2 % (c) The University of Glasgow, 2000
4 \section[HscTypes]{Types for the per-module compiler}
10 ModuleLocation(..), showModMsg,
12 ModDetails(..), ModIface(..),
13 HomeSymbolTable, emptySymbolTable,
15 HomeIfaceTable, PackageIfaceTable, emptyIfaceTable,
16 lookupIface, lookupIfaceByModName,
19 InteractiveContext(..),
21 IfaceDecls, mkIfaceDecls, dcl_tycl, dcl_rules, dcl_insts,
23 VersionInfo(..), initialVersionInfo, lookupVersion,
24 FixityEnv, lookupFixity, collectFixities,
26 TyThing(..), isTyClThing, implicitTyThingIds,
28 TypeEnv, lookupType, mkTypeEnv, emptyTypeEnv,
29 extendTypeEnvList, extendTypeEnvWithIds,
30 typeEnvElts, typeEnvClasses, typeEnvTyCons, typeEnvIds,
32 ImportedModuleInfo, WhetherHasOrphans, ImportVersion, WhatsImported(..),
33 PersistentRenamerState(..), IsBootInterface, DeclsMap,
34 IfaceInsts, IfaceRules, GatedDecl, GatedDecls, GateFn, IsExported,
35 NameSupply(..), OrigNameCache, OrigIParamCache,
36 Avails, AvailEnv, emptyAvailEnv,
37 GenAvailInfo(..), AvailInfo, RdrAvailInfo,
38 ExportItem, RdrExportItem,
39 PersistentCompilerState(..),
41 Deprecations(..), lookupDeprec,
43 InstEnv, ClsInstEnv, DFunId,
44 PackageInstEnv, PackageRuleBase,
46 GlobalRdrEnv, GlobalRdrElt(..), pprGlobalRdrEnv,
47 LocalRdrEnv, extendLocalRdrEnv,
51 Provenance(..), ImportReason(..),
52 pprNameProvenance, hasBetterProv
56 #include "HsVersions.h"
58 import RdrName ( RdrName, RdrNameEnv, addListToRdrEnv,
59 mkRdrUnqual, rdrEnvToList )
60 import Name ( Name, NamedThing, getName, nameOccName, nameModule, nameSrcLoc )
62 import OccName ( OccName )
64 import InstEnv ( InstEnv, ClsInstEnv, DFunId )
65 import Rules ( RuleBase )
66 import CoreSyn ( CoreBind )
68 import Class ( Class, classSelIds )
69 import TyCon ( TyCon, isNewTyCon, tyConGenIds, tyConSelIds, tyConDataCons_maybe )
70 import DataCon ( dataConWorkId, dataConWrapId )
72 import BasicTypes ( Version, initialVersion, Fixity, defaultFixity, IPName )
74 import HsSyn ( DeprecTxt, TyClDecl, tyClDeclName, ifaceRuleDeclName,
76 import RdrHsSyn ( RdrNameInstDecl, RdrNameRuleDecl, RdrNameTyClDecl )
77 import RnHsSyn ( RenamedTyClDecl, RenamedRuleDecl, RenamedInstDecl )
79 import CoreSyn ( IdCoreRule )
83 import Maybes ( seqMaybe, orElse )
85 import SrcLoc ( SrcLoc, isGoodSrcLoc )
86 import Util ( thenCmp, sortLt, unJust )
87 import UniqSupply ( UniqSupply )
90 %************************************************************************
92 \subsection{Which mode we're in
94 %************************************************************************
97 data GhciMode = Batch | Interactive | OneShot
102 %************************************************************************
104 \subsection{Module locations}
106 %************************************************************************
111 ml_hs_file :: Maybe FilePath,
112 ml_hspp_file :: Maybe FilePath, -- path of preprocessed source
113 ml_hi_file :: FilePath,
114 ml_obj_file :: Maybe FilePath
118 instance Outputable ModuleLocation where
121 -- Probably doesn't really belong here, but used in HscMain and InteractiveUI.
123 showModMsg :: Bool -> Module -> ModuleLocation -> String
124 showModMsg use_object mod location =
125 mod_str ++ replicate (max 0 (16 - length mod_str)) ' '
126 ++" ( " ++ unJust "showModMsg" (ml_hs_file location) ++ ", "
128 then unJust "showModMsg" (ml_obj_file location)
131 where mod_str = moduleUserString mod
134 For a module in another package, the hs_file and obj_file
135 components of ModuleLocation are undefined.
137 The locations specified by a ModuleLocation may or may not
138 correspond to actual files yet: for example, even if the object
139 file doesn't exist, the ModuleLocation still contains the path to
140 where the object file will reside if/when it is created.
143 %************************************************************************
145 \subsection{Symbol tables and Module details}
147 %************************************************************************
149 A @ModIface@ plus a @ModDetails@ summarises everything we know
150 about a compiled module. The @ModIface@ is the stuff *before* linking,
151 and can be written out to an interface file. (The @ModDetails@ is after
152 linking; it is the "linked" form of the mi_decls field.)
154 When we *read* an interface file, we also construct a @ModIface@ from it,
155 except that the mi_decls part is empty; when reading we consolidate
156 the declarations into a single indexed map in the @PersistentRenamerState@.
161 mi_module :: !Module,
162 mi_package :: !PackageName, -- Which package the module comes from
163 mi_version :: !VersionInfo, -- Module version number
165 mi_orphan :: WhetherHasOrphans, -- Whether this module has orphans
166 -- NOT STRICT! we fill this field with _|_ sometimes
168 mi_boot :: !IsBootInterface, -- read from an hi-boot file?
170 mi_usages :: ![ImportVersion Name],
171 -- Usages; kept sorted so that it's easy to decide
172 -- whether to write a new iface file (changing usages
173 -- doesn't affect the version of this module)
175 mi_exports :: ![ExportItem],
176 -- What it exports Kept sorted by (mod,occ), to make
177 -- version comparisons easier
179 mi_globals :: !(Maybe GlobalRdrEnv),
180 -- Its top level environment or Nothing if we read this
181 -- interface from a file.
183 mi_fixities :: !FixityEnv, -- Fixities
184 mi_deprecs :: !Deprecations, -- Deprecations
186 mi_decls :: IfaceDecls -- The RnDecls form of ModDetails
187 -- NOT STRICT! we fill this field with _|_ sometimes
190 data IfaceDecls = IfaceDecls { dcl_tycl :: [RenamedTyClDecl], -- Sorted
191 dcl_rules :: [RenamedRuleDecl], -- Sorted
192 dcl_insts :: [RenamedInstDecl] } -- Unsorted
194 mkIfaceDecls :: [RenamedTyClDecl] -> [RenamedRuleDecl] -> [RenamedInstDecl] -> IfaceDecls
195 mkIfaceDecls tycls rules insts
196 = IfaceDecls { dcl_tycl = sortLt lt_tycl tycls,
197 dcl_rules = sortLt lt_rule rules,
200 d1 `lt_tycl` d2 = tyClDeclName d1 < tyClDeclName d2
201 r1 `lt_rule` r2 = ifaceRuleDeclName r1 < ifaceRuleDeclName r2
204 -- typechecker should only look at this, not ModIface
205 -- Should be able to construct ModDetails from mi_decls in ModIface
208 -- The next three fields are created by the typechecker
209 md_types :: !TypeEnv,
210 md_insts :: ![DFunId], -- Dfun-ids for the instances in this module
211 md_rules :: ![IdCoreRule], -- Domain may include Ids from other modules
212 md_binds :: ![CoreBind]
215 -- The ModDetails takes on several slightly different forms:
217 -- After typecheck + desugar
218 -- md_types Contains TyCons, Classes, and implicit Ids
219 -- md_insts All instances from this module (incl derived ones)
220 -- md_rules All rules from this module
221 -- md_binds Desugared bindings
223 -- After simplification
224 -- md_types Same as after typecheck
226 -- md_rules Orphan rules only (local ones now attached to binds)
227 -- md_binds With rules attached
230 -- md_types Now contains Ids as well, replete with final IdInfo
231 -- The Ids are only the ones that are visible from
232 -- importing modules. Without -O that means only
233 -- exported Ids, but with -O importing modules may
234 -- see ids mentioned in unfoldings of exported Ids
236 -- md_insts Same DFunIds as before, but with final IdInfo,
237 -- and the unique might have changed; remember that
238 -- CoreTidy links up the uniques of old and new versions
240 -- md_rules All rules for exported things, substituted with final Ids
244 -- Passed back to compilation manager
245 -- Just as after CoreTidy, but with md_binds nuked
250 emptyModIface :: Module -> ModIface
252 = ModIface { mi_module = mod,
253 mi_package = preludePackage, -- XXX fully bogus
254 mi_version = initialVersionInfo,
259 mi_fixities = emptyNameEnv,
260 mi_globals = Nothing,
261 mi_deprecs = NoDeprecs,
262 mi_decls = panic "emptyModIface: decls"
266 Symbol tables map modules to ModDetails:
269 type SymbolTable = ModuleEnv ModDetails
270 type IfaceTable = ModuleEnv ModIface
272 type HomeIfaceTable = IfaceTable
273 type PackageIfaceTable = IfaceTable
275 type HomeSymbolTable = SymbolTable -- Domain = modules in the home package
277 emptySymbolTable :: SymbolTable
278 emptySymbolTable = emptyModuleEnv
280 emptyIfaceTable :: IfaceTable
281 emptyIfaceTable = emptyModuleEnv
284 Simple lookups in the symbol table.
287 lookupIface :: HomeIfaceTable -> PackageIfaceTable -> Name -> Maybe ModIface
288 -- We often have two IfaceTables, and want to do a lookup
289 lookupIface hit pit name
290 = lookupModuleEnv hit mod `seqMaybe` lookupModuleEnv pit mod
292 mod = nameModule name
294 lookupIfaceByModName :: HomeIfaceTable -> PackageIfaceTable -> ModuleName -> Maybe ModIface
295 -- We often have two IfaceTables, and want to do a lookup
296 lookupIfaceByModName hit pit mod
297 = lookupModuleEnvByName hit mod `seqMaybe` lookupModuleEnvByName pit mod
301 %************************************************************************
303 \subsection{The interactive context}
305 %************************************************************************
308 data InteractiveContext
309 = InteractiveContext {
310 ic_toplev_scope :: [Module], -- Include the "top-level" scope of
313 ic_exports :: [Module], -- Include just the exports of these
316 ic_rn_gbl_env :: GlobalRdrEnv, -- The cached GlobalRdrEnv, built from
317 -- ic_toplev_scope and ic_exports
319 ic_print_unqual :: PrintUnqualified,
320 -- cached PrintUnqualified, as above
322 ic_rn_local_env :: LocalRdrEnv, -- Lexical context for variables bound
323 -- during interaction
325 ic_type_env :: TypeEnv -- Ditto for types
330 %************************************************************************
332 \subsection{Type environment stuff}
334 %************************************************************************
337 data TyThing = AnId Id
341 isTyClThing :: TyThing -> Bool
342 isTyClThing (ATyCon _) = True
343 isTyClThing (AClass _) = True
344 isTyClThing (AnId _) = False
346 instance NamedThing TyThing where
347 getName (AnId id) = getName id
348 getName (ATyCon tc) = getName tc
349 getName (AClass cl) = getName cl
351 instance Outputable TyThing where
352 ppr (AnId id) = ptext SLIT("AnId") <+> ppr id
353 ppr (ATyCon tc) = ptext SLIT("ATyCon") <+> ppr tc
354 ppr (AClass cl) = ptext SLIT("AClass") <+> ppr cl
357 typeEnvElts :: TypeEnv -> [TyThing]
358 typeEnvClasses :: TypeEnv -> [Class]
359 typeEnvTyCons :: TypeEnv -> [TyCon]
360 typeEnvIds :: TypeEnv -> [Id]
362 typeEnvElts env = nameEnvElts env
363 typeEnvClasses env = [cl | AClass cl <- typeEnvElts env]
364 typeEnvTyCons env = [tc | ATyCon tc <- typeEnvElts env]
365 typeEnvIds env = [id | AnId id <- typeEnvElts env]
367 implicitTyThingIds :: [TyThing] -> [Id]
368 -- Add the implicit data cons and selectors etc
369 implicitTyThingIds things
370 = concat (map go things)
373 go (AClass cl) = classSelIds cl
374 go (ATyCon tc) = tyConGenIds tc ++
376 [ n | dc <- tyConDataCons_maybe tc `orElse` [],
377 n <- implicitConIds tc dc]
378 -- Synonyms return empty list of constructors and selectors
380 implicitConIds tc dc -- Newtypes have a constructor wrapper,
382 | isNewTyCon tc = [dataConWrapId dc]
383 | otherwise = [dataConWorkId dc, dataConWrapId dc]
388 type TypeEnv = NameEnv TyThing
390 emptyTypeEnv = emptyNameEnv
392 mkTypeEnv :: [TyThing] -> TypeEnv
393 mkTypeEnv things = extendTypeEnvList emptyTypeEnv things
395 extendTypeEnvList :: TypeEnv -> [TyThing] -> TypeEnv
396 extendTypeEnvList env things
397 = extendNameEnvList env [(getName thing, thing) | thing <- things]
399 extendTypeEnvWithIds :: TypeEnv -> [Id] -> TypeEnv
400 extendTypeEnvWithIds env ids
401 = extendNameEnvList env [(getName id, AnId id) | id <- ids]
405 lookupType :: HomeSymbolTable -> PackageTypeEnv -> Name -> Maybe TyThing
406 lookupType hst pte name
407 = case lookupModuleEnv hst (nameModule name) of
408 Just details -> lookupNameEnv (md_types details) name
409 Nothing -> lookupNameEnv pte name
412 %************************************************************************
414 \subsection{Auxiliary types}
416 %************************************************************************
418 These types are defined here because they are mentioned in ModDetails,
419 but they are mostly elaborated elsewhere
424 vers_module :: Version, -- Changes when anything changes
425 vers_exports :: Version, -- Changes when export list changes
426 vers_rules :: Version, -- Changes when any rule changes
427 vers_decls :: NameEnv Version
428 -- Versions for "big" names only (not data constructors, class ops)
429 -- The version of an Id changes if its fixity changes
430 -- Ditto data constructors, class operations, except that the version of
431 -- the parent class/tycon changes
433 -- If a name isn't in the map, it means 'initialVersion'
436 initialVersionInfo :: VersionInfo
437 initialVersionInfo = VersionInfo { vers_module = initialVersion,
438 vers_exports = initialVersion,
439 vers_rules = initialVersion,
440 vers_decls = emptyNameEnv
443 lookupVersion :: NameEnv Version -> Name -> Version
444 lookupVersion env name = lookupNameEnv env name `orElse` initialVersion
446 data Deprecations = NoDeprecs
447 | DeprecAll DeprecTxt -- Whole module deprecated
448 | DeprecSome (NameEnv (Name,DeprecTxt)) -- Some things deprecated
450 -- We keep the Name in the range, so we can print them out
452 lookupDeprec :: Deprecations -> Name -> Maybe DeprecTxt
453 lookupDeprec NoDeprecs name = Nothing
454 lookupDeprec (DeprecAll txt) name = Just txt
455 lookupDeprec (DeprecSome env) name = case lookupNameEnv env name of
456 Just (_, txt) -> Just txt
459 instance Eq Deprecations where
460 -- Used when checking whether we need write a new interface
461 NoDeprecs == NoDeprecs = True
462 (DeprecAll t1) == (DeprecAll t2) = t1 == t2
463 (DeprecSome e1) == (DeprecSome e2) = nameEnvElts e1 == nameEnvElts e2
469 type Avails = [AvailInfo]
470 type AvailInfo = GenAvailInfo Name
471 type RdrAvailInfo = GenAvailInfo OccName
473 data GenAvailInfo name = Avail name -- An ordinary identifier
474 | AvailTC name -- The name of the type or class
475 [name] -- The available pieces of type/class.
476 -- NB: If the type or class is itself
477 -- to be in scope, it must be in this list.
478 -- Thus, typically: AvailTC Eq [Eq, ==, /=]
480 -- Equality used when deciding if the interface has changed
482 type RdrExportItem = (ModuleName, [RdrAvailInfo])
483 type ExportItem = (ModuleName, [AvailInfo])
485 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
487 emptyAvailEnv :: AvailEnv
488 emptyAvailEnv = emptyNameEnv
490 instance Outputable n => Outputable (GenAvailInfo n) where
493 pprAvail :: Outputable n => GenAvailInfo n -> SDoc
494 pprAvail (AvailTC n ns) = ppr n <> case {- filter (/= n) -} ns of
496 ns' -> braces (hsep (punctuate comma (map ppr ns')))
498 pprAvail (Avail n) = ppr n
502 type FixityEnv = NameEnv Fixity
504 lookupFixity :: FixityEnv -> Name -> Fixity
505 lookupFixity env n = lookupNameEnv env n `orElse` defaultFixity
507 collectFixities :: FixityEnv -> [TyClDecl Name pat] -> [(Name,Fixity)]
508 collectFixities env decls
510 | d <- decls, (n,_) <- tyClDeclNames d,
511 Just fix <- [lookupNameEnv env n]
516 %************************************************************************
518 \subsection{ModIface}
520 %************************************************************************
523 type WhetherHasOrphans = Bool
525 -- * an instance decl in a module other than the defn module for
526 -- one of the tycons or classes in the instance head
527 -- * a transformation rule in a module other than the one defining
528 -- the function in the head of the rule.
530 type IsBootInterface = Bool
532 type ImportVersion name = (ModuleName, WhetherHasOrphans, IsBootInterface, WhatsImported name)
534 data WhatsImported name = NothingAtAll -- The module is below us in the
535 -- hierarchy, but we import nothing
537 | Everything Version -- Used for modules from other packages;
538 -- we record only the module's version number
541 Version -- Module version
542 (Maybe Version) -- Export-list version, if we depend on it
543 [(name,Version)] -- List guaranteed non-empty
544 Version -- Rules version
547 -- 'Specifically' doesn't let you say "I imported f but none of the rules in
548 -- the module". If you use anything in the module you get its rule version
549 -- So if the rules change, you'll recompile, even if you don't use them.
550 -- This is easy to implement, and it's safer: you might not have used the rules last
551 -- time round, but if someone has added a new rule you might need it this time
553 -- The export list field is (Just v) if we depend on the export list:
554 -- we imported the module without saying exactly what we imported
555 -- We need to recompile if the module exports changes, because we might
556 -- now have a name clash in the importing module.
558 type IsExported = Name -> Bool -- True for names that are exported from this module
562 %************************************************************************
564 \subsection{The persistent compiler state}
566 %************************************************************************
568 The @PersistentCompilerState@ persists across successive calls to the
571 * A ModIface for each non-home-package module
573 * An accumulated TypeEnv from all the modules in imported packages
575 * An accumulated InstEnv from all the modules in imported packages
576 The point is that we don't want to keep recreating it whenever
577 we compile a new module. The InstEnv component of pcPST is empty.
578 (This means we might "see" instances that we shouldn't "really" see;
579 but the Haskell Report is vague on what is meant to be visible,
580 so we just take the easy road here.)
584 * The persistent renamer state
587 data PersistentCompilerState
589 pcs_PIT :: !PackageIfaceTable, -- Domain = non-home-package modules
590 -- the mi_decls component is empty
592 pcs_PTE :: !PackageTypeEnv, -- Domain = non-home-package modules
593 -- except that the InstEnv components is empty
595 pcs_insts :: !PackageInstEnv, -- The total InstEnv accumulated from all
596 -- the non-home-package modules
598 pcs_rules :: !PackageRuleBase, -- Ditto RuleEnv
600 pcs_PRS :: !PersistentRenamerState
605 The persistent renamer state contains:
607 * A name supply, which deals with allocating unique names to
608 (Module,OccName) original names,
610 * A "holding pen" for declarations that have been read out of
611 interface files but not yet sucked in, renamed, and typechecked
614 type PackageTypeEnv = TypeEnv
615 type PackageRuleBase = RuleBase
616 type PackageInstEnv = InstEnv
618 data PersistentRenamerState
619 = PRS { prsOrig :: !NameSupply,
620 prsImpMods :: !ImportedModuleInfo,
622 -- Holding pens for stuff that has been read in
623 -- but not yet slurped into the renamer
624 prsDecls :: !DeclsMap,
625 prsInsts :: !IfaceInsts,
626 prsRules :: !IfaceRules
630 The NameSupply makes sure that there is just one Unique assigned for
631 each original name; i.e. (module-name, occ-name) pair. The Name is
632 always stored as a Global, and has the SrcLoc of its binding location.
633 Actually that's not quite right. When we first encounter the original
634 name, we might not be at its binding site (e.g. we are reading an
635 interface file); so we give it 'noSrcLoc' then. Later, when we find
636 its binding site, we fix it up.
638 Exactly the same is true of the Module stored in the Name. When we first
639 encounter the occurrence, we may not know the details of the module, so
640 we just store junk. Then when we find the binding site, we fix it up.
644 = NameSupply { nsUniqs :: UniqSupply,
646 nsNames :: OrigNameCache,
647 -- Ensures that one original name gets one unique
648 nsIPs :: OrigIParamCache
649 -- Ensures that one implicit parameter name gets one unique
652 type OrigNameCache = FiniteMap (ModuleName,OccName) Name
653 type OrigIParamCache = FiniteMap (IPName RdrName) (IPName Name)
656 @ImportedModuleInfo@ contains info ONLY about modules that have not yet
657 been loaded into the iPIT. These modules are mentioned in interfaces we've
658 already read, so we know a tiny bit about them, but we havn't yet looked
659 at the interface file for the module itself. It needs to persist across
660 invocations of the renamer, at least from Rename.checkOldIface to Rename.renameSource.
661 And there's no harm in it persisting across multiple compilations.
664 type ImportedModuleInfo = FiniteMap ModuleName (WhetherHasOrphans, IsBootInterface)
667 A DeclsMap contains a binding for each Name in the declaration
668 including the constructors of a type decl etc. The Bool is True just
672 type DeclsMap = (NameEnv (AvailInfo, Bool, (Module, RdrNameTyClDecl)), Int)
673 -- The Int says how many have been sucked in
675 type IfaceInsts = GatedDecls RdrNameInstDecl
676 type IfaceRules = GatedDecls RdrNameRuleDecl
678 type GatedDecls d = (Bag (GatedDecl d), Int) -- The Int says how many have been sucked in
679 type GatedDecl d = (GateFn, (Module, d))
680 type GateFn = (Name -> Bool) -> Bool -- Returns True <=> gate is open
681 -- The (Name -> Bool) fn returns True for visible Names
682 -- For example, suppose this is in an interface file
683 -- instance C T where ...
684 -- We want to slurp this decl if both C and T are "visible" in
685 -- the importing module. See "The gating story" in RnIfaces for details.
689 %************************************************************************
691 \subsection{Provenance and export info}
693 %************************************************************************
695 A LocalRdrEnv is used for local bindings (let, where, lambda, case)
698 type LocalRdrEnv = RdrNameEnv Name
700 extendLocalRdrEnv :: LocalRdrEnv -> [Name] -> LocalRdrEnv
701 extendLocalRdrEnv env names
702 = addListToRdrEnv env [(mkRdrUnqual (nameOccName n), n) | n <- names]
705 The GlobalRdrEnv gives maps RdrNames to Names. There is a separate
706 one for each module, corresponding to that module's top-level scope.
709 type GlobalRdrEnv = RdrNameEnv [GlobalRdrElt]
710 -- The list is because there may be name clashes
711 -- These only get reported on lookup, not on construction
713 data GlobalRdrElt = GRE Name Provenance (Maybe DeprecTxt)
714 -- The Maybe DeprecTxt tells whether this name is deprecated
717 = vcat (map pp (rdrEnvToList env))
719 pp (rn, nps) = ppr rn <> colon <+>
720 vcat [ppr n <+> pprNameProvenance n p | (GRE n p _) <- nps]
723 The "provenance" of something says how it came to be in scope.
727 = LocalDef -- Defined locally
729 | NonLocalDef -- Defined non-locally
732 -- Just used for grouping error messages (in RnEnv.warnUnusedBinds)
733 instance Eq Provenance where
734 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
736 instance Eq ImportReason where
737 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
739 instance Ord Provenance where
740 compare LocalDef LocalDef = EQ
741 compare LocalDef (NonLocalDef _) = LT
742 compare (NonLocalDef _) LocalDef = GT
744 compare (NonLocalDef reason1) (NonLocalDef reason2)
745 = compare reason1 reason2
747 instance Ord ImportReason where
748 compare ImplicitImport ImplicitImport = EQ
749 compare ImplicitImport (UserImport _ _ _) = LT
750 compare (UserImport _ _ _) ImplicitImport = GT
751 compare (UserImport m1 loc1 _) (UserImport m2 loc2 _)
752 = (m1 `compare` m2) `thenCmp` (loc1 `compare` loc2)
756 = UserImport Module SrcLoc Bool -- Imported from module M on line L
757 -- Note the M may well not be the defining module
759 -- The Bool is true iff the thing was named *explicitly* in the import spec,
760 -- rather than being imported as part of a group; e.g.
763 -- Here, everything imported by B, and the constructors of T
764 -- are not named explicitly; only T is named explicitly.
765 -- This info is used when warning of unused names.
767 | ImplicitImport -- Imported implicitly for some other reason
771 hasBetterProv :: Provenance -> Provenance -> Bool
773 -- a local thing over an imported thing
774 -- a user-imported thing over a non-user-imported thing
775 -- an explicitly-imported thing over an implicitly imported thing
776 hasBetterProv LocalDef _ = True
777 hasBetterProv (NonLocalDef (UserImport _ _ _ )) (NonLocalDef ImplicitImport) = True
778 hasBetterProv _ _ = False
780 pprNameProvenance :: Name -> Provenance -> SDoc
781 pprNameProvenance name LocalDef = ptext SLIT("defined at") <+> ppr (nameSrcLoc name)
782 pprNameProvenance name (NonLocalDef why) = sep [ppr_reason why,
783 nest 2 (ppr_defn (nameSrcLoc name))]
785 ppr_reason ImplicitImport = ptext SLIT("implicitly imported")
786 ppr_reason (UserImport mod loc _) = ptext SLIT("imported from") <+> ppr mod <+> ptext SLIT("at") <+> ppr loc
788 ppr_defn loc | isGoodSrcLoc loc = parens (ptext SLIT("at") <+> ppr loc)