[commit: ghc] master: Clean up some outdated comments (#8418) (7fad107)

[git at git.haskell.org]

Repository : ssh://git at git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/7fad107f61313f11cb0b40e0310ede4c119467fd/ghc

>---------------------------------------------------------------

commit 7fad107f61313f11cb0b40e0310ede4c119467fd
Author: Austin Seipp <austin at well-typed.com>
Date:   Wed Oct 9 03:02:29 2013 -0500

    Clean up some outdated comments (#8418)
    
    Authored-by: Gergely Risko <gergely at risko.hu>
    Signed-off-by: Austin Seipp <austin at well-typed.com>


>---------------------------------------------------------------

7fad107f61313f11cb0b40e0310ede4c119467fd
 compiler/main/DynamicLoading.hs   |    9 ++++++---
 compiler/main/HscTypes.lhs        |    8 ++++----
 compiler/simplCore/SimplCore.lhs  |    4 ++--
 compiler/typecheck/TcRnDriver.lhs |    7 +++++--
 4 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/compiler/main/DynamicLoading.hs b/compiler/main/DynamicLoading.hs
index f262212..0498464 100644
--- a/compiler/main/DynamicLoading.hs
+++ b/compiler/main/DynamicLoading.hs
@@ -7,7 +7,7 @@ module DynamicLoading (
         forceLoadTyCon,
         
         -- * Finding names
-        lookupRdrNameInModule,
+        lookupRdrNameInModuleForPlugins,
         
         -- * Loading values
         getValueSafely,
@@ -141,8 +141,11 @@ lessUnsafeCoerce dflags context what = do
 --
 -- * If the module could not be found
 -- * If we could not determine the imports of the module
-lookupRdrNameInModule :: HscEnv -> ModuleName -> RdrName -> IO (Maybe Name)
-lookupRdrNameInModule hsc_env mod_name rdr_name = do
+--
+-- Can only be used for lookuping up names while handling plugins.
+-- This was introduced by 57d6798.
+lookupRdrNameInModuleForPlugins :: HscEnv -> ModuleName -> RdrName -> IO (Maybe Name)
+lookupRdrNameInModuleForPlugins hsc_env mod_name rdr_name = do
     -- First find the package the module resides in by searching exposed packages and home modules
     found_module <- findImportedModule hsc_env mod_name Nothing
     case found_module of
diff --git a/compiler/main/HscTypes.lhs b/compiler/main/HscTypes.lhs
index 390ac45..265f7f2 100644
--- a/compiler/main/HscTypes.lhs
+++ b/compiler/main/HscTypes.lhs
@@ -505,10 +505,10 @@ lookupIfaceByModule dflags hpt pit mod
 -- of its own, but it doesn't seem worth the bother.
 
 
--- | Find all the instance declarations (of classes and families) that are in
--- modules imported by this one, directly or indirectly, and are in the Home
--- Package Table.  This ensures that we don't see instances from modules @--make@
--- compiled before this one, but which are not below this one.
+-- | Find all the instance declarations (of classes and families) from
+-- the Home Package Table filtered by the provided predicate function.
+-- Used in @tcRnImports@, to select the instances that are in the
+-- transitive closure of imports from the currently compiled module.
 hptInstances :: HscEnv -> (ModuleName -> Bool) -> ([ClsInst], [FamInst])
 hptInstances hsc_env want_this_module
   = let (insts, famInsts) = unzip $ flip hptAllThings hsc_env $ \mod_info -> do
diff --git a/compiler/simplCore/SimplCore.lhs b/compiler/simplCore/SimplCore.lhs
index 4b07d3b..7adee7d 100644
--- a/compiler/simplCore/SimplCore.lhs
+++ b/compiler/simplCore/SimplCore.lhs
@@ -53,7 +53,7 @@ import Type             ( mkTyConTy )
 import RdrName          ( mkRdrQual )
 import OccName          ( mkVarOcc )
 import PrelNames        ( pluginTyConName )
-import DynamicLoading   ( forceLoadTyCon, lookupRdrNameInModule, getValueSafely )
+import DynamicLoading   ( forceLoadTyCon, lookupRdrNameInModuleForPlugins, getValueSafely )
 import Module           ( ModuleName )
 import Panic
 #endif
@@ -335,7 +335,7 @@ loadPlugin :: HscEnv -> ModuleName -> IO Plugin
 loadPlugin hsc_env mod_name
   = do { let plugin_rdr_name = mkRdrQual mod_name (mkVarOcc "plugin")
              dflags = hsc_dflags hsc_env
-       ; mb_name <- lookupRdrNameInModule hsc_env mod_name plugin_rdr_name
+       ; mb_name <- lookupRdrNameInModuleForPlugins hsc_env mod_name plugin_rdr_name
        ; case mb_name of {
             Nothing ->
                 throwGhcExceptionIO (CmdLineError $ showSDoc dflags $ hsep
diff --git a/compiler/typecheck/TcRnDriver.lhs b/compiler/typecheck/TcRnDriver.lhs
index 314d50f..8e5e7f2 100644
--- a/compiler/typecheck/TcRnDriver.lhs
+++ b/compiler/typecheck/TcRnDriver.lhs
@@ -241,7 +241,7 @@ implicitPreludeWarn
 tcRnImports :: HscEnv -> Module
             -> [LImportDecl RdrName] -> TcM TcGblEnv
 tcRnImports hsc_env this_mod import_decls
-  = do  { (rn_imports, rdr_env, imports,hpc_info) <- rnImports import_decls ;
+  = do  { (rn_imports, rdr_env, imports, hpc_info) <- rnImports import_decls ;
 
         ; let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
                 -- Make sure we record the dependencies from the DynFlags in the EPS or we
@@ -257,7 +257,10 @@ tcRnImports hsc_env this_mod import_decls
                 -- We want instance declarations from all home-package
                 -- modules below this one, including boot modules, except
                 -- ourselves.  The 'except ourselves' is so that we don't
-                -- get the instances from this module's hs-boot file
+                -- get the instances from this module's hs-boot file.  This
+                -- filtering also ensures that we don't see instances from
+                -- modules batch (@--make@) compiled before this one, but
+                -- which are not below this one.
               ; want_instances :: ModuleName -> Bool
               ; want_instances mod = mod `elemUFM` dep_mods
                                    && mod /= moduleName this_mod