From c615209582841eb514b50800725d5989d176be13 Mon Sep 17 00:00:00 2001
From: simonpj <unknown>
Date: Mon, 22 May 2000 06:56:04 +0000
Subject: [PATCH] [project @ 2000-05-22 06:56:04 by simonpj] *** NO NEED TO
MERGE WITH 4.07, BUT POSSIBLE ***
Warn about completely unused imported modules (when -fwarn-unused-imports)
---
ghc/compiler/rename/Rename.lhs | 54 +++++++++++++++++++++++-----------
ghc/compiler/rename/RnEnv.lhs | 9 +++++-
2 files changed, 45 insertions(+), 18 deletions(-)
diff --git a/ghc/compiler/rename/Rename.lhs b/ghc/compiler/rename/Rename.lhs
index 3f271942928a..ee176e6af0c1 100644
--- a/ghc/compiler/rename/Rename.lhs
+++ b/ghc/compiler/rename/Rename.lhs
@@ -24,7 +24,8 @@ import RnIfaces ( getImportedInstDecls, importDecl, getImportVersions, getInter
getImportedRules, loadHomeInterface, getSlurped, removeContext
)
import RnEnv ( availName, availsToNameSet, unitAvailEnv, availEnvElts, plusAvailEnv,
- warnUnusedImports, warnUnusedLocalBinds, lookupImplicitOccRn, pprAvail,
+ warnUnusedImports, warnUnusedLocalBinds, warnUnusedModules,
+ lookupImplicitOccRn, pprAvail,
FreeVars, plusFVs, plusFV, unitFV, emptyFVs, isEmptyFVs
)
import Module ( Module, ModuleName, WhereFrom(..),
@@ -46,10 +47,10 @@ import Type ( namesOfType, funTyCon )
import ErrUtils ( printErrorsAndWarnings, dumpIfSet, ghcExit )
import BasicTypes ( NewOrData(..) )
import Bag ( isEmptyBag, bagToList )
-import FiniteMap ( FiniteMap, eltsFM, fmToList, emptyFM, addToFM_C )
+import FiniteMap ( FiniteMap, eltsFM, fmToList, emptyFM, lookupFM, addToFM_C )
import UniqSupply ( UniqSupply )
import UniqFM ( lookupUFM )
-import Maybes ( maybeToBool )
+import Maybes ( maybeToBool, expectJust )
import Outputable
import IO ( openFile, IOMode(..) )
\end{code}
@@ -146,11 +147,6 @@ rename this_mod@(HsModule mod_name vers _ imports local_decls mod_deprec loc)
getImportVersions mod_name export_env `thenRn` \ my_usages ->
getNameSupplyRn `thenRn` \ name_supply ->
- -- REPORT UNUSED NAMES
- reportUnusedNames mod_name gbl_env global_avail_env
- export_env
- source_fvs `thenRn_`
-
-- RETURN THE RENAMED MODULE
let
has_orphans = any isOrphanDecl rn_local_decls
@@ -161,7 +157,13 @@ rename this_mod@(HsModule mod_name vers _ imports local_decls mod_deprec loc)
mod_deprec
loc
in
- rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
+ -- REPORT UNUSED NAMES, AND DEBUG DUMP
+ reportUnusedNames mod_name direct_import_mods
+ gbl_env global_avail_env
+ export_env
+ source_fvs `thenRn_`
+ rnDump rn_imp_decls rn_all_decls `thenRn` \ dump_action ->
+
returnRn (Just (mkThisModule mod_name,
renamed_module,
(InterfaceDetails has_orphans my_usages export_env deprecs),
@@ -528,8 +530,12 @@ getInstDeclGates other = emptyFVs
%*********************************************************
\begin{code}
-reportUnusedNames :: ModuleName -> GlobalRdrEnv -> AvailEnv -> ExportEnv -> NameSet -> RnMG ()
-reportUnusedNames mod_name gbl_env avail_env (ExportEnv export_avails _ _) mentioned_names
+reportUnusedNames :: ModuleName -> [ModuleName]
+ -> GlobalRdrEnv -> AvailEnv
+ -> ExportEnv -> NameSet -> RnMG ()
+reportUnusedNames mod_name direct_import_mods
+ gbl_env avail_env
+ (ExportEnv export_avails _ _) mentioned_names
= let
used_names = mentioned_names `unionNameSets` availsToNameSet export_avails
@@ -565,28 +571,42 @@ reportUnusedNames mod_name gbl_env avail_env (ExportEnv export_avails _ _) menti
nameSetToList (defined_names `minusNameSet` really_used_names)
-- Filter out the ones only defined implicitly
- bad_locals = [n | n <- defined_but_not_used, isLocallyDefined n]
- bad_imps = [n | n <- defined_but_not_used, isUserImportedExplicitlyName n]
+ bad_locals = [n | n <- defined_but_not_used, isLocallyDefined n]
+ bad_imp_names = [n | n <- defined_but_not_used, isUserImportedExplicitlyName n,
+ not (module_unused n)]
deprec_used deprec_env = [ (n,txt)
| n <- nameSetToList mentioned_names,
not (isLocallyDefined n),
Just txt <- [lookupNameEnv deprec_env n] ]
- minimal_imports :: FiniteMap Module AvailEnv
+ minimal_imports :: FiniteMap ModuleName AvailEnv
minimal_imports = foldNameSet add emptyFM really_used_names
add n acc = case maybeUserImportedFrom n of
Nothing -> acc
- Just m -> addToFM_C plusAvailEnv acc m
+ Just m -> addToFM_C plusAvailEnv acc (moduleName m)
(unitAvailEnv (mk_avail n))
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)
+
+ -- 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))]
+
+ module_unused :: Name -> Bool
+ -- Name is imported from a module that's completely unused,
+ -- so don't report stuff about the name (the module covers it)
+ module_unused n = moduleName (expectJust "module_unused" (maybeUserImportedFrom n))
+ `elem` unused_imp_mods
+ -- module_unused is only called if it's user-imported
in
+ warnUnusedModules unused_imp_mods `thenRn_`
warnUnusedLocalBinds bad_locals `thenRn_`
- warnUnusedImports bad_imps `thenRn_`
+ warnUnusedImports bad_imp_names `thenRn_`
printMinimalImports mod_name minimal_imports `thenRn_`
getIfacesRn `thenRn` \ ifaces ->
(if opt_WarnDeprecations
@@ -613,7 +633,7 @@ printMinimalImports mod_name imps
parens (fsep (punctuate comma (map ppr ies)))
to_ies (mod, avail_env) = mapRn to_ie (availEnvElts avail_env) `thenRn` \ ies ->
- returnRn (moduleName mod, ies)
+ returnRn (mod, ies)
to_ie :: AvailInfo -> RnMG (IE Name)
to_ie (Avail n) = returnRn (IEVar n)
diff --git a/ghc/compiler/rename/RnEnv.lhs b/ghc/compiler/rename/RnEnv.lhs
index 118267f893a7..7cef968fe5c2 100644
--- a/ghc/compiler/rename/RnEnv.lhs
+++ b/ghc/compiler/rename/RnEnv.lhs
@@ -763,8 +763,15 @@ mapFvRn f xs = mapRn f xs `thenRn` \ stuff ->
\begin{code}
-warnUnusedLocalBinds, warnUnusedImports, warnUnusedMatches :: [Name] -> RnM d ()
+warnUnusedModules :: [ModuleName] -> RnM d ()
+warnUnusedModules mods
+ | not opt_WarnUnusedImports = returnRn ()
+ | otherwise = mapRn_ (addWarnRn . unused_mod) mods
+ where
+ unused_mod m = ptext SLIT("Module") <+> quotes (ppr m) <+>
+ ptext SLIT("is imported, but nothing from it is used")
+warnUnusedLocalBinds, warnUnusedImports, warnUnusedMatches :: [Name] -> RnM d ()
warnUnusedImports names
| not opt_WarnUnusedImports
= returnRn () -- Don't force names unless necessary
--
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