From 6aeeda714e04ac34205a7b948e5585e00d0fa14d Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Mon, 9 Jul 2018 13:25:36 -0700 Subject: [PATCH] doc: Clarify the lifetime returned by `Box::leak` `Box::leak` mentions that it can return a `'static` reference, but it wasn't immediately clear to me why it doesn't always do so. This is because of the `T: 'a` constraint needed to form a valid reference, and in general we want to be more flexible than requiring `T: 'static`. This patch tries to clarify the relationship between `T` and `'a`. --- src/liballoc/boxed.rs | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs index fb16bdf0ab43a..8a65843b50d7d 100644 --- a/src/liballoc/boxed.rs +++ b/src/liballoc/boxed.rs @@ -194,7 +194,9 @@ impl Box { } /// Consumes and leaks the `Box`, returning a mutable reference, - /// `&'a mut T`. Here, the lifetime `'a` may be chosen to be `'static`. + /// `&'a mut T`. Note that the type `T` must outlive the chosen lifetime + /// `'a`. If the type has only static references, or none at all, then this + /// may be chosen to be `'static`. /// /// This function is mainly useful for data that lives for the remainder of /// the program's life. Dropping the returned reference will cause a memory