From 2fba07842b2553f5abaada91590817032df36f7d Mon Sep 17 00:00:00 2001
From: Markus Everling <markuseverling@gmail.com>
Date: Thu, 1 Dec 2022 12:13:58 +0100
Subject: [PATCH] Make `VecDeque::new` const

---
 library/alloc/src/collections/vec_deque/mod.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index 86d77182bccee..30514cbba92a6 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -531,12 +531,13 @@ impl<T> VecDeque<T> {
     ///
     /// let deque: VecDeque<u32> = VecDeque::new();
     /// ```
-    // FIXME: This should probably be const
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_stable(feature = "const_vec_deque_new", since = "CURRENT_RUSTC_VERSION")]
     #[must_use]
-    pub fn new() -> VecDeque<T> {
-        VecDeque::new_in(Global)
+    pub const fn new() -> VecDeque<T> {
+        // FIXME: This should just be `VecDeque::new_in(Global)` once that hits stable.
+        VecDeque { head: 0, len: 0, buf: RawVec::NEW }
     }
 
     /// Creates an empty deque with space for at least `capacity` elements.