From 7eaecc6508149da3a0e76982f1259f5bf3cf54a8 Mon Sep 17 00:00:00 2001
From: cyqsimon <28627918+cyqsimon@users.noreply.github.com>
Date: Sat, 12 Feb 2022 12:12:11 +0800
Subject: [PATCH] `Result::and_then`: improve basic example

---
 library/core/src/result.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 58d58ff0f72e..d6a0c7dc2929 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -1282,12 +1282,14 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```
-    /// fn squared_string(x: u32) -> Result<String, &'static str> {
-    ///     Ok((x * x).to_string())
+    /// fn sq(x: u32) -> Result<u32, &'static str> {
+    ///     x.checked_mul(x).ok_or("overflowed")
     /// }
     ///
-    /// assert_eq!(Ok(2).and_then(squared_string), Ok(4.to_string()));
-    /// assert_eq!(Err("not a number").and_then(squared_string), Err("not a number"));
+    /// assert_eq!(Ok(2).and_then(sq), Ok(4));
+    /// assert_eq!(Ok(1_000_000).and_then(sq), Err("overflowed"));
+    /// assert_eq!(Err("not a number").and_then(sq), Err("not a number"));
+
     /// ```
     ///
     /// Often used to chain fallible operations that may return [`Err`].