Improve fix to Trac #3007

[ghc-hetmet.git] / compiler / iface / MkIface.lhs

diff --git a/compiler/iface/MkIface.lhs b/compiler/iface/MkIface.lhs
index 478d7d3..7b30a19 100644 (file)
--- a/compiler/iface/MkIface.lhs
+++ b/compiler/iface/MkIface.lhs
@@ -51,7 +51,6 @@ Basic idea:
 #include "HsVersions.h"
 
 import IfaceSyn
-import IfaceType
 import LoadIface
 import Id
 import IdInfo
@@ -77,7 +76,6 @@ import Name
 import RdrName
 import NameEnv
 import NameSet
-import OccName
 import Module
 import BinIface
 import ErrUtils
@@ -95,7 +93,6 @@ import ListSetOps
 import Binary
 import Fingerprint
 import Bag
-import Panic
 
 import Control.Monad
 import Data.List
@@ -188,26 +185,15 @@ mkDependencies
                 --  on M.hi-boot, and hence that we should do the hi-boot consistency 
                 --  check.)
 
-                -- Modules don't compare lexicographically usually, 
-                -- but we want them to do so here.
-        le_mod :: Module -> Module -> Bool         
-        le_mod m1 m2 = moduleNameFS (moduleName m1) 
-                           <= moduleNameFS (moduleName m2)
-
-        le_dep_mod :: (ModuleName, IsBootInterface)
-                    -> (ModuleName, IsBootInterface) -> Bool         
-        le_dep_mod (m1,_) (m2,_) = moduleNameFS m1 <= moduleNameFS m2
-
-        
         pkgs | th_used   = insertList thPackageId (imp_dep_pkgs imports)
              | otherwise = imp_dep_pkgs imports
 
-      return Deps { dep_mods   = sortLe le_dep_mod dep_mods,
-                    dep_pkgs   = sortLe (<=)   pkgs,        
-                    dep_orphs  = sortLe le_mod (imp_orphs  imports),
-                    dep_finsts = sortLe le_mod (imp_finsts imports) }
+      return Deps { dep_mods   = sortBy (stableModuleNameCmp `on` fst) dep_mods,
+                    dep_pkgs   = sortBy stablePackageIdCmp pkgs,
+                    dep_orphs  = sortBy stableModuleCmp (imp_orphs  imports),
+                    dep_finsts = sortBy stableModuleCmp (imp_finsts imports) }
                 -- sort to get into canonical order
-
+                -- NB. remember to use lexicographic ordering
 
 mkIface_ :: HscEnv -> Maybe Fingerprint -> Module -> IsBootInterface
          -> NameSet -> Dependencies -> GlobalRdrEnv
@@ -926,11 +912,14 @@ mkIfaceAnnotation (Annotation { ann_target = target, ann_value = serialized }) =
 \begin{code}
 mkIfaceExports :: [AvailInfo]
                -> [(Module, [GenAvailInfo OccName])]
-  -- Group by module and sort by occurrence
-  -- This keeps the list in canonical order
+                  -- Group by module and sort by occurrence
 mkIfaceExports exports
   = [ (mod, eltsFM avails)
-    | (mod, avails) <- fmToList groupFM
+    | (mod, avails) <- sortBy (stableModuleCmp `on` fst) (fmToList groupFM)
+                       -- NB. the fmToList is in a random order,
+                       -- because Ord Module is not a predictable
+                       -- ordering.  Hence we perform a final sort
+                       -- using the stable Module ordering.
     ]
   where
        -- Group by the module where the exported entities are defined