X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnNames.lhs;h=55fcea2054fc68270add9cba520deb43d19be282;hp=029df843f08ea8c51adccfb2d067565c9a381dc9;hb=65277a1c9ff86c28c656849d6f6cbb392f1eb3e7;hpb=28f7bda61e5f3b2a8e3711ee1f93e863ecb7620b diff --git a/compiler/rename/RnNames.lhs b/compiler/rename/RnNames.lhs index 029df84..55fcea2 100644 --- a/compiler/rename/RnNames.lhs +++ b/compiler/rename/RnNames.lhs @@ -4,28 +4,17 @@ \section[RnNames]{Extracting imported and top-level names in scope} \begin{code} -{-# OPTIONS -w #-} --- The above warning supression flag is a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details - module RnNames ( - rnImports, importsFromLocalDecls, - rnExports, - getLocalDeclBinders, extendRdrEnvRn, - reportUnusedNames, finishDeprecations, + rnImports, getLocalNonValBinders, + rnExports, extendGlobalRdrEnvRn, + reportUnusedNames, finishWarnings, ) where #include "HsVersions.h" import DynFlags -import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, - ForeignDecl(..), HsGroup(..), HsValBindsLR(..), - Sig(..), collectHsBindLocatedBinders, tyClDeclNames, - instDeclATs, isFamInstDecl, - LIE ) +import HsSyn +import TcEnv ( isBrackStage ) import RnEnv import RnHsDoc ( rnHsDoc ) import IfaceEnv ( ifaceExportNames ) @@ -36,9 +25,7 @@ import PrelNames import Module import Name import NameEnv -import UniqFM import NameSet -import OccName import HscTypes import RdrName import Outputable @@ -46,13 +33,13 @@ import Maybes import SrcLoc import FiniteMap import ErrUtils -import BasicTypes ( DeprecTxt, Fixity ) -import DriverPhases ( isHsBoot ) import Util +import FastString import ListSetOps -import Data.List ( partition, concatMap, (\\), delete ) -import IO ( openFile, IOMode(..) ) -import Monad ( when, mplus ) +import Data.List ( partition, (\\), delete ) +import qualified Data.Set as Set +import System.IO +import Control.Monad \end{code} @@ -75,7 +62,7 @@ rnImports imports 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 + is_source_import (L _ (ImportDecl _ _ is_boot _ _ _)) = is_boot ifOptM Opt_WarnImplicitPrelude ( when (notNull prel_imports) $ addWarn (implicitPreludeWarn) @@ -111,37 +98,41 @@ mkPrelImports this_mod implicit_prelude import_decls | otherwise = [preludeImportDecl] where explicit_prelude_import - = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- import_decls, + = notNull [ () | L _ (ImportDecl mod Nothing _ _ _ _) <- import_decls, unLoc mod == 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 -} - loc = mkGeneralSrcSpan FSLIT("Implicit import declaration") + 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 want_boot +rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot qual_only as_mod imp_details)) - = - setSrcSpan loc $ do + = 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") + doc = ppr imp_mod_name <+> ptext (sLit "is directly imported") - iface <- loadSrcInterface doc imp_mod_name want_boot + 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 @@ -149,13 +140,19 @@ rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot -- 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)) + -- 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 + warns = mi_warns iface orph_iface = mi_orphan iface has_finsts = mi_finsts iface deps = mi_deps iface @@ -234,10 +231,10 @@ rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot -- True <=> import M () import_all = case imp_details of Just (is_hiding, ls) -> not is_hiding && null ls - other -> False + _ -> False imports = ImportAvails { - imp_mods = unitModuleEnv imp_mod (imp_mod, [(qual_mod_name, 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, @@ -245,20 +242,21 @@ rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot } -- Complain if we import a deprecated module - ifOptM Opt_WarnDeprecations ( - case deprecs of - DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt) - other -> returnM () + 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 want_boot + let new_imp_decl = L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot qual_only as_mod new_imp_details) - returnM (new_imp_decl, gbl_env, imports, mi_hpc iface) + 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} @@ -274,82 +272,82 @@ From the top-level declarations of this module produce * the ImportAvails created by its bindings. -\begin{code} --- Bool determines shadowing: --- true: names in the group should shadow other UnQuals --- with the same OccName (used in Template Haskell) --- false: duplicates should be reported as an error --- --- The UniqFM (OccName -> FixItem) associates a Name's OccName's --- FastString with a fixity declaration (that needs the actual OccName --- to be plugged in). This fixity must be brought into scope when such --- a Name is. -importsFromLocalDecls :: Bool -> HsGroup RdrName -> UniqFM (Located Fixity) -> RnM TcGblEnv -importsFromLocalDecls shadowP group fixities - = do { gbl_env <- getGblEnv +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. - ; avails <- getLocalDeclBinders gbl_env group - - ; (rdr_env', fix_env') <- extendRdrEnvRn shadowP (tcg_rdr_env gbl_env, - tcg_fix_env gbl_env) - avails fixities - - ; traceRn (text "local avails: " <> ppr avails) - - ; returnM (gbl_env { tcg_rdr_env = rdr_env', - tcg_fix_env = fix_env'}) - } +\begin{code} +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 + gres = gresFromAvails LocalDef avails --- Bool determines shadowing as in importsFromLocalDecls. --- UniqFM FixItem is the same as in importsFromLocalDecls. --- --- 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. --- --- Also update the FixityEnv with the fixities for the names brought into scope. --- --- Note that the return values are the extensions of the two inputs, --- not the extras relative to them. -extendRdrEnvRn :: Bool -> (GlobalRdrEnv, NameEnv FixItem) - -> [AvailInfo] -> UniqFM (Located Fixity) -> RnM (GlobalRdrEnv, NameEnv FixItem) -extendRdrEnvRn shadowP (rdr_env, fix_env) avails fixities = - let -- if there is a fixity decl for the gre, - -- add it to the fixity env - extendFixEnv env gre = - let name = gre_name gre - occ = nameOccName name - curKey = occNameFS occ in - case lookupUFM fixities curKey of - Nothing -> env - Just (L _ fi) -> extendNameEnv env name (FixItem occ fi) - - (rdr_env_to_extend, extender) = - if shadowP - then -- when shadowing is on, - -- (1) we need to remove the existing Unquals for the - -- names we're extending the env with - -- (2) but extending the env is simple - let names = concatMap availNames avails - new_occs = map nameOccName names - trimmed_rdr_env = hideSomeUnquals rdr_env new_occs - in - (trimmed_rdr_env, - \(cur_rdr_env, cur_fix_env) -> \gre -> - return (extendGlobalRdrEnv cur_rdr_env gre, - extendFixEnv cur_fix_env gre)) - else -- when shadowing is off, - -- (1) we don't munge the incoming env - -- (2) but we need to check for dups when extending - (rdr_env, - \(cur_rdr_env, cur_fix_env) -> \gre -> - let gres = lookupGlobalRdrEnv cur_rdr_env (nameOccName (gre_name gre)) - in case filter isLocalGRE gres of -- Check for existing *local* defns - dup_gre:_ -> do { addDupDeclErr (gre_name dup_gre) (gre_name gre) - ; return (cur_rdr_env, cur_fix_env) } - [] -> return (extendGlobalRdrEnv cur_rdr_env gre, - extendFixEnv cur_fix_env gre)) - in foldlM extender (rdr_env_to_extend, fix_env) (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 @@ -359,59 +357,122 @@ used for source code. Instances of type families ~~~~~~~~~~~~~~~~~~~~~~~~~~ -Indexed data/newtype instances contain data constructors that we need to -collect, too. Moreover, we need to descend into the data/newtypes instances -of associated 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'. -We need to be careful with the handling of the type constructor of each type -instance as the family constructor is already defined, and we want to avoid -raising a duplicate declaration error. So, we make a new name for it, but -don't return it in the 'AvailInfo'. +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} --- Note: this function does NOT get the binders of the ValBinds that --- will be bound during renaming -getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [AvailInfo] -getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs, - hs_tyclds = tycl_decls, - hs_instds = inst_decls, - hs_fords = foreign_decls }) - = do { tc_names_s <- mappM new_tc tycl_decls - ; at_names_s <- mappM inst_ats inst_decls - ; val_names <- mappM new_simple val_bndrs - ; return (val_names ++ tc_names_s ++ concat at_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) ; + for_hs_bndrs :: [Located RdrName] for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls] -- 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 - | isFamInstDecl (unLoc tc_decl) - = do { main_name <- lookupFamInstDeclBndr mod main_rdr - ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs - ; return (AvailTC main_name sub_names) } - -- main_name is not bound here! - | otherwise + new_tc tc_decl -- NOT for type/data instances = do { main_name <- newTopSrcBinder mod main_rdr - ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs + ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs ; return (AvailTC main_name (main_name : sub_names)) } where (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl) - inst_ats inst_decl - = mappM new_tc (instDeclATs (unLoc inst_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) -getLocalDeclBinders _ _ = panic "getLocalDeclBinders" -- ValBindsOut can't happen +get_local_binders _ g = pprPanic "get_local_binders" (ppr g) \end{code} @@ -431,8 +492,7 @@ filterImports :: ModIface -> [AvailInfo] -- What's available -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names GlobalRdrEnv) -- Same again, but in GRE form - -filterImports iface decl_spec Nothing all_avails +filterImports _ decl_spec Nothing all_avails = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails)) where prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }] @@ -486,6 +546,7 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails (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) @@ -499,7 +560,7 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails where -- Warn when importing T(..) if T was exported abstractly checkDodgyImport stuff - | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff + | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n)) -- NB. use the RdrName for reporting the warning checkDodgyImport _ @@ -554,7 +615,7 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails return [mkIEThingAbs nameAvail] IEThingWith tc ns -> do - (name, AvailTC name2 subnames, mb_parent) <- lookup_name tc + (name, AvailTC _ subnames, mb_parent) <- lookup_name tc let env = mkOccEnv [(nameOccName s, s) | s <- subnames] mb_children = map (lookupOccEnv env . rdrNameOcc) ns @@ -581,7 +642,7 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails where mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n) - mkIEThingAbs (n, av, Just parent) = (IEThingAbs n, AvailTC parent [n]) + mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n]) catMaybeErr :: [MaybeErr err a] -> [a] @@ -617,17 +678,18 @@ mkUnitAvail me (ParentIs p) = AvailTC p [me] mkUnitAvail me NoParent | isTyConName me = AvailTC me [me] | otherwise = Avail me -plusAvail (Avail n1) (Avail n2) = Avail n1 -plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2) +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 n (Avail _) = NoParent -availParent n (AvailTC m ms) | n==m = NoParent - | otherwise = ParentIs m +availParent _ (Avail _) = NoParent +availParent n (AvailTC m _) | n == m = NoParent + | otherwise = ParentIs m trimAvail :: AvailInfo -> Name -> AvailInfo -trimAvail (Avail n) m = Avail n +trimAvail (Avail n) _ = Avail n trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m] -- | filters 'AvailInfo's by the given predicate @@ -644,14 +706,14 @@ filterAvail keep ie rest = 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. +-- | 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 - other -> \n -> True + IEThingAll name -> \n -> n == name + _ -> \_ -> True prov_fn name = Imported [imp_spec] where imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec } @@ -660,8 +722,8 @@ gresFromIE decl_spec (L loc ie, avail) 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 other_gre env = env + add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_Acc (:) singleton env p n + add _ env = env findChildren :: NameEnv [Name] -> Name -> [Name] findChildren env n = lookupNameEnv env n `orElse` [] @@ -680,6 +742,7 @@ type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains emptyAvailEnv :: AvailEnv emptyAvailEnv = emptyNameEnv +{- Dead code unitAvailEnv :: AvailInfo -> AvailEnv unitAvailEnv a = unitNameEnv (availName a) a @@ -688,6 +751,7 @@ plusAvailEnv = plusNameEnv_C plusAvail availEnvElts :: AvailEnv -> [AvailInfo] availEnvElts = nameEnvElts +-} addAvail :: AvailEnv -> AvailInfo -> AvailEnv addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail @@ -740,6 +804,7 @@ type ExportAccum -- The type of the accumulating parameter of [AvailInfo]) -- The accumulated exported stuff -- Not nub'd! +emptyExportAccum :: ExportAccum emptyExportAccum = ([], emptyOccEnv, []) type ExportOccMap = OccEnv (Name, IE RdrName) @@ -786,7 +851,6 @@ rnExports explicit_mod exports tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet final_avails) }) } - exports_from_avail :: Maybe [LIE RdrName] -- Nothing => no explicit export list -> GlobalRdrEnv @@ -794,7 +858,7 @@ exports_from_avail :: Maybe [LIE RdrName] -> Module -> RnM (Maybe [LIE Name], [AvailInfo]) -exports_from_avail Nothing rdr_env imports this_mod +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 @@ -815,7 +879,7 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod kids_env = mkChildEnv (globalRdrEnvElts rdr_env) imported_modules = [ qual_name - | (_, xs) <- moduleEnvElts $ imp_mods imports, + | xs <- moduleEnvElts $ imp_mods imports, (qual_name, _, _) <- xs ] exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum @@ -825,20 +889,27 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod , 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 = do { implicit_prelude <- doptM Opt_ImplicitPrelude - ; let { exportValid = (mod `elem` imported_modules) + ; warnDodgyExports <- doptM Opt_WarnDodgyExports + ; let { exportValid = (mod `elem` imported_modules) || (moduleName this_mod == mod) - ; gres = filter (isModuleExported implicit_prelude mod) - (globalRdrEnvElts rdr_env) - } + ; gres = filter (isModuleExported implicit_prelude mod) + (globalRdrEnvElts rdr_env) + ; names = map gre_name gres + } - ; checkErr exportValid (moduleNotImported mod) - ; warnIf (exportValid && null gres) (nullModuleExport mod) + ; checkErr exportValid (moduleNotImported mod) + ; warnIf (warnDodgyExports && exportValid && null gres) (nullModuleExport mod) - ; occs' <- check_occs ie occs (map gre_name gres) + ; 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 @@ -881,12 +952,18 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod 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)) - + 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 -- This occurs when you export T(..), but + -- only import T abstractly, or T is a synonym. + addErr (exportItemErr ie) + return (IEThingAll name, AvailTC name (name:kids)) lookup_ie ie@(IEThingWith rdr sub_rdrs) @@ -909,7 +986,7 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod (text "in export list")) return (IEThingWith name names, AvailTC name (name:names)) - lookup_ie ie = panic "lookup_ie" -- Other cases covered earlier + lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier ------------- lookup_doc_ie :: IE RdrName -> RnM (IE Name) @@ -918,9 +995,10 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod 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 ie = panic "lookup_doc_ie" -- Other cases covered earlier + lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier +isDoc :: IE RdrName -> Bool isDoc (IEDoc _) = True isDoc (IEDocNamed _) = True isDoc (IEGroup _ _) = True @@ -935,14 +1013,16 @@ isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov }) -- 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 + -- 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 -> moduleName (nameModule name) == mod + LocalDef | Just name_mod <- nameModule_maybe name + -> moduleName name_mod == mod + | otherwise -> False Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is ------------------------------- @@ -952,18 +1032,18 @@ check_occs ie occs names 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} @@ -975,23 +1055,23 @@ check_occs ie occs names %********************************************************* \begin{code} -finishDeprecations :: DynFlags -> Maybe DeprecTxt - -> TcGblEnv -> RnM TcGblEnv --- (a) Report usasge of deprecated imports --- (b) If the whole module is deprecated, update tcg_deprecs --- All this happens only once per module -finishDeprecations dflags mod_deprec tcg_env +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_WarnDeprecations $ + ; ifOptM Opt_WarnWarningsDeprecations $ mapM_ (check hpt (eps_PIT eps)) all_gres -- By this time, typechecking is complete, -- so the PIT is fully populated - -- Deal with a module deprecation; it overrides all existing deprecs - ; let new_deprecs = case mod_deprec of - Just txt -> DeprecAll txt - Nothing -> tcg_deprecs tcg_env - ; return (tcg_env { tcg_deprecs = new_deprecs }) } + -- 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 @@ -1001,19 +1081,19 @@ finishDeprecations dflags mod_deprec tcg_env | name `elemNameSet` used_names , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre = addWarnAt (importSpecLoc imp_spec) - (sep [ptext SLIT("Deprecated use of") <+> + (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 @@ -1022,18 +1102,19 @@ finishDeprecations dflags mod_deprec tcg_env -- interface lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable - -> GlobalRdrElt -> Maybe DeprecTxt + -> GlobalRdrElt -> Maybe WarningTxt -- The name is definitely imported, so look in HPT, PIT lookupImpDeprec dflags hpt pit gre - = case lookupIfaceByModule dflags hpt pit (nameModule name) of - Just iface -> mi_dep_fn iface name `mplus` -- Bleat if the thing, *or + = 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_dep_fn iface p -- its parent*, is deprec'd + 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 + name = gre_name gre + mod = ASSERT2( isExternalName name, ppr name ) nameModule name \end{code} Note [Used names with interface not loaded] @@ -1047,7 +1128,7 @@ 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 -fno-implicit-prelude) + 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 @@ -1067,13 +1148,10 @@ this is, after all, wired-in stuff. \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 :: NameSet used_names = findUses (tcg_dus gbl_env) emptyNameSet @@ -1087,8 +1165,8 @@ reportUnusedNames export_decls 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 used_names - defined_and_used, defined_but_not_used :: [GlobalRdrElt] - (defined_and_used, defined_but_not_used) + _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 @@ -1109,242 +1187,198 @@ reportUnusedNames export_decls gbl_env 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 = mapCatMaybes unused_imp defined_but_not_used - unused_imp :: GlobalRdrElt -> Maybe GlobalRdrElt -- Result has trimmed Imported provenances - unused_imp gre@(GRE {gre_prov = LocalDef}) = Nothing - unused_imp gre@(GRE {gre_prov = Imported imp_specs}) - | null trimmed_specs = Nothing - | otherwise = Just (gre {gre_prov = Imported trimmed_specs}) - where - trimmed_specs = filter report_if_unused imp_specs - - -- 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 {gre_prov = Imported (imp_spec:_)}) acc - = addToFM_C plusAvailEnv acc - (importSpecModule imp_spec) (unitAvailEnv (greAvail gre)) - add_name gre acc = acc -- Local - - -- 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 +\end{code} - add_inst_mod (mod, _) acc - | mod_name `elemFM` acc = acc -- We import something already - | otherwise = addToFM acc mod_name emptyAvailEnv +%********************************************************* +%* * + 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, [(ModuleName, 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: this code is generally buggy - unused_imp_mods :: [(ModuleName, SrcSpan)] - unused_imp_mods = [(mod_name,loc) - | (mod, xs) <- direct_import_mods, - (_, no_imp, loc) <- xs, - 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 - - report_if_unused :: ImportSpec -> Bool - -- Do we want to report this as an unused import? - report_if_unused (ImpSpec {is_decl = d, is_item = i}) - = not (module_unused (is_mod d)) -- Not if we've already said entire import is unused - && isExplicitItem i -- Only if the import was explicit + 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 ---------------------- -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 - | GRE { gre_name = name, gre_prov = Imported imps } <- gres - , pr <- redundants imps ] + 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} + +\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 - , isExplicitItem (is_item red_imp) - -- Complain only about redundant imports - -- mentioned explicitly by the user - , cov_imp <- take 1 (filter (covers red_imp) imps) ] - -- The 'take 1' picks the first offending group - -- for this particular name - - -- "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 - | otherwise - = not (isExplicitItem cov_item) -- Redundant one is selective and covering one isn't - || red_later -- or both are explicit; tie-break using red_later -{- - | 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 - --- 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 <- initIfaceTcRn $ mappM to_ies (fmToList imps) ; - this_mod <- getModule ; - rdr_env <- getGlobalRdrEnv ; - dflags <- getDOpts ; - ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ; - printForUser h (mkPrintUnqualified dflags 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 -> 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) - = loadSysInterface doc n_mod `thenM` \ iface -> + 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 -> 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 = nameModule n + n_mod = ASSERT( isExternalName n ) nameModule n \end{code} - %************************************************************************ %* * \subsection{Errors} @@ -1352,40 +1386,48 @@ printMinimalImports imps %************************************************************************ \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 -illegalImportItemErr = ptext SLIT("Illegal import item") +illegalImportItemErr :: SDoc +illegalImportItemErr = ptext (sLit "Illegal import item") -dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item -dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) 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 constructors or class methods,"), - ptext SLIT("but it has none") ] - + = 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") ] + = 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 + = 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 @@ -1398,39 +1440,52 @@ exportClashErr global_env name1 name2 ie1 ie2 then (name1, ie1, name2, ie2) else (name2, ie2, name1, ie1) -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) +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")] + = 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") + = 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") - -moduleDeprec mod txt - = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"), - nest 4 (ppr txt) ] - + = 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") + = ptext (sLit "Module `Prelude' implicitly imported") + +packageImportErr :: SDoc +packageImportErr + = ptext (sLit "Package-qualified imports are not enabled; use -XPackageImports") \end{code}