From d9e877fb98212a47dd425e145b8b3e4283e6b487 Mon Sep 17 00:00:00 2001
From: dylni <46035563+dylni@users.noreply.github.com>
Date: Mon, 24 Aug 2020 10:53:25 -0400
Subject: [PATCH] Add more information to safety comment
---
library/alloc/src/collections/vec_deque.rs | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/library/alloc/src/collections/vec_deque.rs b/library/alloc/src/collections/vec_deque.rs
index 54cf548fac5..04014c8eb5a 100644
--- a/library/alloc/src/collections/vec_deque.rs
+++ b/library/alloc/src/collections/vec_deque.rs
@@ -1086,7 +1086,9 @@ impl<T> VecDeque<T> {
where
R: RangeBounds<usize>,
{
- // SAFETY: This buffer is only used to check the range.
+ // SAFETY: This buffer is only used to check the range. It might be partially
+ // uninitialized, but `check_range` needs a contiguous slice.
+ // https://github.com/rust-lang/rust/pull/75207#discussion_r471193682
let buffer = unsafe { slice::from_raw_parts(self.ptr(), self.len()) };
let Range { start, end } = buffer.check_range(range);
let tail = self.wrap_add(self.tail, start);