diff -r 8f84a608883d -r ea97aa6aeba2 src/HOL/Divides.thy
--- a/src/HOL/Divides.thy	Tue Dec 30 08:18:54 2008 +0100
+++ b/src/HOL/Divides.thy	Tue Dec 30 11:10:01 2008 +0100
@@ -127,7 +127,7 @@
   note that ultimately show thesis by blast
 qed
 
-lemma dvd_eq_mod_eq_0 [code]: "a dvd b \<longleftrightarrow> b mod a = 0"
+lemma dvd_eq_mod_eq_0 [code unfold]: "a dvd b \<longleftrightarrow> b mod a = 0"
 proof
   assume "b mod a = 0"
   with mod_div_equality [of b a] have "b div a * a = b" by simp