prevent spurious timeouts

--- a/src/HOL/Metis_Examples/Proxies.thy	Mon May 07 12:20:55 2012 +0200
+++ b/src/HOL/Metis_Examples/Proxies.thy	Mon May 07 14:50:49 2012 +0200
@@ -34,7 +34,7 @@
 "add_swap = (\<lambda>x y. y + x)"
 
 lemma "add_swap m n = n + m"
-sledgehammer [expect = some]
+sledgehammer [expect = some] (add_swap_def)
 by (metis_exhaust add_swap_def)
 
 definition "A = {xs\<Colon>'a list. True}"