diff -r 437bd400d808 -r f9f3006a5579 src/HOL/Power.thy
--- a/src/HOL/Power.thy	Tue Aug 09 23:29:54 2016 +0200
+++ b/src/HOL/Power.thy	Wed Aug 10 09:33:54 2016 +0200
@@ -112,7 +112,7 @@
 
 lemma power_minus_mult:
   "0 < n \<Longrightarrow> a ^ (n - 1) * a = a ^ n"
-  by (simp add: power_commutes split add: nat_diff_split)
+  by (simp add: power_commutes split: nat_diff_split)
 
 end