diff -r 665862241968 -r 1eac228c52b3 src/HOL/Tools/Function/scnp_reconstruct.ML
--- a/src/HOL/Tools/Function/scnp_reconstruct.ML	Wed Nov 03 11:06:22 2010 +0100
+++ b/src/HOL/Tools/Function/scnp_reconstruct.ML	Wed Nov 03 11:11:49 2010 +0100
@@ -171,8 +171,8 @@
           else (thm COMP (Thm.lift_rule (cprop_of thm) @{thm less_imp_le}))
         | SOME (Termination.LessEq (thm, _))  =>
           if not bStrict then thm
-          else sys_error "get_desc_thm"
-        | _ => sys_error "get_desc_thm"
+          else raise Fail "get_desc_thm"
+        | _ => raise Fail "get_desc_thm"
 
     val (label, lev, sl, covering) = certificate