for the binder. This is important because
234 -- when GHCi is reading in an old interface, it just sucks it
235 -- in entire (Rename.loadHomeDecls) which uses lookupTopBndrRn
236 -- rather than via the iface file cache which uses newTopBndrRn
237 -- We must get the correct Module into the thing.
240 getModuleRn `thenRn` \ mod ->
241 getGlobalNameEnv `thenRn` \ global_env ->
242 case lookup_local mod global_env rdr_name of
243 Just name -> returnRn name
244 Nothing -> failWithRn (mkUnboundName rdr_name)
245 (unknownNameErr rdr_name)
247 lookup_local mod global_env rdr_name
248 = case lookupRdrEnv global_env rdr_name of
250 Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
255 -- lookupSigOccRn is used for type signatures and pragmas
261 -- It's clear that the 'f' in the signature must refer to A.f
262 -- The Haskell98 report does not stipulate this, but it will!
263 -- So we must treat the 'f' in the signature in the same way
264 -- as the binding occurrence of 'f', using lookupBndrRn
265 lookupSigOccRn :: RdrName -> RnMS Name
266 lookupSigOccRn = lookupBndrRn
268 -- lookupInstDeclBndr is used for the binders in an
269 -- instance declaration. Here we use the class name to
272 lookupInstDeclBndr :: Name -> RdrName -> RnMS Name
273 -- We use the selector name as the binder
274 lookupInstDeclBndr cls_name rdr_name
275 | isOrig rdr_name -- Occurs in derived instances, where we just
276 -- refer diectly to the right method
277 = lookupOrigName rdr_name
280 = getGlobalAvails `thenRn` \ avail_env ->
281 case lookupNameEnv avail_env cls_name of
282 -- The class itself isn't in scope, so cls_name is unboundName
283 -- e.g. import Prelude hiding( Ord )
284 -- instance Ord T where ...
285 -- The program is wrong, but that should not cause a crash.
286 Nothing -> returnRn (mkUnboundName rdr_name)
287 Just (AvailTC _ ns) -> case [n | n <- ns, nameOccName n == occ] of
288 (n:ns)-> ASSERT( null ns ) returnRn n
289 [] -> failWithRn (mkUnboundName rdr_name)
290 (unknownNameErr rdr_name)
291 other -> pprPanic "lookupInstDeclBndr" (ppr cls_name)
293 occ = rdrNameOcc rdr_name
295 -- lookupOccRn looks up an occurrence of a RdrName
296 lookupOccRn :: RdrName -> RnMS Name
298 = getLocalNameEnv `thenRn` \ local_env ->
299 case lookupRdrEnv local_env rdr_name of
300 Just name -> returnRn name
301 Nothing -> lookupGlobalOccRn rdr_name
303 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
304 -- environment. It's used only for
305 -- record field names
306 -- class op names in class and instance decls
308 lookupGlobalOccRn rdr_name
309 = getModeRn `thenRn` \ mode ->
310 if (isInterfaceMode mode)
311 then lookupIfaceName rdr_name
314 getGlobalNameEnv `thenRn` \ global_env ->
316 SourceMode -> lookupSrcName global_env rdr_name
319 | not (isQual rdr_name) ->
320 lookupSrcName global_env rdr_name
322 -- We allow qualified names on the command line to refer to
323 -- *any* name exported by any module in scope, just as if
324 -- there was an "import qualified M" declaration for every
327 -- First look up the name in the normal environment. If
328 -- it isn't there, we manufacture a new occurrence of an
331 case lookupRdrEnv global_env rdr_name of
332 Just _ -> lookupSrcName global_env rdr_name
333 Nothing -> lookupQualifiedName rdr_name
335 -- a qualified name on the command line can refer to any module at all: we
336 -- try to load the interface if we don't already have it.
337 lookupQualifiedName :: RdrName -> RnM d Name
338 lookupQualifiedName rdr_name
340 mod = rdrNameModule rdr_name
341 occ = rdrNameOcc rdr_name
343 loadInterface (ppr rdr_name) mod ImportByUser `thenRn` \ iface ->
344 case [ name | (_,avails) <- mi_exports iface,
346 name <- availNames avail,
347 nameOccName name == occ ] of
348 (n:ns) -> ASSERT (null ns) returnRn n
349 _ -> failWithRn (mkUnboundName rdr_name) (unknownNameErr rdr_name)
351 lookupSrcName :: GlobalRdrEnv -> RdrName -> RnM d Name
352 -- NB: passed GlobalEnv explicitly, not necessarily in RnMS monad
353 lookupSrcName global_env rdr_name
354 | isOrig rdr_name -- Can occur in source code too
355 = lookupOrigName rdr_name
358 = case lookupRdrEnv global_env rdr_name of
359 Just [GRE name _ Nothing] -> returnRn name
360 Just [GRE name _ (Just deprec)] -> warnDeprec name deprec `thenRn_`
362 Just stuff@(GRE name _ _ : _) -> addNameClashErrRn rdr_name stuff `thenRn_`
364 Nothing -> failWithRn (mkUnboundName rdr_name)
365 (unknownNameErr rdr_name)
367 lookupOrigName :: RdrName -> RnM d Name
368 lookupOrigName rdr_name
369 = -- NO: ASSERT( isOrig rdr_name )
370 -- Now that .hi-boot files are read by the main parser, they contain
371 -- ordinary qualified names (which we treat as Orig names here).
372 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
374 lookupIfaceUnqual :: RdrName -> RnM d Name
375 lookupIfaceUnqual rdr_name
376 = ASSERT( isUnqual rdr_name )
377 -- An Unqual is allowed; interface files contain
378 -- unqualified names for locally-defined things, such as
379 -- constructors of a data type.
380 getModuleRn `thenRn ` \ mod ->
381 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
383 lookupIfaceName :: RdrName -> RnM d Name
384 lookupIfaceName rdr_name
385 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
386 | otherwise = lookupOrigName rdr_name
389 @lookupOrigName@ takes an RdrName representing an {\em original}
390 name, and adds it to the occurrence pool so that it'll be loaded
391 later. This is used when language constructs (such as monad
392 comprehensions, overloaded literals, or deriving clauses) require some
393 stuff to be loaded that isn't explicitly mentioned in the code.
395 This doesn't apply in interface mode, where everything is explicit,
396 but we don't check for this case: it does no harm to record an
397 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
398 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
399 calls it at all I think).
401 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
404 lookupOrigNames :: [RdrName] -> RnM d NameSet
405 lookupOrigNames rdr_names
406 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
407 returnRn (mkNameSet names)
410 lookupSysBinder is used for the "system binders" of a type, class, or
411 instance decl. It ensures that the module is set correctly in the
412 name cache, and sets the provenance on the returned name too. The
413 returned name will end up actually in the type, class, or instance.
416 lookupSysBinder rdr_name
417 = ASSERT( isUnqual rdr_name )
418 getModuleRn `thenRn` \ mod ->
419 getSrcLocRn `thenRn` \ loc ->
420 newTopBinder mod rdr_name loc
424 %*********************************************************
426 \subsection{Looking up fixities}
428 %*********************************************************
430 lookupFixity is a bit strange.
432 * Nested local fixity decls are put in the local fixity env, which we
433 find with getFixtyEnv
435 * Imported fixities are found in the HIT or PIT
437 * Top-level fixity decls in this module may be for Names that are
438 either Global (constructors, class operations)
439 or Local/Exported (everything else)
440 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
441 We put them all in the local fixity environment
444 lookupFixityRn :: Name -> RnMS Fixity
446 = getModuleRn `thenRn` \ this_mod ->
447 if nameIsLocalOrFrom this_mod name
448 then -- It's defined in this module
449 getFixityEnv `thenRn` \ local_fix_env ->
450 returnRn (lookupLocalFixity local_fix_env name)
452 else -- It's imported
453 -- For imported names, we have to get their fixities by doing a
454 -- loadHomeInterface, and consulting the Ifaces that comes back
455 -- from that, because the interface file for the Name might not
456 -- have been loaded yet. Why not? Suppose you import module A,
457 -- which exports a function 'f', thus;
458 -- module CurrentModule where
460 -- module A( f ) where
462 -- Then B isn't loaded right away (after all, it's possible that
463 -- nothing from B will be used). When we come across a use of
464 -- 'f', we need to know its fixity, and it's then, and only
465 -- then, that we load B.hi. That is what's happening here.
466 loadInterface doc name_mod ImportBySystem `thenRn` \ iface ->
467 returnRn (lookupFixity (mi_fixities iface) name)
469 doc = ptext SLIT("Checking fixity for") <+> ppr name
470 name_mod = moduleName (nameModule name)
472 --------------------------------
473 lookupLocalFixity :: LocalFixityEnv -> Name -> Fixity
474 lookupLocalFixity env name
475 = case lookupNameEnv env name of
476 Just (FixitySig _ fix _) -> fix
477 Nothing -> defaultFixity
479 extendNestedFixityEnv :: [(Name, RenamedFixitySig)] -> RnMS a -> RnMS a
480 -- Used for nested fixity decls
481 -- No need to worry about type constructors here,
482 -- Should check for duplicates but we don't
483 extendNestedFixityEnv fixes enclosed_scope
484 = getFixityEnv `thenRn` \ fix_env ->
486 new_fix_env = extendNameEnvList fix_env fixes
488 setFixityEnv new_fix_env enclosed_scope
490 mkTopFixityEnv :: GlobalRdrEnv -> [RdrNameFixitySig] -> RnMG LocalFixityEnv
491 mkTopFixityEnv gbl_env fix_sigs
492 = getModuleRn `thenRn` \ mod ->
494 -- GHC extension: look up both the tycon and data con
495 -- for con-like things
496 -- If neither are in scope, report an error; otherwise
497 -- add both to the fixity env
498 go fix_env (FixitySig rdr_name fixity loc)
499 = case catMaybes (map (lookup_local mod gbl_env) rdr_names) of
500 [] -> addErrRn (unknownNameErr rdr_name) `thenRn_`
502 ns -> foldlRn add fix_env ns
506 = case lookupNameEnv fix_env name of
507 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc') `thenRn_`
509 Nothing -> returnRn (extendNameEnv fix_env name (FixitySig name fixity loc))
511 rdr_names | isDataSymOcc occ = [rdr_name, rdr_name_tc]
512 | otherwise = [rdr_name]
514 occ = rdrNameOcc rdr_name
515 rdr_name_tc = setRdrNameOcc rdr_name (setOccNameSpace occ tcName)
517 foldlRn go emptyLocalFixityEnv fix_sigs
521 %*********************************************************
523 \subsection{Implicit free vars and sugar names}
525 %*********************************************************
527 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
528 mentioned explicitly, but which might be needed by the type checker.
531 getImplicitStmtFVs -- Compiling a statement
532 = returnRn (mkFVs [printName, bindIOName, thenIOName,
533 returnIOName, failIOName]
534 `plusFV` ubiquitousNames)
535 -- These are all needed implicitly when compiling a statement
536 -- See TcModule.tc_stmts
538 getImplicitModuleFVs decls -- Compiling a module
539 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
540 returnRn (deriving_names `plusFV` ubiquitousNames)
542 -- deriv_classes is now a list of HsTypes, so a "normal" one
543 -- appears as a (HsClassP c []). The non-normal ones for the new
544 -- newtype-deriving extension, and they don't require any
545 -- implicit names, so we can silently filter them out.
546 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
547 HsClassP cls [] <- deriv_classes,
548 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
550 -- ubiquitous_names are loaded regardless, because
551 -- they are needed in virtually every program
553 = mkFVs [unpackCStringName, unpackCStringFoldrName,
554 unpackCStringUtf8Name, eqStringName]
555 -- Virtually every program has error messages in it somewhere
558 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
559 -- Add occurrences for very frequently used types.
560 -- (e.g. we don't want to be bothered with making funTyCon a
561 -- free var at every function application!)
563 namesNeededForFlattening
564 -- this will be empty unless flattening is activated
566 checkMain ghci_mode mod_name gbl_env
567 -- LOOKUP main IF WE'RE IN MODULE Main
568 -- The main point of this is to drag in the declaration for 'main',
569 -- its in another module, and for the Prelude function 'runMain',
570 -- so that the type checker will find them
572 -- We have to return the main_name separately, because it's a
573 -- bona fide 'use', and should be recorded as such, but the others
575 | mod_name /= mAIN_Name
576 = returnRn (Nothing, emptyFVs, emptyFVs)
578 | not (main_RDR_Unqual `elemRdrEnv` gbl_env)
579 = complain_no_main `thenRn_`
580 returnRn (Nothing, emptyFVs, emptyFVs)
583 = lookupSrcName gbl_env main_RDR_Unqual `thenRn` \ main_name ->
584 returnRn (Just main_name, unitFV main_name, unitFV runMainName)
587 complain_no_main | ghci_mode == Interactive = addWarnRn noMainMsg
588 | otherwise = addErrRn noMainMsg
589 -- In interactive mode, only warn about the absence of main
592 %************************************************************************
594 \subsection{Re-bindable desugaring names}
596 %************************************************************************
598 Haskell 98 says that when you say "3" you get the "fromInteger" from the
599 Standard Prelude, regardless of what is in scope. However, to experiment
600 with having a language that is less coupled to the standard prelude, we're
601 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
602 happens to be in scope. Then you can
604 import MyPrelude as Prelude
605 to get the desired effect.
607 At the moment this just happens for
608 * fromInteger, fromRational on literals (in expressions and patterns)
609 * negate (in expressions)
610 * minus (arising from n+k patterns)
612 We store the relevant Name in the HsSyn tree, in
613 * HsIntegral/HsFractional
616 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
617 fromRationalName etc), but the renamer changes this to the appropriate user
618 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
621 lookupSyntaxName :: Name -- The standard name
622 -> RnMS Name -- Possibly a non-standard name
623 lookupSyntaxName std_name
624 = doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
625 if not no_prelude then
626 returnRn std_name -- Normal case
629 rdr_name = mkRdrUnqual (nameOccName std_name)
630 -- Get the similarly named thing from the local environment
636 %*********************************************************
640 %*********************************************************
643 newLocalsRn :: [(RdrName,SrcLoc)]
645 newLocalsRn rdr_names_w_loc
646 = getNameSupplyRn `thenRn` \ name_supply ->
648 (us', us1) = splitUniqSupply (nsUniqs name_supply)
649 uniqs = uniqsFromSupply us1
650 names = [ mkInternalName uniq (rdrNameOcc rdr_name) loc
651 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
654 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
658 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
659 -> [(RdrName,SrcLoc)]
660 -> ([Name] -> RnMS a)
662 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
663 = getModeRn `thenRn` \ mode ->
664 getLocalNameEnv `thenRn` \ local_env ->
665 getGlobalNameEnv `thenRn` \ global_env ->
667 -- Check for duplicate names
668 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
670 -- Warn about shadowing, but only in source modules
672 check_shadow (rdr_name,loc)
673 | rdr_name `elemRdrEnv` local_env
674 || rdr_name `elemRdrEnv` global_env
675 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
681 SourceMode -> ifOptRn Opt_WarnNameShadowing $
682 mapRn_ check_shadow rdr_names_w_loc
686 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
688 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
690 setLocalNameEnv new_local_env (enclosed_scope names)
692 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
693 -- A specialised variant when renaming stuff from interface
694 -- files (of which there is a lot)
696 -- * no checks for shadowing
698 -- * deal with free vars
699 bindCoreLocalRn rdr_name enclosed_scope
700 = getSrcLocRn `thenRn` \ loc ->
701 getLocalNameEnv `thenRn` \ name_env ->
702 getNameSupplyRn `thenRn` \ name_supply ->
704 (us', us1) = splitUniqSupply (nsUniqs name_supply)
705 uniq = uniqFromSupply us1
706 name = mkInternalName uniq (rdrNameOcc rdr_name) loc
708 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
710 new_name_env = extendRdrEnv name_env rdr_name name
712 setLocalNameEnv new_name_env (enclosed_scope name)
714 bindCoreLocalsRn [] thing_inside = thing_inside []
715 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
716 bindCoreLocalsRn bs $ \ names' ->
717 thing_inside (name':names')
719 bindLocalNames names enclosed_scope
720 = getLocalNameEnv `thenRn` \ name_env ->
721 setLocalNameEnv (extendLocalRdrEnv name_env names)
724 bindLocalNamesFV names enclosed_scope
725 = bindLocalNames names $
726 enclosed_scope `thenRn` \ (thing, fvs) ->
727 returnRn (thing, delListFromNameSet fvs names)
730 -------------------------------------
731 bindLocalRn doc rdr_name enclosed_scope
732 = getSrcLocRn `thenRn` \ loc ->
733 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
737 bindLocalsRn doc rdr_names enclosed_scope
738 = getSrcLocRn `thenRn` \ loc ->
739 bindLocatedLocalsRn doc
740 (rdr_names `zip` repeat loc)
743 -- binLocalsFVRn is the same as bindLocalsRn
744 -- except that it deals with free vars
745 bindLocalsFVRn doc rdr_names enclosed_scope
746 = bindLocalsRn doc rdr_names $ \ names ->
747 enclosed_scope names `thenRn` \ (thing, fvs) ->
748 returnRn (thing, delListFromNameSet fvs names)
750 -------------------------------------
751 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
752 -- This tiresome function is used only in rnSourceDecl on InstDecl
753 extendTyVarEnvFVRn tyvars enclosed_scope
754 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
755 returnRn (thing, delListFromNameSet fvs tyvars)
757 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
758 -> ([HsTyVarBndr Name] -> RnMS a)
760 bindTyVarsRn doc_str tyvar_names enclosed_scope
761 = getSrcLocRn `thenRn` \ loc ->
763 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
765 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
766 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
768 bindPatSigTyVars :: [RdrNameHsType]
769 -> RnMS (a, FreeVars)
770 -> RnMS (a, FreeVars)
771 -- Find the type variables in the pattern type
772 -- signatures that must be brought into scope
774 bindPatSigTyVars tys enclosed_scope
775 = getLocalNameEnv `thenRn` \ name_env ->
776 getSrcLocRn `thenRn` \ loc ->
778 forall_tyvars = nub [ tv | ty <- tys,
779 tv <- extractHsTyRdrTyVars ty,
780 not (tv `elemFM` name_env)
782 -- The 'nub' is important. For example:
783 -- f (x :: t) (y :: t) = ....
784 -- We don't want to complain about binding t twice!
786 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
787 doc_sig = text "In a pattern type-signature"
789 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
790 enclosed_scope `thenRn` \ (thing, fvs) ->
791 returnRn (thing, delListFromNameSet fvs names)
794 -------------------------------------
795 checkDupOrQualNames, checkDupNames :: SDoc
796 -> [(RdrName, SrcLoc)]
798 -- Works in any variant of the renamer monad
800 checkDupOrQualNames doc_str rdr_names_w_loc
801 = -- Check for use of qualified names
802 mapRn_ (qualNameErr doc_str) quals `thenRn_`
803 checkDupNames doc_str rdr_names_w_loc
805 quals = filter (isQual . fst) rdr_names_w_loc
807 checkDupNames doc_str rdr_names_w_loc
808 = -- Check for duplicated names in a binding group
809 mapRn_ (dupNamesErr doc_str) dups
811 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
815 %************************************************************************
817 \subsection{GlobalRdrEnv}
819 %************************************************************************
822 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
823 -> Bool -- True <=> want unqualified import
824 -> (Name -> Provenance)
825 -> Avails -- Whats imported
829 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
832 -- Make the name environment. We're talking about a
833 -- single module here, so there must be no name clashes.
834 -- In practice there only ever will be if it's the module
837 -- Add qualified names for the things that are available
838 -- (Qualified names are always imported)
839 gbl_env1 = foldl add_avail emptyRdrEnv avails
841 -- Add unqualified names
842 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
843 | otherwise = gbl_env1
845 add_unqual env (qual_name, elts)
846 = foldl add_one env elts
848 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
849 unqual_name = unqualifyRdrName qual_name
850 -- The qualified import should only have added one
851 -- binding for each qualified name! But if there's an error in
852 -- the module (multiple bindings for the same name) we may get
853 -- duplicates. So the simple thing is to do the fold.
855 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
856 add_avail env avail = foldl add_name env (availNames avail)
858 add_name env name -- Add qualified name only
859 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
861 occ = nameOccName name
862 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
866 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
867 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
869 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
870 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
872 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
873 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
875 combine_globals :: [GlobalRdrElt] -- Old
876 -> [GlobalRdrElt] -- New
878 combine_globals ns_old ns_new -- ns_new is often short
879 = foldr add ns_old ns_new
881 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
884 choose n m | n `beats` m = n
887 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
889 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
890 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
891 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
894 We treat two bindings of a locally-defined name as a duplicate,
895 because they might be two separate, local defns and we want to report
896 and error for that, {\em not} eliminate a duplicate.
898 On the other hand, if you import the same name from two different
899 import statements, we {\em do} want to eliminate the duplicate, not report
902 If a module imports itself then there might be a local defn and an imported
903 defn of the same name; in this case the names will compare as equal, but
904 will still have different provenances.
907 @unQualInScope@ returns a function that takes a @Name@ and tells whether
908 its unqualified name is in scope. This is put as a boolean flag in
909 the @Name@'s provenance to guide whether or not to print the name qualified
913 unQualInScope :: GlobalRdrEnv -> Name -> Bool
914 -- True if 'f' is in scope, and has only one binding,
915 -- and the thing it is bound to is the name we are looking for
916 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
918 -- This fn is only efficient if the shared
919 -- partial application is used a lot.
921 = (`elemNameSet` unqual_names)
923 unqual_names :: NameSet
924 unqual_names = foldRdrEnv add emptyNameSet env
925 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
926 add _ _ unquals = unquals
930 %************************************************************************
934 %************************************************************************
937 plusAvail (Avail n1) (Avail n2) = Avail n1
938 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
941 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
944 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
945 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
947 unitAvailEnv :: AvailInfo -> AvailEnv
948 unitAvailEnv a = unitNameEnv (availName a) a
950 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
951 plusAvailEnv = plusNameEnv_C plusAvail
953 availEnvElts = nameEnvElts
955 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
956 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
958 availsToNameSet :: [AvailInfo] -> NameSet
959 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
961 availName :: GenAvailInfo name -> name
962 availName (Avail n) = n
963 availName (AvailTC n _) = n
965 availNames :: GenAvailInfo name -> [name]
966 availNames (Avail n) = [n]
967 availNames (AvailTC n ns) = ns
969 -------------------------------------
970 filterAvail :: RdrNameIE -- Wanted
971 -> AvailInfo -- Available
972 -> Maybe AvailInfo -- Resulting available;
973 -- Nothing if (any of the) wanted stuff isn't there
975 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
976 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
977 | otherwise = Nothing
979 is_wanted name = nameOccName name `elem` wanted_occs
980 sub_names_ok = all (`elem` avail_occs) wanted_occs
981 avail_occs = map nameOccName ns
982 wanted_occs = map rdrNameOcc (want:wants)
984 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
987 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
989 filterAvail (IEVar _) avail@(Avail n) = Just avail
990 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
992 wanted n = nameOccName n == occ
994 -- The second equation happens if we import a class op, thus
996 -- where op is a class operation
998 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
999 -- We don't complain even if the IE says T(..), but
1000 -- no constrs/class ops of T are available
1001 -- Instead that's caught with a warning by the caller
1003 filterAvail ie avail = Nothing
1005 -------------------------------------
1006 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
1007 -- Group by module and sort by occurrence
1008 -- This keeps the list in canonical order
1009 groupAvails this_mod avails
1010 = [ (mkSysModuleNameFS fs, sortLt lt avails)
1011 | (fs,avails) <- fmToList groupFM
1014 groupFM :: FiniteMap FastString Avails
1015 -- Deliberately use the FastString so we
1016 -- get a canonical ordering
1017 groupFM = foldl add emptyFM avails
1019 add env avail = addToFM_C combine env mod_fs [avail']
1021 mod_fs = moduleNameFS (moduleName avail_mod)
1022 avail_mod = case nameModule_maybe (availName avail) of
1025 combine old _ = avail':old
1026 avail' = sortAvail avail
1028 a1 `lt` a2 = occ1 < occ2
1030 occ1 = nameOccName (availName a1)
1031 occ2 = nameOccName (availName a2)
1033 sortAvail :: AvailInfo -> AvailInfo
1034 -- Sort the sub-names into canonical order.
1035 -- The canonical order has the "main name" at the beginning
1036 -- (if it's there at all)
1037 sortAvail (Avail n) = Avail n
1038 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
1039 | otherwise = AvailTC n ( sortLt lt ns)
1041 n1 `lt` n2 = nameOccName n1 < nameOccName n2
1045 pruneAvails :: (Name -> Bool) -- Keep if this is True
1048 pruneAvails keep avails
1049 = mapMaybe del avails
1051 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
1052 del (Avail n) | keep n = Just (Avail n)
1053 | otherwise = Nothing
1054 del (AvailTC n ns) | null ns' = Nothing
1055 | otherwise = Just (AvailTC n ns')
1057 ns' = filter keep ns
1060 %************************************************************************
1062 \subsection{Free variable manipulation}
1064 %************************************************************************
1068 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
1070 (ys, fvs_s) = unzip stuff
1072 returnRn (ys, plusFVs fvs_s)
1076 %************************************************************************
1078 \subsection{Envt utility functions}
1080 %************************************************************************
1083 warnUnusedModules :: [ModuleName] -> RnM d ()
1084 warnUnusedModules mods
1085 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
1087 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
1088 text "is imported, but nothing from it is used",
1089 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
1092 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
1093 warnUnusedImports names
1094 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
1096 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
1097 warnUnusedLocalBinds names
1098 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
1100 warnUnusedMatches names
1101 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
1103 -------------------------
1105 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
1106 warnUnusedBinds names
1107 = mapRn_ warnUnusedGroup groups
1109 -- Group by provenance
1110 groups = equivClasses cmp names
1111 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
1114 -------------------------
1116 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
1117 warnUnusedGroup names
1118 | null filtered_names = returnRn ()
1119 | not is_local = returnRn ()
1121 = pushSrcLocRn def_loc $
1123 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
1125 filtered_names = filter reportable names
1126 (name1, prov1) = head filtered_names
1127 (is_local, def_loc, msg)
1129 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
1131 NonLocalDef (UserImport mod loc _)
1132 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
1134 reportable (name,_) = case occNameUserString (nameOccName name) of
1137 -- Haskell 98 encourages compilers to suppress warnings about
1138 -- unused names in a pattern if they start with "_".
1142 addNameClashErrRn rdr_name (np1:nps)
1143 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1144 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1146 msg1 = ptext SLIT("either") <+> mk_ref np1
1147 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1148 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1150 shadowedNameWarn shadow
1151 = hsep [ptext SLIT("This binding for"),
1152 quotes (ppr shadow),
1153 ptext SLIT("shadows an existing binding")]
1155 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1158 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1160 flavour = occNameFlavour (rdrNameOcc name)
1163 = ptext SLIT("Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
1164 -- The rdrNameOcc is because we don't want to print Prelude.(,)
1166 qualNameErr descriptor (name,loc)
1167 = pushSrcLocRn loc $
1168 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1171 dupNamesErr descriptor ((name,loc) : dup_things)
1172 = pushSrcLocRn loc $
1173 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1177 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1179 = ifOptRn Opt_WarnDeprecations $
1180 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1181 quotes (ppr name) <+> text "is deprecated:",
1184 dupFixityDecl rdr_name loc1 loc2
1185 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
1186 ptext SLIT("at ") <+> ppr loc1,
1187 ptext SLIT("and") <+> ppr loc2]