%
% (c) The GRASP/AQUA Project, Glasgow University, 19921998
%
\section[RnNames]{Extracting imported and toplevel names in scope}
\begin{code}
module RnNames (
rnImports, getLocalNonValBinders,
rnExports, extendGlobalRdrEnvRn,
reportUnusedNames, finishWarnings,
) where
#include "HsVersions.h"
import DynFlags
import HsSyn
import TcEnv ( isBrackStage )
import RnEnv
import RnHsDoc ( rnHsDoc )
import IfaceEnv ( ifaceExportNames )
import LoadIface ( loadSrcInterface, loadSysInterface )
import TcRnMonad hiding (LIE)
import PrelNames
import Module
import Name
import NameEnv
import NameSet
import HscTypes
import RdrName
import Outputable
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 System.IO
import Control.Monad
\end{code}
%************************************************************************
%* *
rnImports
%* *
%************************************************************************
\begin{code}
rnImports :: [LImportDecl RdrName]
-> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
rnImports imports
= do this_mod <- getModule
implicit_prelude <- doptM Opt_ImplicitPrelude
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]
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)
Nothing
False
False
Nothing
Nothing
loc = mkGeneralSrcSpan (fsLit "Implicit import declaration")
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
let
imp_mod_name = unLoc loc_imp_mod_name
doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg
WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
dflags <- getDOpts
warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags))
(warnRedundantSourceImport imp_mod_name)
let
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
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 filtered_exports
(new_imp_details, gbl_env) <-
filterImports iface imp_spec imp_details total_avails
dflags <- getDOpts
let
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)
(dependent_mods, dependent_pkgs)
| pkg == thisPackage dflags =
((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
| otherwise =
ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
([], pkg : dep_pkgs deps)
import_all = case imp_details of
Just (is_hiding, ls) -> not is_hiding && null ls
_ -> False
imports = ImportAvails {
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
}
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)
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")
<+> quotes (ppr mod_name)
\end{code}
%************************************************************************
%* *
importsFromLocalDecls
%* *
%************************************************************************
From the toplevel declarations of this module produce
* the lexical environment
* the ImportAvails
created by its bindings.
Note [Toplevel 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
whereclause, 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}
extendGlobalRdrEnvRn :: [AvailInfo]
-> MiniFixityEnv
-> RnM (TcGblEnv, TcLclEnv)
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
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
gres = gresFromAvails LocalDef avails
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
used for source code.
*** 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}
getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
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 {
let (tyinst_decls1, tycl_decls_noinsts)
= partition (isFamInstDecl . unLoc) tycl_decls
tyinst_decls = tyinst_decls1 ++
concatMap (instDeclATs . unLoc) inst_decls
; tc_names <- mapM new_tc tycl_decls_noinsts
; let tc_gres = gresFromAvails LocalDef tc_names
tc_name_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv tc_gres
; ti_names <- mapM (new_ti tc_name_env) tyinst_decls
; 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) ;
for_hs_bndrs :: [Located RdrName]
for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
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
= 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
= do { main_name <- lookupFamInstDeclBndr tc_name_env main_rdr
; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
; return (AvailTC main_name sub_names) }
where
(main_rdr : sub_rdrs) = tyClDeclNames (unLoc ti_decl)
get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
\end{code}
%************************************************************************
%* *
\subsection{Filtering imports}
%* *
%************************************************************************
@filterImports@ takes the @ExportEnv@ telling what the imported module makes
available, and filters it through the import spec (if any).
\begin{code}
filterImports :: ModIface
-> ImpDeclSpec
-> Maybe (Bool, [LIE RdrName])
-> [AvailInfo]
-> RnM (Maybe (Bool, [LIE Name]),
GlobalRdrEnv)
filterImports _ decl_spec Nothing all_avails
= return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
where
prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
= do
opt_typeFamilies <- doptM Opt_TypeFamilies
items1 <- mapM (lookup_lie opt_typeFamilies) import_items
let items2 :: [(LIE Name, AvailInfo)]
items2 = concat items1
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
occ_env :: OccEnv (Name,
AvailInfo,
Maybe Name)
occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
| a <- all_avails, n <- availNames a]
where
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
checkDodgyImport stuff
| IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
= ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
checkDodgyImport _
= return ()
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 rdr
| isQual rdr = Failed (qualImportItemErr rdr)
| Just nm <- lookupOccEnv occ_env (rdrNameOcc rdr) = return nm
| otherwise = bad_ie
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
Nothing -> return [(IEThingAll name, avail)]
Just parent -> return [(IEThingAll name,
AvailTC name2 (subs \\ [name])),
(IEThingAll name, AvailTC parent [name])]
IEThingAbs tc
| want_hiding
-> 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)
when (not opt_typeFamilies && any isTyConName children) $
Failed (typeItemErr (head . filter isTyConName $ children)
(text "in import list"))
case mb_parent of
Nothing -> return [(IEThingWith name children,
AvailTC name (name:children))]
Just parent -> return [(IEThingWith name children,
AvailTC name children),
(IEThingWith name children,
AvailTC parent [name])]
_other -> Failed illegalImportItemErr
where
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}
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]
filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
filterAvails keep avails = foldr (filterAvail keep) [] avails
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
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
emptyAvailEnv :: AvailEnv
emptyAvailEnv = emptyNameEnv
addAvail :: AvailEnv -> AvailInfo -> AvailEnv
addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
mkAvailEnv :: [AvailInfo] -> AvailEnv
mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
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
nubAvails :: [AvailInfo] -> [AvailInfo]
nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
\end{code}
%************************************************************************
%* *
\subsection{Export list processing}
%* *
%************************************************************************
Processing the export list.
You might think that we should record things that appear in the export
list as ``occurrences'' (using @addOccurrenceName@), but you'd be
wrong. We do check (here) that they are in scope, but there is no
need to slurp in their actual declaration (which is what
@addOccurrenceName@ forces).
Indeed, doing so would big trouble when compiling @PrelBase@, because
it reexports @GHC@, which includes @takeMVar#@, whose type includes
@ConcBase.StateAndSynchVar#@, and so on...
\begin{code}
type ExportAccum
= ([LIE Name],
ExportOccMap,
[AvailInfo])
emptyExportAccum :: ExportAccum
emptyExportAccum = ([], emptyOccEnv, [])
type ExportOccMap = OccEnv (Name, IE RdrName)
rnExports :: Bool
-> Maybe [LIE RdrName]
-> TcGblEnv
-> RnM TcGblEnv
rnExports explicit_mod exports
tcg_env@(TcGblEnv { tcg_mod = this_mod,
tcg_rdr_env = rdr_env,
tcg_imports = imports })
= do {
; dflags <- getDOpts
; let real_exports
| explicit_mod = exports
| ghcLink dflags == LinkInMemory = Nothing
| otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
; let final_avails = nubAvails avails
; 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]
-> GlobalRdrEnv
-> ImportAvails
-> Module
-> RnM (Maybe [LIE Name], [AvailInfo])
exports_from_avail Nothing rdr_env _imports _this_mod
=
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
do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
kids_env :: NameEnv [Name]
kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
imported_modules = [ qual_name
| xs <- moduleEnvElts $ imp_mods imports,
(qual_name, _, _) <- xs ]
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
= do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
warnIf warn_dup_exports (dupModuleExport mod) ;
return acc }
| otherwise
= do { implicit_prelude <- doptM Opt_ImplicitPrelude
; warnDodgyExports <- doptM Opt_WarnDodgyExports
; 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 (warnDodgyExports && exportValid && null gres) (nullModuleExport mod)
; addUsedRdrNames (concat [ [mkRdrQual mod occ, mkRdrUnqual occ]
| occ <- map nameOccName names ])
; occs' <- check_occs ie occs names
; 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)
| otherwise
= do (new_ie, avail) <- lookup_ie ie
if isUnboundName (ieName new_ie)
then return acc
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
mkKidRdrName = case isQual_maybe rdr of
Nothing -> mkRdrUnqual
Just (modName, _) -> mkRdrQual modName
addUsedRdrNames $ map (mkKidRdrName . nameOccName) kids
warnDodgyExports <- doptM Opt_WarnDodgyExports
when (null kids) $
if isTyConName name
then when warnDodgyExports $ addWarn (dodgyExportWarn name)
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"
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"
isDoc :: IE RdrName -> Bool
isDoc (IEDoc _) = True
isDoc (IEDocNamed _) = True
isDoc (IEGroup _ _) = True
isDoc _ = False
isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
| implicit_prelude && isBuiltInSyntax name = False
| 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
check_occs ie occs names
= foldlM check occs names
where
check occs name
= case lookupOccEnv occs name_occ of
Nothing -> return (extendOccEnv occs name_occ (name, ie))
Just (name', ie')
| name == name'
-> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
return occs }
| otherwise
-> do { global_env <- getGlobalRdrEnv ;
addErr (exportClashErr global_env name' name ie' ie) ;
return occs }
where
name_occ = nameOccName name
\end{code}
%*********************************************************
%* *
Deprecations
%* *
%*********************************************************
\begin{code}
finishWarnings :: DynFlags -> Maybe WarningTxt
-> TcGblEnv -> RnM TcGblEnv
finishWarnings dflags mod_warn tcg_env
= do { (eps,hpt) <- getEpsAndHpt
; ifOptM Opt_WarnWarningsDeprecations $
mapM_ (check hpt (eps_PIT eps)) all_gres
; 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)
all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
| name `elemNameSet` used_names
, 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 = ASSERT2( isExternalName name, ppr name ) nameModule name
imp_mod = importSpecModule imp_spec
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
check _ _ _ = return ()
lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
-> GlobalRdrElt -> Maybe WarningTxt
lookupImpDeprec dflags hpt pit gre
= case lookupIfaceByModule dflags hpt pit mod of
Just iface -> mi_warn_fn iface name `mplus`
case gre_par gre of
ParentIs p -> mi_warn_fn iface p
NoParent -> Nothing
Nothing -> Nothing
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 inscope 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, wiredin stuff.
%*********************************************************
%* *
Unused names
%* *
%*********************************************************
\begin{code}
reportUnusedNames :: Maybe [LIE RdrName]
-> TcGblEnv -> RnM ()
reportUnusedNames _export_decls gbl_env
= do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
; warnUnusedImportDecls gbl_env
; warnUnusedTopBinds unused_locals }
where
used_names :: NameSet
used_names = findUses (tcg_dus gbl_env) emptyNameSet
defined_names :: [GlobalRdrElt]
defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
_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
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)
unused_locals :: [GlobalRdrElt]
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)
\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
, [AvailInfo]
, [Name] )
\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
\end{code}
\begin{code}
findImportUsage :: [LImportDecl Name]
-> GlobalRdrEnv
-> [RdrName]
-> [ImportDeclUsage]
type ImportMap = FiniteMap SrcLoc [AvailInfo]
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
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 -> []
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
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}
\begin{code}
warnUnusedImport :: ImportDeclUsage -> RnM ()
warnUnusedImport (L loc decl, used, unused)
| Just (False,[]) <- ideclHiding decl
= return ()
| null used = addWarnAt loc msg1
| null unused = return ()
| otherwise = addWarnAt loc msg2
where
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 usersupplied 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')) }
}
where
mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
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 -> IfG (IE Name)
to_ie (Avail n) = return (IEVar n)
to_ie (AvailTC n [m]) = ASSERT( n==m )
return (IEThingAbs n)
to_ie (AvailTC n ns) = do
iface <- loadSysInterface doc n_mod
case [xs | (m,as) <- mi_exports iface,
m == n_mod,
AvailTC x xs <- as,
x == nameOccName n] of
[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) $
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 = ASSERT( isExternalName n ) nameModule n
\end{code}
%************************************************************************
%* *
\subsection{Errors}
%* *
%************************************************************************
\begin{code}
qualImportItemErr :: RdrName -> SDoc
qualImportItemErr rdr
= hang (ptext (sLit "Illegal qualified name in import item:"))
2 (ppr rdr)
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)]
where
source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
| otherwise = empty
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 (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") ]
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' ]
where
occ = nameOccName name1
ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
quotes (ppr name) <+> pprNameProvenance (get_gre name))
get_gre name
= case lookupGRE_Name global_env name of
(gre:_) -> gre
[] -> pprPanic "exportClashErr" (ppr name)
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)) $
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)]
dupModuleExport :: ModuleName -> SDoc
dupModuleExport mod
= 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 2 (vcat (map ppr txt)) ]
moduleWarn mod (DeprecatedTxt txt)
= sep [ ptext (sLit "Module") <+> quotes (ppr mod)
<+> ptext (sLit "is deprecated:"),
nest 2 (vcat (map 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}