From bbc230478c5a282a83592830dc338407ed9804eb Mon Sep 17 00:00:00 2001
From: Sven Bartscher <sven.bartscher@netapp.com>
Date: Mon, 9 Oct 2023 11:08:48 +0200
Subject: [PATCH] Make BTreeMap::new_in const

Closes rust-lang/wg-allocators#118
---
 library/alloc/src/collections/btree/map.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 5481b327d69..4bdd9639557 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -669,7 +669,7 @@ pub fn clear(&mut self) {
     /// map.insert(1, "a");
     /// ```
     #[unstable(feature = "btreemap_alloc", issue = "32838")]
-    pub fn new_in(alloc: A) -> BTreeMap<K, V, A> {
+    pub const fn new_in(alloc: A) -> BTreeMap<K, V, A> {
         BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(alloc), _marker: PhantomData }
     }
 }