[project @ 2004-05-25 08:09:37 by simonpj]

[ghc-hetmet.git] / ghc / compiler / rename / RnNames.lhs

diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs
index 1604915..f3fe011 100644 (file)
--- a/ghc/compiler/rename/RnNames.lhs
+++ b/ghc/compiler/rename/RnNames.lhs
@@ -50,7 +50,7 @@ import RdrName                ( RdrName, rdrNameOcc, setRdrNameSpace,
 import Outputable
 import Maybes          ( isJust, isNothing, catMaybes, mapCatMaybes, seqMaybe )
 import SrcLoc          ( noSrcLoc, Located(..), mkGeneralSrcSpan,
-                         unLoc, noLoc, srcLocSpan )
+                         unLoc, noLoc, srcLocSpan, SrcSpan )
 import BasicTypes      ( DeprecTxt )
 import ListSetOps      ( removeDups )
 import Util            ( sortLt, notNull, isSingleton )
@@ -228,7 +228,7 @@ importsFromImportDecl this_mod
        imports   = ImportAvails { 
                        imp_qual     = unitModuleEnvByName qual_mod_name avail_env,
                        imp_env      = avail_env,
-                       imp_mods     = unitModuleEnv imp_mod (imp_mod, import_all),
+                       imp_mods     = unitModuleEnv imp_mod (imp_mod, import_all, loc),
                        imp_orphs    = orphans,
                        imp_dep_mods = mkModDeps dependent_mods,
                        imp_dep_pkgs = dependent_pkgs }
@@ -852,8 +852,7 @@ reportUnusedNames gbl_env
        -- 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_name = n, 
-                  gre_prov = Imported imp_specs _}) acc 
+    add_name (GRE {gre_name = n, gre_prov = Imported imp_specs _}) acc 
        = addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
                    (unitAvailEnv (mk_avail n (nameParent_maybe n)))
     add_name other acc 
@@ -864,38 +863,35 @@ reportUnusedNames gbl_env
     mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
                       | otherwise               = Avail n
     
-    add_inst_mod m acc 
-      | m `elemFM` acc = acc   -- We import something already
-      | otherwise      = addToFM acc m 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 :: [ModuleName]
-    direct_import_mods = map (moduleName . fst) 
-                            (moduleEnvElts (imp_mods imports))
-
-    hasEmptyImpList :: ModuleName -> Bool
-    hasEmptyImpList m = 
-       case lookupModuleEnvByName (imp_mods imports) m of
-        Just (_,Just x) -> not x
-        _ -> False
+    direct_import_mods :: [(Module, Maybe 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]
-    unused_imp_mods = [m | m <- direct_import_mods,
-                      isNothing (lookupFM minimal_imports1 m),
-                      m /= pRELUDE_Name,
-                      not (hasEmptyImpList m)]
-       -- hasEmptyImpList arranges not to complain about
+    unused_imp_mods = [(mod_name,loc) | (mod,imp,loc) <- direct_import_mods,
+                      let mod_name = moduleName mod,
+                      not (mod_name `elemFM` minimal_imports1),
+                      mod_name /= pRELUDE_Name,
+                      imp /= Just False]
+       -- The Just False part is not to complain about
        -- import M (), which is an idiom for importing
        -- instance declarations
     
     module_unused :: ModuleName -> Bool
-    module_unused mod = mod `elem` unused_imp_mods
+    module_unused mod = any (((==) mod) . fst) unused_imp_mods
 
 ---------------------
 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()