From 21d2a6c9868541ec9829ced9a5bae936b18741c5 Mon Sep 17 00:00:00 2001
From: MaloJaffre <jaffre.malo@gmail.com>
Date: Wed, 29 Aug 2018 13:39:57 +0200
Subject: [PATCH] Add another assert

---
 src/liballoc/collections/vec_deque.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index 7b6693268ae..c53549ab85d 100644
--- a/src/liballoc/collections/vec_deque.rs
+++ b/src/liballoc/collections/vec_deque.rs
@@ -19,6 +19,7 @@
 
 use core::cmp::Ordering;
 use core::fmt;
+use core::isize;
 use core::iter::{repeat, FromIterator, FusedIterator};
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
@@ -210,6 +211,9 @@ impl<T> VecDeque<T> {
     /// If so, this function never panics.
     #[inline]
     unsafe fn copy_slice(&mut self, src: &[T]) {
+        /// This is guaranteed by `RawVec`.
+        debug_assert!(self.capacity() <= isize::MAX as usize);
+
         let expected_new_len = self.len() + src.len();
         debug_assert!(self.capacity() >= expected_new_len);