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)
613 We store the relevant Name in the HsSyn tree, in
614 * HsIntegral/HsFractional
618 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
619 fromRationalName etc), but the renamer changes this to the appropriate user
620 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
623 lookupSyntaxName :: Name -- The standard name
624 -> RnMS Name -- Possibly a non-standard name
625 lookupSyntaxName std_name
626 = getModeRn `thenRn` \ mode ->
628 InterfaceMode -> returnRn std_name ; -- Happens for 'derived' code
629 -- where we don't want to rebind
632 doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
633 if not no_prelude then
634 returnRn std_name -- Normal case
636 -- Get the similarly named thing from the local environment
637 lookupOccRn (mkRdrUnqual (nameOccName std_name)) }
641 %*********************************************************
645 %*********************************************************
648 newLocalsRn :: [(RdrName,SrcLoc)]
650 newLocalsRn rdr_names_w_loc
651 = getNameSupplyRn `thenRn` \ name_supply ->
653 (us', us1) = splitUniqSupply (nsUniqs name_supply)
654 uniqs = uniqsFromSupply us1
655 names = [ mkInternalName uniq (rdrNameOcc rdr_name) loc
656 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
659 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
663 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
664 -> [(RdrName,SrcLoc)]
665 -> ([Name] -> RnMS a)
667 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
668 = getModeRn `thenRn` \ mode ->
669 getLocalNameEnv `thenRn` \ local_env ->
670 getGlobalNameEnv `thenRn` \ global_env ->
672 -- Check for duplicate names
673 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
675 -- Warn about shadowing, but only in source modules
677 check_shadow (rdr_name,loc)
678 | rdr_name `elemRdrEnv` local_env
679 || rdr_name `elemRdrEnv` global_env
680 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
686 SourceMode -> ifOptRn Opt_WarnNameShadowing $
687 mapRn_ check_shadow rdr_names_w_loc
691 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
693 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
695 setLocalNameEnv new_local_env (enclosed_scope names)
697 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
698 -- A specialised variant when renaming stuff from interface
699 -- files (of which there is a lot)
701 -- * no checks for shadowing
703 -- * deal with free vars
704 bindCoreLocalRn rdr_name enclosed_scope
705 = getSrcLocRn `thenRn` \ loc ->
706 getLocalNameEnv `thenRn` \ name_env ->
707 getNameSupplyRn `thenRn` \ name_supply ->
709 (us', us1) = splitUniqSupply (nsUniqs name_supply)
710 uniq = uniqFromSupply us1
711 name = mkInternalName uniq (rdrNameOcc rdr_name) loc
713 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
715 new_name_env = extendRdrEnv name_env rdr_name name
717 setLocalNameEnv new_name_env (enclosed_scope name)
719 bindCoreLocalsRn [] thing_inside = thing_inside []
720 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
721 bindCoreLocalsRn bs $ \ names' ->
722 thing_inside (name':names')
724 bindLocalNames names enclosed_scope
725 = getLocalNameEnv `thenRn` \ name_env ->
726 setLocalNameEnv (extendLocalRdrEnv name_env names)
729 bindLocalNamesFV names enclosed_scope
730 = bindLocalNames names $
731 enclosed_scope `thenRn` \ (thing, fvs) ->
732 returnRn (thing, delListFromNameSet fvs names)
735 -------------------------------------
736 bindLocalRn doc rdr_name enclosed_scope
737 = getSrcLocRn `thenRn` \ loc ->
738 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
742 bindLocalsRn doc rdr_names enclosed_scope
743 = getSrcLocRn `thenRn` \ loc ->
744 bindLocatedLocalsRn doc
745 (rdr_names `zip` repeat loc)
748 -- binLocalsFVRn is the same as bindLocalsRn
749 -- except that it deals with free vars
750 bindLocalsFVRn doc rdr_names enclosed_scope
751 = bindLocalsRn doc rdr_names $ \ names ->
752 enclosed_scope names `thenRn` \ (thing, fvs) ->
753 returnRn (thing, delListFromNameSet fvs names)
755 -------------------------------------
756 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
757 -- This tiresome function is used only in rnSourceDecl on InstDecl
758 extendTyVarEnvFVRn tyvars enclosed_scope
759 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
760 returnRn (thing, delListFromNameSet fvs tyvars)
762 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
763 -> ([HsTyVarBndr Name] -> RnMS a)
765 bindTyVarsRn doc_str tyvar_names enclosed_scope
766 = getSrcLocRn `thenRn` \ loc ->
768 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
770 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
771 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
773 bindPatSigTyVars :: [RdrNameHsType]
774 -> RnMS (a, FreeVars)
775 -> RnMS (a, FreeVars)
776 -- Find the type variables in the pattern type
777 -- signatures that must be brought into scope
779 bindPatSigTyVars tys enclosed_scope
780 = getLocalNameEnv `thenRn` \ name_env ->
781 getSrcLocRn `thenRn` \ loc ->
783 forall_tyvars = nub [ tv | ty <- tys,
784 tv <- extractHsTyRdrTyVars ty,
785 not (tv `elemFM` name_env)
787 -- The 'nub' is important. For example:
788 -- f (x :: t) (y :: t) = ....
789 -- We don't want to complain about binding t twice!
791 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
792 doc_sig = text "In a pattern type-signature"
794 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
795 enclosed_scope `thenRn` \ (thing, fvs) ->
796 returnRn (thing, delListFromNameSet fvs names)
799 -------------------------------------
800 checkDupOrQualNames, checkDupNames :: SDoc
801 -> [(RdrName, SrcLoc)]
803 -- Works in any variant of the renamer monad
805 checkDupOrQualNames doc_str rdr_names_w_loc
806 = -- Check for use of qualified names
807 mapRn_ (qualNameErr doc_str) quals `thenRn_`
808 checkDupNames doc_str rdr_names_w_loc
810 quals = filter (isQual . fst) rdr_names_w_loc
812 checkDupNames doc_str rdr_names_w_loc
813 = -- Check for duplicated names in a binding group
814 mapRn_ (dupNamesErr doc_str) dups
816 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
820 %************************************************************************
822 \subsection{GlobalRdrEnv}
824 %************************************************************************
827 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
828 -> Bool -- True <=> want unqualified import
829 -> (Name -> Provenance)
830 -> Avails -- Whats imported
834 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
837 -- Make the name environment. We're talking about a
838 -- single module here, so there must be no name clashes.
839 -- In practice there only ever will be if it's the module
842 -- Add qualified names for the things that are available
843 -- (Qualified names are always imported)
844 gbl_env1 = foldl add_avail emptyRdrEnv avails
846 -- Add unqualified names
847 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
848 | otherwise = gbl_env1
850 add_unqual env (qual_name, elts)
851 = foldl add_one env elts
853 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
854 unqual_name = unqualifyRdrName qual_name
855 -- The qualified import should only have added one
856 -- binding for each qualified name! But if there's an error in
857 -- the module (multiple bindings for the same name) we may get
858 -- duplicates. So the simple thing is to do the fold.
860 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
861 add_avail env avail = foldl add_name env (availNames avail)
863 add_name env name -- Add qualified name only
864 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
866 occ = nameOccName name
867 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
871 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
872 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
874 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
875 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
877 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
878 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
880 combine_globals :: [GlobalRdrElt] -- Old
881 -> [GlobalRdrElt] -- New
883 combine_globals ns_old ns_new -- ns_new is often short
884 = foldr add ns_old ns_new
886 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
889 choose n m | n `beats` m = n
892 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
894 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
895 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
896 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
899 We treat two bindings of a locally-defined name as a duplicate,
900 because they might be two separate, local defns and we want to report
901 and error for that, {\em not} eliminate a duplicate.
903 On the other hand, if you import the same name from two different
904 import statements, we {\em do} want to eliminate the duplicate, not report
907 If a module imports itself then there might be a local defn and an imported
908 defn of the same name; in this case the names will compare as equal, but
909 will still have different provenances.
912 @unQualInScope@ returns a function that takes a @Name@ and tells whether
913 its unqualified name is in scope. This is put as a boolean flag in
914 the @Name@'s provenance to guide whether or not to print the name qualified
918 unQualInScope :: GlobalRdrEnv -> Name -> Bool
919 -- True if 'f' is in scope, and has only one binding,
920 -- and the thing it is bound to is the name we are looking for
921 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
923 -- This fn is only efficient if the shared
924 -- partial application is used a lot.
926 = (`elemNameSet` unqual_names)
928 unqual_names :: NameSet
929 unqual_names = foldRdrEnv add emptyNameSet env
930 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
931 add _ _ unquals = unquals
935 %************************************************************************
939 %************************************************************************
942 plusAvail (Avail n1) (Avail n2) = Avail n1
943 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
946 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
949 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
950 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
952 unitAvailEnv :: AvailInfo -> AvailEnv
953 unitAvailEnv a = unitNameEnv (availName a) a
955 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
956 plusAvailEnv = plusNameEnv_C plusAvail
958 availEnvElts = nameEnvElts
960 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
961 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
963 availsToNameSet :: [AvailInfo] -> NameSet
964 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
966 availName :: GenAvailInfo name -> name
967 availName (Avail n) = n
968 availName (AvailTC n _) = n
970 availNames :: GenAvailInfo name -> [name]
971 availNames (Avail n) = [n]
972 availNames (AvailTC n ns) = ns
974 -------------------------------------
975 filterAvail :: RdrNameIE -- Wanted
976 -> AvailInfo -- Available
977 -> Maybe AvailInfo -- Resulting available;
978 -- Nothing if (any of the) wanted stuff isn't there
980 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
981 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
982 | otherwise = Nothing
984 is_wanted name = nameOccName name `elem` wanted_occs
985 sub_names_ok = all (`elem` avail_occs) wanted_occs
986 avail_occs = map nameOccName ns
987 wanted_occs = map rdrNameOcc (want:wants)
989 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
992 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
994 filterAvail (IEVar _) avail@(Avail n) = Just avail
995 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
997 wanted n = nameOccName n == occ
999 -- The second equation happens if we import a class op, thus
1001 -- where op is a class operation
1003 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
1004 -- We don't complain even if the IE says T(..), but
1005 -- no constrs/class ops of T are available
1006 -- Instead that's caught with a warning by the caller
1008 filterAvail ie avail = Nothing
1010 -------------------------------------
1011 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
1012 -- Group by module and sort by occurrence
1013 -- This keeps the list in canonical order
1014 groupAvails this_mod avails
1015 = [ (mkSysModuleNameFS fs, sortLt lt avails)
1016 | (fs,avails) <- fmToList groupFM
1019 groupFM :: FiniteMap FastString Avails
1020 -- Deliberately use the FastString so we
1021 -- get a canonical ordering
1022 groupFM = foldl add emptyFM avails
1024 add env avail = addToFM_C combine env mod_fs [avail']
1026 mod_fs = moduleNameFS (moduleName avail_mod)
1027 avail_mod = case nameModule_maybe (availName avail) of
1030 combine old _ = avail':old
1031 avail' = sortAvail avail
1033 a1 `lt` a2 = occ1 < occ2
1035 occ1 = nameOccName (availName a1)
1036 occ2 = nameOccName (availName a2)
1038 sortAvail :: AvailInfo -> AvailInfo
1039 -- Sort the sub-names into canonical order.
1040 -- The canonical order has the "main name" at the beginning
1041 -- (if it's there at all)
1042 sortAvail (Avail n) = Avail n
1043 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
1044 | otherwise = AvailTC n ( sortLt lt ns)
1046 n1 `lt` n2 = nameOccName n1 < nameOccName n2
1050 pruneAvails :: (Name -> Bool) -- Keep if this is True
1053 pruneAvails keep avails
1054 = mapMaybe del avails
1056 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
1057 del (Avail n) | keep n = Just (Avail n)
1058 | otherwise = Nothing
1059 del (AvailTC n ns) | null ns' = Nothing
1060 | otherwise = Just (AvailTC n ns')
1062 ns' = filter keep ns
1065 %************************************************************************
1067 \subsection{Free variable manipulation}
1069 %************************************************************************
1073 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
1075 (ys, fvs_s) = unzip stuff
1077 returnRn (ys, plusFVs fvs_s)
1081 %************************************************************************
1083 \subsection{Envt utility functions}
1085 %************************************************************************
1088 warnUnusedModules :: [ModuleName] -> RnM d ()
1089 warnUnusedModules mods
1090 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
1092 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
1093 text "is imported, but nothing from it is used",
1094 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
1097 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
1098 warnUnusedImports names
1099 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
1101 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
1102 warnUnusedLocalBinds names
1103 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
1105 warnUnusedMatches names
1106 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
1108 -------------------------
1110 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
1111 warnUnusedBinds names
1112 = mapRn_ warnUnusedGroup groups
1114 -- Group by provenance
1115 groups = equivClasses cmp names
1116 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
1119 -------------------------
1121 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
1122 warnUnusedGroup names
1123 | null filtered_names = returnRn ()
1124 | not is_local = returnRn ()
1126 = pushSrcLocRn def_loc $
1128 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
1130 filtered_names = filter reportable names
1131 (name1, prov1) = head filtered_names
1132 (is_local, def_loc, msg)
1134 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
1136 NonLocalDef (UserImport mod loc _)
1137 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
1139 reportable (name,_) = case occNameUserString (nameOccName name) of
1142 -- Haskell 98 encourages compilers to suppress warnings about
1143 -- unused names in a pattern if they start with "_".
1147 addNameClashErrRn rdr_name (np1:nps)
1148 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1149 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1151 msg1 = ptext SLIT("either") <+> mk_ref np1
1152 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1153 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1155 shadowedNameWarn shadow
1156 = hsep [ptext SLIT("This binding for"),
1157 quotes (ppr shadow),
1158 ptext SLIT("shadows an existing binding")]
1160 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1163 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1165 flavour = occNameFlavour (rdrNameOcc name)
1168 = ptext SLIT("Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name)
1169 -- The rdrNameOcc is because we don't want to print Prelude.(,)
1171 qualNameErr descriptor (name,loc)
1172 = pushSrcLocRn loc $
1173 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1176 dupNamesErr descriptor ((name,loc) : dup_things)
1177 = pushSrcLocRn loc $
1178 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1182 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1184 = ifOptRn Opt_WarnDeprecations $
1185 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1186 quotes (ppr name) <+> text "is deprecated:",
1189 dupFixityDecl rdr_name loc1 loc2
1190 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
1191 ptext SLIT("at ") <+> ppr loc1,
1192 ptext SLIT("and") <+> ppr loc2]