\begin{code}
module RnNames (
- rnImports, mkRdrEnvAndImports, importsFromLocalDecls,
- rnExports, mkExportNameSet,
- getLocalDeclBinders, extendRdrEnvRn,
- reportUnusedNames, reportDeprecations
+ rnImports, getLocalNonValBinders,
+ rnExports, extendGlobalRdrEnvRn,
+ reportUnusedNames, finishWarnings,
) where
#include "HsVersions.h"
-import DynFlags ( DynFlag(..), GhcMode(..), DynFlags(..) )
-import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
- ForeignDecl(..), HsGroup(..), HsValBinds(..),
- Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
- LIE )
+import DynFlags
+import HsSyn
+import TcEnv ( isBrackStage )
import RnEnv
+import RnHsDoc ( rnHsDoc )
import IfaceEnv ( ifaceExportNames )
-import LoadIface ( loadSrcInterface )
+import LoadIface ( loadSrcInterface, loadSysInterface )
import TcRnMonad hiding (LIE)
-import FiniteMap
import PrelNames
import Module
-import Name ( Name, nameSrcLoc, nameOccName, nameModule, isWiredInName,
- nameParent, nameParent_maybe, isExternalName,
- isBuiltInSyntax )
-import NameSet
+import Name
import NameEnv
-import OccName ( srcDataName, isTcOcc, pprNonVarNameSpace,
- occNameSpace,
- OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv,
- extendOccEnv )
-import HscTypes ( GenAvailInfo(..), AvailInfo,
- HomePackageTable, PackageIfaceTable,
- mkPrintUnqualified,
- Deprecs(..), ModIface(..), Dependencies(..),
- lookupIfaceByModule, ExternalPackageState(..)
- )
-import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
- GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
- emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
- extendGlobalRdrEnv, lookupGlobalRdrEnv, unQualOK, lookupGRE_Name,
- Provenance(..), ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..),
- importSpecLoc, importSpecModule, isLocalGRE, pprNameProvenance )
+import NameSet
+import HscTypes
+import RdrName
import Outputable
-import UniqFM
-import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse )
-import SrcLoc ( Located(..), mkGeneralSrcSpan,
- unLoc, noLoc, srcLocSpan, SrcSpan )
-import BasicTypes ( DeprecTxt )
-import DriverPhases ( isHsBoot )
-import Util ( notNull )
-import List ( partition )
+import Maybes
+import SrcLoc
+import FiniteMap
+import ErrUtils
+import Util
+import FastString
+import ListSetOps
+import Data.List ( partition, (\\), delete )
+import qualified Data.Set as Set
import IO ( openFile, IOMode(..) )
+import Monad ( when, mplus )
\end{code}
%************************************************************************
\begin{code}
-rnImports :: [LImportDecl RdrName] -> RnM [LImportDecl Name]
+rnImports :: [LImportDecl RdrName]
+ -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
+
rnImports imports
-- PROCESS IMPORT DECLS
-- Do the non {- SOURCE -} ones first, so that we get a helpful
-- warning for {- SOURCE -} ones that are unnecessary
= do this_mod <- getModule
implicit_prelude <- doptM Opt_ImplicitPrelude
- let all_imports = mk_prel_imports this_mod implicit_prelude ++ imports
- (source, ordinary) = partition is_source_import all_imports
- is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
- get_imports = rnImportDecl this_mod
-
- stuff1 <- mapM get_imports ordinary
- stuff2 <- mapM get_imports source
- return (stuff1 ++ stuff2)
+ let prel_imports = mkPrelImports this_mod implicit_prelude imports
+ (source, ordinary) = partition is_source_import imports
+ is_source_import (L _ (ImportDecl _ _ is_boot _ _ _)) = is_boot
+
+ ifOptM Opt_WarnImplicitPrelude (
+ when (notNull prel_imports) $ addWarn (implicitPreludeWarn)
+ )
+
+ stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
+ stuff2 <- mapM (rnImportDecl this_mod) source
+ let (decls, rdr_env, imp_avails,hpc_usage) = combine (stuff1 ++ stuff2)
+ return (decls, rdr_env, imp_avails,hpc_usage)
+
where
+ combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)]
+ -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
+ combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails,False)
+ where plus (decl, gbl_env1, imp_avails1,hpc_usage1)
+ (decls, gbl_env2, imp_avails2,hpc_usage2)
+ = (decl:decls,
+ gbl_env1 `plusGlobalRdrEnv` gbl_env2,
+ imp_avails1 `plusImportAvails` imp_avails2,
+ hpc_usage1 || hpc_usage2)
+
+mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName]
+-- Consruct the implicit declaration "import Prelude" (or not)
+--
-- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
-- because the former doesn't even look at Prelude.hi for instance
-- declarations, whereas the latter does.
- mk_prel_imports this_mod implicit_prelude
- | this_mod == pRELUDE
- || explicit_prelude_import
- || not implicit_prelude
- = []
- | otherwise = [preludeImportDecl]
- explicit_prelude_import
- = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
+mkPrelImports this_mod implicit_prelude import_decls
+ | this_mod == pRELUDE
+ || explicit_prelude_import
+ || not implicit_prelude
+ = []
+ | otherwise = [preludeImportDecl]
+ where
+ explicit_prelude_import
+ = notNull [ () | L _ (ImportDecl mod Nothing _ _ _ _) <- import_decls,
unLoc mod == pRELUDE_NAME ]
-preludeImportDecl :: LImportDecl RdrName
-preludeImportDecl
- = L loc $
- ImportDecl (L loc pRELUDE_NAME)
+ preludeImportDecl :: LImportDecl RdrName
+ preludeImportDecl
+ = L loc $
+ ImportDecl (L loc pRELUDE_NAME)
+ Nothing {- no specific package -}
False {- Not a boot interface -}
False {- Not qualified -}
Nothing {- No "as" -}
Nothing {- No import list -}
- where
- loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
-
-mkRdrEnvAndImports :: [LImportDecl Name] -> RnM (GlobalRdrEnv, ImportAvails)
-mkRdrEnvAndImports imports
- = do this_mod <- getModule
- let get_imports = importsFromImportDecl this_mod
- stuff <- mapM get_imports imports
- let (imp_gbl_envs, imp_avails) = unzip stuff
- gbl_env :: GlobalRdrEnv
- gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs
-
- all_avails :: ImportAvails
- all_avails = foldr plusImportAvails emptyImportAvails imp_avails
- -- ALL DONE
- return (gbl_env, all_avails)
-\end{code}
-
-\begin{code}
-rnImportDecl :: Module
- -> LImportDecl RdrName
- -> RnM (LImportDecl Name)
-rnImportDecl this_mod (L loc importDecl@(ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
- = setSrcSpan loc $
- do iface <- loadSrcInterface doc imp_mod_name want_boot
- let qual_mod_name = case as_mod of
- Nothing -> imp_mod_name
- Just another_name -> another_name
- imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
- is_dloc = loc, is_as = qual_mod_name }
- total_avails <- ifaceExportNames (mi_exports iface)
- importDecl' <- rnImportDecl' iface imp_spec importDecl total_avails
- return (L loc importDecl')
- where imp_mod_name = unLoc loc_imp_mod_name
- doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
-
-rnImportDecl' :: ModIface -> ImpDeclSpec -> ImportDecl RdrName -> NameSet -> RnM (ImportDecl Name)
-rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod Nothing) all_names
- = return $ ImportDecl mod_name want_boot qual_only as_mod Nothing
-rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,import_items))) all_names
- = do import_items_mbs <- mapM (srcSpanWrapper) import_items
- let rn_import_items = concat . catMaybes $ import_items_mbs
- return $ ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,rn_import_items))
- where
- srcSpanWrapper (L span ieRdr)
- = setSrcSpan span $
- case get_item ieRdr of
- Nothing
- -> do addErr (badImportItemErr iface decl_spec ieRdr)
- return Nothing
- Just ieNames
- -> return (Just [L span ie | ie <- ieNames])
- occ_env :: OccEnv Name -- Maps OccName to corresponding Name
- occ_env = mkOccEnv [(nameOccName n, n) | n <- nameSetToList all_names]
- -- This env will have entries for data constructors too,
- -- they won't make any difference because naked entities like T
- -- in an import list map to TcOccs, not VarOccs.
+ loc = mkGeneralSrcSpan (fsLit "Implicit import declaration")
- sub_env :: NameEnv [Name]
- sub_env = mkSubNameEnv all_names
-
- get_item :: IE RdrName -> Maybe [IE Name]
- -- Empty result for a bad item.
- -- Singleton result is typical case.
- -- Can have two when we are hiding, and mention C which might be
- -- both a class and a data constructor.
- get_item item@(IEModuleContents _)
- = Nothing
- get_item (IEThingAll tc)
- = do name <- check_name tc
- return [IEThingAll name]
- get_item (IEThingAbs tc)
- | want_hiding -- hiding ( C )
- -- Here the 'C' can be a data constructor
- -- *or* a type/class, or even both
- = case catMaybes [check_name tc, check_name (setRdrNameSpace tc srcDataName)] of
- [] -> Nothing
- names -> return [ IEThingAbs n | n <- names ]
- | otherwise
- = do name <- check_name tc
- return [IEThingAbs name]
- get_item (IEThingWith n ns) -- import (C (A,B))
- = do name <- check_name n
- let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name]
- mb_names = map (lookupOccEnv env . rdrNameOcc) ns
- names <- sequence mb_names
- return [IEThingWith name names]
- get_item (IEVar n)
- = do name <- check_name n
- return [IEVar name]
-
- check_name :: RdrName -> Maybe Name
- check_name rdrName
- = lookupOccEnv occ_env (rdrNameOcc rdrName)
-
-
-importsFromImportDecl :: Module
- -> LImportDecl Name
- -> RnM (GlobalRdrEnv, ImportAvails)
-
-importsFromImportDecl this_mod
- (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
- =
- setSrcSpan loc $
+
+rnImportDecl :: Module
+ -> LImportDecl RdrName
+ -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
+
+rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
+ qual_only as_mod imp_details))
+ = setSrcSpan loc $ do
+
+ when (isJust mb_pkg) $ do
+ pkg_imports <- doptM Opt_PackageImports
+ when (not pkg_imports) $ addErr packageImportErr
-- If there's an error in loadInterface, (e.g. interface
-- file not found) we get lots of spurious errors from 'filterImports'
let
imp_mod_name = unLoc loc_imp_mod_name
- doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
- in
- loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
+ doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
+
+ iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg
-- Compiler sanity check: if the import didn't say
-- {-# SOURCE #-} we should not get a hi-boot file
- WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
+ WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
-- Issue a user warning for a redundant {- SOURCE -} import
-- NB that we arrange to read all the ordinary imports before
- -- any of the {- SOURCE -} imports
- warnIf (want_boot && not (mi_boot iface))
- (warnRedundantSourceImport imp_mod_name) `thenM_`
+ -- any of the {- SOURCE -} imports.
+ --
+ -- in --make and GHCi, the compilation manager checks for this,
+ -- and indeed we shouldn't do it here because the existence of
+ -- the non-boot module depends on the compilation order, which
+ -- is not deterministic. The hs-boot test can show this up.
+ dflags <- getDOpts
+ warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags))
+ (warnRedundantSourceImport imp_mod_name)
let
- imp_mod = mi_module iface
- deprecs = mi_deprecs iface
- is_orph = mi_orphan iface
- deps = mi_deps iface
+ imp_mod = mi_module iface
+ warns = mi_warns iface
+ orph_iface = mi_orphan iface
+ has_finsts = mi_finsts iface
+ deps = mi_deps iface
filtered_exports = filter not_this_mod (mi_exports iface)
not_this_mod (mod,_) = mod /= this_mod
- -- If the module exports anything defined in this module, just ignore it.
- -- Reason: otherwise it looks as if there are two local definition sites
- -- for the thing, and an error gets reported. Easiest thing is just to
- -- filter them out up front. This situation only arises if a module
- -- imports itself, or another module that imported it. (Necessarily,
- -- this invoves a loop.)
+ -- If the module exports anything defined in this module, just
+ -- ignore it. Reason: otherwise it looks as if there are two
+ -- local definition sites for the thing, and an error gets
+ -- reported. Easiest thing is just to filter them out up
+ -- front. This situation only arises if a module imports
+ -- itself, or another module that imported it. (Necessarily,
+ -- this invoves a loop.)
--
-- Tiresome consequence: if you say
-- module A where
Just another_name -> another_name
imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
is_dloc = loc, is_as = qual_mod_name }
- in
- -- Get the total imports, and filter them according to the import list
- ifaceExportNames filtered_exports `thenM` \ total_avails ->
- filterImports iface imp_spec
- imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
+ -- in
+
+ -- Get the total exports from this module
+ total_avails <- ifaceExportNames filtered_exports
- getDOpts `thenM` \ dflags ->
+ -- filter the imports according to the import declaration
+ (new_imp_details, gbl_env) <-
+ filterImports iface imp_spec imp_details total_avails
+
+ dflags <- getDOpts
let
-- Compute new transitive dependencies
- orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) )
- imp_mod : dep_orphs deps
- | otherwise = dep_orphs deps
+ orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
+ imp_mod : dep_orphs deps
+ | otherwise = dep_orphs deps
+
+ finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
+ imp_mod : dep_finsts deps
+ | otherwise = dep_finsts deps
pkg = modulePackageId (mi_module iface)
-- True <=> import M ()
import_all = case imp_details of
Just (is_hiding, ls) -> not is_hiding && null ls
- other -> False
+ _ -> False
- -- unqual_avails is the Avails that are visible in *unqualified* form
- -- We need to know this so we know what to export when we see
- -- module M ( module P ) where ...
- -- Then we must export whatever came from P unqualified.
imports = ImportAvails {
- imp_env = unitUFM qual_mod_name avail_env,
- imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
+ imp_mods = unitModuleEnv imp_mod [(qual_mod_name, import_all, loc)],
imp_orphs = orphans,
+ imp_finsts = finsts,
imp_dep_mods = mkModDeps dependent_mods,
- imp_dep_pkgs = dependent_pkgs }
+ imp_dep_pkgs = dependent_pkgs
+ }
- in
-- Complain if we import a deprecated module
- ifOptM Opt_WarnDeprecations (
- case deprecs of
- DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
- other -> returnM ()
- ) `thenM_`
+ ifOptM Opt_WarnWarningsDeprecations (
+ case warns of
+ WarnAll txt -> addWarn (moduleWarn imp_mod_name txt)
+ _ -> return ()
+ )
+
+ let new_imp_decl = L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
+ qual_only as_mod new_imp_details)
- returnM (gbl_env, imports)
+ return (new_imp_decl, gbl_env, imports, mi_hpc iface)
+ )
+warnRedundantSourceImport :: ModuleName -> SDoc
warnRedundantSourceImport mod_name
- = ptext SLIT("Unnecessary {-# SOURCE #-} in the import of module")
+ = ptext (sLit "Unnecessary {-# SOURCE #-} in the import of module")
<+> quotes (ppr mod_name)
\end{code}
* the ImportAvails
created by its bindings.
-Complain about duplicate bindings
+Note [Top-level Names in Template Haskell decl quotes]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider a Template Haskell declaration quotation like this:
+ module M where
+ f x = h [d| f = 3 |]
+When renaming the declarations inside [d| ...|], we treat the
+top level binders specially in two ways
+
+1. We give them an Internal name, not (as usual) an External one.
+ Otherwise the NameCache gets confused by a second allocation of
+ M.f. (We used to invent a fake module ThFake to avoid this, but
+ that had other problems, notably in getting the correct answer for
+ nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module
+ unaffected.)
+
+2. We make them *shadow* the outer bindings. If we don't do that,
+ we'll get a complaint when extending the GlobalRdrEnv, saying that
+ there are two bindings for 'f'.
+
+ This shadowing applies even if the binding for 'f' is in a
+ where-clause, and hence is in the *local* RdrEnv not the *global*
+ RdrEnv.
+
+We find out whether we are inside a [d| ... |] by testing the TH
+stage. This is a slight hack, because the stage field was really meant for
+the type checker, and here we are not interested in the fields of Brack,
+hence the error thunks in thRnBrack.
\begin{code}
-importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv
-importsFromLocalDecls group
- = do { gbl_env <- getGblEnv
-
- ; names <- getLocalDeclBinders gbl_env group
-
- ; implicit_prelude <- doptM Opt_ImplicitPrelude
- ; let {
- -- Optimisation: filter out names for built-in syntax
- -- They just clutter up the environment (esp tuples), and the parser
- -- will generate Exact RdrNames for them, so the cluttered
- -- envt is no use. To avoid doing this filter all the time,
- -- we use -fno-implicit-prelude as a clue that the filter is
- -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
- --
- -- It's worth doing because it makes the environment smaller for
- -- every module that imports the Prelude
- --
- -- Note: don't filter the gbl_env (hence all_names, not filered_all_names
- -- in defn of gres above). Stupid reason: when parsing
- -- data type decls, the constructors start as Exact tycon-names,
- -- and then get turned into data con names by zapping the name space;
- -- but that stops them being Exact, so they get looked up.
- -- Ditto in fixity decls; e.g. infix 5 :
- -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
- -- The important thing is to trim down the exports.
- filtered_names
- | implicit_prelude = names
- | otherwise = filter (not . isBuiltInSyntax) names ;
-
- ; this_mod = tcg_mod gbl_env
- ; imports = emptyImportAvails {
- imp_env = unitUFM (moduleName this_mod) $
- mkNameSet filtered_names
- }
- }
-
- ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) names
-
- ; returnM (gbl_env { tcg_rdr_env = rdr_env',
- tcg_imports = imports `plusImportAvails` tcg_imports gbl_env })
- }
-
-extendRdrEnvRn :: GlobalRdrEnv -> [Name] -> RnM GlobalRdrEnv
--- Add the new locally-bound names one by one, checking for duplicates as
--- we do so. Remember that in Template Haskell the duplicates
--- might *already be* in the GlobalRdrEnv from higher up the module
-extendRdrEnvRn rdr_env names
- = foldlM add_local rdr_env names
+extendGlobalRdrEnvRn :: [AvailInfo]
+ -> MiniFixityEnv
+ -> RnM (TcGblEnv, TcLclEnv)
+ -- Updates both the GlobalRdrEnv and the FixityEnv
+ -- We return a new TcLclEnv only becuase we might have to
+ -- delete some bindings from it;
+ -- see Note [Top-level Names in Template Haskell decl quotes]
+
+extendGlobalRdrEnvRn avails new_fixities
+ = do { (gbl_env, lcl_env) <- getEnvs
+ ; stage <- getStage
+ ; let rdr_env = tcg_rdr_env gbl_env
+ fix_env = tcg_fix_env gbl_env
+
+ -- Delete new_occs from global and local envs
+ -- If we are in a TemplateHaskell decl bracket,
+ -- we are going to shadow them
+ -- See Note [Top-level Names in Template Haskell decl quotes]
+ shadowP = isBrackStage stage
+ new_occs = map (nameOccName . gre_name) gres
+ rdr_env1 = hideSomeUnquals rdr_env new_occs
+ lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
+ (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
+ | otherwise = (rdr_env, lcl_env)
+
+ rdr_env3 = foldl extendGlobalRdrEnv rdr_env2 gres
+ fix_env' = foldl extend_fix_env fix_env gres
+ (rdr_env', dups) = findLocalDupsRdrEnv rdr_env3 new_occs
+
+ gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
+
+ ; mapM_ addDupDeclErr dups
+
+ ; traceRn (text "extendGlobalRdrEnvRn" <+> (ppr new_fixities $$ ppr fix_env $$ ppr fix_env'))
+ ; return (gbl_env', lcl_env2) }
where
- add_local rdr_env name
- | gres <- lookupGlobalRdrEnv rdr_env (nameOccName name)
- , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns
- = do { addDupDeclErr (gre_name dup_gre) name
- ; return rdr_env }
- | otherwise
- = return (extendGlobalRdrEnv rdr_env new_gre)
- where
- new_gre = GRE {gre_name = name, gre_prov = LocalDef}
+ gres = gresFromAvails LocalDef avails
+
+ -- If there is a fixity decl for the gre, add it to the fixity env
+ extend_fix_env fix_env gre
+ | Just (L _ fi) <- lookupFsEnv new_fixities (occNameFS occ)
+ = extendNameEnv fix_env name (FixItem occ fi)
+ | otherwise
+ = fix_env
+ where
+ name = gre_name gre
+ occ = nameOccName name
\end{code}
@getLocalDeclBinders@ returns the names for an @HsDecl@. It's
*** See "THE NAMING STORY" in HsDecls ****
+Instances of type families
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+Family instances contain data constructors that we need to collect and we also
+need to descend into the type instances of associated families in class
+instances. The type constructor of a family instance is a usage occurence.
+Hence, we don't return it as a subname in 'AvailInfo'; otherwise, we would get
+a duplicate declaration error.
+
+Note [Looking up family names in family instances]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider
+
+ module M where
+ type family T a :: *
+ type instance M.T Int = Bool
+
+We might think that we can simply use 'lookupOccRn' when processing the type
+instance to look up 'M.T'. Alas, we can't! The type family declaration is in
+the *same* HsGroup as the type instance declaration. Hence, as we are
+currently collecting the binders declared in that HsGroup, these binders will
+not have been added to the global environment yet.
+
+In the case of type classes, this problem does not arise, as a class instance
+does not define any binders of it's own. So, we simply don't attempt to look
+up the class names of class instances in 'get_local_binders' below.
+
+If we don't look up class instances, can't we get away without looking up type
+instances, too? No, we can't. Data type instances define data constructors
+and we need to
+
+ (1) collect those in 'get_local_binders' and
+ (2) we need to get their parent name in 'get_local_binders', too, to
+ produce an appropriate 'AvailTC'.
+
+This parent name is exactly the family name of the type instance that is so
+difficult to look up.
+
+We solve this problem as follows:
+
+ (a) We process all type declarations other than type instances first.
+ (b) Then, we compute a 'GlobalRdrEnv' from the result of the first step.
+ (c) Finally, we process all type instances (both those on the toplevel and
+ those nested in class instances) and check for the family names in the
+ 'GlobalRdrEnv' produced in the previous step before using 'lookupOccRn'.
+
\begin{code}
-getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [Name]
-getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs,
- hs_tyclds = tycl_decls,
- hs_fords = foreign_decls })
- = do { tc_names_s <- mappM new_tc tycl_decls
- ; val_names <- mappM new_simple val_bndrs
- ; return (foldr (++) val_names tc_names_s) }
+getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
+-- Get all the top-level binders bound the group *except*
+-- for value bindings, which are treated separately
+-- Specificaly we return AvailInfo for
+-- type decls
+-- class decls
+-- associated types
+-- foreign imports
+-- (in hs-boot files) value signatures
+
+getLocalNonValBinders group
+ = do { gbl_env <- getGblEnv
+ ; get_local_binders gbl_env group }
+
+get_local_binders :: TcGblEnv -> HsGroup RdrName -> RnM [GenAvailInfo Name]
+get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
+ hs_tyclds = tycl_decls,
+ hs_instds = inst_decls,
+ hs_fords = foreign_decls })
+ = do { -- separate out the family instance declarations
+ let (tyinst_decls1, tycl_decls_noinsts)
+ = partition (isFamInstDecl . unLoc) tycl_decls
+ tyinst_decls = tyinst_decls1 ++
+ concatMap (instDeclATs . unLoc) inst_decls
+
+ -- process all type/class decls except family instances
+ ; tc_names <- mapM new_tc tycl_decls_noinsts
+
+ -- create a temporary rdr env of the type binders
+ ; let tc_gres = gresFromAvails LocalDef tc_names
+ tc_name_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv tc_gres
+
+ -- process all family instances
+ ; ti_names <- mapM (new_ti tc_name_env) tyinst_decls
+
+ -- finish off with value binder in case of a hs-boot file
+ ; val_names <- mapM new_simple val_bndrs
+ ; return (val_names ++ tc_names ++ ti_names) }
where
mod = tcg_mod gbl_env
is_hs_boot = isHsBoot (tcg_src gbl_env) ;
- val_bndrs | is_hs_boot = sig_hs_bndrs
- | otherwise = for_hs_bndrs ++ val_hs_bndrs
- -- In a hs-boot file, the value binders come from the
- -- *signatures*, and there should be no foreign binders
- new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name
-
- sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs]
- val_hs_bndrs = collectHsBindLocatedBinders val_decls
+ for_hs_bndrs :: [Located RdrName]
for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
- new_tc tc_decl
- = do { main_name <- newTopSrcBinder mod Nothing main_rdr
- ; sub_names <- mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs
- ; return (main_name : sub_names) }
- where
- (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
+ -- In a hs-boot file, the value binders come from the
+ -- *signatures*, and there should be no foreign binders
+ val_bndrs :: [Located RdrName]
+ val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
+ | otherwise = for_hs_bndrs
+
+ new_simple :: Located RdrName -> RnM (GenAvailInfo Name)
+ new_simple rdr_name = do
+ nm <- newTopSrcBinder mod rdr_name
+ return (Avail nm)
+
+ new_tc tc_decl -- NOT for type/data instances
+ = do { main_name <- newTopSrcBinder mod main_rdr
+ ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
+ ; return (AvailTC main_name (main_name : sub_names)) }
+ where
+ (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
+
+ new_ti tc_name_env ti_decl -- ONLY for type/data instances
+ = do { main_name <- lookupFamInstDeclBndr tc_name_env main_rdr
+ ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
+ ; return (AvailTC main_name sub_names) }
+ -- main_name is not bound here!
+ where
+ (main_rdr : sub_rdrs) = tyClDeclNames (unLoc ti_decl)
+
+get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
\end{code}
\begin{code}
filterImports :: ModIface
-> ImpDeclSpec -- The span for the entire import decl
- -> Maybe (Bool, [LIE Name]) -- Import spec; True => hiding
- -> NameSet -- What's available
- -> RnM (NameSet, -- What's imported (qualified or unqualified)
+ -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
+ -> [AvailInfo] -- What's available
+ -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
GlobalRdrEnv) -- Same again, but in GRE form
-
- -- Complains if import spec mentions things that the module doesn't export
- -- Warns/informs if import spec contains duplicates.
-
-mkGenericRdrEnv decl_spec names
- = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] }
- | name <- nameSetToList names ]
+filterImports _ decl_spec Nothing all_avails
+ = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
where
- imp_spec = ImpSpec { is_decl = decl_spec, is_item = ImpAll }
-
-filterImports iface decl_spec Nothing all_names
- = return (all_names, mkGenericRdrEnv decl_spec all_names)
-
-filterImports iface decl_spec (Just (want_hiding, import_items)) all_names
- = mapM (addLocM get_item) import_items >>= \gres_s ->
- let gres = concat gres_s
- specified_names = mkNameSet (map gre_name gres)
- in if not want_hiding then
- return (specified_names, mkGlobalRdrEnv gres)
- else let keep n = not (n `elemNameSet` specified_names)
- pruned_avails = filterNameSet keep all_names
- in return (pruned_avails, mkGenericRdrEnv decl_spec pruned_avails)
+ prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
+
+
+filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
+ = do -- check for errors, convert RdrNames to Names
+ opt_typeFamilies <- doptM Opt_TypeFamilies
+ items1 <- mapM (lookup_lie opt_typeFamilies) import_items
+
+ let items2 :: [(LIE Name, AvailInfo)]
+ items2 = concat items1
+ -- NB the AvailInfo may have duplicates, and several items
+ -- for the same parent; e.g N(x) and N(y)
+
+ names = availsToNameSet (map snd items2)
+ keep n = not (n `elemNameSet` names)
+ pruned_avails = filterAvails keep all_avails
+ hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
+
+ gres | want_hiding = gresFromAvails hiding_prov pruned_avails
+ | otherwise = concatMap (gresFromIE decl_spec) items2
+
+ return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
where
- sub_env :: NameEnv [Name] -- Classify each name by its parent
- sub_env = mkSubNameEnv all_names
+ -- This environment is how we map names mentioned in the import
+ -- list to the actual Name they correspond to, and the name family
+ -- that the Name belongs to (the AvailInfo). The situation is
+ -- complicated by associated families, which introduce a three-level
+ -- hierachy, where class = grand parent, assoc family = parent, and
+ -- data constructors = children. The occ_env entries for associated
+ -- families needs to capture all this information; hence, we have the
+ -- third component of the environment that gives the class name (=
+ -- grand parent) in case of associated families.
+ --
+ -- This env will have entries for data constructors too,
+ -- they won't make any difference because naked entities like T
+ -- in an import list map to TcOccs, not VarOccs.
+ occ_env :: OccEnv (Name, -- the name
+ AvailInfo, -- the export item providing the name
+ Maybe Name) -- the parent of associated types
+ occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
+ | a <- all_avails, n <- availNames a]
+ where
+ -- we know that (1) there are at most entries for one name, (2) their
+ -- first component is identical, (3) they are for tys/cls, and (4) one
+ -- entry has the name in its parent position (the other doesn't)
+ combine (name, AvailTC p1 subs1, Nothing)
+ (_ , AvailTC p2 subs2, Nothing)
+ = let
+ (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
+ in
+ (name, AvailTC name subs, Just parent)
+ combine x y = pprPanic "filterImports/combine" (ppr x $$ ppr y)
+
+ lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
+ lookup_lie opt_typeFamilies (L loc ieRdr)
+ = do
+ stuff <- setSrcSpan loc $
+ case lookup_ie opt_typeFamilies ieRdr of
+ Failed err -> addErr err >> return []
+ Succeeded a -> return a
+ checkDodgyImport stuff
+ return [ (L loc ie, avail) | (ie,avail) <- stuff ]
+ where
+ -- Warn when importing T(..) if T was exported abstractly
+ checkDodgyImport stuff
+ | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
+ = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
+ -- NB. use the RdrName for reporting the warning
+ checkDodgyImport _
+ = return ()
+
+ -- For each import item, we convert its RdrNames to Names,
+ -- and at the same time construct an AvailInfo corresponding
+ -- to what is actually imported by this item.
+ -- Returns Nothing on error.
+ -- We return a list here, because in the case of an import
+ -- item like C, if we are hiding, then C refers to *both* a
+ -- type/class and a data constructor. Moreover, when we import
+ -- data constructors of an associated family, we need separate
+ -- AvailInfos for the data constructors and the family (as they have
+ -- different parents). See the discussion at occ_env.
+ lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
+ lookup_ie opt_typeFamilies ie
+ = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
+
+ lookup_name rdrName =
+ case lookupOccEnv occ_env (rdrNameOcc rdrName) of
+ Nothing -> bad_ie
+ Just n -> return n
+ in
+ case ie of
+ IEVar n -> do
+ (name, avail, _) <- lookup_name n
+ return [(IEVar name, trimAvail avail name)]
+
+ IEThingAll tc -> do
+ (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
+ case mb_parent of
+ -- non-associated ty/cls
+ Nothing -> return [(IEThingAll name, avail)]
+ -- associated ty
+ Just parent -> return [(IEThingAll name,
+ AvailTC name2 (subs \\ [name])),
+ (IEThingAll name, AvailTC parent [name])]
+
+ IEThingAbs tc
+ | want_hiding -- hiding ( C )
+ -- Here the 'C' can be a data constructor
+ -- *or* a type/class, or even both
+ -> let tc_name = lookup_name tc
+ dc_name = lookup_name (setRdrNameSpace tc srcDataName)
+ in
+ case catMaybeErr [ tc_name, dc_name ] of
+ [] -> bad_ie
+ names -> return [mkIEThingAbs name | name <- names]
+ | otherwise
+ -> do nameAvail <- lookup_name tc
+ return [mkIEThingAbs nameAvail]
+
+ IEThingWith tc ns -> do
+ (name, AvailTC _ subnames, mb_parent) <- lookup_name tc
+ let
+ env = mkOccEnv [(nameOccName s, s) | s <- subnames]
+ mb_children = map (lookupOccEnv env . rdrNameOcc) ns
+ children <- if any isNothing mb_children
+ then bad_ie
+ else return (catMaybes mb_children)
+ -- check for proper import of type families
+ when (not opt_typeFamilies && any isTyConName children) $
+ Failed (typeItemErr (head . filter isTyConName $ children)
+ (text "in import list"))
+ case mb_parent of
+ -- non-associated ty/cls
+ Nothing -> return [(IEThingWith name children,
+ AvailTC name (name:children))]
+ -- associated ty
+ Just parent -> return [(IEThingWith name children,
+ AvailTC name children),
+ (IEThingWith name children,
+ AvailTC parent [name])]
+
+ _other -> Failed illegalImportItemErr
+ -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
+ -- all errors.
- succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt]
- succeed_with all_explicit names
- = do { loc <- getSrcSpanM
- ; returnM (map (mk_gre loc) names) }
where
- mk_gre loc name = GRE { gre_name = name,
- gre_prov = Imported [imp_spec] }
- where
- imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
- item_spec = ImpSome { is_explicit = explicit, is_iloc = loc }
- explicit = all_explicit || isNothing (nameParent_maybe name)
-
- get_item :: IE Name -> RnM [GlobalRdrElt]
- -- Empty result for a bad item.
- -- Singleton result is typical case.
- -- Can have two when we are hiding, and mention C which might be
- -- both a class and a data constructor.
- get_item item@(IEModuleContents _)
- -- This case should be filtered out by 'rnImports'.
- = panic "filterImports: IEModuleContents?"
-
- get_item (IEThingAll name)
- = case subNames sub_env name of
- [] -> -- This occurs when you import T(..), but
- -- only export T abstractly.
- do ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn name))
- succeed_with False [name]
- names -> succeed_with False (name:names)
-
- get_item (IEThingAbs name)
- = succeed_with True [name]
-
- get_item (IEThingWith name names)
- = succeed_with True (name:names)
- get_item (IEVar name)
- = succeed_with True [name]
+ mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
+ mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n])
+
+
+catMaybeErr :: [MaybeErr err a] -> [a]
+catMaybeErr ms = [ a | Succeeded a <- ms ]
+\end{code}
+
+%************************************************************************
+%* *
+ Import/Export Utils
+%* *
+%************************************************************************
+
+\begin{code}
+-- | make a 'GlobalRdrEnv' where all the elements point to the same
+-- import declaration (useful for "hiding" imports, or imports with
+-- no details).
+gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
+gresFromAvails prov avails
+ = concatMap (gresFromAvail (const prov)) avails
+
+gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
+gresFromAvail prov_fn avail
+ = [ GRE {gre_name = n,
+ gre_par = availParent n avail,
+ gre_prov = prov_fn n}
+ | n <- availNames avail ]
+
+greAvail :: GlobalRdrElt -> AvailInfo
+greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
+
+mkUnitAvail :: Name -> Parent -> AvailInfo
+mkUnitAvail me (ParentIs p) = AvailTC p [me]
+mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
+ | otherwise = Avail me
+
+plusAvail :: GenAvailInfo Name -> GenAvailInfo Name -> GenAvailInfo Name
+plusAvail (Avail n1) (Avail _) = Avail n1
+plusAvail (AvailTC _ ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
+plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
+
+availParent :: Name -> AvailInfo -> Parent
+availParent _ (Avail _) = NoParent
+availParent n (AvailTC m _) | n == m = NoParent
+ | otherwise = ParentIs m
+
+trimAvail :: AvailInfo -> Name -> AvailInfo
+trimAvail (Avail n) _ = Avail n
+trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
+
+-- | filters 'AvailInfo's by the given predicate
+filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
+filterAvails keep avails = foldr (filterAvail keep) [] avails
+
+-- | filters an 'AvailInfo' by the given predicate
+filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
+filterAvail keep ie rest =
+ case ie of
+ Avail n | keep n -> ie : rest
+ | otherwise -> rest
+ AvailTC tc ns ->
+ let left = filter keep ns in
+ if null left then rest else AvailTC tc left : rest
+
+-- | Given an import\/export spec, construct the appropriate 'GlobalRdrElt's.
+gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
+gresFromIE decl_spec (L loc ie, avail)
+ = gresFromAvail prov_fn avail
+ where
+ is_explicit = case ie of
+ IEThingAll name -> \n -> n == name
+ _ -> \_ -> True
+ prov_fn name = Imported [imp_spec]
+ where
+ imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
+ item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
+
+mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
+mkChildEnv gres = foldr add emptyNameEnv gres
+ where
+ add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
+ add _ env = env
+
+findChildren :: NameEnv [Name] -> Name -> [Name]
+findChildren env n = lookupNameEnv env n `orElse` []
+\end{code}
+---------------------------------------
+ AvailEnv and friends
+
+All this AvailEnv stuff is hardly used; only in a very small
+part of RnNames. Todo: remove?
+---------------------------------------
+
+\begin{code}
+type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
+
+emptyAvailEnv :: AvailEnv
+emptyAvailEnv = emptyNameEnv
+
+{- Dead code
+unitAvailEnv :: AvailInfo -> AvailEnv
+unitAvailEnv a = unitNameEnv (availName a) a
+
+plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
+plusAvailEnv = plusNameEnv_C plusAvail
+
+availEnvElts :: AvailEnv -> [AvailInfo]
+availEnvElts = nameEnvElts
+-}
+
+addAvail :: AvailEnv -> AvailInfo -> AvailEnv
+addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
+
+mkAvailEnv :: [AvailInfo] -> AvailEnv
+ -- 'avails' may have several items with the same availName
+ -- E.g import Ix( Ix(..), index )
+ -- will give Ix(Ix,index,range) and Ix(index)
+ -- We want to combine these; addAvail does that
+mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
+
+-- After combining the avails, we need to ensure that the parent name is the
+-- first entry in the list of subnames, if it is included at all. (Subsequent
+-- functions rely on that.)
+normaliseAvail :: AvailInfo -> AvailInfo
+normaliseAvail avail@(Avail _) = avail
+normaliseAvail (AvailTC name subs) = AvailTC name subs'
+ where
+ subs' = if name `elem` subs then name : (delete name subs) else subs
+
+-- | combines 'AvailInfo's from the same family
+nubAvails :: [AvailInfo] -> [AvailInfo]
+nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
\end{code}
\begin{code}
type ExportAccum -- The type of the accumulating parameter of
-- the main worker function in rnExports
- = ([ModuleName], -- 'module M's seen so far
+ = ([LIE Name], -- Export items with Names
ExportOccMap, -- Tracks exported occurrence names
- NameSet) -- The accumulated exported stuff
-emptyExportAccum = ([], emptyOccEnv, emptyNameSet)
+ [AvailInfo]) -- The accumulated exported stuff
+ -- Not nub'd!
+
+emptyExportAccum :: ExportAccum
+emptyExportAccum = ([], emptyOccEnv, [])
type ExportOccMap = OccEnv (Name, IE RdrName)
-- Tracks what a particular exported OccName
-- it came from. It's illegal to export two distinct things
-- that have the same occurrence name
-rnExports :: Maybe [LIE RdrName]
- -> RnM (Maybe [LIE Name])
-rnExports Nothing = return Nothing
-rnExports (Just exports)
- = do TcGblEnv { tcg_imports = ImportAvails { imp_env = imp_env } } <- getGblEnv
- let sub_env :: NameEnv [Name] -- Classify each name by its parent
- sub_env = mkSubNameEnv (foldUFM unionNameSets emptyNameSet imp_env)
- rnExport (IEVar rdrName)
- = do name <- lookupGlobalOccRn rdrName
- return (IEVar name)
- rnExport (IEThingAbs rdrName)
- = do name <- lookupGlobalOccRn rdrName
- return (IEThingAbs name)
- rnExport (IEThingAll rdrName)
- = do name <- lookupGlobalOccRn rdrName
- return (IEThingAll name)
- rnExport ie@(IEThingWith rdrName rdrNames)
- = do name <- lookupGlobalOccRn rdrName
- if isUnboundName name
- then return (IEThingWith name [])
- else do
- let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name]
- mb_names = map (lookupOccEnv env . rdrNameOcc) rdrNames
- if any isNothing mb_names
- then do addErr (exportItemErr ie)
- return (IEThingWith name [])
- else return (IEThingWith name (catMaybes mb_names))
- rnExport (IEModuleContents mod)
- = return (IEModuleContents mod)
- rn_exports <- mapM (wrapLocM rnExport) exports
- return (Just rn_exports)
-
-mkExportNameSet :: Bool -- False => no 'module M(..) where' header at all
- -> Maybe ([LIE Name], [LIE RdrName]) -- Nothing => no explicit export list
- -> RnM NameSet
+rnExports :: Bool -- False => no 'module M(..) where' header at all
+ -> Maybe [LIE RdrName] -- Nothing => no explicit export list
+ -> TcGblEnv
+ -> RnM TcGblEnv
+
-- Complains if two distinct exports have same OccName
-- Warns about identical exports.
-- Complains about exports items not in scope
-mkExportNameSet explicit_mod exports
- = do TcGblEnv { tcg_rdr_env = rdr_env,
- tcg_imports = imports } <- getGblEnv
-
+rnExports explicit_mod exports
+ tcg_env@(TcGblEnv { tcg_mod = this_mod,
+ tcg_rdr_env = rdr_env,
+ tcg_imports = imports })
+ = do {
-- If the module header is omitted altogether, then behave
-- as if the user had written "module Main(main) where..."
-- EXCEPT in interactive mode, when we behave as if he had
-- written "module Main where ..."
-- Reason: don't want to complain about 'main' not in scope
-- in interactive mode
- ghc_mode <- getGhcMode
- real_exports <- case () of
- () | explicit_mod
- -> return exports
- | ghc_mode == Interactive
- -> return Nothing
- | otherwise
- -> do mainName <- lookupGlobalOccRn main_RDR_Unqual
- return (Just ([noLoc (IEVar mainName)]
- ,[noLoc (IEVar main_RDR_Unqual)]))
- -- ToDo: the 'noLoc' here is unhelpful if 'main' turns out to be out of scope
- exports_from_avail real_exports rdr_env imports
-
-
-exports_from_avail Nothing rdr_env imports
- = -- Export all locally-defined things
- -- We do this by filtering the global RdrEnv,
- -- keeping only things that are locally-defined
- return (mkNameSet [ gre_name gre
- | gre <- globalRdrEnvElts rdr_env,
- isLocalGRE gre ])
-
-exports_from_avail (Just (items,origItems)) rdr_env (ImportAvails { imp_env = imp_env })
- = do (_, _, exports) <- foldlM do_litem emptyExportAccum (zip items origItems)
- return exports
+ ; dflags <- getDOpts
+ ; let real_exports
+ | explicit_mod = exports
+ | ghcLink dflags == LinkInMemory = Nothing
+ | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
+ -- ToDo: the 'noLoc' here is unhelpful if 'main'
+ -- turns out to be out of scope
+
+ ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
+ ; let final_avails = nubAvails avails -- Combine families
+
+ ; return (tcg_env { tcg_exports = final_avails,
+ tcg_rn_exports = case tcg_rn_exports tcg_env of
+ Nothing -> Nothing
+ Just _ -> rn_exports,
+ tcg_dus = tcg_dus tcg_env `plusDU`
+ usesOnly (availsToNameSet final_avails) }) }
+
+exports_from_avail :: Maybe [LIE RdrName]
+ -- Nothing => no explicit export list
+ -> GlobalRdrEnv
+ -> ImportAvails
+ -> Module
+ -> RnM (Maybe [LIE Name], [AvailInfo])
+
+exports_from_avail Nothing rdr_env _imports _this_mod
+ = -- The same as (module M) where M is the current module name,
+ -- so that's how we handle it.
+ let
+ avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
+ isLocalGRE gre ]
+ in
+ return (Nothing, avails)
+
+exports_from_avail (Just rdr_items) rdr_env imports this_mod
+ = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
+
+ return (Just ie_names, exports)
where
- sub_env :: NameEnv [Name] -- Classify each name by its parent
- sub_env = mkSubNameEnv (foldUFM unionNameSets emptyNameSet imp_env)
+ do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
+ do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
+
+ kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
+ kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
- do_litem :: ExportAccum -> (LIE Name, LIE RdrName) -> RnM ExportAccum
- do_litem acc (ieName, ieRdr)
- = addLocM (exports_from_item acc (unLoc ieRdr)) ieName
+ imported_modules = [ qual_name
+ | xs <- moduleEnvElts $ imp_mods imports,
+ (qual_name, _, _) <- xs ]
- exports_from_item :: ExportAccum -> IE RdrName -> IE Name -> RnM ExportAccum
- exports_from_item acc@(mods, occs, exports) ieRdr@(IEModuleContents mod) ie
- | mod `elem` mods -- Duplicate export of M
+ exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
+ exports_from_item acc@(ie_names, occs, exports)
+ (L loc ie@(IEModuleContents mod))
+ | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
+ , mod `elem` earlier_mods -- Duplicate export of M
= do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
warnIf warn_dup_exports (dupModuleExport mod) ;
- returnM acc }
+ return acc }
| otherwise
- = case lookupUFM imp_env mod of
- Nothing -> do addErr (modExportErr mod)
- return acc
- Just names
- -> do let new_exports = filterNameSet (inScopeUnqual rdr_env) names
- -- This check_occs not only finds conflicts between this item
- -- and others, but also internally within this item. That is,
- -- if 'M.x' is in scope in several ways, we'll have several
- -- members of mod_avails with the same OccName.
- occs' <- check_occs ieRdr occs (nameSetToList new_exports)
- return (mod:mods, occs', exports `unionNameSets` new_exports)
-
- exports_from_item acc@(mods, occs, exports) ieRdr ie
- = if isUnboundName (ieName ie)
- then return acc -- Avoid error cascade
- else let new_exports = filterAvail ie sub_env in
- do -- checkErr (not (null (drop 1 new_exports))) (exportItemErr ie)
- checkForDodgyExport ie new_exports
- occs' <- check_occs ieRdr occs new_exports
- return (mods, occs', addListToNameSet exports new_exports)
-
--------------------------------
-filterAvail :: IE Name -- Wanted
- -> NameEnv [Name] -- Maps type/class names to their sub-names
- -> [Name]
-
-filterAvail (IEVar n) subs = [n]
-filterAvail (IEThingAbs n) subs = [n]
-filterAvail (IEThingAll n) subs = n : subNames subs n
-filterAvail (IEThingWith n ns) subs = n : ns
-filterAvail (IEModuleContents _) _ = panic "filterAvail"
-
-subNames :: NameEnv [Name] -> Name -> [Name]
-subNames env n = lookupNameEnv env n `orElse` []
-
-mkSubNameEnv :: NameSet -> NameEnv [Name]
--- Maps types and classes to their constructors/classops respectively
--- This mapping just makes it easier to deal with A(..) export items
-mkSubNameEnv names
- = foldNameSet add_name emptyNameEnv names
- where
- add_name name env
- | Just parent <- nameParent_maybe name
- = extendNameEnv_C (\ns _ -> name:ns) env parent [name]
- | otherwise = env
+ = do { implicit_prelude <- doptM Opt_ImplicitPrelude
+ ; let { exportValid = (mod `elem` imported_modules)
+ || (moduleName this_mod == mod)
+ ; gres = filter (isModuleExported implicit_prelude mod)
+ (globalRdrEnvElts rdr_env)
+ ; names = map gre_name gres
+ }
+
+ ; checkErr exportValid (moduleNotImported mod)
+ ; warnIf (exportValid && null gres) (nullModuleExport mod)
+
+ ; addUsedRdrNames (concat [ [mkRdrQual mod occ, mkRdrUnqual occ]
+ | occ <- map nameOccName names ])
+ -- The qualified and unqualified version of all of
+ -- these names are, in effect, used by this export
+
+ ; occs' <- check_occs ie occs names
+ -- This check_occs not only finds conflicts
+ -- between this item and others, but also
+ -- internally within this item. That is, if
+ -- 'M.x' is in scope in several ways, we'll have
+ -- several members of mod_avails with the same
+ -- OccName.
+ ; return (L loc (IEModuleContents mod) : ie_names,
+ occs', map greAvail gres ++ exports) }
+
+ exports_from_item acc@(lie_names, occs, exports) (L loc ie)
+ | isDoc ie
+ = do new_ie <- lookup_doc_ie ie
+ return (L loc new_ie : lie_names, occs, exports)
--------------------------------
-inScopeUnqual :: GlobalRdrEnv -> Name -> Bool
--- Checks whether the Name is in scope unqualified,
--- regardless of whether it's ambiguous or not
-inScopeUnqual env n = any unQualOK (lookupGRE_Name env n)
+ | otherwise
+ = do (new_ie, avail) <- lookup_ie ie
+ if isUnboundName (ieName new_ie)
+ then return acc -- Avoid error cascade
+ else do
+
+ occs' <- check_occs ie occs (availNames avail)
+
+ return (L loc new_ie : lie_names, occs', avail : exports)
+
+ -------------
+ lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
+ lookup_ie (IEVar rdr)
+ = do gre <- lookupGreRn rdr
+ return (IEVar (gre_name gre), greAvail gre)
+
+ lookup_ie (IEThingAbs rdr)
+ = do gre <- lookupGreRn rdr
+ let name = gre_name gre
+ case gre_par gre of
+ NoParent -> return (IEThingAbs name,
+ AvailTC name [name])
+ ParentIs p -> return (IEThingAbs name,
+ AvailTC p [name])
+
+ lookup_ie ie@(IEThingAll rdr)
+ = do name <- lookupGlobalOccRn rdr
+ let kids = findChildren kids_env name
+ when (null kids)
+ (if (isTyConName name) then addWarn (dodgyExportWarn name)
+ -- This occurs when you export T(..), but
+ -- only import T abstractly, or T is a synonym.
+ else addErr (exportItemErr ie))
+
+ return (IEThingAll name, AvailTC name (name:kids))
+
+ lookup_ie ie@(IEThingWith rdr sub_rdrs)
+ = do name <- lookupGlobalOccRn rdr
+ if isUnboundName name
+ then return (IEThingWith name [], AvailTC name [name])
+ else do
+ let env = mkOccEnv [ (nameOccName s, s)
+ | s <- findChildren kids_env name ]
+ mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
+ if any isNothing mb_names
+ then do addErr (exportItemErr ie)
+ return (IEThingWith name [], AvailTC name [name])
+ else do let names = catMaybes mb_names
+ optTyFam <- doptM Opt_TypeFamilies
+ when (not optTyFam && any isTyConName names) $
+ addErr (typeItemErr ( head
+ . filter isTyConName
+ $ names )
+ (text "in export list"))
+ return (IEThingWith name names, AvailTC name (name:names))
+
+ lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier
+
+ -------------
+ lookup_doc_ie :: IE RdrName -> RnM (IE Name)
+ lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
+ return (IEGroup lev rn_doc)
+ lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
+ return (IEDoc rn_doc)
+ lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
+ lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier
+
+
+isDoc :: IE RdrName -> Bool
+isDoc (IEDoc _) = True
+isDoc (IEDocNamed _) = True
+isDoc (IEGroup _ _) = True
+isDoc _ = False
-------------------------------
-checkForDodgyExport :: IE Name -> [Name] -> RnM ()
-checkForDodgyExport ie@(IEThingAll tc) [n]
- | isTcOcc (nameOccName n) = addWarn (dodgyExportWarn tc)
- -- This occurs when you export T(..), but
- -- only import T abstractly, or T is a synonym.
- -- The single [n] is the type or class itself
- | otherwise = addErr (exportItemErr ie)
- -- This happes if you export x(..), which is bogus
-checkForDodgyExport _ _ = return ()
+isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
+-- True if the thing is in scope *both* unqualified, *and* with qualifier M
+isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
+ | implicit_prelude && isBuiltInSyntax name = False
+ -- Optimisation: filter out names for built-in syntax
+ -- They just clutter up the environment (esp tuples), and the parser
+ -- will generate Exact RdrNames for them, so the cluttered
+ -- envt is no use. To avoid doing this filter all the time,
+ -- we use -XNoImplicitPrelude as a clue that the filter is
+ -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
+ --
+ -- It's worth doing because it makes the environment smaller for
+ -- every module that imports the Prelude
+ | otherwise
+ = case prov of
+ LocalDef | Just name_mod <- nameModule_maybe name
+ -> moduleName name_mod == mod
+ | otherwise -> False
+ Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
-------------------------------
check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
where
check occs name
= case lookupOccEnv occs name_occ of
- Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
+ Nothing -> return (extendOccEnv occs name_occ (name, ie))
Just (name', ie')
| name == name' -- Duplicate export
-> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
- returnM occs }
+ return occs }
| otherwise -- Same occ name but different names: an error
-> do { global_env <- getGlobalRdrEnv ;
addErr (exportClashErr global_env name' name ie' ie) ;
- returnM occs }
+ return occs }
where
name_occ = nameOccName name
\end{code}
%*********************************************************
\begin{code}
-reportDeprecations :: DynFlags -> TcGblEnv -> RnM ()
-reportDeprecations dflags tcg_env
- = ifOptM Opt_WarnDeprecations $
- do { (eps,hpt) <- getEpsAndHpt
+finishWarnings :: DynFlags -> Maybe WarningTxt
+ -> TcGblEnv -> RnM TcGblEnv
+-- (a) Report usage of imports that are deprecated or have other warnings
+-- (b) If the whole module is warned about or deprecated, update tcg_warns
+-- All this happens only once per module
+finishWarnings dflags mod_warn tcg_env
+ = do { (eps,hpt) <- getEpsAndHpt
+ ; ifOptM Opt_WarnWarningsDeprecations $
+ mapM_ (check hpt (eps_PIT eps)) all_gres
-- By this time, typechecking is complete,
-- so the PIT is fully populated
- ; mapM_ (check hpt (eps_PIT eps)) all_gres }
+
+ -- Deal with a module deprecation; it overrides all existing warns
+ ; let new_warns = case mod_warn of
+ Just txt -> WarnAll txt
+ Nothing -> tcg_warns tcg_env
+ ; return (tcg_env { tcg_warns = new_warns }) }
where
used_names = allUses (tcg_dus tcg_env)
-- Report on all deprecated uses; hence allUses
all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
- check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
+ check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
| name `elemNameSet` used_names
- , Just deprec_txt <- lookupDeprec dflags hpt pit name
- = setSrcSpan (importSpecLoc imp_spec) $
- addWarn (sep [ptext SLIT("Deprecated use of") <+>
+ , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
+ = addWarnAt (importSpecLoc imp_spec)
+ (sep [ptext (sLit "In the use of") <+>
pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
quotes (ppr name),
(parens imp_msg) <> colon,
(ppr deprec_txt) ])
where
- name_mod = nameModule name
+ name_mod = ASSERT2( isExternalName name, ppr name ) nameModule name
imp_mod = importSpecModule imp_spec
- imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
+ imp_msg = ptext (sLit "imported from") <+> ppr imp_mod <> extra
extra | imp_mod == moduleName name_mod = empty
- | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
+ | otherwise = ptext (sLit ", but defined in") <+> ppr name_mod
- check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
+ check _ _ _ = return () -- Local, or not used, or not deprectated
-- The Imported pattern-match: don't deprecate locally defined names
-- For a start, we may be exporting a deprecated thing
-- Also we may use a deprecated thing in the defn of another
-- the defn of a non-deprecated thing, when changing a module's
-- interface
-lookupDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
- -> Name -> Maybe DeprecTxt
-lookupDeprec dflags hpt pit n
- = case lookupIfaceByModule dflags hpt pit (nameModule n) of
- Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or
- mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd
- Nothing
- | isWiredInName n -> Nothing
- -- We have not necessarily loaded the .hi file for a
- -- wired-in name (yet), although we *could*.
- -- And we never deprecate them
-
- | otherwise -> pprPanic "lookupDeprec" (ppr n)
- -- By now all the interfaces should have been loaded
-
-gre_is_used :: NameSet -> GlobalRdrElt -> Bool
-gre_is_used used_names gre = gre_name gre `elemNameSet` used_names
+lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
+ -> GlobalRdrElt -> Maybe WarningTxt
+-- The name is definitely imported, so look in HPT, PIT
+lookupImpDeprec dflags hpt pit gre
+ = case lookupIfaceByModule dflags hpt pit mod of
+ Just iface -> mi_warn_fn iface name `mplus` -- Bleat if the thing, *or
+ case gre_par gre of
+ ParentIs p -> mi_warn_fn iface p -- its parent*, is warn'd
+ NoParent -> Nothing
+
+ Nothing -> Nothing -- See Note [Used names with interface not loaded]
+ where
+ name = gre_name gre
+ mod = ASSERT2( isExternalName name, ppr name ) nameModule name
\end{code}
+Note [Used names with interface not loaded]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+By now all the interfaces should have been loaded,
+because reportDeprecations happens after typechecking.
+However, it's still (just) possible to to find a used
+Name whose interface hasn't been loaded:
+
+a) It might be a WiredInName; in that case we may not load
+ its interface (although we could).
+
+b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
+ These are seen as "used" by the renamer (if -XNoImplicitPrelude)
+ is on), but the typechecker may discard their uses
+ if in fact the in-scope fromRational is GHC.Read.fromRational,
+ (see tcPat.tcOverloadedLit), and the typechecker sees that the type
+ is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
+ In that obscure case it won't force the interface in.
+
+In both cases we simply don't permit deprecations;
+this is, after all, wired-in stuff.
+
+
%*********************************************************
%* *
Unused names
\begin{code}
reportUnusedNames :: Maybe [LIE RdrName] -- Export list
-> TcGblEnv -> RnM ()
-reportUnusedNames export_decls gbl_env
+reportUnusedNames _export_decls gbl_env
= do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
- ; warnUnusedTopBinds unused_locals
- ; warnUnusedModules unused_imp_mods
- ; warnUnusedImports unused_imports
- ; warnDuplicateImports defined_and_used
- ; printMinimalImports minimal_imports }
+ ; warnUnusedImportDecls gbl_env
+ ; warnUnusedTopBinds unused_locals }
where
- used_names, all_used_names :: NameSet
+ used_names :: NameSet
used_names = findUses (tcg_dus gbl_env) emptyNameSet
-- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
-- Hence findUses
- all_used_names = used_names `unionNameSets`
- mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names))
- -- A use of C implies a use of T,
- -- if C was brought into scope by T(..) or T(C)
-
-- Collect the defined names from the in-scope environment
defined_names :: [GlobalRdrElt]
defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
-- Note that defined_and_used, defined_but_not_used
-- are both [GRE]; that's why we need defined_and_used
- -- rather than just all_used_names
- defined_and_used, defined_but_not_used :: [GlobalRdrElt]
- (defined_and_used, defined_but_not_used)
- = partition (gre_is_used all_used_names) defined_names
+ -- rather than just used_names
+ _defined_and_used, defined_but_not_used :: [GlobalRdrElt]
+ (_defined_and_used, defined_but_not_used)
+ = partition (gre_is_used used_names) defined_names
+ kids_env = mkChildEnv defined_names
+ -- This is done in mkExports too; duplicated work
+
+ gre_is_used :: NameSet -> GlobalRdrElt -> Bool
+ gre_is_used used_names (GRE {gre_name = name})
+ = name `elemNameSet` used_names
+ || any (`elemNameSet` used_names) (findChildren kids_env name)
+ -- A use of C implies a use of T,
+ -- if C was brought into scope by T(..) or T(C)
+
-- Filter out the ones that are
-- (a) defined in this module, and
-- (b) not defined by a 'deriving' clause
unused_locals = filter is_unused_local defined_but_not_used
is_unused_local :: GlobalRdrElt -> Bool
is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
-
- unused_imports :: [GlobalRdrElt]
- unused_imports = filter unused_imp defined_but_not_used
- unused_imp (GRE {gre_prov = Imported imp_specs})
- = not (all (module_unused . importSpecModule) imp_specs)
- && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs]
- -- Don't complain about unused imports if we've already said the
- -- entire import is unused
- unused_imp other = False
-
- -- To figure out the minimal set of imports, start with the things
- -- that are in scope (i.e. in gbl_env). Then just combine them
- -- into a bunch of avails, so they are properly grouped
- --
- -- BUG WARNING: this does not deal properly with qualified imports!
- minimal_imports :: FiniteMap ModuleName AvailEnv
- minimal_imports0 = foldr add_expall emptyFM expall_mods
- minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
- minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
- -- The last line makes sure that we retain all direct imports
- -- even if we import nothing explicitly.
- -- It's not necessarily redundant to import such modules. Consider
- -- module This
- -- import M ()
- --
- -- The import M() is not *necessarily* redundant, even if
- -- we suck in no instance decls from M (e.g. it contains
- -- no instance decls, or This contains no code). It may be
- -- that we import M solely to ensure that M's orphan instance
- -- decls (or those in its imports) are visible to people who
- -- import This. Sigh.
- -- There's really no good way to detect this, so the error message
- -- in RnEnv.warnUnusedModules is weakened instead
-
- -- We've carefully preserved the provenance so that we can
- -- construct minimal imports that import the name by (one of)
- -- the same route(s) as the programmer originally did.
- add_name (GRE {gre_name = n, gre_prov = Imported imp_specs}) acc
- = addToFM_C plusAvailEnv acc (importSpecModule (head imp_specs))
- (unitAvailEnv (mk_avail n (nameParent_maybe n)))
- add_name other acc
- = acc
-
- -- Modules mentioned as 'module M' in the export list
- expall_mods = case export_decls of
- Nothing -> []
- Just es -> [m | L _ (IEModuleContents m) <- es]
-
- -- This is really bogus. The idea is that if we see 'module M' in
- -- the export list we must retain the import decls that drive it
- -- If we aren't careful we might see
- -- module A( module M ) where
- -- import M
- -- import N
- -- and suppose that N exports everything that M does. Then we
- -- must not drop the import of M even though N brings it all into
- -- scope.
- --
- -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
- --
- -- The reason that add_expall is bogus is that it doesn't take
- -- qualified imports into account. But it's an improvement.
- add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
-
- -- n is the name of the thing, p is the name of its parent
- mk_avail n (Just p) = AvailTC p [p,n]
- mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
- | otherwise = Avail n
-
- add_inst_mod (mod,_,_) acc
- | mod_name `elemFM` acc = acc -- We import something already
- | otherwise = addToFM acc mod_name emptyAvailEnv
+\end{code}
+
+%*********************************************************
+%* *
+ Unused imports
+%* *
+%*********************************************************
+
+This code finds which import declarations are unused. The
+specification and implementation notes are here:
+ http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/UnusedImports
+
+\begin{code}
+type ImportDeclUsage
+ = ( LImportDecl Name -- The import declaration
+ , [AvailInfo] -- What *is* used (normalised)
+ , [Name] ) -- What is imported but *not* used
+\end{code}
+
+\begin{code}
+warnUnusedImportDecls :: TcGblEnv -> RnM ()
+warnUnusedImportDecls gbl_env
+ = do { uses <- readMutVar (tcg_used_rdrnames gbl_env)
+ ; let imports = filter explicit_import (tcg_rn_imports gbl_env)
+ rdr_env = tcg_rdr_env gbl_env
+
+ ; let usage :: [ImportDeclUsage]
+ usage = findImportUsage imports rdr_env (Set.elems uses)
+
+ ; ifOptM Opt_WarnUnusedImports $
+ mapM_ warnUnusedImport usage
+
+ ; ifOptM Opt_D_dump_minimal_imports $
+ printMinimalImports usage }
+ where
+ explicit_import (L loc _) = isGoodSrcSpan loc
+ -- Filter out the implicit Prelude import
+ -- which we do not want to bleat about
+\end{code}
+
+\begin{code}
+findImportUsage :: [LImportDecl Name]
+ -> GlobalRdrEnv
+ -> [RdrName]
+ -> [ImportDeclUsage]
+
+type ImportMap = FiniteMap SrcLoc [AvailInfo]
+ -- The intermediate data struture records, for each import
+ -- declaration, what stuff brought into scope by that
+ -- declaration is actually used in the module.
+ --
+ -- The SrcLoc is the location of the start
+ -- of a particular 'import' declaration
+ --
+ -- The AvailInfos are the things imported from that decl
+ -- (just a list, not normalised)
+
+findImportUsage imports rdr_env rdrs
+ = map unused_decl imports
+ where
+ import_usage :: ImportMap
+ import_usage = foldr add_rdr emptyFM rdrs
+
+ unused_decl decl@(L loc (ImportDecl { ideclHiding = imps }))
+ = (decl, nubAvails used_avails, unused_imps)
where
- mod_name = moduleName mod
- -- Add an empty collection of imports for a module
- -- from which we have sucked only instance decls
-
- imports = tcg_imports gbl_env
-
- direct_import_mods :: [(Module, Bool, SrcSpan)]
- -- See the type of the imp_mods for this triple
- direct_import_mods = moduleEnvElts (imp_mods imports)
-
- -- unused_imp_mods are the directly-imported modules
- -- that are not mentioned in minimal_imports1
- -- [Note: not 'minimal_imports', because that includes directly-imported
- -- modules even if we use nothing from them; see notes above]
- --
- -- BUG WARNING: does not deal correctly with multiple imports of the same module
- -- becuase direct_import_mods has only one entry per module
- unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods,
- let mod_name = moduleName mod,
- not (mod_name `elemFM` minimal_imports1),
- mod /= pRELUDE,
- not no_imp]
- -- The not no_imp part is not to complain about
- -- import M (), which is an idiom for importing
- -- instance declarations
-
- module_unused :: ModuleName -> Bool
- module_unused mod = any (((==) mod) . fst) unused_imp_mods
+ used_avails = lookupFM import_usage (srcSpanStart loc) `orElse` []
+ used_names = availsToNameSet used_avails
+
+ unused_imps = case imps of
+ Just (False, imp_ies) -> nameSetToList unused_imps
+ where
+ imp_names = mkNameSet (concatMap (ieNames . unLoc) imp_ies)
+ unused_imps = imp_names `minusNameSet` used_names
+
+ _other -> [] -- No explicit import list => no unused-name list
+
+ add_rdr :: RdrName -> ImportMap -> ImportMap
+ add_rdr rdr iu
+ = case lookupGRE_RdrName rdr rdr_env of
+ [gre] | Imported imps <- gre_prov gre
+ -> add_imp gre (bestImport imps) iu
+ _other -> iu
+
+ add_imp :: GlobalRdrElt -> ImportSpec -> ImportMap -> ImportMap
+ add_imp gre (ImpSpec { is_decl = imp_decl_spec }) iu
+ = addToFM_C add iu decl_loc [avail]
+ where
+ add avails _ = avail : avails
+ decl_loc = srcSpanStart (is_dloc imp_decl_spec)
+ name = gre_name gre
+ avail = case gre_par gre of
+ ParentIs p -> AvailTC p [p,name]
+ NoParent | isTyConName name -> AvailTC name [name]
+ | otherwise -> Avail name
+ -- If you use (+) from Num, then for this purpose we want
+ -- to say that Num is used as well. That is why in the
+ -- ParentIs case we have [p,name] in the ParentIs case
+
+bestImport :: [ImportSpec] -> ImportSpec
+bestImport iss
+ = case partition isImpAll iss of
+ ([], imp_somes) -> textuallyFirst imp_somes
+ (imp_alls, _) -> textuallyFirst imp_alls
+
+textuallyFirst :: [ImportSpec] -> ImportSpec
+textuallyFirst iss = case sortWith (is_dloc . is_decl) iss of
+ [] -> pprPanic "textuallyFirst" (ppr iss)
+ (is:_) -> is
+
+isImpAll :: ImportSpec -> Bool
+isImpAll (ImpSpec { is_item = ImpAll }) = True
+isImpAll _other = False
+\end{code}
----------------------
-warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
--- Given the GREs for names that are used, figure out which imports
--- could be omitted without changing the top-level environment.
---
--- NB: Given import Foo( T )
--- import qualified Foo
--- we do not report a duplicate import, even though Foo.T is brought
--- into scope by both, because there's nothing you can *omit* without
--- changing the top-level environment. So we complain only if it's
--- explicitly named in both imports or neither.
---
--- Furthermore, we complain about Foo.T only if
--- there is no complaint about (unqualified) T
-
-warnDuplicateImports gres
- = ifOptM Opt_WarnUnusedImports $
- sequenceM_ [ warn name pr
- -- The 'head' picks the first offending group
- -- for this particular name
- | GRE { gre_name = name, gre_prov = Imported imps } <- gres
- , pr <- redundants imps ]
+\begin{code}
+warnUnusedImport :: ImportDeclUsage -> RnM ()
+warnUnusedImport (L loc decl, used, unused)
+ | Just (False,[]) <- ideclHiding decl
+ = return () -- Do not warn for 'import M()'
+ | null used = addWarnAt loc msg1 -- Nothing used; drop entire decl
+ | null unused = return () -- Everything imported is used; nop
+ | otherwise = addWarnAt loc msg2 -- Some imports are unused
where
- warn name (red_imp, cov_imp)
- = addWarnAt (importSpecLoc red_imp)
- (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name,
- ptext SLIT("It is also") <+> ppr cov_imp])
- where
- pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
- | otherwise = ppr occ
- occ = nameOccName name
- red_decl = is_decl red_imp
-
- redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
- -- The returned pair is (redundant-import, covering-import)
- redundants imps
- = [ (red_imp, cov_imp)
- | red_imp <- imps
- , cov_imp <- take 1 (filter (covers red_imp) imps) ]
-
- -- "red_imp" is a putative redundant import
- -- "cov_imp" potentially covers it
- -- This test decides whether red_imp could be dropped
- --
- -- NOTE: currently the test does not warn about
- -- import M( x )
- -- imoprt N( x )
- -- even if the same underlying 'x' is involved, because dropping
- -- either import would change the qualified names in scope (M.x, N.x)
- -- But if the qualified names aren't used, the import is indeed redundant
- -- Sadly we don't know that. Oh well.
- covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item })
- cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
- | red_loc == cov_loc
- = False -- Ignore diagonal elements
- | not (is_as red_decl == is_as cov_decl)
- = False -- They bring into scope different qualified names
- | not (is_qual red_decl) && is_qual cov_decl
- = False -- Covering one doesn't bring unqualified name into scope
- | red_selective
- = not cov_selective -- Redundant one is selective and covering one isn't
- || red_later -- Both are explicit; tie-break using red_later
- | otherwise
- = not cov_selective -- Neither import is selective
- && (is_mod red_decl == is_mod cov_decl) -- They import the same module
- && red_later -- Tie-break
- where
- red_loc = importSpecLoc red_imp
- cov_loc = importSpecLoc cov_imp
- red_later = red_loc > cov_loc
- cov_selective = selectiveImpItem cov_item
- red_selective = selectiveImpItem red_item
-
-selectiveImpItem :: ImpItemSpec -> Bool
-selectiveImpItem ImpAll = False
-selectiveImpItem (ImpSome {}) = True
-
--- ToDo: deal with original imports with 'qualified' and 'as M' clauses
-printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
- -> RnM ()
-printMinimalImports imps
- = ifOptM Opt_D_dump_minimal_imports $ do {
-
- mod_ies <- mappM to_ies (fmToList imps) ;
- this_mod <- getModule ;
- rdr_env <- getGlobalRdrEnv ;
- ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
- printForUser h (mkPrintUnqualified rdr_env)
- (vcat (map ppr_mod_ie mod_ies)) })
- }
+ msg1 = vcat [pp_herald <+> quotes pp_mod <+> pp_not_used,
+ nest 2 (ptext (sLit "except perhaps to import instances from")
+ <+> quotes pp_mod),
+ ptext (sLit "To import instances alone, use:")
+ <+> ptext (sLit "import") <+> pp_mod <> parens empty ]
+ msg2 = sep [pp_herald <+> quotes (pprWithCommas ppr unused),
+ text "from module" <+> quotes pp_mod <+> pp_not_used]
+ pp_herald = text "The import of"
+ pp_mod = ppr (unLoc (ideclName decl))
+ pp_not_used = text "is redundant"
+\end{code}
+
+To print the minimal imports we walk over the user-supplied import
+decls, and simply trim their import lists. NB that
+
+ * We do *not* change the 'qualified' or 'as' parts!
+
+ * We do not disard a decl altogether; we might need instances
+ from it. Instead we just trim to an empty import list
+
+\begin{code}
+printMinimalImports :: [ImportDeclUsage] -> RnM ()
+printMinimalImports imports_w_usage
+ = do { imports' <- mapM mk_minimal imports_w_usage
+ ; this_mod <- getModule
+ ; liftIO $
+ do { h <- openFile (mkFilename this_mod) WriteMode
+ ; printForUser h neverQualify (vcat (map ppr imports')) }
+ -- The neverQualify is important. We are printing Names
+ -- but they are in the context of an 'import' decl, and
+ -- we never qualify things inside there
+ -- E.g. import Blag( f, b )
+ -- not import Blag( Blag.f, Blag.g )!
+ }
where
mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
- ppr_mod_ie (mod_name, ies)
- | mod_name == moduleName pRELUDE
- = empty
- | null ies -- Nothing except instances comes from here
- = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
- | otherwise
- = ptext SLIT("import") <+> ppr mod_name <>
- parens (fsep (punctuate comma (map ppr ies)))
- to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
- returnM (mod, ies)
+ mk_minimal (L l decl, used, unused)
+ | null unused
+ , Just (False, _) <- ideclHiding decl
+ = return (L l decl)
+ | otherwise
+ = do { ies <- initIfaceTcRn $ mapM to_ie used
+ ; return (L l (decl { ideclHiding = Just (False, map (L l) ies) })) }
- to_ie :: AvailInfo -> RnM (IE Name)
+ to_ie :: AvailInfo -> IfG (IE Name)
-- The main trick here is that if we're importing all the constructors
-- we want to say "T(..)", but if we're importing only a subset we want
-- to say "T(A,B,C)". So we have to find out what the module exports.
- to_ie (Avail n) = returnM (IEVar n)
+ to_ie (Avail n) = return (IEVar n)
to_ie (AvailTC n [m]) = ASSERT( n==m )
- returnM (IEThingAbs n)
- to_ie (AvailTC n ns)
- = loadSrcInterface doc n_mod False `thenM` \ iface ->
+ return (IEThingAbs n)
+ to_ie (AvailTC n ns) = do
+ iface <- loadSysInterface doc n_mod
case [xs | (m,as) <- mi_exports iface,
- moduleName m == n_mod,
+ m == n_mod,
AvailTC x xs <- as,
x == nameOccName n] of
- [xs] | all_used xs -> returnM (IEThingAll n)
- | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
+ [xs] | all_used xs -> return (IEThingAll n)
+ | otherwise -> return (IEThingWith n (filter (/= n) ns))
other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
- returnM (IEVar n)
+ return (IEVar n)
where
all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
doc = text "Compute minimal imports from" <+> ppr n
- n_mod = moduleName (nameModule n)
+ n_mod = ASSERT( isExternalName n ) nameModule n
\end{code}
-
%************************************************************************
%* *
\subsection{Errors}
%************************************************************************
\begin{code}
+badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc
badImportItemErr iface decl_spec ie
- = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
- ptext SLIT("does not export"), quotes (ppr ie)]
+ = sep [ptext (sLit "Module"), quotes (ppr (is_mod decl_spec)), source_import,
+ ptext (sLit "does not export"), quotes (ppr ie)]
where
- source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
+ source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
| otherwise = empty
-dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
-dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
+illegalImportItemErr :: SDoc
+illegalImportItemErr = ptext (sLit "Illegal import item")
+dodgyImportWarn :: RdrName -> SDoc
+dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item
+dodgyExportWarn :: Name -> SDoc
+dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item
+
+dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc
dodgyMsg kind tc
- = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
- ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
- ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
-
-modExportErr mod
- = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
+ = sep [ ptext (sLit "The") <+> kind <+> ptext (sLit "item") <+> quotes (ppr (IEThingAll tc))
+ <+> ptext (sLit "suggests that"),
+ quotes (ppr tc) <+> ptext (sLit "has (in-scope) constructors or class methods,"),
+ ptext (sLit "but it has none") ]
+exportItemErr :: IE RdrName -> SDoc
exportItemErr export_item
- = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
- ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
+ = sep [ ptext (sLit "The export item") <+> quotes (ppr export_item),
+ ptext (sLit "attempts to export constructors or class methods that are not visible here") ]
+
+typeItemErr :: Name -> SDoc -> SDoc
+typeItemErr name wherestr
+ = sep [ ptext (sLit "Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
+ ptext (sLit "Use -XTypeFamilies to enable this extension") ]
+exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
+ -> Message
exportClashErr global_env name1 name2 ie1 ie2
- = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
- , ppr_export ie1 name1
- , ppr_export ie2 name2 ]
+ = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon
+ , ppr_export ie1' name1'
+ , ppr_export ie2' name2' ]
where
occ = nameOccName name1
- ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
+ ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
quotes (ppr name) <+> pprNameProvenance (get_gre name))
-- get_gre finds a GRE for the Name, so that we can show its provenance
= case lookupGRE_Name global_env name of
(gre:_) -> gre
[] -> pprPanic "exportClashErr" (ppr name)
-
-addDupDeclErr :: Name -> Name -> TcRn ()
-addDupDeclErr name_a name_b
- = addErrAt (srcLocSpan loc2) $
- vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
- ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]]
- where
- loc2 = nameSrcLoc name2
- (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a)
- | otherwise = (name_a,name_b)
+ get_loc name = nameSrcLoc $ gre_name $ get_gre name
+ (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
+ then (name1, ie1, name2, ie2)
+ else (name2, ie2, name1, ie1)
+
+addDupDeclErr :: [Name] -> TcRn ()
+addDupDeclErr []
+ = panic "addDupDeclErr: empty list"
+addDupDeclErr names@(name : _)
+ = addErrAt (getSrcSpan (last sorted_names)) $
-- Report the error at the later location
+ vcat [ptext (sLit "Multiple declarations of") <+> quotes (ppr name),
+ ptext (sLit "Declared at:") <+> vcat (map (ppr . nameSrcLoc) sorted_names)]
+ where
+ sorted_names = sortWith nameSrcLoc names
+dupExportWarn :: OccName -> IE RdrName -> IE RdrName -> SDoc
dupExportWarn occ_name ie1 ie2
= hsep [quotes (ppr occ_name),
- ptext SLIT("is exported by"), quotes (ppr ie1),
- ptext SLIT("and"), quotes (ppr ie2)]
+ ptext (sLit "is exported by"), quotes (ppr ie1),
+ ptext (sLit "and"), quotes (ppr ie2)]
+dupModuleExport :: ModuleName -> SDoc
dupModuleExport mod
- = hsep [ptext SLIT("Duplicate"),
- quotes (ptext SLIT("Module") <+> ppr mod),
- ptext SLIT("in export list")]
-
-moduleDeprec mod txt
- = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),
- nest 4 (ppr txt) ]
+ = hsep [ptext (sLit "Duplicate"),
+ quotes (ptext (sLit "Module") <+> ppr mod),
+ ptext (sLit "in export list")]
+
+moduleNotImported :: ModuleName -> SDoc
+moduleNotImported mod
+ = ptext (sLit "The export item `module") <+> ppr mod <>
+ ptext (sLit "' is not imported")
+
+nullModuleExport :: ModuleName -> SDoc
+nullModuleExport mod
+ = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing")
+
+moduleWarn :: ModuleName -> WarningTxt -> SDoc
+moduleWarn mod (WarningTxt txt)
+ = sep [ ptext (sLit "Module") <+> quotes (ppr mod) <> ptext (sLit ":"),
+ nest 4 (ppr txt) ]
+moduleWarn mod (DeprecatedTxt txt)
+ = sep [ ptext (sLit "Module") <+> quotes (ppr mod)
+ <+> ptext (sLit "is deprecated:"),
+ nest 4 (ppr txt) ]
+
+implicitPreludeWarn :: SDoc
+implicitPreludeWarn
+ = ptext (sLit "Module `Prelude' implicitly imported")
+
+packageImportErr :: SDoc
+packageImportErr
+ = ptext (sLit "Package-qualified imports are not enabled; use -XPackageImports")
\end{code}
projects / ghc-hetmet.git / blobdiff