[project @ 2000-04-07 15:24:15 by simonpj]

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

diff --git a/ghc/compiler/rename/RnIfaces.lhs b/ghc/compiler/rename/RnIfaces.lhs
index 6b1b90c..7368d34 100644 (file)
--- a/ghc/compiler/rename/RnIfaces.lhs
+++ b/ghc/compiler/rename/RnIfaces.lhs
@@ -33,7 +33,7 @@ import RdrHsSyn               ( RdrNameHsDecl, RdrNameInstDecl, RdrNameTyClDecl, RdrNameRuleD
 import RnEnv           ( mkImportedGlobalName, newImportedBinder, mkImportedGlobalFromRdrName,
                          lookupOccRn, lookupImplicitOccRn,
                          pprAvail,
-                         availName, availNames, addAvailToNameSet,
+                         availName, availNames, addAvailToNameSet, addSysAvails,
                          FreeVars, emptyFVs
                        )
 import RnMonad
@@ -50,7 +50,7 @@ import Name           ( Name {-instance NamedThing-},
                         )
 import Module          ( Module, moduleString, pprModule,
                          mkVanillaModule, pprModuleName,
-                         moduleUserString, moduleName, isLibModule,
+                         moduleUserString, moduleName, isPrelModule,
                          ModuleName, WhereFrom(..),
                        )
 import RdrName         ( RdrName, rdrNameOcc )
@@ -123,8 +123,7 @@ loadInterface doc_str mod_name from
        mod_map_result ->
 
        -- READ THE MODULE IN
-   findAndReadIface doc_str mod_name from below_me
-   `thenRn` \ (hi_boot_read, read_result) ->
+   findAndReadIface doc_str mod_name from below_me   `thenRn` \ (hi_boot_read, read_result) ->
    case read_result of {
        Nothing ->      -- Not found, so add an empty export env to the Ifaces map
                        -- so that we don't look again
@@ -188,7 +187,7 @@ addModDeps :: Module -> ImportedModuleInfo
 addModDeps mod mod_deps new_deps
   = foldr add mod_deps new_deps
   where
-    is_lib = isLibModule mod   -- Don't record dependencies when importing a library module
+    is_lib = isPrelModule mod  -- Don't record dependencies when importing a prelude module
     add (imp_mod, version, has_orphans, is_boot, _) deps
        | is_lib && not has_orphans = deps
        | otherwise  =  addToFM_C combine deps imp_mod (version, has_orphans, is_boot, Nothing)
@@ -196,12 +195,10 @@ addModDeps mod mod_deps new_deps
        --      either are dependent via a non-library module
        --      or contain orphan rules or instance decls
 
-       -- Don't ditch a module that's already loaded
-       -- If it isn't loaded, and together the is_boot-ness
-    combine old@(_, _, _, Just _)  new = old
-    combine old@(_, _, old_is_boot, Nothing) 
-            new@(version, has_orphans, new_is_boot, _) 
-               = (version, has_orphans, old_is_boot && new_is_boot, Nothing)
+    combine old@(_, _, old_is_boot, cts) new
+       | maybeToBool cts || not old_is_boot = old      -- Keep the old info if it's already loaded
+                                                       -- or if it's a non-boot pending load
+       | otherwise                          = new      -- Otherwise pick new info
 
 loadExport :: ModuleName -> ExportItem -> RnM d [AvailInfo]
 loadExport this_mod (mod, entities)
@@ -265,10 +262,15 @@ loadDecl mod decls_map (version, decl)
 
     getDeclSysBinders new_name decl    `thenRn` \ sys_bndrs ->
     let
+       full_avail    = addSysAvails avail sys_bndrs
+               -- Add the sys-binders to avail.  When we import the decl,
+               -- it's full_avail that will get added to the 'already-slurped' set (iSlurp)
+               -- If we miss out sys-binders, we'll read the decl multiple times!
+
        main_name     = availName avail
        new_decls_map = foldl add_decl decls_map
-                                      [ (name, (version, avail, name==main_name, (mod, decl'))) 
-                                      | name <- sys_bndrs ++ availNames avail]
+                                      [ (name, (version, full_avail, name==main_name, (mod, decl'))) 
+                                      | name <- availNames full_avail]
        add_decl decls_map (name, stuff)
          = WARN( name `elemNameEnv` decls_map, ppr name )
            addToNameEnv decls_map name stuff
@@ -756,6 +758,13 @@ getImportVersions this_mod (ExportEnv _ _ export_all_mods)
        -- I can't be bothered just now.
 
        mk_version_info mod_name (version, has_orphans, is_boot, contents) so_far
+          | mod_name == this_mod       -- Check if M appears in the set of modules 'below' M
+                                       -- This seems like a convenient place to check
+          = WARN( not is_boot, ptext SLIT("Wierd:") <+> ppr this_mod <+> 
+                               ptext SLIT("imports itself (perhaps indirectly)") )
+            so_far
+ 
+          | otherwise
           = let
                go_for_it exports = (mod_name, version, has_orphans, is_boot, exports) 
                                     : so_far
@@ -786,13 +795,9 @@ getImportVersions this_mod (ExportEnv _ _ export_all_mods)
                                                -- but don't actually *use* anything from Foo
                                                -- In which case record an empty dependency list
                   where
-                    is_lib_module     = isLibModule mod
+                    is_lib_module = isPrelModule mod
             
     in
-       -- A module shouldn't load its own interface
-       -- This seems like a convenient place to check
-    WARN( maybeToBool (lookupFM mod_map this_mod), 
-         ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
 
     returnRn (foldFM mk_version_info [] mod_map)
   where
@@ -977,11 +982,11 @@ findAndReadIface doc_str mod_name from hi_file
          (False, lookupFM hi_map mod_name)
 
       | otherwise
-               -- Check if there's a library module of that name
+               -- Check if there's a prelude module of that name
                -- If not, look for an hi-boot file
       = case lookupFM hi_map mod_name of
-          stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
-          other                                   -> (True, lookupFM hiboot_map mod_name)
+          stuff@(Just (_, mod)) | isPrelModule mod -> (False, stuff)
+          other                                    -> (True, lookupFM hiboot_map mod_name)
 
     trace_msg = sep [hsep [ptext SLIT("Reading"), 
                           ppr from,
@@ -1043,7 +1048,9 @@ cannaeReadFile file err
          text (show err)]
 
 getDeclErr name
-  = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
+  = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
+         ptext SLIT("from module") <+> quotes (ppr (nameModule name))
+        ]
 
 getDeclWarn name loc
   = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),