Add another assert

diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index 7b6693268ae3f60709665b2c0d27bc1c81d2990f..c53549ab85d6d5aa075e9f0e168f0d4e512ae206 100644 (file)
--- 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 @@ unsafe fn copy_nonoverlapping(&self, dst: usize, src: usize, len: usize) {
     /// 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);