diff -r 92de7d74b8f8 -r e1b262e7480c src/HOL/Algebra/Cycles.thy
--- a/src/HOL/Algebra/Cycles.thy	Tue Jun 16 08:41:39 2020 +0000
+++ b/src/HOL/Algebra/Cycles.thy	Tue Jun 16 08:41:39 2020 +0000
@@ -160,7 +160,7 @@
       using aui_lemma[OF assms] by simp
   next
     case 2 thus ?thesis
-      using aui_lemma[OF assms(2,1)] assms(3) by (simp add: ac_simps(8))
+      using aui_lemma[OF assms(2,1)] assms(3) by (simp add: ac_simps)
   next
     case 3 thus ?thesis
       by (simp add: id_outside_supp)