Fix bug in -ddump-minimal imports Trac #1025

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

diff --git a/compiler/rename/RnNames.lhs b/compiler/rename/RnNames.lhs
index ae5ec95..d85089f 100644 (file)
--- a/compiler/rename/RnNames.lhs
+++ b/compiler/rename/RnNames.lhs
@@ -17,12 +17,12 @@ import DynFlags             ( DynFlag(..), GhcMode(..), DynFlags(..) )
 import HsSyn           ( IE(..), ieName, ImportDecl(..), LImportDecl,
                          ForeignDecl(..), HsGroup(..), HsValBinds(..),
                          Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
-                         instDeclATs, isIdxTyDecl,
+                         instDeclATs, isFamInstDecl,
                          LIE )
 import RnEnv
 import RnHsDoc          ( rnHsDoc )
 import IfaceEnv                ( ifaceExportNames )
-import LoadIface       ( loadSrcInterface )
+import LoadIface       ( loadSrcInterface, loadSysInterface )
 import TcRnMonad hiding (LIE)
 
 import PrelNames
@@ -336,7 +336,7 @@ getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs,
     for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
 
     new_tc tc_decl 
-      | isIdxTyDecl (unLoc tc_decl)
+      | isFamInstDecl (unLoc tc_decl)
        = do { main_name <- lookupFamInstDeclBndr mod main_rdr
             ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs
             ; return (AvailTC main_name sub_names) }
@@ -1134,8 +1134,6 @@ warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
 warnDuplicateImports gres
   = ifOptM Opt_WarnUnusedImports $ 
     sequenceM_ [ warn name pr
-                       -- The 'head' picks the first offending group
-                       -- for this particular name
                | GRE { gre_name = name, gre_prov = Imported imps } <- gres
                , pr <- redundants imps ]
   where
@@ -1154,7 +1152,12 @@ warnDuplicateImports gres
     redundants imps 
        = [ (red_imp, cov_imp) 
          | red_imp <- imps
+         , isExplicitItem (is_item red_imp)
+               -- Complain only about redundant imports
+               -- mentioned explicitly by the user                             
          , cov_imp <- take 1 (filter (covers red_imp) imps) ]
+                       -- The 'take 1' picks the first offending group
+                       -- for this particular name
 
        -- "red_imp" is a putative redundant import
        -- "cov_imp" potentially covers it
@@ -1175,6 +1178,10 @@ warnDuplicateImports gres
        = False         -- They bring into scope different qualified names
        | not (is_qual red_decl) && is_qual cov_decl
        = False         -- Covering one doesn't bring unqualified name into scope
+       | otherwise
+       = not (isExplicitItem cov_item) -- Redundant one is selective and covering one isn't
+         || red_later                  -- or both are explicit; tie-break using red_later
+{-
        | red_selective
        = not cov_selective     -- Redundant one is selective and covering one isn't
          || red_later          -- Both are explicit; tie-break using red_later
@@ -1182,16 +1189,11 @@ warnDuplicateImports gres
        = not cov_selective     -- Neither import is selective
          && (is_mod red_decl == is_mod cov_decl)       -- They import the same module
          && red_later          -- Tie-break
+-}
        where
          red_loc   = importSpecLoc red_imp
          cov_loc   = importSpecLoc cov_imp
          red_later = red_loc > cov_loc
-         cov_selective = selectiveImpItem cov_item
-         red_selective = selectiveImpItem red_item
-
-selectiveImpItem :: ImpItemSpec -> Bool
-selectiveImpItem ImpAll       = False
-selectiveImpItem (ImpSome {}) = True
 
 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
 printMinimalImports :: FiniteMap ModuleName AvailEnv   -- Minimal imports
@@ -1199,7 +1201,7 @@ printMinimalImports :: FiniteMap ModuleName AvailEnv      -- Minimal imports
 printMinimalImports imps
  = ifOptM Opt_D_dump_minimal_imports $ do {
 
-   mod_ies  <-  mappM to_ies (fmToList imps) ;
+   mod_ies  <-  initIfaceTcRn $ mappM to_ies (fmToList imps) ;
    this_mod <- getModule ;
    rdr_env  <- getGlobalRdrEnv ;
    ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
@@ -1220,7 +1222,7 @@ printMinimalImports imps
     to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
                                  returnM (mod, ies)
 
-    to_ie :: AvailInfo -> RnM (IE Name)
+    to_ie :: AvailInfo -> IfG (IE Name)
        -- The main trick here is that if we're importing all the constructors
        -- we want to say "T(..)", but if we're importing only a subset we want
        -- to say "T(A,B,C)".  So we have to find out what the module exports.
@@ -1228,9 +1230,9 @@ printMinimalImports imps
     to_ie (AvailTC n [m]) = ASSERT( n==m ) 
                            returnM (IEThingAbs n)
     to_ie (AvailTC n ns)  
-       = loadSrcInterface doc n_mod False                      `thenM` \ iface ->
+       = loadSysInterface doc n_mod                    `thenM` \ iface ->
          case [xs | (m,as) <- mi_exports iface,
-                    moduleName m == n_mod,
+                    m == n_mod,
                     AvailTC x xs <- as, 
                     x == nameOccName n] of
              [xs] | all_used xs -> returnM (IEThingAll n)
@@ -1240,7 +1242,7 @@ printMinimalImports imps
        where
          all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
          doc = text "Compute minimal imports from" <+> ppr n
-         n_mod = moduleName (nameModule n)
+         n_mod = nameModule n
 \end{code}