X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnNames.lhs;h=3867e17693306e2aef9f270d5c9b2c9218e966b3;hp=36716763f1b1961c30b56dfcf3837f85ceda6c24;hb=b2bd63f99d643f6b3eb30bb72bb9ae26d4183252;hpb=26a4a13d5823ef77d2693c1f62ecd99634d80a88 diff --git a/compiler/rename/RnNames.lhs b/compiler/rename/RnNames.lhs index 3671676..3867e17 100644 --- a/compiler/rename/RnNames.lhs +++ b/compiler/rename/RnNames.lhs @@ -5,360 +5,504 @@ \begin{code} module RnNames ( - rnImports, importsFromLocalDecls, - rnExports, - getLocalDeclBinders, extendRdrEnvRn, - reportUnusedNames, reportDeprecations + rnImports, getLocalNonValBinders, + rnExports, extendGlobalRdrEnvRn, + gresFromAvails, + reportUnusedNames, finishWarnings, ) where #include "HsVersions.h" -import DynFlags ( DynFlag(..), GhcMode(..), DynFlags(..) ) -import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, - ForeignDecl(..), HsGroup(..), HsValBinds(..), - Sig(..), collectHsBindLocatedBinders, tyClDeclNames, - instDeclATs, isIdxTyDecl, - LIE ) +import DynFlags +import HsSyn +import TcEnv ( isBrackStage ) import RnEnv import RnHsDoc ( rnHsDoc ) import IfaceEnv ( ifaceExportNames ) -import LoadIface ( loadSrcInterface ) -import TcRnMonad hiding (LIE) +import LoadIface ( loadSrcInterface ) +import TcRnMonad +import HeaderInfo ( mkPrelImports ) import PrelNames import Module import Name import NameEnv import NameSet -import OccName import HscTypes import RdrName import Outputable import Maybes import SrcLoc -import FiniteMap import ErrUtils -import BasicTypes ( DeprecTxt ) -import DriverPhases ( isHsBoot ) import Util +import FastString import ListSetOps -import Data.List ( partition, concatMap, (\\), delete ) -import IO ( openFile, IOMode(..) ) -import Monad ( when ) +import Data.List ( partition, (\\), delete, find ) +import qualified Data.Set as Set +import System.IO +import Control.Monad +import Data.Map ( Map ) +import qualified Data.Map as Map \end{code} %************************************************************************ -%* * - rnImports -%* * +%* * +\subsection{rnImports} +%* * %************************************************************************ \begin{code} rnImports :: [LImportDecl RdrName] - -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails) + -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage) rnImports imports -- PROCESS IMPORT DECLS -- Do the non {- SOURCE -} ones first, so that we get a helpful -- warning for {- SOURCE -} ones that are unnecessary = do this_mod <- getModule - implicit_prelude <- doptM Opt_ImplicitPrelude - let prel_imports = mkPrelImports this_mod implicit_prelude imports + implicit_prelude <- xoptM Opt_ImplicitPrelude + let prel_imports = mkPrelImports (moduleName 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 - stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary) - stuff2 <- mapM (rnImportDecl this_mod) source - let (decls, rdr_env, imp_avails) = combine (stuff1 ++ stuff2) - return (decls, rdr_env, imp_avails) + ifDOptM Opt_WarnImplicitPrelude ( + when (notNull prel_imports) $ addWarn (implicitPreludeWarn) + ) + + stuff1 <- mapM (rnImportDecl this_mod True) prel_imports + stuff2 <- mapM (rnImportDecl this_mod False) ordinary + stuff3 <- mapM (rnImportDecl this_mod False) source + let (decls, rdr_env, imp_avails, hpc_usage) = combine (stuff1 ++ stuff2 ++ stuff3) + return (decls, rdr_env, imp_avails, hpc_usage) where - combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails)] - -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails) - combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails) - where plus (decl, gbl_env1, imp_avails1) - (decls, gbl_env2, imp_avails2) - = (decl:decls, + 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) - -mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName] --- Consruct the implicit declaration "import Prelude" (or not) --- --- NB: opt_NoImplicitPrelude is slightly different to import Prelude (); --- because the former doesn't even look at Prelude.hi for instance --- declarations, whereas the latter does. -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 _ _ _ _) <- import_decls, - unLoc mod == pRELUDE_NAME ] + imp_avails1 `plusImportAvails` imp_avails2, + hpc_usage1 || hpc_usage2) - preludeImportDecl :: LImportDecl RdrName - preludeImportDecl - = L loc $ - ImportDecl (L loc pRELUDE_NAME) - False {- Not a boot interface -} - False {- Not qualified -} - Nothing {- No "as" -} - Nothing {- No import list -} +rnImportDecl :: Module -> Bool + -> LImportDecl RdrName + -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage) - loc = mkGeneralSrcSpan FSLIT("Implicit import declaration") +rnImportDecl this_mod implicit_prelude + (L loc (ImportDecl { ideclName = loc_imp_mod_name, ideclPkgQual = mb_pkg + , ideclSource = want_boot, ideclQualified = qual_only + , ideclAs = as_mod, ideclHiding = imp_details })) + = setSrcSpan loc $ do + when (isJust mb_pkg) $ do + pkg_imports <- xoptM Opt_PackageImports + when (not pkg_imports) $ addErr packageImportErr -rnImportDecl :: Module - -> LImportDecl RdrName - -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails) - -rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot - qual_only as_mod imp_details)) - = - setSrcSpan loc $ do - - -- If there's an error in loadInterface, (e.g. interface - -- file not found) we get lots of spurious errors from 'filterImports' + -- 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") - - iface <- loadSrcInterface doc imp_mod_name want_boot - - -- Compiler sanity check: if the import didn't say - -- {-# SOURCE #-} we should not get a hi-boot file + imp_mod_name = unLoc loc_imp_mod_name + doc = ppr imp_mod_name <+> ptext (sLit "is directly imported") + + -- Check for a missing import list + -- (Opt_WarnMissingImportList also checks for T(..) items + -- but that is done in checkDodgyImport below) + case imp_details of + Just (False, _) -> return () -- Explicit import list + _ | implicit_prelude -> return () + | qual_only -> return () + | otherwise -> ifDOptM Opt_WarnMissingImportList $ + addWarn (missingImportListWarn imp_mod_name) + + iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg + + -- Compiler sanity check: if the import didn't say + -- {-# SOURCE #-} we should not get a hi-boot file WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do - -- Issue a user warning for a redundant {- SOURCE -} import - -- NB that we arrange to read all the ordinary imports before - -- any of the {- SOURCE -} imports - warnIf (want_boot && not (mi_boot iface)) - (warnRedundantSourceImport imp_mod_name) + -- 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. + -- + -- in --make and GHCi, the compilation manager checks for this, + -- and indeed we shouldn't do it here because the existence of + -- the non-boot module depends on the compilation order, which + -- is not deterministic. The hs-boot test can show this up. + dflags <- getDOpts + warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags)) + (warnRedundantSourceImport imp_mod_name) let - imp_mod = mi_module iface - deprecs = mi_deprecs iface - is_orph = mi_orphan iface - has_finsts = mi_finsts iface - deps = mi_deps iface - - filtered_exports = filter not_this_mod (mi_exports iface) - not_this_mod (mod,_) = mod /= this_mod - -- If the module exports anything defined in this module, just - -- ignore it. Reason: otherwise it looks as if there are two - -- local definition sites for the thing, and an error gets - -- reported. Easiest thing is just to filter them out up - -- front. This situation only arises if a module imports - -- itself, or another module that imported it. (Necessarily, - -- this invoves a loop.) - -- - -- Tiresome consequence: if you say - -- module A where - -- import B( AType ) - -- type AType = ... - -- - -- module B( AType ) where - -- import {-# SOURCE #-} A( AType ) - -- - -- then you'll get a 'B does not export AType' message. Oh well. - - 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 } - -- in - - -- Get the total exports from this module + imp_mod = mi_module iface + warns = mi_warns iface + orph_iface = mi_orphan iface + has_finsts = mi_finsts iface + deps = mi_deps iface + + filtered_exports = filter not_this_mod (mi_exports iface) + not_this_mod (mod,_) = mod /= this_mod + -- If the module exports anything defined in this module, just + -- ignore it. Reason: otherwise it looks as if there are two + -- local definition sites for the thing, and an error gets + -- reported. Easiest thing is just to filter them out up + -- front. This situation only arises if a module imports + -- itself, or another module that imported it. (Necessarily, + -- this invoves a loop.) + -- + -- Tiresome consequence: if you say + -- module A where + -- import B( AType ) + -- type AType = ... + -- + -- module B( AType ) where + -- import {-# SOURCE #-} A( AType ) + -- + -- then you'll get a 'B does not export AType' message. Oh well. + + 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 } + + -- Get the total exports from this module total_avails <- ifaceExportNames filtered_exports - -- filter the imports according to the import declaration - (new_imp_details, gbl_env) <- + -- filter the imports according to the import declaration + (new_imp_details, gbl_env) <- filterImports iface imp_spec imp_details total_avails dflags <- getDOpts let - -- Compute new transitive dependencies - - orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) ) - imp_mod : dep_orphs deps - | otherwise = dep_orphs deps - - 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 = - -- Imported module is from the home package - -- Take its dependent modules and add imp_mod itself - -- Take its dependent packages unchanged - -- - -- NB: (dep_mods deps) might include a hi-boot file - -- for the module being compiled, CM. Do *not* filter - -- this out (as we used to), because when we've - -- finished dealing with the direct imports we want to - -- know if any of them depended on CM.hi-boot, in - -- which case we should do the hi-boot consistency - -- check. See LoadIface.loadHiBootInterface - ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps) - - | otherwise = - -- Imported module is from another package - -- Dump the dependent modules - -- Add the package imp_mod comes from to the dependent packages - ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) ) - ([], pkg : dep_pkgs deps) - - -- True <=> import M () - import_all = case imp_details of - Just (is_hiding, ls) -> not is_hiding && null ls - other -> False - - imports = ImportAvails { - imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc), - imp_orphs = orphans, - imp_finsts = finsts, - imp_dep_mods = mkModDeps dependent_mods, - imp_dep_pkgs = dependent_pkgs + -- Compute new transitive dependencies + + 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 = + -- Imported module is from the home package + -- Take its dependent modules and add imp_mod itself + -- Take its dependent packages unchanged + -- + -- NB: (dep_mods deps) might include a hi-boot file + -- for the module being compiled, CM. Do *not* filter + -- this out (as we used to), because when we've + -- finished dealing with the direct imports we want to + -- know if any of them depended on CM.hi-boot, in + -- which case we should do the hi-boot consistency + -- check. See LoadIface.loadHiBootInterface + ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps) + + | otherwise = + -- Imported module is from another package + -- Dump the dependent modules + -- Add the package imp_mod comes from to the dependent packages + ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) ) + ([], pkg : dep_pkgs deps) + + -- True <=> import M () + 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 } - -- Complain if we import a deprecated module - ifOptM Opt_WarnDeprecations ( - case deprecs of - DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt) - other -> returnM () + -- Complain if we import a deprecated module + ifDOptM 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) + 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} %************************************************************************ -%* * - importsFromLocalDecls -%* * +%* * +\subsection{importsFromLocalDecls} +%* * %************************************************************************ From the top-level declarations of this module produce - * the lexical environment - * the ImportAvails -created by its bindings. - -Complain about duplicate bindings + * the lexical environment + * the ImportAvails +created by its bindings. + +Note [Top-level Names in Template Haskell decl quotes] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider a Template Haskell declaration quotation like this: + module M where + f x = h [d| f = 3 |] +When renaming the declarations inside [d| ...|], we treat the +top level binders specially in two ways + +1. We give them an Internal name, not (as usual) an External one. + Otherwise the NameCache gets confused by a second allocation of + M.f. (We used to invent a fake module ThFake to avoid this, but + that had other problems, notably in getting the correct answer for + nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module + unaffected.) + +2. We make them *shadow* the outer bindings. If we don't do that, + we'll get a complaint when extending the GlobalRdrEnv, saying that + there are two bindings for 'f'. There are several tricky points: + + * 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. + + * The *qualified* name M.f from the enclosing module must certainly + still be available. So we don't nuke it entirely; we just make + it seem like qualified import. + + * We only shadow *External* names (which come from the main module) + Do not shadow *Inernal* names because in the bracket + [d| class C a where f :: a + f = 4 |] + rnSrcDecls will first call extendGlobalRdrEnvRn with C[f] from the + class decl, and *separately* extend the envt with the value binding. + +3. We find out whether we are inside a [d| ... |] by testing the TH + stage. This is a slight hack, because the stage field was really + meant for the type checker, and here we are not interested in the + fields of Brack, hence the error thunks in thRnBrack. \begin{code} -importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv -importsFromLocalDecls group - = do { gbl_env <- getGblEnv - - ; avails <- getLocalDeclBinders gbl_env group - - ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) avails +extendGlobalRdrEnvRn :: [AvailInfo] + -> MiniFixityEnv + -> RnM (TcGblEnv, TcLclEnv) +-- Updates both the GlobalRdrEnv and the FixityEnv +-- We return a new TcLclEnv only because 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 = transformGREs qual_gre new_occs rdr_env + 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 - ; traceRn (text "local avails: " <> ppr 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 + + qual_gre :: GlobalRdrElt -> GlobalRdrElt + -- Transform top-level GREs from the module being compiled + -- so that they are out of the way of new definitions in a Template + -- Haskell bracket + -- See Note [Top-level Names in Template Haskell decl quotes] + -- Seems like 5 times as much work as it deserves! + -- + -- For a LocalDef we make a (fake) qualified imported GRE for a + -- local GRE so that the original *qualified* name is still in scope + -- but the *unqualified* one no longer is. What a hack! + + qual_gre gre@(GRE { gre_prov = LocalDef, gre_name = name }) + | isExternalName name = gre { gre_prov = Imported [imp_spec] } + | otherwise = gre + -- Do not shadow Internal (ie Template Haskell) Names + -- See Note [Top-level Names in Template Haskell decl quotes] + where + mod = ASSERT2( isExternalName name, ppr name) moduleName (nameModule name) + imp_spec = ImpSpec { is_item = ImpAll, is_decl = decl_spec } + decl_spec = ImpDeclSpec { is_mod = mod, is_as = mod, + is_qual = True, -- Qualified only! + is_dloc = srcLocSpan (nameSrcLoc name) } - ; returnM (gbl_env { tcg_rdr_env = rdr_env' }) - } + qual_gre gre@(GRE { gre_prov = Imported specs }) + = gre { gre_prov = Imported (map qual_spec specs) } -extendRdrEnvRn :: GlobalRdrEnv -> [AvailInfo] -> RnM GlobalRdrEnv --- Add the new locally-bound names one by one, checking for duplicates as --- we do so. Remember that in Template Haskell the duplicates --- might *already be* in the GlobalRdrEnv from higher up the module -extendRdrEnvRn rdr_env avails - = foldlM add_local rdr_env (gresFromAvails LocalDef avails) - where - add_local rdr_env gre - | gres <- lookupGlobalRdrEnv rdr_env (nameOccName (gre_name gre)) - , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns - = do { addDupDeclErr (gre_name dup_gre) (gre_name gre) - ; return rdr_env } - | otherwise - = return (extendGlobalRdrEnv rdr_env gre) + qual_spec spec@(ImpSpec { is_decl = decl_spec }) + = spec { is_decl = decl_spec { is_qual = True } } \end{code} @getLocalDeclBinders@ returns the names for an @HsDecl@. It's used for source code. - *** See "THE NAMING STORY" in HsDecls **** + *** See "THE NAMING STORY" in HsDecls **** -Instances of indexed types +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. -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'. +If we don't look up class instances, can't we get away without looking up type +instances, too? No, we can't. Data type instances define data constructors +and we need to + + (1) collect those in 'get_local_binders' and + (2) we need to get their parent name in 'get_local_binders', too, to + produce an appropriate 'AvailTC'. + +This parent name is exactly the family name of the type instance that is so +difficult to look up. + +We solve this problem as follows: + + (a) We process all type declarations other than type instances first. + (b) Then, we compute a 'GlobalRdrEnv' from the result of the first step. + (c) Finally, we process all type instances (both those on the toplevel and + those nested in class instances) and check for the family names in the + 'GlobalRdrEnv' produced in the previous step before using 'lookupOccRn'. \begin{code} -getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [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 (incl constructors and record selectors) +-- class decls (including class ops) +-- 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) (concat tycl_decls) + tyinst_decls = tyinst_decls1 ++ instDeclATs inst_decls + + -- process all type/class decls except family instances + ; tc_names <- mapM new_tc tycl_decls_noinsts + + -- create a temporary rdr env of the type binders + ; let tc_gres = gresFromAvails LocalDef tc_names + tc_name_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv tc_gres + + -- process all family instances + ; ti_names <- mapM (new_ti tc_name_env) tyinst_decls + + -- finish off with value binder in case of a hs-boot file + ; val_names <- mapM new_simple val_bndrs + ; return (val_names ++ tc_names ++ ti_names) } where - mod = tcg_mod gbl_env is_hs_boot = isHsBoot (tcg_src gbl_env) ; - val_bndrs | is_hs_boot = sig_hs_bndrs - | otherwise = for_hs_bndrs ++ val_hs_bndrs - -- In a hs-boot file, the value binders come from the - -- *signatures*, and there should be no foreign binders + 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 + nm <- newTopSrcBinder rdr_name return (Avail nm) - sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs] - val_hs_bndrs = collectHsBindLocatedBinders val_decls - for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls] - - new_tc tc_decl - | isIdxTyDecl (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 - = do { main_name <- newTopSrcBinder mod main_rdr - ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs - ; return (AvailTC main_name (main_name : sub_names)) } + new_tc tc_decl -- NOT for type/data instances + = do { main_name <- newTopSrcBinder main_rdr + ; sub_names <- mapM newTopSrcBinder sub_rdrs + ; return (AvailTC main_name (main_name : sub_names)) } where - (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl) + (main_rdr : sub_rdrs) = hsTyClDeclBinders 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 sub_rdrs + ; return (AvailTC main_name sub_names) } + -- main_name is not bound here! + where + (main_rdr : sub_rdrs) = hsTyClDeclBinders ti_decl -getLocalDeclBinders _ _ = panic "getLocalDeclBinders" -- ValBindsOut can't happen +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 @@ -366,39 +510,38 @@ available, and filters it through the import spec (if any). \begin{code} filterImports :: ModIface - -> ImpDeclSpec -- The span for the entire import decl - -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding - -> [AvailInfo] -- What's available - -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names - GlobalRdrEnv) -- Same again, but in GRE form - -filterImports iface decl_spec Nothing all_avails + -> ImpDeclSpec -- The span for the entire import decl + -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding + -> [AvailInfo] -- What's available + -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names + GlobalRdrEnv) -- Same again, but in GRE form +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 -- check for errors, convert RdrNames to Names - opt_indexedtypes <- doptM Opt_IndexedTypes - items1 <- mapM (lookup_lie opt_indexedtypes) import_items + = do -- check for errors, convert RdrNames to Names + opt_typeFamilies <- xoptM Opt_TypeFamilies + items1 <- mapM (lookup_lie opt_typeFamilies) import_items let items2 :: [(LIE Name, AvailInfo)] items2 = concat items1 - -- NB the AvailInfo may have duplicates, and several items - -- for the same parent; e.g N(x) and N(y) + -- NB the AvailInfo may have duplicates, and several items + -- for the same parent; e.g N(x) and N(y) names = availsToNameSet (map snd items2) - keep n = not (n `elemNameSet` names) - pruned_avails = filterAvails keep all_avails - hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }] + 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 + gres | want_hiding = gresFromAvails hiding_prov pruned_avails + | otherwise = concatMap (gresFromIE decl_spec) items2 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres) where - -- This environment is how we map names mentioned in the import + -- This environment is how we map names mentioned in the import -- list to the actual Name they correspond to, and the name family -- that the Name belongs to (the AvailInfo). The situation is -- complicated by associated families, which introduce a three-level @@ -408,40 +551,45 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails -- third component of the environment that gives the class name (= -- grand parent) in case of associated families. -- - -- This env will have entries for data constructors too, - -- they won't make any difference because naked entities like T - -- in an import list map to TcOccs, not VarOccs. - occ_env :: OccEnv (Name, -- the name - AvailInfo, -- the export item providing the name - Maybe Name) -- the parent of associated types - occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing)) - | a <- all_avails, n <- availNames a] + -- This env will have entries for data constructors too, + -- they won't make any difference because naked entities like T + -- in an import list map to TcOccs, not VarOccs. + occ_env :: OccEnv (Name, -- the name + AvailInfo, -- the export item providing the name + Maybe Name) -- the parent of associated types + occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing)) + | a <- all_avails, n <- availNames a] where -- we know that (1) there are at most entries for one name, (2) their -- first component is identical, (3) they are for tys/cls, and (4) one -- entry has the name in its parent position (the other doesn't) combine (name, AvailTC p1 subs1, Nothing) - (_ , AvailTC p2 subs2, Nothing) + (_ , AvailTC p2 subs2, Nothing) = let - (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2) - in - (name, AvailTC name subs, Just parent) + (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_indexedtypes (L loc ieRdr) - = do - stuff <- setSrcSpan loc $ - case lookup_ie opt_indexedtypes ieRdr of + lookup_lie opt_typeFamilies (L loc ieRdr) + = do + stuff <- setSrcSpan loc $ + case lookup_ie opt_typeFamilies ieRdr of Failed err -> addErr err >> return [] Succeeded a -> return a checkDodgyImport stuff return [ (L loc ie, avail) | (ie,avail) <- stuff ] where - -- Warn when importing T(..) if T was exported abstractly + -- Warn when importing T(..) if T was exported abstractly checkDodgyImport stuff - | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff - = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n)) + | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff + = ifDOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n)) -- NB. use the RdrName for reporting the warning + | IEThingAll {} <- ieRdr + , not (is_qual decl_spec) + = ifDOptM Opt_WarnMissingImportList $ + addWarn (missingImportListItem ieRdr) checkDodgyImport _ = return () @@ -452,17 +600,18 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails -- We return a list here, because in the case of an import -- item like C, if we are hiding, then C refers to *both* a -- type/class and a data constructor. Moreover, when we import - -- data constructors of an associated family, we need separate - -- AvailInfos for the data constructors and the family (as they have - -- different parents). See the discussion at occ_env. + -- data constructors of an associated family, we need separate + -- AvailInfos for the data constructors and the family (as they have + -- different parents). See the discussion at occ_env. lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)] - lookup_ie opt_indexedtypes ie - = let bad_ie = Failed (badImportItemErr iface decl_spec ie) - - lookup_name rdrName = - case lookupOccEnv occ_env (rdrNameOcc rdrName) of - Nothing -> bad_ie - Just n -> return n + lookup_ie opt_typeFamilies ie + = let bad_ie :: MaybeErr Message a + bad_ie = Failed (badImportItemErr iface decl_spec ie all_avails) + + 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 @@ -472,16 +621,16 @@ filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails IEThingAll tc -> do (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc case mb_parent of - -- non-associated ty/cls - Nothing -> return [(IEThingAll name, avail)] - -- associated ty - Just parent -> return [(IEThingAll name, - AvailTC name2 (subs \\ [name])), - (IEThingAll name, AvailTC parent [name])] + -- non-associated ty/cls + Nothing -> return [(IEThingAll name, avail)] + -- associated ty + Just parent -> return [(IEThingAll name, + AvailTC name2 (subs \\ [name])), + (IEThingAll name, AvailTC parent [name])] IEThingAbs tc | want_hiding -- hiding ( C ) - -- Here the 'C' can be a data constructor + -- Here the 'C' can be a data constructor -- *or* a type/class, or even both -> let tc_name = lookup_name tc dc_name = lookup_name (setRdrNameSpace tc srcDataName) @@ -494,34 +643,34 @@ 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 - let - env = mkOccEnv [(nameOccName s, s) | s <- subnames] - mb_children = map (lookupOccEnv env . rdrNameOcc) ns - children <- if any isNothing mb_children + (name, AvailTC _ subnames, mb_parent) <- lookup_name tc + let + env = mkOccEnv [(nameOccName s, s) | s <- subnames] + mb_children = map (lookupOccEnv env . rdrNameOcc) ns + children <- if any isNothing mb_children then bad_ie else return (catMaybes mb_children) - -- check for proper import of indexed types - when (not opt_indexedtypes && any isTyConName children) $ + -- check for proper import of type families + when (not opt_typeFamilies && any isTyConName children) $ Failed (typeItemErr (head . filter isTyConName $ children) - (text "in import list")) + (text "in import list")) case mb_parent of - -- non-associated ty/cls - Nothing -> return [(IEThingWith name children, - AvailTC name (name:children))] - -- associated ty - Just parent -> return [(IEThingWith name children, - AvailTC name children), - (IEThingWith name children, - AvailTC parent [name])] + -- non-associated ty/cls + Nothing -> return [(IEThingWith name children, + AvailTC name (name:children))] + -- associated ty + Just parent -> return [(IEThingWith name children, + AvailTC name children), + (IEThingWith name children, + AvailTC parent [name])] _other -> Failed illegalImportItemErr -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed -- all errors. where - mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n) - mkIEThingAbs (n, av, Just parent) = (IEThingAbs n, AvailTC parent [n]) + mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n) + mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n]) catMaybeErr :: [MaybeErr err a] -> [a] @@ -529,9 +678,9 @@ catMaybeErr ms = [ a | Succeeded a <- ms ] \end{code} %************************************************************************ -%* * - Import/Export Utils -%* * +%* * +\subsection{Import/Export Utils} +%* * %************************************************************************ \begin{code} @@ -544,30 +693,31 @@ gresFromAvails 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} + = [ 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 (ParentIs p) = AvailTC p [me] mkUnitAvail me NoParent | isTyConName me = AvailTC me [me] - | otherwise = Avail 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 @@ -584,42 +734,43 @@ 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 } - item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc } + 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 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` [] \end{code} --------------------------------------- - AvailEnv and friends + AvailEnv and friends All this AvailEnv stuff is hardly used; only in a very small part of RnNames. Todo: remove? --------------------------------------- \begin{code} -type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it +type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it emptyAvailEnv :: AvailEnv emptyAvailEnv = emptyNameEnv +{- Dead code unitAvailEnv :: AvailInfo -> AvailEnv unitAvailEnv a = unitNameEnv (availName a) a @@ -628,15 +779,16 @@ plusAvailEnv = plusNameEnv_C plusAvail availEnvElts :: AvailEnv -> [AvailInfo] availEnvElts = nameEnvElts +-} addAvail :: AvailEnv -> AvailInfo -> AvailEnv addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail mkAvailEnv :: [AvailInfo] -> AvailEnv - -- 'avails' may have several items with the same availName - -- E.g import Ix( Ix(..), index ) - -- will give Ix(Ix,index,range) and Ix(index) - -- We want to combine these; addAvail does that +-- 'avails' may have several items with the same availName +-- E.g import Ix( Ix(..), index ) +-- will give Ix(Ix,index,range) and Ix(index) +-- We want to combine these; addAvail does that mkAvailEnv avails = foldl addAvail emptyAvailEnv avails -- After combining the avails, we need to ensure that the parent name is the @@ -655,9 +807,9 @@ nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails %************************************************************************ -%* * +%* * \subsection{Export list processing} -%* * +%* * %************************************************************************ Processing the export list. @@ -673,56 +825,59 @@ it re-exports @GHC@, which includes @takeMVar#@, whose type includes @ConcBase.StateAndSynchVar#@, and so on... \begin{code} -type ExportAccum -- The type of the accumulating parameter of - -- the main worker function in rnExports +type ExportAccum -- The type of the accumulating parameter of + -- the main worker function in rnExports = ([LIE Name], -- Export items with Names - ExportOccMap, -- Tracks exported occurrence names - [AvailInfo]) -- The accumulated exported stuff - -- Not nub'd! + ExportOccMap, -- Tracks exported occurrence names + [AvailInfo]) -- The accumulated exported stuff + -- Not nub'd! -emptyExportAccum = ([], emptyOccEnv, []) +emptyExportAccum :: ExportAccum +emptyExportAccum = ([], emptyOccEnv, []) type ExportOccMap = OccEnv (Name, IE RdrName) - -- Tracks what a particular exported OccName - -- in an export list refers to, and which item - -- it came from. It's illegal to export two distinct things - -- that have the same occurrence name + -- Tracks what a particular exported OccName + -- in an export list refers to, and which item + -- it came from. It's illegal to export two distinct things + -- that have the same occurrence name -rnExports :: Bool -- False => no 'module M(..) where' header at all +rnExports :: Bool -- False => no 'module M(..) where' header at all -> Maybe [LIE RdrName] -- Nothing => no explicit export list - -> RnM (Maybe [LIE Name], [AvailInfo]) + -> TcGblEnv + -> RnM TcGblEnv - -- Complains if two distinct exports have same OccName + -- Complains if two distinct exports have same OccName -- Warns about identical exports. - -- Complains about exports items not in scope + -- Complains about exports items not in scope rnExports explicit_mod exports - = do TcGblEnv { tcg_mod = this_mod, - tcg_rdr_env = rdr_env, - tcg_imports = imports } <- getGblEnv - - -- If the module header is omitted altogether, then behave - -- as if the user had written "module Main(main) where..." - -- EXCEPT in interactive mode, when we behave as if he had - -- written "module Main where ..." - -- Reason: don't want to complain about 'main' not in scope - -- in interactive mode - ghc_mode <- getGhcMode - real_exports <- - case () of - () | explicit_mod - -> return exports - | ghc_mode == Interactive - -> return Nothing - | otherwise - -> do mainName <- lookupGlobalOccRn main_RDR_Unqual - return (Just ([noLoc (IEVar main_RDR_Unqual)])) - -- ToDo: the 'noLoc' here is unhelpful if 'main' turns - -- out to be out of scope - - (exp_spec, avails) <- exports_from_avail real_exports rdr_env imports this_mod - - return (exp_spec, nubAvails avails) -- Combine families + tcg_env@(TcGblEnv { tcg_mod = this_mod, + tcg_rdr_env = rdr_env, + tcg_imports = imports }) + = do { + -- If the module header is omitted altogether, then behave + -- as if the user had written "module Main(main) where..." + -- EXCEPT in interactive mode, when we behave as if he had + -- written "module Main where ..." + -- Reason: don't want to complain about 'main' not in scope + -- in interactive mode + ; dflags <- getDOpts + ; let real_exports + | explicit_mod = exports + | ghcLink dflags == LinkInMemory = Nothing + | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)]) + -- ToDo: the 'noLoc' here is unhelpful if 'main' + -- turns out to be out of scope + + ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod + ; let final_avails = nubAvails avails -- Combine families + + ; return (tcg_env { tcg_exports = final_avails, + tcg_rn_exports = case tcg_rn_exports tcg_env of + Nothing -> Nothing + Just _ -> rn_exports, + tcg_dus = tcg_dus tcg_env `plusDU` + usesOnly (availsToNameSet final_avails) }) } exports_from_avail :: Maybe [LIE RdrName] -- Nothing => no explicit export list @@ -731,7 +886,7 @@ 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 @@ -748,44 +903,59 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie) - kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children + kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children 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) + exports_from_item acc@(ie_names, occs, exports) (L loc ie@(IEModuleContents mod)) - | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ] - , mod `elem` earlier_mods -- Duplicate export of M - = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ; - warnIf warn_dup_exports (dupModuleExport mod) ; - returnM acc } + | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ] + , mod `elem` earlier_mods -- Duplicate export of M + = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ; + warnIf warn_dup_exports (dupModuleExport mod) ; + return acc } + + | otherwise + = do { implicit_prelude <- xoptM 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 + } - | otherwise - = do { implicit_prelude <- doptM Opt_ImplicitPrelude - ; let gres = filter (isModuleExported implicit_prelude mod) - (globalRdrEnvElts rdr_env) + ; checkErr exportValid (moduleNotImported mod) + ; warnIf (warnDodgyExports && exportValid && null gres) (nullModuleExport mod) - ; warnIf (null gres) (nullModuleExport mod) + ; addUsedRdrNames (concat [ [mkRdrQual mod occ, mkRdrUnqual occ] + | occ <- map nameOccName names ]) + -- The qualified and unqualified version of all of + -- these names are, in effect, used by this export - ; occs' <- check_occs ie occs (map gre_name gres) + ; occs' <- check_occs ie occs names -- This check_occs not only finds conflicts -- between this item and others, but also -- internally within this item. That is, if -- 'M.x' is in scope in several ways, we'll have -- several members of mod_avails with the same -- OccName. - ; return (L loc (IEModuleContents mod) : ie_names, + ; 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) + | isDoc ie + = do new_ie <- lookup_doc_ie ie + return (L loc new_ie : lie_names, occs, exports) - | otherwise + | otherwise = do (new_ie, avail) <- lookup_ie ie if isUnboundName (ieName new_ie) - then return acc -- Avoid error cascade + then return acc -- Avoid error cascade else do occs' <- check_occs ie occs (availNames avail) @@ -794,28 +964,34 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod ------------- lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo) - lookup_ie (IEVar rdr) + lookup_ie (IEVar rdr) = do gre <- lookupGreRn rdr return (IEVar (gre_name gre), greAvail gre) - lookup_ie (IEThingAbs rdr) + 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) + let name = gre_name gre + case gre_par gre of + NoParent -> return (IEThingAbs name, + AvailTC name [name]) + ParentIs p -> return (IEThingAbs name, + AvailTC p [name]) + + lookup_ie ie@(IEThingAll rdr) = do name <- lookupGlobalOccRn rdr - let kids = findChildren kids_env name - when (null kids) - (if (isTyConName name) then addWarn (dodgyExportWarn name) - -- This occurs when you export T(..), but - -- only import T abstractly, or T is a synonym. - else addErr (exportItemErr ie)) - + 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 -- 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) @@ -823,33 +999,34 @@ exports_from_avail (Just rdr_items) rdr_env imports this_mod if isUnboundName name then return (IEThingWith name [], AvailTC name [name]) else do - let env = mkOccEnv [ (nameOccName s, s) + 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 - optIdxTypes <- doptM Opt_IndexedTypes - when (not optIdxTypes && any isTyConName names) $ + optTyFam <- xoptM Opt_TypeFamilies + when (not optTyFam && any isTyConName names) $ addErr (typeItemErr ( head - . filter isTyConName + . filter isTyConName $ names ) (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) lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc - return (IEGroup lev rn_doc) + return (IEGroup lev rn_doc) lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc - return (IEDoc rn_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 @@ -860,19 +1037,21 @@ isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool -- True if the thing is in scope *both* unqualified, *and* with qualifier M isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov }) | implicit_prelude && isBuiltInSyntax name = False - -- Optimisation: filter out names for built-in syntax - -- They just clutter up the environment (esp tuples), and the parser - -- will generate Exact RdrNames for them, so the cluttered - -- envt is no use. To avoid doing this filter all the time, - -- we use -fno-implicit-prelude as a clue that the filter is - -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple. - -- - -- It's worth doing because it makes the environment smaller for - -- every module that imports the Prelude + -- Optimisation: filter out names for built-in syntax + -- They just clutter up the environment (esp tuples), and the parser + -- will generate Exact RdrNames for them, so the cluttered + -- envt is no use. To avoid doing this filter all the time, + -- we use -XNoImplicitPrelude as a clue that the filter is + -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple. + -- + -- It's worth doing because it makes the environment smaller for + -- every module that imports the Prelude | otherwise = case prov of - LocalDef -> moduleName (nameModule name) == mod - Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is + 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 @@ -881,432 +1060,563 @@ check_occs ie occs names where check occs name = case lookupOccEnv occs name_occ of - Nothing -> returnM (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 } - - | otherwise -- Same occ name but different names: an error - -> do { global_env <- getGlobalRdrEnv ; - addErr (exportClashErr global_env name' name ie' ie) ; - returnM occs } + Nothing -> return (extendOccEnv occs name_occ (name, ie)) + + Just (name', ie') + | name == name' -- Duplicate export + -- But we don't want to warn if the same thing is exported + -- by two different module exports. See ticket #4478. + -> do unless (diffModules ie ie') $ do + warn_dup_exports <- doptM Opt_WarnDuplicateExports + warnIf warn_dup_exports (dupExportWarn name_occ ie ie') + return occs + + | otherwise -- Same occ name but different names: an error + -> do { global_env <- getGlobalRdrEnv ; + addErr (exportClashErr global_env name' name ie' ie) ; + return occs } where - name_occ = nameOccName name + name_occ = nameOccName name + -- True if the two IE RdrName are different module exports. + diffModules (IEModuleContents n1) (IEModuleContents n2) = n1 /= n2 + diffModules _ _ = False \end{code} %********************************************************* -%* * - Deprecations -%* * +%* * +\subsection{Deprecations} +%* * %********************************************************* \begin{code} -reportDeprecations :: DynFlags -> TcGblEnv -> RnM () -reportDeprecations dflags tcg_env - = ifOptM Opt_WarnDeprecations $ - do { (eps,hpt) <- getEpsAndHpt - -- By this time, typechecking is complete, - -- so the PIT is fully populated - ; mapM_ (check hpt (eps_PIT eps)) all_gres } +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 + ; ifDOptM 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 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 + used_names = allUses (tcg_dus tcg_env) + -- Report on all deprecated uses; hence allUses all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env) check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)}) | name `elemNameSet` used_names - , Just deprec_txt <- lookupDeprec dflags hpt pit gre + , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre = addWarnAt (importSpecLoc imp_spec) - (sep [ptext SLIT("Deprecated use of") <+> - pprNonVarNameSpace (occNameSpace (nameOccName name)) <+> - quotes (ppr name), - (parens imp_msg) <> colon, - (ppr deprec_txt) ]) - where - name_mod = 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 hpt pit ok_gre = returnM () -- 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 - -- deprecated things. We may even use a deprecated thing in - -- the defn of a non-deprecated thing, when changing a module's - -- interface - -lookupDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable - -> GlobalRdrElt -> Maybe DeprecTxt -lookupDeprec dflags hpt pit gre - = case lookupIfaceByModule dflags hpt pit (nameModule name) of - Just iface -> mi_dep_fn iface name `seqMaybe` -- Bleat if the thing, *or - case gre_par gre of - ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd - NoParent -> Nothing - Nothing - | isWiredInName name -> Nothing - -- We have not necessarily loaded the .hi file for a - -- wired-in name (yet), although we *could*. - -- And we never deprecate them - - | otherwise -> pprPanic "lookupDeprec" (ppr name) - -- By now all the interfaces should have been loaded + (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 () -- 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 + -- deprecated things. We may even use a deprecated thing in + -- the defn of a non-deprecated thing, when changing a module's + -- interface + +lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable + -> GlobalRdrElt -> Maybe WarningTxt +-- The name is definitely imported, so look in HPT, PIT +lookupImpDeprec dflags hpt pit gre + = case lookupIfaceByModule dflags hpt pit mod of + Just iface -> mi_warn_fn iface name `mplus` -- Bleat if the thing, *or + case gre_par gre of + ParentIs p -> mi_warn_fn iface p -- its parent*, is warn'd + NoParent -> Nothing + + Nothing -> Nothing -- See Note [Used names with interface not loaded] where - name = gre_name gre + 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 -XRebindableSyntax) + is on), but the typechecker may discard their uses + if in fact the in-scope fromRational is GHC.Read.fromRational, + (see tcPat.tcOverloadedLit), and the typechecker sees that the type + is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst). + In that obscure case it won't force the interface in. + +In both cases we simply don't permit deprecations; +this is, after all, wired-in stuff. + + %********************************************************* -%* * - Unused names -%* * +%* * +\subsection{Unused names} +%* * %********************************************************* \begin{code} -reportUnusedNames :: Maybe [LIE RdrName] -- Export list - -> TcGblEnv -> RnM () -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 } +reportUnusedNames :: Maybe [LIE RdrName] -- Export list + -> 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 - -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used - -- Hence findUses + -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used + -- Hence findUses - -- Collect the defined names from the in-scope environment + -- Collect the defined names from the in-scope environment defined_names :: [GlobalRdrElt] defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env) - -- Note that defined_and_used, defined_but_not_used - -- are both [GRE]; that's why we need defined_and_used - -- rather than just used_names - defined_and_used, defined_but_not_used :: [GlobalRdrElt] - (defined_and_used, defined_but_not_used) - = partition (gre_is_used used_names) defined_names - + -- 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) + = partition (gre_is_used used_names) defined_names + kids_env = mkChildEnv defined_names - -- This is done in mkExports too; duplicated work + -- This is done in mkExports too; duplicated work gre_is_used :: NameSet -> GlobalRdrElt -> Bool gre_is_used used_names (GRE {gre_name = name}) - = name `elemNameSet` used_names - || any (`elemNameSet` used_names) (findChildren kids_env name) - -- A use of C implies a use of T, - -- if C was brought into scope by T(..) or T(C) - - -- Filter out the ones that are - -- (a) defined in this module, and - -- (b) not defined by a 'deriving' clause - -- The latter have an Internal Name, so we can filter them out easily + = name `elemNameSet` used_names + || any (`elemNameSet` used_names) (findChildren kids_env name) + -- A use of C implies a use of T, + -- if C was brought into scope by T(..) or T(C) + + -- Filter out the ones that are + -- (a) defined in this module, and + -- (b) not defined by a 'deriving' clause + -- The latter have an Internal Name, so we can filter them out easily 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) - - unused_imports :: [GlobalRdrElt] - unused_imports = filter unused_imp defined_but_not_used - unused_imp (GRE {gre_prov = Imported imp_specs}) - = not (all (module_unused . importSpecModule) imp_specs) - && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs] - -- Don't complain about unused imports if we've already said the - -- entire import is unused - unused_imp other = False - - -- To figure out the minimal set of imports, start with the things - -- that are in scope (i.e. in gbl_env). Then just combine them - -- into a bunch of avails, so they are properly grouped - -- - -- BUG WARNING: this does not deal properly with qualified imports! - minimal_imports :: FiniteMap ModuleName AvailEnv - minimal_imports0 = foldr add_expall emptyFM expall_mods - minimal_imports1 = foldr add_name minimal_imports0 defined_and_used - minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods - -- The last line makes sure that we retain all direct imports - -- even if we import nothing explicitly. - -- It's not necessarily redundant to import such modules. Consider - -- module This - -- import M () - -- - -- The import M() is not *necessarily* redundant, even if - -- we suck in no instance decls from M (e.g. it contains - -- no instance decls, or This contains no code). It may be - -- that we import M solely to ensure that M's orphan instance - -- decls (or those in its imports) are visible to people who - -- import This. Sigh. - -- There's really no good way to detect this, so the error message - -- in RnEnv.warnUnusedModules is weakened instead - - -- We've carefully preserved the provenance so that we can - -- construct minimal imports that import the name by (one of) - -- the same route(s) as the programmer originally did. - add_name gre@(GRE {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 - - add_inst_mod (mod,_,_) acc - | mod_name `elemFM` acc = acc -- We import something already - | otherwise = addToFM acc mod_name emptyAvailEnv - where - mod_name = moduleName mod - -- Add an empty collection of imports for a module - -- from which we have sucked only instance decls - - imports = tcg_imports gbl_env - - direct_import_mods :: [(Module, Bool, SrcSpan)] - -- See the type of the imp_mods for this triple - direct_import_mods = moduleEnvElts (imp_mods imports) - - -- unused_imp_mods are the directly-imported modules - -- that are not mentioned in minimal_imports1 - -- [Note: not 'minimal_imports', because that includes directly-imported - -- modules even if we use nothing from them; see notes above] - -- - -- BUG WARNING: does not deal correctly with multiple imports of the same module - -- becuase direct_import_mods has only one entry per module - unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods, - let mod_name = moduleName mod, - not (mod_name `elemFM` minimal_imports1), - mod /= pRELUDE, - not no_imp] - -- The not no_imp part is not to complain about - -- import M (), which is an idiom for importing - -- instance declarations - - module_unused :: ModuleName -> Bool - module_unused mod = any (((==) mod) . fst) unused_imp_mods - ---------------------- -warnDuplicateImports :: [GlobalRdrElt] -> RnM () --- Given the GREs for names that are used, figure out which imports --- could be omitted without changing the top-level environment. +\end{code} + +%********************************************************* +%* * +\subsection{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) + + ; ifDOptM Opt_WarnUnusedImports $ + mapM_ warnUnusedImport usage + + ; ifDOptM Opt_D_dump_minimal_imports $ + printMinimalImports usage } + where + explicit_import (L loc _) = case loc of + UnhelpfulSpan _ -> False + RealSrcSpan _ -> True + -- 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 = Map 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. -- --- 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. +-- The SrcLoc is the location of the start +-- of a particular 'import' declaration -- --- Furthermore, we complain about Foo.T only if --- there is no complaint about (unqualified) T - -warnDuplicateImports gres - = ifOptM Opt_WarnUnusedImports $ - sequenceM_ [ warn name pr - -- The 'head' picks the first offending group - -- for this particular name - | GRE { gre_name = name, gre_prov = Imported imps } <- gres - , pr <- redundants imps ] +-- 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 (addUsedRdrName rdr_env) Map.empty rdrs + + unused_decl decl@(L loc (ImportDecl { ideclHiding = imps })) + = (decl, nubAvails used_avails, unused_imps) + where + used_avails = Map.lookup (srcSpanStart loc) import_usage `orElse` [] + dont_report_as_unused = foldr add emptyNameSet used_avails + add (Avail n) s = s `addOneToNameSet` n + add (AvailTC n ns) s = s `addListToNameSet` (n:ns) + -- If you use 'signum' from Num, then the user may well have + -- imported Num(signum). We don't want to complain that + -- Num is not itself mentioned. Hence adding 'n' as + -- well to the list of of "don't report if unused" names + + 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` dont_report_as_unused + + _other -> [] -- No explicit import list => no unused-name list + +addUsedRdrName :: GlobalRdrEnv -> RdrName -> ImportMap -> ImportMap +-- For a used RdrName, find all the import decls that brought +-- it into scope; choose one of them (bestImport), and record +-- the RdrName in that import decl's entry in the ImportMap +addUsedRdrName rdr_env rdr imp_map + | [gre] <- lookupGRE_RdrName rdr rdr_env + , Imported imps <- gre_prov gre + = add_imp gre (bestImport imps) imp_map + | otherwise + = imp_map + where + add_imp :: GlobalRdrElt -> ImportSpec -> ImportMap -> ImportMap + add_imp gre (ImpSpec { is_decl = imp_decl_spec }) imp_map + = Map.insertWith add decl_loc [avail] imp_map + where + add _ avails = avail : avails -- add is really just a specialised (++) + decl_loc = srcSpanStart (is_dloc imp_decl_spec) + name = gre_name gre + avail = case gre_par gre of + ParentIs p -> AvailTC 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 () -- Do not warn for 'import M()' + | null used = addWarnAt loc msg1 -- Nothing used; drop entire decl + | null unused = return () -- Everything imported is used; nop + | otherwise = addWarnAt loc msg2 -- Some imports are unused where - warn name (red_imp, cov_imp) - = addWarnAt (importSpecLoc red_imp) - (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name, - ptext SLIT("It is also") <+> ppr cov_imp]) - where - pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ - | otherwise = ppr occ - occ = nameOccName name - red_decl = is_decl red_imp - - redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)] - -- The returned pair is (redundant-import, covering-import) - redundants imps - = [ (red_imp, cov_imp) - | red_imp <- imps - , cov_imp <- take 1 (filter (covers red_imp) imps) ] - - -- "red_imp" is a putative redundant import - -- "cov_imp" potentially covers it - -- This test decides whether red_imp could be dropped - -- - -- NOTE: currently the test does not warn about - -- import M( x ) - -- imoprt N( x ) - -- even if the same underlying 'x' is involved, because dropping - -- either import would change the qualified names in scope (M.x, N.x) - -- But if the qualified names aren't used, the import is indeed redundant - -- Sadly we don't know that. Oh well. - covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item }) - cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item }) - | red_loc == cov_loc - = False -- Ignore diagonal elements - | not (is_as red_decl == is_as cov_decl) - = False -- They bring into scope different qualified names - | not (is_qual red_decl) && is_qual cov_decl - = False -- Covering one doesn't bring unqualified name into scope - | red_selective - = not cov_selective -- Redundant one is selective and covering one isn't - || red_later -- Both are explicit; tie-break using red_later - | otherwise - = not cov_selective -- Neither import is selective - && (is_mod red_decl == is_mod cov_decl) -- They import the same module - && red_later -- Tie-break - where - red_loc = importSpecLoc red_imp - cov_loc = importSpecLoc cov_imp - red_later = red_loc > cov_loc - cov_selective = selectiveImpItem cov_item - red_selective = selectiveImpItem red_item - -selectiveImpItem :: ImpItemSpec -> Bool -selectiveImpItem ImpAll = False -selectiveImpItem (ImpSome {}) = True - --- ToDo: deal with original imports with 'qualified' and 'as M' clauses -printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports - -> RnM () -printMinimalImports imps - = ifOptM Opt_D_dump_minimal_imports $ do { - - mod_ies <- mappM to_ies (fmToList imps) ; - this_mod <- getModule ; - rdr_env <- getGlobalRdrEnv ; - ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ; - printForUser h (mkPrintUnqualified rdr_env) - (vcat (map ppr_mod_ie mod_ies)) }) - } + msg1 = vcat [pp_herald <+> quotes pp_mod <+> pp_not_used, + nest 2 (ptext (sLit "except perhaps to import instances from") + <+> quotes pp_mod), + ptext (sLit "To import instances alone, use:") + <+> ptext (sLit "import") <+> pp_mod <> parens empty ] + msg2 = sep [pp_herald <+> quotes (pprWithCommas ppr unused), + text "from module" <+> quotes pp_mod <+> pp_not_used] + pp_herald = text "The import of" + pp_mod = ppr (unLoc (ideclName decl)) + pp_not_used = text "is redundant" +\end{code} + +To print the minimal imports we walk over the user-supplied import +decls, and simply trim their import lists. NB that + + * We do *not* change the 'qualified' or 'as' parts! + + * We do not disard a decl altogether; we might need instances + from it. Instead we just trim to an empty import list + +\begin{code} +printMinimalImports :: [ImportDeclUsage] -> RnM () +printMinimalImports imports_w_usage + = do { imports' <- mapM mk_minimal imports_w_usage + ; this_mod <- getModule + ; liftIO $ + do { h <- openFile (mkFilename this_mod) WriteMode + ; printForUser h neverQualify (vcat (map ppr imports')) } + -- The neverQualify is important. We are printing Names + -- but they are in the context of an 'import' decl, and + -- we never qualify things inside there + -- E.g. import Blag( f, b ) + -- not import Blag( Blag.f, Blag.g )! + } where mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports" - ppr_mod_ie (mod_name, ies) - | mod_name == moduleName pRELUDE - = empty - | null ies -- Nothing except instances comes from here - = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only") - | otherwise - = ptext SLIT("import") <+> ppr mod_name <> - parens (fsep (punctuate comma (map ppr ies))) - - to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env) - returnM (mod, ies) - - to_ie :: AvailInfo -> RnM (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 (AvailTC n [m]) = ASSERT( n==m ) - returnM (IEThingAbs n) - to_ie (AvailTC n ns) - = loadSrcInterface doc n_mod False `thenM` \ iface -> - case [xs | (m,as) <- mi_exports iface, - moduleName 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)) - other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $ - returnM (IEVar n) - where - all_used avail_occs = all (`elem` map nameOccName ns) avail_occs - doc = text "Compute minimal imports from" <+> ppr n - n_mod = moduleName (nameModule n) + + mk_minimal (L l decl, used, unused) + | null unused + , Just (False, _) <- ideclHiding decl + = return (L l decl) + | otherwise + = do { let ImportDecl { ideclName = L _ mod_name + , ideclSource = is_boot + , ideclPkgQual = mb_pkg } = decl + ; iface <- loadSrcInterface doc mod_name is_boot mb_pkg + ; let lies = map (L l) (concatMap (to_ie iface) used) + ; return (L l (decl { ideclHiding = Just (False, lies) })) } + where + doc = text "Compute minimal imports for" <+> ppr decl + + to_ie :: ModIface -> AvailInfo -> [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) + = [IEVar n] + to_ie _ (AvailTC n [m]) + | n==m = [IEThingAbs n] + to_ie iface (AvailTC n ns) + = case [xs | (m,as) <- mi_exports iface + , m == n_mod + , AvailTC x xs <- as + , x == nameOccName n + , x `elem` xs -- Note [Partial export] + ] of + [xs] | all_used xs -> [IEThingAll n] + | otherwise -> [IEThingWith n (filter (/= n) ns)] + _other -> (map IEVar ns) + where + all_used avail_occs = all (`elem` map nameOccName ns) avail_occs + n_mod = ASSERT( isExternalName n ) nameModule n \end{code} +Note [Partial export] +~~~~~~~~~~~~~~~~~~~~~ +Suppose we have + + module A( op ) where + class C a where + op :: a -> a + + module B where + import A + f = ..op... + +Then the minimal import for module B is + import A( op ) +not + import A( C( op ) ) +which we would usually generate if C was exported from B. Hence +the (x `elem` xs) test when deciding what to generate. + %************************************************************************ -%* * +%* * \subsection{Errors} -%* * +%* * %************************************************************************ \begin{code} -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)] +qualImportItemErr :: RdrName -> SDoc +qualImportItemErr rdr + = hang (ptext (sLit "Illegal qualified name in import item:")) + 2 (ppr rdr) + +badImportItemErrStd :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc +badImportItemErrStd 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 = ptext SLIT("Illegal import item") - -dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item -dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item - + source_import | mi_boot iface = ptext (sLit "(hi-boot interface)") + | otherwise = empty + +badImportItemErrDataCon :: OccName -> ModIface -> ImpDeclSpec -> IE RdrName -> SDoc +badImportItemErrDataCon dataType iface decl_spec ie + = vcat [ ptext (sLit "In module") + <+> quotes (ppr (is_mod decl_spec)) + <+> source_import <> colon + , nest 2 $ quotes datacon + <+> ptext (sLit "is a data constructor of") + <+> quotes (ppr dataType) + , ptext (sLit "To import it use") + , nest 2 $ quotes (ptext (sLit "import") + <+> ppr (is_mod decl_spec) + <+> parens (ppr dataType <+> parens datacon)) + , ptext (sLit "or") + , nest 2 $ quotes (ptext (sLit "import") + <+> ppr (is_mod decl_spec) + <+> parens (ppr dataType <+> parens (ptext $ sLit ".."))) + ] + where + datacon = ppr . rdrNameOcc $ ieName ie + source_import | mi_boot iface = ptext (sLit "(hi-boot interface)") + | otherwise = empty + +badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> [AvailInfo] -> SDoc +badImportItemErr iface decl_spec ie avails + = case find checkIfDataCon avails of + Just con -> badImportItemErrDataCon (availOccName con) iface decl_spec ie + Nothing -> badImportItemErrStd iface decl_spec ie + where + checkIfDataCon (AvailTC _ ns) = + case find (\n -> importedFS == nameOccNameFS n) ns of + Just n -> isDataConName n + Nothing -> False + checkIfDataCon _ = False + availOccName = nameOccName . availName + nameOccNameFS = occNameFS . nameOccName + importedFS = occNameFS . rdrNameOcc $ ieName ie + +illegalImportItemErr :: SDoc +illegalImportItemErr = ptext (sLit "Illegal import item") + +dodgyImportWarn :: RdrName -> SDoc +dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item +dodgyExportWarn :: Name -> SDoc +dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item + +dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc dodgyMsg kind tc - = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)), - ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"), - ptext SLIT("but it has none; it is a type synonym or abstract type or class") ] - + = 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 -findexed-types 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 - , ppr_export ie1 name1 - , ppr_export ie2 name2 ] + = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon + , ppr_export ie1' name1' + , ppr_export ie2' name2' ] where occ = nameOccName name1 - ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+> - quotes (ppr name) <+> pprNameProvenance (get_gre name)) + 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 + -- get_gre finds a GRE for the Name, so that we can show its provenance get_gre name - = case lookupGRE_Name global_env name of - (gre:_) -> gre - [] -> pprPanic "exportClashErr" (ppr name) - -addDupDeclErr :: Name -> Name -> TcRn () -addDupDeclErr name_a name_b - = addErrAt (srcLocSpan loc2) $ - vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1), - ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]] + = case lookupGRE_Name global_env name of + (gre:_) -> gre + [] -> pprPanic "exportClashErr" (ppr name) + get_loc name = greSrcSpan (get_gre name) + (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2 + then (name1, ie1, name2, ie2) + else (name2, ie2, name1, ie1) + +-- the SrcSpan that pprNameProvenance prints out depends on whether +-- the Name is defined locally or not: for a local definition the +-- definition site is used, otherwise the location of the import +-- declaration. We want to sort the export locations in +-- exportClashErr by this SrcSpan, we need to extract it: +greSrcSpan :: GlobalRdrElt -> SrcSpan +greSrcSpan gre + | Imported (is:_) <- gre_prov gre = is_dloc (is_decl is) + | otherwise = name_span where - loc2 = nameSrcLoc name2 - (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a) - | otherwise = (name_a,name_b) - -- Report the error at the later location + name_span = nameSrcSpan (gre_name gre) + +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)] + = 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")] + = hsep [ptext (sLit "Duplicate"), + quotes (ptext (sLit "Module") <+> ppr mod), + ptext (sLit "in export list")] -nullModuleExport mod - = ptext SLIT("The export item `module") <+> ppr mod <> ptext SLIT("' exports nothing") +moduleNotImported :: ModuleName -> SDoc +moduleNotImported mod + = ptext (sLit "The export item `module") <+> ppr mod <> + ptext (sLit "' is not imported") -moduleDeprec mod txt - = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"), - nest 4 (ppr txt) ] +nullModuleExport :: ModuleName -> SDoc +nullModuleExport mod + = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing") + +missingImportListWarn :: ModuleName -> SDoc +missingImportListWarn mod + = ptext (sLit "The module") <+> quotes (ppr mod) <+> ptext (sLit "does not have an explicit import list") + +missingImportListItem :: IE RdrName -> SDoc +missingImportListItem ie + = ptext (sLit "The import item") <+> quotes (ppr ie) <+> ptext (sLit "does not have an explicit import list") + +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}