X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fiface%2FBuildTyCl.lhs;h=e71eefe33925a35c1b148f8dbc7bb04b3fe71f1f;hb=5463b55b7dadc1e9918edb2d8666bf3ed195bc61;hp=de57feb928e1b9d9f689f392c701c3f25aa01819;hpb=d2ce0f52d42edf32bb9f13796e6ba6edba8bd516;p=ghc-hetmet.git

diff --git a/compiler/iface/BuildTyCl.lhs b/compiler/iface/BuildTyCl.lhs
index de57feb..e71eefe 100644
--- a/compiler/iface/BuildTyCl.lhs
+++ b/compiler/iface/BuildTyCl.lhs
@@ -112,16 +112,14 @@ mkDataTyConRhs :: [DataCon] -> AlgTyConRhs
 mkDataTyConRhs cons
   = DataTyCon {
         data_cons = cons,
-        is_enum = -- We define datatypes with no constructors to not be
-                  -- enumerations; this fixes trac #2578,  Otherwise we
-                  -- end up generating an empty table for
-                  --   <mod>_<type>_closure_tbl
-                  -- which is used by tagToEnum# to map Int# to constructors
-                  -- in an enumeration. The empty table apparently upset
-                  -- the linker.
-                  not (null cons) &&
-                  all isNullarySrcDataCon cons
+        is_enum = not (null cons) && all is_enum_con cons
+		  -- See Note [Enumeration types] in TyCon
     }
+  where
+    is_enum_con con
+       | (_tvs, theta, arg_tys, _res) <- dataConSig con
+       = null theta && null arg_tys
+
 
 mkNewTyConRhs :: Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
 -- ^ Monadic because it makes a Name for the coercion TyCon