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 [] -> pushSrcLocRn loc $
501 addErrRn (unknownNameErr rdr_name) `thenRn_`
503 ns -> foldlRn add fix_env ns
507 = case lookupNameEnv fix_env name of
508 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc') `thenRn_`
510 Nothing -> returnRn (extendNameEnv fix_env name (FixitySig name fixity loc))
512 rdr_names | isDataSymOcc occ = [rdr_name, rdr_name_tc]
513 | otherwise = [rdr_name]
515 occ = rdrNameOcc rdr_name
516 rdr_name_tc = setRdrNameOcc rdr_name (setOccNameSpace occ tcName)
518 foldlRn go emptyLocalFixityEnv fix_sigs
522 %*********************************************************
524 \subsection{Implicit free vars and sugar names}
526 %*********************************************************
528 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
529 mentioned explicitly, but which might be needed by the type checker.
532 getImplicitStmtFVs -- Compiling a statement
533 = returnRn (mkFVs [printName, bindIOName, thenIOName,
534 returnIOName, failIOName]
535 `plusFV` ubiquitousNames)
536 -- These are all needed implicitly when compiling a statement
537 -- See TcModule.tc_stmts
539 getImplicitModuleFVs decls -- Compiling a module
540 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
541 returnRn (deriving_names `plusFV` ubiquitousNames)
543 -- deriv_classes is now a list of HsTypes, so a "normal" one
544 -- appears as a (HsClassP c []). The non-normal ones for the new
545 -- newtype-deriving extension, and they don't require any
546 -- implicit names, so we can silently filter them out.
547 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
548 HsClassP cls [] <- deriv_classes,
549 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
551 -- ubiquitous_names are loaded regardless, because
552 -- they are needed in virtually every program
554 = mkFVs [unpackCStringName, unpackCStringFoldrName,
555 unpackCStringUtf8Name, eqStringName]
556 -- Virtually every program has error messages in it somewhere
559 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
560 -- Add occurrences for very frequently used types.
561 -- (e.g. we don't want to be bothered with making funTyCon a
562 -- free var at every function application!)
564 namesNeededForFlattening
565 -- this will be empty unless flattening is activated
567 checkMain ghci_mode mod_name gbl_env
568 -- LOOKUP main IF WE'RE IN MODULE Main
569 -- The main point of this is to drag in the declaration for 'main',
570 -- its in another module, and for the Prelude function 'runMain',
571 -- so that the type checker will find them
573 -- We have to return the main_name separately, because it's a
574 -- bona fide 'use', and should be recorded as such, but the others
576 | mod_name /= mAIN_Name
577 = returnRn (Nothing, emptyFVs, emptyFVs)
579 | not (main_RDR_Unqual `elemRdrEnv` gbl_env)
580 = complain_no_main `thenRn_`
581 returnRn (Nothing, emptyFVs, emptyFVs)
584 = lookupSrcName gbl_env main_RDR_Unqual `thenRn` \ main_name ->
585 returnRn (Just main_name, unitFV main_name, unitFV runMainName)
588 complain_no_main | ghci_mode == Interactive = addWarnRn noMainMsg
589 | otherwise = addErrRn noMainMsg
590 -- In interactive mode, only warn about the absence of main
593 %************************************************************************
595 \subsection{Re-bindable desugaring names}
597 %************************************************************************
599 Haskell 98 says that when you say "3" you get the "fromInteger" from the
600 Standard Prelude, regardless of what is in scope. However, to experiment
601 with having a language that is less coupled to the standard prelude, we're
602 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
603 happens to be in scope. Then you can
605 import MyPrelude as Prelude
606 to get the desired effect.
608 At the moment this just happens for
609 * fromInteger, fromRational on literals (in expressions and patterns)
610 * negate (in expressions)
611 * minus (arising from n+k patterns)
614 We store the relevant Name in the HsSyn tree, in
615 * HsIntegral/HsFractional
619 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
620 fromRationalName etc), but the renamer changes this to the appropriate user
621 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
624 lookupSyntaxName :: Name -- The standard name
625 -> RnMS Name -- Possibly a non-standard name
626 lookupSyntaxName std_name
627 = getModeRn `thenRn` \ mode ->
629 InterfaceMode -> returnRn std_name ; -- Happens for 'derived' code
630 -- where we don't want to rebind
633 doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
634 if not no_prelude then
635 returnRn std_name -- Normal case
637 -- Get the similarly named thing from the local environment
638 lookupOccRn (mkRdrUnqual (nameOccName std_name)) }
642 %*********************************************************
646 %*********************************************************
649 newLocalsRn :: [(RdrName,SrcLoc)]
651 newLocalsRn rdr_names_w_loc
652 = getNameSupplyRn `thenRn` \ name_supply ->
654 (us', us1) = splitUniqSupply (nsUniqs name_supply)
655 uniqs = uniqsFromSupply us1
656 names = [ mkInternalName uniq (rdrNameOcc rdr_name) loc
657 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
660 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
664 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
665 -> [(RdrName,SrcLoc)]
666 -> ([Name] -> RnMS a)
668 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
669 = getModeRn `thenRn` \ mode ->
670 getLocalNameEnv `thenRn` \ local_env ->
671 getGlobalNameEnv `thenRn` \ global_env ->
673 -- Check for duplicate names
674 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
676 -- Warn about shadowing, but only in source modules
678 check_shadow (rdr_name,loc)
679 | rdr_name `elemRdrEnv` local_env
680 || rdr_name `elemRdrEnv` global_env
681 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
687 SourceMode -> ifOptRn Opt_WarnNameShadowing $
688 mapRn_ check_shadow rdr_names_w_loc
692 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
694 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
696 setLocalNameEnv new_local_env (enclosed_scope names)
698 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
699 -- A specialised variant when renaming stuff from interface
700 -- files (of which there is a lot)
702 -- * no checks for shadowing
704 -- * deal with free vars
705 bindCoreLocalRn rdr_name enclosed_scope
706 = getSrcLocRn `thenRn` \ loc ->
707 getLocalNameEnv `thenRn` \ name_env ->
708 getNameSupplyRn `thenRn` \ name_supply ->
710 (us', us1) = splitUniqSupply (nsUniqs name_supply)
711 uniq = uniqFromSupply us1
712 name = mkInternalName uniq (rdrNameOcc rdr_name) loc
714 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
716 new_name_env = extendRdrEnv name_env rdr_name name
718 setLocalNameEnv new_name_env (enclosed_scope name)
720 bindCoreLocalsRn [] thing_inside = thing_inside []
721 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
722 bindCoreLocalsRn bs $ \ names' ->
723 thing_inside (name':names')
725 bindLocalNames names enclosed_scope
726 = getLocalNameEnv `thenRn` \ name_env ->
727 setLocalNameEnv (extendLocalRdrEnv name_env names)
730 bindLocalNamesFV names enclosed_scope
731 = bindLocalNames names $
732 enclosed_scope `thenRn` \ (thing, fvs) ->
733 returnRn (thing, delListFromNameSet fvs names)
736 -------------------------------------
737 bindLocalRn doc rdr_name enclosed_scope
738 = getSrcLocRn `thenRn` \ loc ->
739 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
743 bindLocalsRn doc rdr_names enclosed_scope
744 = getSrcLocRn `thenRn` \ loc ->
745 bindLocatedLocalsRn doc
746 (rdr_names `zip` repeat loc)
749 -- binLocalsFVRn is the same as bindLocalsRn
750 -- except that it deals with free vars
751 bindLocalsFVRn doc rdr_names enclosed_scope
752 = bindLocalsRn doc rdr_names $ \ names ->
753 enclosed_scope names `thenRn` \ (thing, fvs) ->
754 returnRn (thing, delListFromNameSet fvs names)
756 -------------------------------------
757 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
758 -- This tiresome function is used only in rnSourceDecl on InstDecl
759 extendTyVarEnvFVRn tyvars enclosed_scope
760 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
761 returnRn (thing, delListFromNameSet fvs tyvars)
763 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
764 -> ([HsTyVarBndr Name] -> RnMS a)
766 bindTyVarsRn doc_str tyvar_names enclosed_scope
767 = getSrcLocRn `thenRn` \ loc ->
769 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
771 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
772 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
774 bindPatSigTyVars :: [RdrNameHsType]
775 -> RnMS (a, FreeVars)
776 -> RnMS (a, FreeVars)
777 -- Find the type variables in the pattern type
778 -- signatures that must be brought into scope
780 bindPatSigTyVars tys enclosed_scope
781 = getLocalNameEnv `thenRn` \ name_env ->
782 getSrcLocRn `thenRn` \ loc ->
784 forall_tyvars = nub [ tv | ty <- tys,
785 tv <- extractHsTyRdrTyVars ty,
786 not (tv `elemFM` name_env)
788 -- The 'nub' is important. For example:
789 -- f (x :: t) (y :: t) = ....
790 -- We don't want to complain about binding t twice!
792 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
793 doc_sig = text "In a pattern type-signature"
795 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
796 enclosed_scope `thenRn` \ (thing, fvs) ->
797 returnRn (thing, delListFromNameSet fvs names)
800 -------------------------------------
801 checkDupOrQualNames, checkDupNames :: SDoc
802 -> [(RdrName, SrcLoc)]
804 -- Works in any variant of the renamer monad
806 checkDupOrQualNames doc_str rdr_names_w_loc
807 = -- Check for use of qualified names
808 mapRn_ (qualNameErr doc_str) quals `thenRn_`
809 checkDupNames doc_str rdr_names_w_loc
811 quals = filter (isQual . fst) rdr_names_w_loc
813 checkDupNames doc_str rdr_names_w_loc
814 = -- Check for duplicated names in a binding group
815 mapRn_ (dupNamesErr doc_str) dups
817 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
821 %************************************************************************
823 \subsection{GlobalRdrEnv}
825 %************************************************************************
828 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
829 -> Bool -- True <=> want unqualified import
830 -> (Name -> Provenance)
831 -> Avails -- Whats imported
835 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
838 -- Make the name environment. We're talking about a
839 -- single module here, so there must be no name clashes.
840 -- In practice there only ever will be if it's the module
843 -- Add qualified names for the things that are available
844 -- (Qualified names are always imported)
845 gbl_env1 = foldl add_avail emptyRdrEnv avails
847 -- Add unqualified names
848 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
849 | otherwise = gbl_env1
851 add_unqual env (qual_name, elts)
852 = foldl add_one env elts
854 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
855 unqual_name = unqualifyRdrName qual_name
856 -- The qualified import should only have added one
857 -- binding for each qualified name! But if there's an error in
858 -- the module (multiple bindings for the same name) we may get
859 -- duplicates. So the simple thing is to do the fold.
861 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
862 add_avail env avail = foldl add_name env (availNames avail)
864 add_name env name -- Add qualified name only
865 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
867 occ = nameOccName name
868 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
872 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
873 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
875 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
876 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
878 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
879 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
881 combine_globals :: [GlobalRdrElt] -- Old
882 -> [GlobalRdrElt] -- New
884 combine_globals ns_old ns_new -- ns_new is often short
885 = foldr add ns_old ns_new
887 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
890 choose n m | n `beats` m = n
893 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
895 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
896 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
897 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
900 We treat two bindings of a locally-defined name as a duplicate,
901 because they might be two separate, local defns and we want to report
902 and error for that, {\em not} eliminate a duplicate.
904 On the other hand, if you import the same name from two different
905 import statements, we {\em do} want to eliminate the duplicate, not report
908 If a module imports itself then there might be a local defn and an imported
909 defn of the same name; in this case the names will compare as equal, but
910 will still have different provenances.
913 @unQualInScope@ returns a function that takes a @Name@ and tells whether
914 its unqualified name is in scope. This is put as a boolean flag in
915 the @Name@'s provenance to guide whether or not to print the name qualified
919 unQualInScope :: GlobalRdrEnv -> Name -> Bool
920 -- True if 'f' is in scope, and has only one binding,
921 -- and the thing it is bound to is the name we are looking for
922 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
924 -- This fn is only efficient if the shared
925 -- partial application is used a lot.
927 = (`elemNameSet` unqual_names)
929 unqual_names :: NameSet
930 unqual_names = foldRdrEnv add emptyNameSet env
931 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
932 add _ _ unquals = unquals
936 %************************************************************************
940 %************************************************************************
943 plusAvail (Avail n1) (Avail n2) = Avail n1
944 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
947 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
950 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
951 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
953 unitAvailEnv :: AvailInfo -> AvailEnv
954 unitAvailEnv a = unitNameEnv (availName a) a
956 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
957 plusAvailEnv = plusNameEnv_C plusAvail
959 availEnvElts = nameEnvElts
961 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
962 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
964 availsToNameSet :: [AvailInfo] -> NameSet
965 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
967 availName :: GenAvailInfo name -> name
968 availName (Avail n) = n
969 availName (AvailTC n _) = n
971 availNames :: GenAvailInfo name -> [name]
972 availNames (Avail n) = [n]
973 availNames (AvailTC n ns) = ns
975 -------------------------------------
976 filterAvail :: RdrNameIE -- Wanted
977 -> AvailInfo -- Available
978 -> Maybe AvailInfo -- Resulting available;
979 -- Nothing if (any of the) wanted stuff isn't there
981 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
982 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
983 | otherwise = Nothing
985 is_wanted name = nameOccName name `elem` wanted_occs
986 sub_names_ok = all (`elem` avail_occs) wanted_occs
987 avail_occs = map nameOccName ns
988 wanted_occs = map rdrNameOcc (want:wants)
990 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
993 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
995 filterAvail (IEVar _) avail@(Avail n) = Just avail
996 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
998 wanted n = nameOccName n == occ
1000 -- The second equation happens if we import a class op, thus
1002 -- where op is a class operation
1004 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
1005 -- We don't complain even if the IE says T(..), but
1006 -- no constrs/class ops of T are available
1007 -- Instead that's caught with a warning by the caller
1009 filterAvail ie avail = Nothing
1011 -------------------------------------
1012 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
1013 -- Group by module and sort by occurrence
1014 -- This keeps the list in canonical order
1015 groupAvails this_mod avails
1016 = [ (mkSysModuleNameFS fs, sortLt lt avails)
1017 | (fs,avails) <- fmToList groupFM
1020 groupFM :: FiniteMap FastString Avails
1021 -- Deliberately use the FastString so we
1022 -- get a canonical ordering
1023 groupFM = foldl add emptyFM avails
1025 add env avail = addToFM_C combine env mod_fs [avail']
1027 mod_fs = moduleNameFS (moduleName avail_mod)
1028 avail_mod = case nameModule_maybe (availName avail) of
1031 combine old _ = avail':old
1032 avail' = sortAvail avail
1034 a1 `lt` a2 = occ1 < occ2
1036 occ1 = nameOccName (availName a1)
1037 occ2 = nameOccName (availName a2)
1039 sortAvail :: AvailInfo -> AvailInfo
1040 -- Sort the sub-names into canonical order.
1041 -- The canonical order has the "main name" at the beginning
1042 -- (if it's there at all)
1043 sortAvail (Avail n) = Avail n
1044 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
1045 | otherwise = AvailTC n ( sortLt lt ns)
1047 n1 `lt` n2 = nameOccName n1 < nameOccName n2
1051 pruneAvails :: (Name -> Bool) -- Keep if this is True
1054 pruneAvails keep avails
1055 = mapMaybe del avails
1057 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
1058 del (Avail n) | keep n = Just (Avail n)
1059 | otherwise = Nothing
1060 del (AvailTC n ns) | null ns' = Nothing
1061 | otherwise = Just (AvailTC n ns')
1063 ns' = filter keep ns
1066 %************************************************************************
1068 \subsection{Free variable manipulation}
1070 %************************************************************************
1074 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
1076 (ys, fvs_s) = unzip stuff
1078 returnRn (ys, plusFVs fvs_s)
1082 %************************************************************************
1084 \subsection{Envt utility functions}
1086 %************************************************************************
1089 warnUnusedModules :: [ModuleName] -> RnM d ()
1090 warnUnusedModules mods
1091 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
1093 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
1094 text "is imported, but nothing from it is used",
1095 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
1098 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
1099 warnUnusedImports names
1100 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
1102 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
1103 warnUnusedLocalBinds names
1104 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
1106 warnUnusedMatches names
1107 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
1109 -------------------------
1111 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
1112 warnUnusedBinds names
1113 = mapRn_ warnUnusedGroup groups
1115 -- Group by provenance
1116 groups = equivClasses cmp names
1117 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
1120 -------------------------
1122 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
1123 warnUnusedGroup names
1124 | null filtered_names = returnRn ()
1125 | not is_local = returnRn ()
1127 = pushSrcLocRn def_loc $
1129 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
1131 filtered_names = filter reportable names
1132 (name1, prov1) = head filtered_names
1133 (is_local, def_loc, msg)
1135 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
1137 NonLocalDef (UserImport mod loc _)
1138 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
1140 reportable (name,_) = case occNameUserString (nameOccName name) of
1143 -- Haskell 98 encourages compilers to suppress warnings about
1144 -- unused names in a pattern if they start with "_".
1148 addNameClashErrRn rdr_name (np1:nps)
1149 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1150 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1152 msg1 = ptext SLIT("either") <+> mk_ref np1
1153 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1154 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1156 shadowedNameWarn shadow
1157 = hsep [ptext SLIT("This binding for"),
1158 quotes (ppr shadow),
1159 ptext SLIT("shadows an existing binding")]
1161 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1164 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1166 flavour = occNameFlavour (rdrNameOcc name)
1169 = ptext SLIT("Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
1170 -- The rdrNameOcc is because we don't want to print Prelude.(,)
1172 qualNameErr descriptor (name,loc)
1173 = pushSrcLocRn loc $
1174 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1177 dupNamesErr descriptor ((name,loc) : dup_things)
1178 = pushSrcLocRn loc $
1179 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1183 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1185 = ifOptRn Opt_WarnDeprecations $
1186 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1187 quotes (ppr name) <+> text "is deprecated:",
1190 dupFixityDecl rdr_name loc1 loc2
1191 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
1192 ptext SLIT("at ") <+> ppr loc1,
1193 ptext SLIT("and") <+> ppr loc2]