diff --git a/src/libcore/time.rs b/src/libcore/time.rs
index 6a5ba0afa42a6b1a4660d56c4dc1a0bbc37af8be..5a0e4388e0325b485f66d4e841dc9c1d7dcd638d 100644
--- a/src/libcore/time.rs
+++ b/src/libcore/time.rs
@@ -689,6 +689,7 @@ pub fn div_f32(self, rhs: f32) -> Duration {
     ///
     /// # Examples
     /// ```
+    /// #![feature(div_duration)]
     /// use std::time::Duration;
     ///
     /// let dur1 = Duration::new(2, 700_000_000);
@@ -705,6 +706,7 @@ pub fn div_duration_f64(self, rhs: Duration) -> f64 {
     ///
     /// # Examples
     /// ```
+    /// #![feature(div_duration)]
     /// use std::time::Duration;
     ///
     /// let dur1 = Duration::new(2, 700_000_000);