diff -r c5d1a01d2d6c -r d7d90ed4c74e src/HOL/Analysis/Simplex_Content.thy
--- a/src/HOL/Analysis/Simplex_Content.thy	Fri Sep 25 12:05:21 2020 +0100
+++ b/src/HOL/Analysis/Simplex_Content.thy	Fri Sep 25 14:11:48 2020 +0100
@@ -89,7 +89,7 @@
   also have "t ^ n / n / fact (card A) = t ^ n / fact n"
     by (simp add: n_def)
   also have "n = card (insert b A)"
-    using insert.hyps by (subst card_insert) (auto simp: n_def)
+    using insert.hyps by (subst card.insert_remove) (auto simp: n_def)
   finally show ?case .
 qed