Improve handling of newtypes (fixes Trac 1495)

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

diff --git a/compiler/main/TidyPgm.lhs b/compiler/main/TidyPgm.lhs
index 131b617..fc951cc 100644 (file)
--- a/compiler/main/TidyPgm.lhs
+++ b/compiler/main/TidyPgm.lhs
@@ -403,13 +403,14 @@ mustExposeTyCon exports tc
   | isEnumerationTyCon tc      -- For an enumeration, exposing the constructors
   = True                       -- won't lead to the need for further exposure
                                -- (This includes data types with no constructors.)
-  | isOpenTyCon tc             -- open type family
+  | isOpenTyCon tc             -- Open type family
   = True
+
   | otherwise                  -- Newtype, datatype
   = any exported_con (tyConDataCons tc)
        -- Expose rep if any datacon or field is exported
 
-  || (isNewTyCon tc && isFFITy (snd (newTyConRep tc)))
+  || (isNewTyCon tc && isFFITy (snd (newTyConRhs tc)))
        -- Expose the rep for newtypes if the rep is an FFI type.  
        -- For a very annoying reason.  'Foreign import' is meant to
        -- be able to look through newtypes transparently, but it