diff -r 745d31e63c21 -r 13252110a6fe src/HOL/Tools/groebner.ML
--- a/src/HOL/Tools/groebner.ML	Thu Apr 07 22:09:23 2016 +0200
+++ b/src/HOL/Tools/groebner.ML	Fri Apr 08 20:15:20 2016 +0200
@@ -787,7 +787,7 @@
   in
     Simplifier.cert_simproc (Thm.theory_of_thm idl_sub) "poly_eq_simproc"
      {lhss = [Thm.term_of (Thm.lhs_of idl_sub)],
-      proc = fn _ => fn _ => proc, identifier = []}
+      proc = fn _ => fn _ => proc}
   end;
 
 val poly_eq_ss =