[project @ 2005-07-22 14:00:34 by simonpj]

[ghc-hetmet.git] / ghc / compiler / main / HscTypes.lhs

diff --git a/ghc/compiler/main/HscTypes.lhs b/ghc/compiler/main/HscTypes.lhs
index 3f93389..20e84ab 100644 (file)
--- a/ghc/compiler/main/HscTypes.lhs
+++ b/ghc/compiler/main/HscTypes.lhs
@@ -822,9 +822,16 @@ data Usage
        -- time round, but if someone has added a new rule you might need it this time
 
        -- The export list field is (Just v) if we depend on the export list:
-       --      i.e. we imported the module without saying exactly what we imported
-       -- We need to recompile if the module exports changes, because we might
-       -- now have a name clash in the importing module.
+       --      i.e. we imported the module directly, whether or not we
+       --           enumerated the things we imported, or just imported everything
+       -- We need to recompile if M's exports change, because 
+       -- if the import was    import M,       we might now have a name clash in the 
+       --                                      importing module.
+       -- if the import was    import M(x)     M might no longer export x
+       -- The only way we don't depend on the export list is if we have
+       --                      import M()
+       -- And of course, for modules that aren't imported directly we don't
+       -- depend on their export lists
 \end{code}