--- a/Nominal/Parser.thy	Thu Mar 18 18:10:20 2010 +0100
+++ b/Nominal/Parser.thy	Thu Mar 18 23:19:55 2010 +0100
@@ -410,7 +410,7 @@
   val (_, lthy20) = Local_Theory.note ((Binding.empty,
     [Attrib.internal (fn _ => Nominal_ThmDecls.eqvt_add)]), q_eqvt) lthy19;
   val _ = tracing "Finite Support";
-  val supports = map (prove_supports lthy20 q_perm) consts
+  val supports = map (prove_supports lthy20 q_perm) consts handle _ => []
   val fin_supp = HOLogic.conj_elims (prove_fs lthy20 q_induct supports q_tys) handle _ => []
   val thy3 = Local_Theory.exit_global lthy20;
   val lthy21 = Theory_Target.instantiation (qty_full_names, [], @{sort fs}) thy3;