diff --git a/src/lib.rs b/src/lib.rs
index 2232f37a..5380cad1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -25,7 +25,7 @@
 #![cfg_attr(not(feature = "sha2"), doc = "```ignore")]
 //! use rsa::{RsaPrivateKey, RsaPublicKey, Oaep, sha2::Sha256};
 //!
-//! let mut rng = rand::thread_rng();
+//! let mut rng = rand::thread_rng(); // rand@0.8
 //!
 //! let bits = 2048;
 //! let private_key = RsaPrivateKey::new(&mut rng, bits).expect("failed to generate a key");