+reportUnusedNames :: ModuleName -> [ModuleName]
+ -> GlobalRdrEnv -> AvailEnv
+ -> Avails -> NameSet -> [RenamedHsDecl]
+ -> RnMG ()
+reportUnusedNames mod_name direct_import_mods
+ gbl_env avail_env
+ export_avails mentioned_names
+ imported_decls
+ = warnUnusedModules unused_imp_mods `thenRn_`
+ warnUnusedLocalBinds bad_locals `thenRn_`
+ warnUnusedImports bad_imp_names `thenRn_`
+ printMinimalImports mod_name minimal_imports `thenRn_`
+ warnDeprecations really_used_names `thenRn_`
+ returnRn ()
+
+ where
+ used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
+
+ -- Now, a use of C implies a use of T,
+ -- if C was brought into scope by T(..) or T(C)
+ really_used_names = used_names `unionNameSets`
+ mkNameSet [ parent_name
+ | sub_name <- nameSetToList used_names
+
+ -- Usually, every used name will appear in avail_env, but there
+ -- is one time when it doesn't: tuples and other built in syntax. When you
+ -- write (a,b) that gives rise to a *use* of "(,)", so that the
+ -- instances will get pulled in, but the tycon "(,)" isn't actually
+ -- in scope. Also, (-x) gives rise to an implicit use of 'negate';
+ -- similarly, 3.5 gives rise to an implcit use of :%
+ -- Hence the silent 'False' in all other cases
+
+ , Just parent_name <- [case lookupNameEnv avail_env sub_name of
+ Just (AvailTC n _) -> Just n
+ other -> Nothing]
+ ]
+
+ defined_names, defined_and_used, defined_but_not_used :: [(Name,Provenance)]
+ defined_names = concat (rdrEnvElts gbl_env)
+ (defined_and_used, defined_but_not_used) = partition used defined_names
+ used (name,_) = not (name `elemNameSet` really_used_names)
+
+ -- Filter out the ones only defined implicitly
+ bad_locals :: [Name]
+ bad_locals = [n | (n,LocalDef) <- defined_but_not_used]
+
+ bad_imp_names :: [(Name,Provenance)]
+ bad_imp_names = [(n,p) | (n,p@(NonLocalDef (UserImport mod _ True) _)) <- defined_but_not_used,
+ not (module_unused mod)]
+
+ -- inst_mods are directly-imported modules that
+ -- contain instance decl(s) that the renamer decided to suck in
+ -- It's not necessarily redundant to import such modules.
+ --
+ -- NOTE: 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
+ inst_mods :: [ModuleName]
+ inst_mods = [m | InstD (InstDecl _ _ _ (Just dfun) _) <- imported_decls,
+ let m = moduleName (nameModule dfun),
+ m `elem` direct_import_mods
+ ]
+
+ -- 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
+ minimal_imports :: FiniteMap ModuleName AvailEnv
+ minimal_imports0 = emptyFM
+ minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
+ minimal_imports = foldr add_inst_mod minimal_imports1 inst_mods
+
+ add_name (n,NonLocalDef (UserImport m _ _) _) acc = addToFM_C plusAvailEnv acc (moduleName (nameModule n))
+ (unitAvailEnv (mk_avail n))
+ add_name (n,other_prov) acc = acc
+
+ mk_avail n = case lookupNameEnv avail_env n of
+ Just (AvailTC m _) | n==m -> AvailTC n [n]
+ | otherwise -> AvailTC m [n,m]
+ Just avail -> Avail n
+ Nothing -> pprPanic "mk_avail" (ppr n)
+
+ add_inst_mod m acc
+ | m `elemFM` acc = acc -- We import something already
+ | otherwise = addToFM acc m emptyAvailEnv
+ -- Add an empty collection of imports for a module
+ -- from which we have sucked only instance decls
+
+ -- unused_imp_mods are the directly-imported modules
+ -- that are not mentioned in minimal_imports
+ unused_imp_mods = [m | m <- direct_import_mods,
+ not (maybeToBool (lookupFM minimal_imports m)),
+ m /= pRELUDE_Name]
+
+ module_unused :: Module -> Bool
+ module_unused mod = moduleName mod `elem` unused_imp_mods
+
+
+warnDeprecations used_names
+ = doptRn Opt_WarnDeprecations `thenRn` \ warn_drs ->
+ if not warn_drs then returnRn () else
+
+ getIfacesRn `thenRn` \ ifaces ->
+ getHomeIfaceTableRn `thenRn` \ hit ->
+ let
+ pit = iPIT ifaces
+ deprecs = [ (n,txt)
+ | n <- nameSetToList used_names,
+ Just txt <- [lookup_deprec hit pit n] ]
+ in
+ mapRn_ warnDeprec deprecs
+
+ where
+ lookup_deprec hit pit n
+ = case lookupModuleEnv hit mod of
+ Just iface -> lookupDeprec iface n
+ Nothing -> case lookupModuleEnv pit mod of
+ Just iface -> lookupDeprec iface n
+ Nothing -> pprPanic "warnDeprecations:" (ppr n)
+ where
+ mod = nameModule n
+
+-- ToDo: deal with original imports with 'qualified' and 'as M' clauses
+printMinimalImports mod_name imps
+ = doptRn Opt_D_dump_minimal_imports `thenRn` \ dump_minimal ->
+ if not dump_minimal then returnRn () else
+
+ mapRn to_ies (fmToList imps) `thenRn` \ mod_ies ->
+ ioToRnM (do { h <- openFile filename WriteMode ;
+ printForUser h (vcat (map ppr_mod_ie mod_ies))
+ }) `thenRn_`
+ returnRn ()
+ where
+ filename = moduleNameUserString mod_name ++ ".imports"
+ ppr_mod_ie (mod_name, ies)
+ | mod_name == pRELUDE_Name
+ = empty
+ | otherwise
+ = ptext SLIT("import") <+> ppr mod_name <>
+ parens (fsep (punctuate comma (map ppr ies)))
+
+ to_ies (mod, avail_env) = mapRn to_ie (availEnvElts avail_env) `thenRn` \ ies ->
+ returnRn (mod, ies)
+
+ to_ie :: AvailInfo -> RnMG (IE Name)
+ to_ie (Avail n) = returnRn (IEVar n)
+ to_ie (AvailTC n [m]) = ASSERT( n==m )
+ returnRn (IEThingAbs n)
+ to_ie (AvailTC n ns) = getInterfaceExports (moduleName (nameModule n))
+ ImportBySystem `thenRn` \ (_, avails) ->
+ case [ms | AvailTC m ms <- avails, m == n] of
+ [ms] | all (`elem` ns) ms -> returnRn (IEThingAll n)
+ | otherwise -> returnRn (IEThingWith n (filter (/= n) ns))
+ other -> pprTrace "to_ie" (ppr n <+> ppr (nameModule n) <+> ppr other) $
+ returnRn (IEVar n)
+
+rnDump :: [RenamedHsDecl] -- Renamed imported decls
+ -> [RenamedHsDecl] -- Renamed local decls
+ -> RnMG (IO ())
+rnDump imp_decls local_decls
+ = doptRn Opt_D_dump_rn_trace `thenRn` \ dump_rn_trace ->
+ doptRn Opt_D_dump_rn_stats `thenRn` \ dump_rn_stats ->
+ doptRn Opt_D_dump_rn `thenRn` \ dump_rn ->
+ if dump_rn_trace || dump_rn_stats || dump_rn then
+ getRnStats imp_decls `thenRn` \ stats_msg ->
+ returnRn (printErrs stats_msg >>
+ dumpIfSet dump_rn "Renamer:"
+ (vcat (map ppr (local_decls ++ imp_decls))))
+ else
+ returnRn (return ())
+\end{code}
+
+
+%*********************************************************
+%* *
+\subsection{Statistics}
+%* *
+%*********************************************************
+
+\begin{code}
+getRnStats :: [RenamedHsDecl] -> RnMG SDoc
+getRnStats imported_decls
+ = getIfacesRn `thenRn` \ ifaces ->
+ let
+ n_mods = length [() | (_, _, True) <- eltsFM (iImpModInfo ifaces)]
+
+ decls_read = [decl | (avail, True, (_,decl)) <- nameEnvElts (iDecls ifaces),
+ -- Data, newtype, and class decls are in the decls_fm
+ -- under multiple names; the tycon/class, and each
+ -- constructor/class op too.
+ -- The 'True' selects just the 'main' decl
+ not (isLocallyDefined (availName avail))
+ ]
+
+ (cd_rd, dd_rd, nd_rd, sd_rd, vd_rd, _) = count_decls decls_read
+ (cd_sp, dd_sp, nd_sp, sd_sp, vd_sp, id_sp) = count_decls imported_decls
+
+ unslurped_insts = iInsts ifaces
+ inst_decls_unslurped = length (bagToList unslurped_insts)
+ inst_decls_read = id_sp + inst_decls_unslurped
+
+ stats = vcat
+ [int n_mods <+> text "interfaces read",
+ hsep [ int cd_sp, text "class decls imported, out of",
+ int cd_rd, text "read"],
+ hsep [ int dd_sp, text "data decls imported, out of",
+ int dd_rd, text "read"],
+ hsep [ int nd_sp, text "newtype decls imported, out of",
+ int nd_rd, text "read"],
+ hsep [int sd_sp, text "type synonym decls imported, out of",
+ int sd_rd, text "read"],
+ hsep [int vd_sp, text "value signatures imported, out of",
+ int vd_rd, text "read"],
+ hsep [int id_sp, text "instance decls imported, out of",
+ int inst_decls_read, text "read"],
+ text "cls dcls slurp" <+> fsep (map (ppr . tyClDeclName)
+ [d | TyClD d <- imported_decls, isClassDecl d]),
+ text "cls dcls read" <+> fsep (map (ppr . tyClDeclName)
+ [d | TyClD d <- decls_read, isClassDecl d])]
+ in
+ returnRn (hcat [text "Renamer stats: ", stats])
+
+count_decls decls
+ = (class_decls,
+ data_decls,
+ newtype_decls,
+ syn_decls,
+ val_decls,
+ inst_decls)
+ where
+ tycl_decls = [d | TyClD d <- decls]
+ (class_decls, data_decls, newtype_decls, syn_decls) = countTyClDecls tycl_decls
+
+ val_decls = length [() | SigD _ <- decls]
+ inst_decls = length [() | InstD _ <- decls]
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Errors and warnings}
+%* *
+%************************************************************************
+
+\begin{code}
+warnDeprec :: (Name, DeprecTxt) -> RnM d ()
+warnDeprec (name, txt)
+ = pushSrcLocRn (getSrcLoc name) $
+ addWarnRn $
+ sep [ text (occNameFlavour (nameOccName name)) <+> ppr name <+>
+ text "is deprecated:", nest 4 (ppr txt) ]
+
+
+unusedFixityDecl rdr_name fixity
+ = hsep [ptext SLIT("Unused fixity declaration for"), quotes (ppr rdr_name)]
+
+dupFixityDecl rdr_name loc1 loc2
+ = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
+ ptext SLIT("at ") <+> ppr loc1,
+ ptext SLIT("and") <+> ppr loc2]
+
+badDeprec d
+ = sep [ptext SLIT("Illegal deprecation when whole module is deprecated"),
+ nest 4 (ppr d)]