[project @ 2002-10-09 16:28:56 by simonpj]

Fix and simplify renamer warnings about export lists

diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs
index f1c7992..5877872 100644 (file)
--- a/ghc/compiler/rename/RnNames.lhs
+++ b/ghc/compiler/rename/RnNames.lhs
@@ -180,7 +180,7 @@ importsFromImportDecl this_mod_name
 
        mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits)) 
        gbl_env      = mkGlobalRdrEnv qual_mod unqual_imp mk_prov filtered_avails deprecs
-       imports      = mkImportAvails qual_mod unqual_imp gbl_env filtered_avails
+       imports      = mkImportAvails qual_mod unqual_imp filtered_avails
     in
     returnM (gbl_env, imports { imp_mods = dir_imp})
     }
@@ -241,9 +241,9 @@ importsFromLocalDecls group
            -- 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 type,
+           -- 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 Base and Tuple.
+           -- 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
@@ -255,7 +255,7 @@ importsFromLocalDecls group
            -- but that stops them being Exact, so they get looked up.  Sigh.
            -- It doesn't matter because it only affects the Data.Tuple really.
            -- The important thing is to trim down the exports.
-       imports = mkImportAvails mod_name unqual_imp gbl_env avails'
+       imports = mkImportAvails mod_name unqual_imp avails'
        avails' | implicit_prelude = filter not_built_in_syntax avails
                | otherwise        = avails
        not_built_in_syntax a = not (all isBuiltInSyntaxName (availNames a))
@@ -513,12 +513,14 @@ exports_from_avail export_items warn_dup_exports
        = case lookupModuleEnvByName mod_avail_env mod of
            Nothing             -> addErr (modExportErr mod)    `thenM_`
                                   returnM acc
-           Just mod_avails 
-               -> foldlM (check_occs warn_dup_exports ie) 
-                         occs mod_avails                  `thenM` \ occs' ->
-                  let
+           Just avail_env
+               -> let
+                       mod_avails = availEnvElts avail_env
                        avails' = foldl addAvail avails mod_avails
                   in
+                  foldlM (check_occs warn_dup_exports ie) 
+                         occs mod_avails       `thenM` \ occs' ->
+
                   returnM (mod:mods, occs', avails')
 
     exports_from_item acc@(mods, occs, avails) ie

diff --git a/ghc/compiler/typecheck/TcRnTypes.lhs b/ghc/compiler/typecheck/TcRnTypes.lhs
index 81909bf..2a3ca22 100644 (file)
--- a/ghc/compiler/typecheck/TcRnTypes.lhs
+++ b/ghc/compiler/typecheck/TcRnTypes.lhs
@@ -48,7 +48,7 @@ import RnHsSyn                ( RenamedHsExpr, RenamedPat, RenamedArithSeqInfo )
 import HscTypes                ( GhciMode, ExternalPackageState, HomePackageTable, NameCache,
                          GlobalRdrEnv, LocalRdrEnv, FixityEnv, TypeEnv, TyThing, 
                          Avails, GenAvailInfo(..), AvailInfo, availName,
-                         IsBootInterface, Deprecations, unQualInScope )
+                         IsBootInterface, Deprecations )
 import TcType          ( TcTyVarSet, TcType, TcTauType, TcThetaType, TcPredType, TcKind,
                          tcCmpPred, tcCmpType, tcCmpTypes )
 import InstEnv         ( DFunId, InstEnv )
@@ -468,13 +468,13 @@ data ImportAvails
                -- i.e. *excluding* class ops and constructors
                --      (which appear inside their parent AvailTC)
 
-       imp_unqual :: ModuleEnv Avails,
+       imp_unqual :: ModuleEnv AvailEnv,
                -- Used to figure out "module M" export specifiers
                -- Domain is only modules with *unqualified* imports
                -- (see 1.4 Report Section 5.1.1)
-               -- The list of Avails is cumulative, not necessarily
-               -- nicely uniquified. For example, we might have Maybe(Nothing)
-               -- and Maybe(Just) in the list, separately.
+               -- We keep the stuff as an AvailEnv so that it's easy to 
+               -- combine stuff coming from different (unqualified) 
+               -- imports of the same module
 
        imp_mods :: ModuleEnv (Module, Bool)
                -- Domain is all directly-imported modules
@@ -499,12 +499,12 @@ plusImportAvails
   (ImportAvails { imp_env = env1, imp_unqual = unqual1, imp_mods = mods1 })
   (ImportAvails { imp_env = env2, imp_unqual = unqual2, imp_mods = mods2 })
   = ImportAvails { imp_env    = env1 `plusAvailEnv` env2, 
-                  imp_unqual = plusModuleEnv_C (++) unqual1 unqual2, 
+                  imp_unqual = plusModuleEnv_C plusAvailEnv unqual1 unqual2, 
                   imp_mods   = mods1 `plusModuleEnv` mods2 }
 
 mkImportAvails :: ModuleName -> Bool
-              -> GlobalRdrEnv -> [AvailInfo] -> ImportAvails
-mkImportAvails mod_name unqual_imp gbl_env avails 
+              -> [AvailInfo] -> ImportAvails
+mkImportAvails mod_name unqual_imp avails 
   = ImportAvails { imp_unqual = mod_avail_env, 
                   imp_env    = entity_avail_env,
                   imp_mods   = emptyModuleEnv }-- Stays empty for module being compiled;
@@ -517,8 +517,8 @@ mkImportAvails mod_name unqual_imp gbl_env avails
        --      module M ( module P ) where ...
        -- Then we must export whatever came from P unqualified.
 
-    unqual_avails | not unqual_imp = []        -- Short cut when no unqualified imports
-                 | otherwise      = pruneAvails (unQualInScope gbl_env) avails
+    unqual_avails | not unqual_imp = emptyAvailEnv     -- Qualified import
+                 | otherwise      = entity_avail_env   -- Unqualified import
 
     entity_avail_env = foldl insert emptyAvailEnv avails
     insert env avail = extendNameEnv_C plusAvail env (availName avail) avail