diff -r 163626ddaa19 -r 919a1b23c192 src/HOL/Library/Tree.thy
--- a/src/HOL/Library/Tree.thy Wed Oct 03 13:20:05 2018 +0200
+++ b/src/HOL/Library/Tree.thy Wed Oct 03 20:55:59 2018 +0200
@@ -351,7 +351,7 @@
have "(2::nat) ^ height t \ 2 ^ height t'"
proof -
have "2 ^ height t = size1 t"
- using True by (simp add: complete_iff_height size1_if_complete)
+ using True by (simp add: size1_if_complete)
also have "\ \ size1 t'" using assms(2) by(simp add: size1_size)
also have "\ \ 2 ^ height t'" by (rule size1_height)
finally show ?thesis .