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
13 import FlattenInfo ( namesNeededForFlattening )
15 import RdrHsSyn ( RdrNameIE, RdrNameHsType, extractHsTyRdrTyVars )
16 import RdrName ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
17 mkRdrUnqual, mkRdrQual,
18 lookupRdrEnv, foldRdrEnv, rdrEnvToList, elemRdrEnv,
21 import HsTypes ( hsTyVarName, replaceTyVarName )
22 import HscTypes ( Provenance(..), pprNameProvenance, hasBetterProv,
23 ImportReason(..), GlobalRdrEnv, GlobalRdrElt(..), AvailEnv,
24 AvailInfo, Avails, GenAvailInfo(..), NameSupply(..),
25 ModIface(..), GhciMode(..),
26 Deprecations(..), lookupDeprec,
31 getSrcLoc, nameIsLocalOrFrom,
32 mkInternalName, mkExternalName,
33 mkIPName, nameOccName, nameModule_maybe,
38 import OccName ( OccName, occNameUserString, occNameFlavour )
39 import Module ( ModuleName, moduleName, mkVanillaModule,
40 mkSysModuleNameFS, moduleNameFS, WhereFrom(..) )
41 import PrelNames ( mkUnboundName,
43 mAIN_Name, main_RDR_Unqual,
44 runMainName, intTyConName,
45 boolTyConName, funTyConName,
46 unpackCStringName, unpackCStringFoldrName, unpackCStringUtf8Name,
47 eqStringName, printName,
48 bindIOName, returnIOName, failIOName, thenIOName
50 import TysWiredIn ( unitTyCon ) -- A little odd
53 import SrcLoc ( SrcLoc, noSrcLoc )
55 import ListSetOps ( removeDups, equivClasses )
56 import Util ( sortLt )
57 import BasicTypes ( mapIPName )
59 import UniqFM ( lookupWithDefaultUFM )
60 import Maybe ( mapMaybe )
62 import FastString ( FastString )
65 %*********************************************************
67 \subsection{Making new names}
69 %*********************************************************
72 newTopBinder :: Module -> RdrName -> SrcLoc -> RnM d Name
73 -- newTopBinder puts into the cache the binder with the
74 -- module information set correctly. When the decl is later renamed,
75 -- the binding site will thereby get the correct module.
76 -- There maybe occurrences that don't have the correct Module, but
77 -- by the typechecker will propagate the binding definition to all
78 -- the occurrences, so that doesn't matter
80 newTopBinder mod rdr_name loc
81 = -- First check the cache
83 -- There should never be a qualified name in a binding position (except in instance decls)
84 -- The parser doesn't check this because the same parser parses instance decls
85 (if isQual rdr_name then
86 qualNameErr (text "In its declaration") (rdr_name,loc)
91 getNameSupplyRn `thenRn` \ name_supply ->
93 occ = rdrNameOcc rdr_name
94 key = (moduleName mod, occ)
95 cache = nsNames name_supply
97 case lookupFM cache key of
99 -- A hit in the cache! We are at the binding site of the name, and
100 -- this is the moment when we know all about
101 -- a) the Name's host Module (in particular, which
102 -- package it comes from)
103 -- b) its defining SrcLoc
104 -- So we update this info
107 new_name = setNameModuleAndLoc name mod loc
108 new_cache = addToFM cache key new_name
110 setNameSupplyRn (name_supply {nsNames = new_cache}) `thenRn_`
111 -- traceRn (text "newTopBinder: overwrite" <+> ppr new_name) `thenRn_`
114 -- Miss in the cache!
115 -- Build a completely new Name, and put it in the cache
116 -- Even for locally-defined names we use implicitImportProvenance;
117 -- updateProvenances will set it to rights
119 (us', us1) = splitUniqSupply (nsUniqs name_supply)
120 uniq = uniqFromSupply us1
121 new_name = mkExternalName uniq mod occ loc
122 new_cache = addToFM cache key new_name
124 setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
125 -- traceRn (text "newTopBinder: new" <+> ppr new_name) `thenRn_`
129 newGlobalName :: ModuleName -> OccName -> RnM d Name
130 -- Used for *occurrences*. We make a place-holder Name, really just
131 -- to agree on its unique, which gets overwritten when we read in
132 -- the binding occurence later (newTopBinder)
133 -- The place-holder Name doesn't have the right SrcLoc, and its
134 -- Module won't have the right Package either.
136 -- (We have to pass a ModuleName, not a Module, because we may be
137 -- simply looking at an occurrence M.x in an interface file.)
139 -- This means that a renamed program may have incorrect info
140 -- on implicitly-imported occurrences, but the correct info on the
141 -- *binding* declaration. It's the type checker that propagates the
142 -- correct information to all the occurrences.
143 -- Since implicitly-imported names never occur in error messages,
144 -- it doesn't matter that we get the correct info in place till later,
145 -- (but since it affects DLL-ery it does matter that we get it right
147 newGlobalName mod_name occ
148 = getNameSupplyRn `thenRn` \ name_supply ->
150 key = (mod_name, occ)
151 cache = nsNames name_supply
153 case lookupFM cache key of
154 Just name -> -- traceRn (text "newGlobalName: hit" <+> ppr name) `thenRn_`
157 Nothing -> setNameSupplyRn (name_supply {nsUniqs = us', nsNames = new_cache}) `thenRn_`
158 -- traceRn (text "newGlobalName: new" <+> ppr name) `thenRn_`
161 (us', us1) = splitUniqSupply (nsUniqs name_supply)
162 uniq = uniqFromSupply us1
163 mod = mkVanillaModule mod_name
164 name = mkExternalName uniq mod occ noSrcLoc
165 new_cache = addToFM cache key name
167 newIPName rdr_name_ip
168 = getNameSupplyRn `thenRn` \ name_supply ->
170 ipcache = nsIPs name_supply
172 case lookupFM ipcache key of
173 Just name_ip -> returnRn name_ip
174 Nothing -> setNameSupplyRn new_ns `thenRn_`
177 (us', us1) = splitUniqSupply (nsUniqs name_supply)
178 uniq = uniqFromSupply us1
179 name_ip = mapIPName mk_name rdr_name_ip
180 mk_name rdr_name = mkIPName uniq (rdrNameOcc rdr_name)
181 new_ipcache = addToFM ipcache key name_ip
182 new_ns = name_supply {nsUniqs = us', nsIPs = new_ipcache}
184 key = rdr_name_ip -- Ensures that ?x and %x get distinct Names
187 %*********************************************************
189 \subsection{Looking up names}
191 %*********************************************************
193 Looking up a name in the RnEnv.
196 lookupBndrRn rdr_name
197 = getLocalNameEnv `thenRn` \ local_env ->
198 case lookupRdrEnv local_env rdr_name of
199 Just name -> returnRn name
200 Nothing -> lookupTopBndrRn rdr_name
202 lookupTopBndrRn rdr_name
203 -- Look up a top-level local binder. We may be looking up an unqualified 'f',
204 -- and there may be several imported 'f's too, which must not confuse us.
205 -- So we have to filter out the non-local ones.
206 -- A separate function (importsFromLocalDecls) reports duplicate top level
207 -- decls, so here it's safe just to choose an arbitrary one.
210 -- This is here just to catch the PrelBase defn of (say) [] and similar
211 -- The parser reads the special syntax and returns an Orig RdrName
212 -- But the global_env contains only Qual RdrNames, so we won't
213 -- find it there; instead just get the name via the Orig route
214 = lookupOrigName rdr_name
217 = getModeRn `thenRn` \ mode ->
218 if isInterfaceMode mode
219 then lookupSysBinder rdr_name
220 -- lookupSysBinder uses the Module in the monad to set
221 -- the correct module for the binder. This is important because
222 -- when GHCi is reading in an old interface, it just sucks it
223 -- in entire (Rename.loadHomeDecls) which uses lookupTopBndrRn
224 -- rather than via the iface file cache which uses newTopBndrRn
225 -- We must get the correct Module into the thing.
228 getModuleRn `thenRn` \ mod ->
229 getGlobalNameEnv `thenRn` \ global_env ->
230 case lookup_local mod global_env rdr_name of
231 Just name -> returnRn name
232 Nothing -> failWithRn (mkUnboundName rdr_name)
233 (unknownNameErr rdr_name)
235 lookup_local mod global_env rdr_name
236 = case lookupRdrEnv global_env rdr_name of
238 Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
243 -- lookupSigOccRn is used for type signatures and pragmas
249 -- It's clear that the 'f' in the signature must refer to A.f
250 -- The Haskell98 report does not stipulate this, but it will!
251 -- So we must treat the 'f' in the signature in the same way
252 -- as the binding occurrence of 'f', using lookupBndrRn
253 lookupSigOccRn :: RdrName -> RnMS Name
254 lookupSigOccRn = lookupBndrRn
256 -- lookupInstDeclBndr is used for the binders in an
257 -- instance declaration. Here we use the class name to
260 lookupInstDeclBndr :: Name -> RdrName -> RnMS Name
261 -- We use the selector name as the binder
262 lookupInstDeclBndr cls_name rdr_name
263 | isOrig rdr_name -- Occurs in derived instances, where we just
264 -- refer diectly to the right method
265 = lookupOrigName rdr_name
268 = getGlobalAvails `thenRn` \ avail_env ->
269 case lookupNameEnv avail_env cls_name of
270 -- The class itself isn't in scope, so cls_name is unboundName
271 -- e.g. import Prelude hiding( Ord )
272 -- instance Ord T where ...
273 -- The program is wrong, but that should not cause a crash.
274 Nothing -> returnRn (mkUnboundName rdr_name)
275 Just (AvailTC _ ns) -> case [n | n <- ns, nameOccName n == occ] of
276 (n:ns)-> ASSERT( null ns ) returnRn n
277 [] -> failWithRn (mkUnboundName rdr_name)
278 (unknownNameErr rdr_name)
279 other -> pprPanic "lookupInstDeclBndr" (ppr cls_name)
281 occ = rdrNameOcc rdr_name
283 -- lookupOccRn looks up an occurrence of a RdrName
284 lookupOccRn :: RdrName -> RnMS Name
286 = getLocalNameEnv `thenRn` \ local_env ->
287 case lookupRdrEnv local_env rdr_name of
288 Just name -> returnRn name
289 Nothing -> lookupGlobalOccRn rdr_name
291 -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
292 -- environment. It's used only for
293 -- record field names
294 -- class op names in class and instance decls
296 lookupGlobalOccRn rdr_name
297 = getModeRn `thenRn` \ mode ->
298 if (isInterfaceMode mode)
299 then lookupIfaceName rdr_name
302 getGlobalNameEnv `thenRn` \ global_env ->
304 SourceMode -> lookupSrcName global_env rdr_name
307 | not (isQual rdr_name) ->
308 lookupSrcName global_env rdr_name
310 -- We allow qualified names on the command line to refer to
311 -- *any* name exported by any module in scope, just as if
312 -- there was an "import qualified M" declaration for every
315 -- First look up the name in the normal environment. If
316 -- it isn't there, we manufacture a new occurrence of an
319 case lookupRdrEnv global_env rdr_name of
320 Just _ -> lookupSrcName global_env rdr_name
321 Nothing -> lookupQualifiedName rdr_name
323 -- a qualified name on the command line can refer to any module at all: we
324 -- try to load the interface if we don't already have it.
325 lookupQualifiedName :: RdrName -> RnM d Name
326 lookupQualifiedName rdr_name
328 mod = rdrNameModule rdr_name
329 occ = rdrNameOcc rdr_name
331 loadInterface (ppr rdr_name) mod ImportByUser `thenRn` \ iface ->
332 case [ name | (_,avails) <- mi_exports iface,
334 name <- availNames avail,
335 nameOccName name == occ ] of
336 (n:ns) -> ASSERT (null ns) returnRn n
337 _ -> failWithRn (mkUnboundName rdr_name) (unknownNameErr rdr_name)
339 lookupSrcName :: GlobalRdrEnv -> RdrName -> RnM d Name
340 -- NB: passed GlobalEnv explicitly, not necessarily in RnMS monad
341 lookupSrcName global_env rdr_name
342 | isOrig rdr_name -- Can occur in source code too
343 = lookupOrigName rdr_name
346 = case lookupRdrEnv global_env rdr_name of
347 Just [GRE name _ Nothing] -> returnRn name
348 Just [GRE name _ (Just deprec)] -> warnDeprec name deprec `thenRn_`
350 Just stuff@(GRE name _ _ : _) -> addNameClashErrRn rdr_name stuff `thenRn_`
352 Nothing -> failWithRn (mkUnboundName rdr_name)
353 (unknownNameErr rdr_name)
355 lookupOrigName :: RdrName -> RnM d Name
356 lookupOrigName rdr_name
357 = -- NO: ASSERT( isOrig rdr_name )
358 -- Now that .hi-boot files are read by the main parser, they contain
359 -- ordinary qualified names (which we treat as Orig names here).
360 newGlobalName (rdrNameModule rdr_name) (rdrNameOcc rdr_name)
362 lookupIfaceUnqual :: RdrName -> RnM d Name
363 lookupIfaceUnqual rdr_name
364 = ASSERT( isUnqual rdr_name )
365 -- An Unqual is allowed; interface files contain
366 -- unqualified names for locally-defined things, such as
367 -- constructors of a data type.
368 getModuleRn `thenRn ` \ mod ->
369 newGlobalName (moduleName mod) (rdrNameOcc rdr_name)
371 lookupIfaceName :: RdrName -> RnM d Name
372 lookupIfaceName rdr_name
373 | isUnqual rdr_name = lookupIfaceUnqual rdr_name
374 | otherwise = lookupOrigName rdr_name
377 @lookupOrigName@ takes an RdrName representing an {\em original}
378 name, and adds it to the occurrence pool so that it'll be loaded
379 later. This is used when language constructs (such as monad
380 comprehensions, overloaded literals, or deriving clauses) require some
381 stuff to be loaded that isn't explicitly mentioned in the code.
383 This doesn't apply in interface mode, where everything is explicit,
384 but we don't check for this case: it does no harm to record an
385 ``extra'' occurrence and @lookupOrigNames@ isn't used much in
386 interface mode (it's only the @Nothing@ clause of @rnDerivs@ that
387 calls it at all I think).
389 \fbox{{\em Jan 98: this comment is wrong: @rnHsType@ uses it quite a bit.}}
392 lookupOrigNames :: [RdrName] -> RnM d NameSet
393 lookupOrigNames rdr_names
394 = mapRn lookupOrigName rdr_names `thenRn` \ names ->
395 returnRn (mkNameSet names)
398 lookupSysBinder is used for the "system binders" of a type, class, or
399 instance decl. It ensures that the module is set correctly in the
400 name cache, and sets the provenance on the returned name too. The
401 returned name will end up actually in the type, class, or instance.
404 lookupSysBinder rdr_name
405 = ASSERT( isUnqual rdr_name )
406 getModuleRn `thenRn` \ mod ->
407 getSrcLocRn `thenRn` \ loc ->
408 newTopBinder mod rdr_name loc
412 %*********************************************************
414 \subsection{Implicit free vars and sugar names}
416 %*********************************************************
418 @getXImplicitFVs@ forces the renamer to slurp in some things which aren't
419 mentioned explicitly, but which might be needed by the type checker.
422 getImplicitStmtFVs -- Compiling a statement
423 = returnRn (mkFVs [printName, bindIOName, thenIOName,
424 returnIOName, failIOName]
425 `plusFV` ubiquitousNames)
426 -- These are all needed implicitly when compiling a statement
427 -- See TcModule.tc_stmts
429 getImplicitModuleFVs decls -- Compiling a module
430 = lookupOrigNames deriv_occs `thenRn` \ deriving_names ->
431 returnRn (deriving_names `plusFV` ubiquitousNames)
433 -- deriv_classes is now a list of HsTypes, so a "normal" one
434 -- appears as a (HsClassP c []). The non-normal ones for the new
435 -- newtype-deriving extension, and they don't require any
436 -- implicit names, so we can silently filter them out.
437 deriv_occs = [occ | TyClD (TyData {tcdDerivs = Just deriv_classes}) <- decls,
438 HsClassP cls [] <- deriv_classes,
439 occ <- lookupWithDefaultUFM derivingOccurrences [] cls ]
441 -- ubiquitous_names are loaded regardless, because
442 -- they are needed in virtually every program
444 = mkFVs [unpackCStringName, unpackCStringFoldrName,
445 unpackCStringUtf8Name, eqStringName]
446 -- Virtually every program has error messages in it somewhere
449 mkFVs [getName unitTyCon, funTyConName, boolTyConName, intTyConName]
450 -- Add occurrences for very frequently used types.
451 -- (e.g. we don't want to be bothered with making funTyCon a
452 -- free var at every function application!)
454 namesNeededForFlattening
455 -- this will be empty unless flattening is activated
457 checkMain ghci_mode mod_name gbl_env
458 -- LOOKUP main IF WE'RE IN MODULE Main
459 -- The main point of this is to drag in the declaration for 'main',
460 -- its in another module, and for the Prelude function 'runMain',
461 -- so that the type checker will find them
463 -- We have to return the main_name separately, because it's a
464 -- bona fide 'use', and should be recorded as such, but the others
466 | mod_name /= mAIN_Name
467 = returnRn (Nothing, emptyFVs, emptyFVs)
469 | not (main_RDR_Unqual `elemRdrEnv` gbl_env)
470 = complain_no_main `thenRn_`
471 returnRn (Nothing, emptyFVs, emptyFVs)
474 = lookupSrcName gbl_env main_RDR_Unqual `thenRn` \ main_name ->
475 returnRn (Just main_name, unitFV main_name, unitFV runMainName)
478 complain_no_main | ghci_mode == Interactive = addWarnRn noMainMsg
479 | otherwise = addErrRn noMainMsg
480 -- In interactive mode, only warn about the absence of main
483 %************************************************************************
485 \subsection{Re-bindable desugaring names}
487 %************************************************************************
489 Haskell 98 says that when you say "3" you get the "fromInteger" from the
490 Standard Prelude, regardless of what is in scope. However, to experiment
491 with having a language that is less coupled to the standard prelude, we're
492 trying a non-standard extension that instead gives you whatever "Prelude.fromInteger"
493 happens to be in scope. Then you can
495 import MyPrelude as Prelude
496 to get the desired effect.
498 At the moment this just happens for
499 * fromInteger, fromRational on literals (in expressions and patterns)
500 * negate (in expressions)
501 * minus (arising from n+k patterns)
503 We store the relevant Name in the HsSyn tree, in
504 * HsIntegral/HsFractional
507 respectively. Initially, we just store the "standard" name (PrelNames.fromIntegralName,
508 fromRationalName etc), but the renamer changes this to the appropriate user
509 name if Opt_NoImplicitPrelude is on. That is what lookupSyntaxName does.
512 lookupSyntaxName :: Name -- The standard name
513 -> RnMS Name -- Possibly a non-standard name
514 lookupSyntaxName std_name
515 = doptRn Opt_NoImplicitPrelude `thenRn` \ no_prelude ->
516 if not no_prelude then
517 returnRn std_name -- Normal case
520 rdr_name = mkRdrUnqual (nameOccName std_name)
521 -- Get the similarly named thing from the local environment
527 %*********************************************************
531 %*********************************************************
534 newLocalsRn :: [(RdrName,SrcLoc)]
536 newLocalsRn rdr_names_w_loc
537 = getNameSupplyRn `thenRn` \ name_supply ->
539 (us', us1) = splitUniqSupply (nsUniqs name_supply)
540 uniqs = uniqsFromSupply us1
541 names = [ mkInternalName uniq (rdrNameOcc rdr_name) loc
542 | ((rdr_name,loc), uniq) <- rdr_names_w_loc `zip` uniqs
545 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
549 bindLocatedLocalsRn :: SDoc -- Documentation string for error message
550 -> [(RdrName,SrcLoc)]
551 -> ([Name] -> RnMS a)
553 bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope
554 = getModeRn `thenRn` \ mode ->
555 getLocalNameEnv `thenRn` \ local_env ->
556 getGlobalNameEnv `thenRn` \ global_env ->
558 -- Check for duplicate names
559 checkDupOrQualNames doc_str rdr_names_w_loc `thenRn_`
561 -- Warn about shadowing, but only in source modules
563 check_shadow (rdr_name,loc)
564 | rdr_name `elemRdrEnv` local_env
565 || rdr_name `elemRdrEnv` global_env
566 = pushSrcLocRn loc $ addWarnRn (shadowedNameWarn rdr_name)
572 SourceMode -> ifOptRn Opt_WarnNameShadowing $
573 mapRn_ check_shadow rdr_names_w_loc
577 newLocalsRn rdr_names_w_loc `thenRn` \ names ->
579 new_local_env = addListToRdrEnv local_env (map fst rdr_names_w_loc `zip` names)
581 setLocalNameEnv new_local_env (enclosed_scope names)
583 bindCoreLocalRn :: RdrName -> (Name -> RnMS a) -> RnMS a
584 -- A specialised variant when renaming stuff from interface
585 -- files (of which there is a lot)
587 -- * no checks for shadowing
589 -- * deal with free vars
590 bindCoreLocalRn rdr_name enclosed_scope
591 = getSrcLocRn `thenRn` \ loc ->
592 getLocalNameEnv `thenRn` \ name_env ->
593 getNameSupplyRn `thenRn` \ name_supply ->
595 (us', us1) = splitUniqSupply (nsUniqs name_supply)
596 uniq = uniqFromSupply us1
597 name = mkInternalName uniq (rdrNameOcc rdr_name) loc
599 setNameSupplyRn (name_supply {nsUniqs = us'}) `thenRn_`
601 new_name_env = extendRdrEnv name_env rdr_name name
603 setLocalNameEnv new_name_env (enclosed_scope name)
605 bindCoreLocalsRn [] thing_inside = thing_inside []
606 bindCoreLocalsRn (b:bs) thing_inside = bindCoreLocalRn b $ \ name' ->
607 bindCoreLocalsRn bs $ \ names' ->
608 thing_inside (name':names')
610 bindLocalNames names enclosed_scope
611 = getLocalNameEnv `thenRn` \ name_env ->
612 setLocalNameEnv (extendLocalRdrEnv name_env names)
615 bindLocalNamesFV names enclosed_scope
616 = bindLocalNames names $
617 enclosed_scope `thenRn` \ (thing, fvs) ->
618 returnRn (thing, delListFromNameSet fvs names)
621 -------------------------------------
622 bindLocalRn doc rdr_name enclosed_scope
623 = getSrcLocRn `thenRn` \ loc ->
624 bindLocatedLocalsRn doc [(rdr_name,loc)] $ \ (n:ns) ->
628 bindLocalsRn doc rdr_names enclosed_scope
629 = getSrcLocRn `thenRn` \ loc ->
630 bindLocatedLocalsRn doc
631 (rdr_names `zip` repeat loc)
634 -- binLocalsFVRn is the same as bindLocalsRn
635 -- except that it deals with free vars
636 bindLocalsFVRn doc rdr_names enclosed_scope
637 = bindLocalsRn doc rdr_names $ \ names ->
638 enclosed_scope names `thenRn` \ (thing, fvs) ->
639 returnRn (thing, delListFromNameSet fvs names)
641 -------------------------------------
642 extendTyVarEnvFVRn :: [Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
643 -- This tiresome function is used only in rnSourceDecl on InstDecl
644 extendTyVarEnvFVRn tyvars enclosed_scope
645 = bindLocalNames tyvars enclosed_scope `thenRn` \ (thing, fvs) ->
646 returnRn (thing, delListFromNameSet fvs tyvars)
648 bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
649 -> ([HsTyVarBndr Name] -> RnMS a)
651 bindTyVarsRn doc_str tyvar_names enclosed_scope
652 = getSrcLocRn `thenRn` \ loc ->
654 located_tyvars = [(hsTyVarName tv, loc) | tv <- tyvar_names]
656 bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
657 enclosed_scope (zipWith replaceTyVarName tyvar_names names)
659 bindPatSigTyVars :: [RdrNameHsType]
660 -> RnMS (a, FreeVars)
661 -> RnMS (a, FreeVars)
662 -- Find the type variables in the pattern type
663 -- signatures that must be brought into scope
665 bindPatSigTyVars tys enclosed_scope
666 = getLocalNameEnv `thenRn` \ name_env ->
667 getSrcLocRn `thenRn` \ loc ->
669 forall_tyvars = nub [ tv | ty <- tys,
670 tv <- extractHsTyRdrTyVars ty,
671 not (tv `elemFM` name_env)
673 -- The 'nub' is important. For example:
674 -- f (x :: t) (y :: t) = ....
675 -- We don't want to complain about binding t twice!
677 located_tyvars = [(tv, loc) | tv <- forall_tyvars]
678 doc_sig = text "In a pattern type-signature"
680 bindLocatedLocalsRn doc_sig located_tyvars $ \ names ->
681 enclosed_scope `thenRn` \ (thing, fvs) ->
682 returnRn (thing, delListFromNameSet fvs names)
685 -------------------------------------
686 checkDupOrQualNames, checkDupNames :: SDoc
687 -> [(RdrName, SrcLoc)]
689 -- Works in any variant of the renamer monad
691 checkDupOrQualNames doc_str rdr_names_w_loc
692 = -- Check for use of qualified names
693 mapRn_ (qualNameErr doc_str) quals `thenRn_`
694 checkDupNames doc_str rdr_names_w_loc
696 quals = filter (isQual . fst) rdr_names_w_loc
698 checkDupNames doc_str rdr_names_w_loc
699 = -- Check for duplicated names in a binding group
700 mapRn_ (dupNamesErr doc_str) dups
702 (_, dups) = removeDups (\(n1,l1) (n2,l2) -> n1 `compare` n2) rdr_names_w_loc
706 %************************************************************************
708 \subsection{GlobalRdrEnv}
710 %************************************************************************
713 mkGlobalRdrEnv :: ModuleName -- Imported module (after doing the "as M" name change)
714 -> Bool -- True <=> want unqualified import
715 -> (Name -> Provenance)
716 -> Avails -- Whats imported
720 mkGlobalRdrEnv this_mod unqual_imp mk_provenance avails deprecs
723 -- Make the name environment. We're talking about a
724 -- single module here, so there must be no name clashes.
725 -- In practice there only ever will be if it's the module
728 -- Add qualified names for the things that are available
729 -- (Qualified names are always imported)
730 gbl_env1 = foldl add_avail emptyRdrEnv avails
732 -- Add unqualified names
733 gbl_env2 | unqual_imp = foldl add_unqual gbl_env1 (rdrEnvToList gbl_env1)
734 | otherwise = gbl_env1
736 add_unqual env (qual_name, elts)
737 = foldl add_one env elts
739 add_one env elt = addOneToGlobalRdrEnv env unqual_name elt
740 unqual_name = unqualifyRdrName qual_name
741 -- The qualified import should only have added one
742 -- binding for each qualified name! But if there's an error in
743 -- the module (multiple bindings for the same name) we may get
744 -- duplicates. So the simple thing is to do the fold.
746 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
747 add_avail env avail = foldl add_name env (availNames avail)
749 add_name env name -- Add qualified name only
750 = addOneToGlobalRdrEnv env (mkRdrQual this_mod occ) elt
752 occ = nameOccName name
753 elt = GRE name (mk_provenance name) (lookupDeprec deprecs name)
757 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
758 plusGlobalRdrEnv env1 env2 = plusFM_C combine_globals env1 env2
760 addOneToGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrElt -> GlobalRdrEnv
761 addOneToGlobalRdrEnv env rdr_name name = addToFM_C combine_globals env rdr_name [name]
763 delOneFromGlobalRdrEnv :: GlobalRdrEnv -> RdrName -> GlobalRdrEnv
764 delOneFromGlobalRdrEnv env rdr_name = delFromFM env rdr_name
766 combine_globals :: [GlobalRdrElt] -- Old
767 -> [GlobalRdrElt] -- New
769 combine_globals ns_old ns_new -- ns_new is often short
770 = foldr add ns_old ns_new
772 add n ns | any (is_duplicate n) ns_old = map (choose n) ns -- Eliminate duplicates
775 choose n m | n `beats` m = n
778 (GRE n pn _) `beats` (GRE m pm _) = n==m && pn `hasBetterProv` pm
780 is_duplicate :: GlobalRdrElt -> GlobalRdrElt -> Bool
781 is_duplicate (GRE n1 LocalDef _) (GRE n2 LocalDef _) = False
782 is_duplicate (GRE n1 _ _) (GRE n2 _ _) = n1 == n2
785 We treat two bindings of a locally-defined name as a duplicate,
786 because they might be two separate, local defns and we want to report
787 and error for that, {\em not} eliminate a duplicate.
789 On the other hand, if you import the same name from two different
790 import statements, we {\em do} want to eliminate the duplicate, not report
793 If a module imports itself then there might be a local defn and an imported
794 defn of the same name; in this case the names will compare as equal, but
795 will still have different provenances.
798 @unQualInScope@ returns a function that takes a @Name@ and tells whether
799 its unqualified name is in scope. This is put as a boolean flag in
800 the @Name@'s provenance to guide whether or not to print the name qualified
804 unQualInScope :: GlobalRdrEnv -> Name -> Bool
805 -- True if 'f' is in scope, and has only one binding,
806 -- and the thing it is bound to is the name we are looking for
807 -- (i.e. false if A.f and B.f are both in scope as unqualified 'f')
809 -- This fn is only efficient if the shared
810 -- partial application is used a lot.
812 = (`elemNameSet` unqual_names)
814 unqual_names :: NameSet
815 unqual_names = foldRdrEnv add emptyNameSet env
816 add rdr_name [GRE name _ _] unquals | isUnqual rdr_name = addOneToNameSet unquals name
817 add _ _ unquals = unquals
821 %************************************************************************
825 %************************************************************************
828 plusAvail (Avail n1) (Avail n2) = Avail n1
829 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (nub (ns1 ++ ns2))
832 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
835 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
836 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
838 unitAvailEnv :: AvailInfo -> AvailEnv
839 unitAvailEnv a = unitNameEnv (availName a) a
841 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
842 plusAvailEnv = plusNameEnv_C plusAvail
844 availEnvElts = nameEnvElts
846 addAvailToNameSet :: NameSet -> AvailInfo -> NameSet
847 addAvailToNameSet names avail = addListToNameSet names (availNames avail)
849 availsToNameSet :: [AvailInfo] -> NameSet
850 availsToNameSet avails = foldl addAvailToNameSet emptyNameSet avails
852 availName :: GenAvailInfo name -> name
853 availName (Avail n) = n
854 availName (AvailTC n _) = n
856 availNames :: GenAvailInfo name -> [name]
857 availNames (Avail n) = [n]
858 availNames (AvailTC n ns) = ns
860 -------------------------------------
861 filterAvail :: RdrNameIE -- Wanted
862 -> AvailInfo -- Available
863 -> Maybe AvailInfo -- Resulting available;
864 -- Nothing if (any of the) wanted stuff isn't there
866 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
867 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
868 | otherwise = Nothing
870 is_wanted name = nameOccName name `elem` wanted_occs
871 sub_names_ok = all (`elem` avail_occs) wanted_occs
872 avail_occs = map nameOccName ns
873 wanted_occs = map rdrNameOcc (want:wants)
875 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
878 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
880 filterAvail (IEVar _) avail@(Avail n) = Just avail
881 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
883 wanted n = nameOccName n == occ
885 -- The second equation happens if we import a class op, thus
887 -- where op is a class operation
889 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
890 -- We don't complain even if the IE says T(..), but
891 -- no constrs/class ops of T are available
892 -- Instead that's caught with a warning by the caller
894 filterAvail ie avail = Nothing
896 -------------------------------------
897 groupAvails :: Module -> Avails -> [(ModuleName, Avails)]
898 -- Group by module and sort by occurrence
899 -- This keeps the list in canonical order
900 groupAvails this_mod avails
901 = [ (mkSysModuleNameFS fs, sortLt lt avails)
902 | (fs,avails) <- fmToList groupFM
905 groupFM :: FiniteMap FastString Avails
906 -- Deliberately use the FastString so we
907 -- get a canonical ordering
908 groupFM = foldl add emptyFM avails
910 add env avail = addToFM_C combine env mod_fs [avail']
912 mod_fs = moduleNameFS (moduleName avail_mod)
913 avail_mod = case nameModule_maybe (availName avail) of
916 combine old _ = avail':old
917 avail' = sortAvail avail
919 a1 `lt` a2 = occ1 < occ2
921 occ1 = nameOccName (availName a1)
922 occ2 = nameOccName (availName a2)
924 sortAvail :: AvailInfo -> AvailInfo
925 -- Sort the sub-names into canonical order.
926 -- The canonical order has the "main name" at the beginning
927 -- (if it's there at all)
928 sortAvail (Avail n) = Avail n
929 sortAvail (AvailTC n ns) | n `elem` ns = AvailTC n (n : sortLt lt (filter (/= n) ns))
930 | otherwise = AvailTC n ( sortLt lt ns)
932 n1 `lt` n2 = nameOccName n1 < nameOccName n2
936 pruneAvails :: (Name -> Bool) -- Keep if this is True
939 pruneAvails keep avails
940 = mapMaybe del avails
942 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
943 del (Avail n) | keep n = Just (Avail n)
944 | otherwise = Nothing
945 del (AvailTC n ns) | null ns' = Nothing
946 | otherwise = Just (AvailTC n ns')
951 %************************************************************************
953 \subsection{Free variable manipulation}
955 %************************************************************************
959 mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
961 (ys, fvs_s) = unzip stuff
963 returnRn (ys, plusFVs fvs_s)
967 %************************************************************************
969 \subsection{Envt utility functions}
971 %************************************************************************
974 warnUnusedModules :: [ModuleName] -> RnM d ()
975 warnUnusedModules mods
976 = ifOptRn Opt_WarnUnusedImports (mapRn_ (addWarnRn . unused_mod) mods)
978 unused_mod m = vcat [ptext SLIT("Module") <+> quotes (ppr m) <+>
979 text "is imported, but nothing from it is used",
980 parens (ptext SLIT("except perhaps to re-export instances visible in") <+>
983 warnUnusedImports :: [(Name,Provenance)] -> RnM d ()
984 warnUnusedImports names
985 = ifOptRn Opt_WarnUnusedImports (warnUnusedBinds names)
987 warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> RnM d ()
988 warnUnusedLocalBinds names
989 = ifOptRn Opt_WarnUnusedBinds (warnUnusedBinds [(n,LocalDef) | n<-names])
991 warnUnusedMatches names
992 = ifOptRn Opt_WarnUnusedMatches (warnUnusedGroup [(n,LocalDef) | n<-names])
994 -------------------------
996 warnUnusedBinds :: [(Name,Provenance)] -> RnM d ()
997 warnUnusedBinds names
998 = mapRn_ warnUnusedGroup groups
1000 -- Group by provenance
1001 groups = equivClasses cmp names
1002 (_,prov1) `cmp` (_,prov2) = prov1 `compare` prov2
1005 -------------------------
1007 warnUnusedGroup :: [(Name,Provenance)] -> RnM d ()
1008 warnUnusedGroup names
1009 | null filtered_names = returnRn ()
1010 | not is_local = returnRn ()
1012 = pushSrcLocRn def_loc $
1014 sep [msg <> colon, nest 4 (fsep (punctuate comma (map (ppr.fst) filtered_names)))]
1016 filtered_names = filter reportable names
1017 (name1, prov1) = head filtered_names
1018 (is_local, def_loc, msg)
1020 LocalDef -> (True, getSrcLoc name1, text "Defined but not used")
1022 NonLocalDef (UserImport mod loc _)
1023 -> (True, loc, text "Imported from" <+> quotes (ppr mod) <+> text "but not used")
1025 reportable (name,_) = case occNameUserString (nameOccName name) of
1028 -- Haskell 98 encourages compilers to suppress warnings about
1029 -- unused names in a pattern if they start with "_".
1033 addNameClashErrRn rdr_name (np1:nps)
1034 = addErrRn (vcat [ptext SLIT("Ambiguous occurrence") <+> quotes (ppr rdr_name),
1035 ptext SLIT("It could refer to") <+> vcat (msg1 : msgs)])
1037 msg1 = ptext SLIT("either") <+> mk_ref np1
1038 msgs = [ptext SLIT(" or") <+> mk_ref np | np <- nps]
1039 mk_ref (GRE name prov _) = quotes (ppr name) <> comma <+> pprNameProvenance name prov
1041 shadowedNameWarn shadow
1042 = hsep [ptext SLIT("This binding for"),
1043 quotes (ppr shadow),
1044 ptext SLIT("shadows an existing binding")]
1046 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1049 = sep [text flavour, ptext SLIT("not in scope:"), quotes (ppr name)]
1051 flavour = occNameFlavour (rdrNameOcc name)
1053 qualNameErr descriptor (name,loc)
1054 = pushSrcLocRn loc $
1055 addErrRn (vcat [ ptext SLIT("Invalid use of qualified name") <+> quotes (ppr name),
1058 dupNamesErr descriptor ((name,loc) : dup_things)
1059 = pushSrcLocRn loc $
1060 addErrRn ((ptext SLIT("Conflicting definitions for") <+> quotes (ppr name))
1064 warnDeprec :: Name -> DeprecTxt -> RnM d ()
1066 = ifOptRn Opt_WarnDeprecations $
1067 addWarnRn (sep [ text (occNameFlavour (nameOccName name)) <+>
1068 quotes (ppr name) <+> text "is deprecated:",