diff -r a017ec64f675 -r 7e55468ffe38 gameServer/CoreTypes.hs
--- a/gameServer/CoreTypes.hs	Tue Jun 02 18:37:40 2015 +0100
+++ b/gameServer/CoreTypes.hs	Tue Jun 02 19:51:04 2015 +0100
@@ -38,7 +38,7 @@
 instance NFData B.ByteString
 #endif
 
-instance NFData (Chan a)
+instance NFData (Chan a) where rnf a  = ()
 
 instance NFData Action where
     rnf (AnswerClients chans msg) = chans `deepseq` msg `deepseq` ()