diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
index 5f0b4088fc0..a167b2e57c0 100644
--- a/src/liballoc/str.rs
+++ b/src/liballoc/str.rs
@@ -363,16 +363,16 @@ impl str {
     /// # Examples
     ///
     /// ```
-    /// let mut v = String::from("🗻∈🌏");
+    /// let v = String::from("🗻∈🌏");
     ///
     /// assert_eq!(Some("🗻"), v.get(0..4));
     ///
     /// // indices not on UTF-8 sequence boundaries
-    /// assert!(v.get_mut(1..).is_none());
-    /// assert!(v.get_mut(..8).is_none());
+    /// assert!(v.get(1..).is_none());
+    /// assert!(v.get(..8).is_none());
     ///
     /// // out of bounds
-    /// assert!(v.get_mut(..42).is_none());
+    /// assert!(v.get(..42).is_none());
     /// ```
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
     #[inline]