[project @ 2003-09-23 16:52:44 by sof]

If the user explicitly did an instances-only import, i.e.,
"import Foo ()", don't emit an unused-import warning.

diff --git a/ghc/compiler/main/MkIface.lhs b/ghc/compiler/main/MkIface.lhs
index 0172930..9f31e70 100644 (file)
--- a/ghc/compiler/main/MkIface.lhs
+++ b/ghc/compiler/main/MkIface.lhs
@@ -519,8 +519,8 @@ mkUsageInfo hsc_env eps
     pit = eps_PIT eps
     
     import_all mod = case lookupModuleEnv dir_imp_mods mod of
-                       Just (_,imp_all) -> imp_all
-                       Nothing          -> False
+                       Just (_, Nothing) -> True
+                       _                 -> False
     
     -- ent_map groups together all the things imported and used
     -- from a particular module in this package

diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs
index 9197fd9..d1a4f01 100644 (file)
--- a/ghc/compiler/rename/RnNames.lhs
+++ b/ghc/compiler/rename/RnNames.lhs
@@ -193,9 +193,10 @@ importsFromImportDecl this_mod
        not_self (m, _) = m /= this_mod_name
 
        import_all = case imp_spec of
-                       (Just (False, _)) -> False      -- Imports are spec'd explicitly
-                       other             -> True       -- Everything is imported, 
-                                                       -- (or almost everything [hiding])
+                       Just (isHid, ls) -- Imports are spec'd explicitly
+                         | not isHid  -> Just (not (null ls)) 
+                       _       -> Nothing      -- Everything is imported, 
+                                               -- (or almost everything [hiding])
 
        qual_mod_name = case as_mod of
                          Nothing           -> imp_mod_name
@@ -788,14 +789,21 @@ reportUnusedNames gbl_env dus
     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
+
     -- unused_imp_mods are the directly-imported modules 
     -- that are not mentioned in minimal_imports1
     -- [Note: not 'minimal_imports', because that includes direcly-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]
-    
+                      m /= pRELUDE_Name,
+                      not (hasEmptyImpList m)]
+
     module_unused :: Module -> Bool
     module_unused mod = moduleName mod `elem` unused_imp_mods
 

diff --git a/ghc/compiler/typecheck/TcRnTypes.lhs b/ghc/compiler/typecheck/TcRnTypes.lhs
index 1408eda..47a9ed8 100644 (file)
--- a/ghc/compiler/typecheck/TcRnTypes.lhs
+++ b/ghc/compiler/typecheck/TcRnTypes.lhs
@@ -595,10 +595,16 @@ data ImportAvails
                -- combine stuff coming from different (unqualified) 
                -- imports of the same module
 
-       imp_mods :: ModuleEnv (Module, Bool),
+       imp_mods :: ModuleEnv (Module, Maybe Bool),
                -- Domain is all directly-imported modules
-               -- Bool is True if there was an unrestricted import
-               --      (i.e. not a selective list)
+               -- Maybe value answers the question "is the import restricted?"
+               --   Nothing    => unrestricted import (e.g., "import Foo")
+               --   Just True  => restricted import, at least one entity (e.g., "import Foo(x)")
+               --   Just False => fully restricted import (e.g., "import Foo ()")
+               --
+               --  A distinction is made between the first and the third in order
+               --  to more precisely emit warnings about unused imports.
+               --
                -- We need the Module in the range because we can't get
                --      the keys of a ModuleEnv
                -- Used