From fb7deda27419eae61da3cbf5a5b1b4f51ae16d04 Mon Sep 17 00:00:00 2001
From: Scott McMurray <scottmcm@users.noreply.github.com>
Date: Fri, 30 Mar 2018 23:06:05 -0700
Subject: Add #[must_use] to a few standard library methods

Chosen to start a precedent of using it on ones that are potentially-expensive and where using it for side effects is particularly discouraged.

Discuss :)
---
 src/liballoc/borrow.rs | 1 +
 1 file changed, 1 insertion(+)

(limited to 'src/liballoc')

diff --git a/src/liballoc/borrow.rs b/src/liballoc/borrow.rs
index acae0daa86b..c6741ddb822 100644
--- a/src/liballoc/borrow.rs
+++ b/src/liballoc/borrow.rs
@@ -59,6 +59,7 @@ pub trait ToOwned {
     /// let vv: Vec<i32> = v.to_owned();
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use = "cloning is often expensive and is not expected to have side effects"]
     fn to_owned(&self) -> Self::Owned;
 
     /// Uses borrowed data to replace owned data, usually by cloning.
-- 
cgit 1.4.1-3-g733a5