$OpenBSD: patch-src_Pugs_AST_Types_hs,v 1.1 2010/09/14 18:58:01 kili Exp $
--- src/Pugs/AST/Types.hs.orig	Wed Dec 16 15:02:44 2009
+++ src/Pugs/AST/Types.hs	Tue Sep 14 20:37:46 2010
@@ -21,7 +21,11 @@ data VThread = MkThread
     { threadId      :: ThreadId
     , threadLock    :: TMVar Val
     }
-    deriving (Show, Eq, Ord, Typeable)
+    deriving (Show, Ord, Typeable)
+
+instance Eq VThread where
+    v == w = threadId v == threadId w &&
+             addressOf (threadLock v) == addressOf (threadLock w)
 
 data VSubst
     = MkSubst
