From 7976819967f93f61e0f47409d398cd108c5428ab Mon Sep 17 00:00:00 2001
From: CreativeStoic <xianmasur@gmail.com>
Date: Thu, 18 Jul 2024 15:48:10 -0400
Subject: [PATCH] fix unsoundness in mapped_futures cancel

---
 futures-util/src/stream/mapped_futures/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/futures-util/src/stream/mapped_futures/mod.rs b/futures-util/src/stream/mapped_futures/mod.rs
index dfb37a756..4df4a95c9 100644
--- a/futures-util/src/stream/mapped_futures/mod.rs
+++ b/futures-util/src/stream/mapped_futures/mod.rs
@@ -166,7 +166,8 @@ impl<K: Hash + Eq, Fut> MappedFutures<K, Fut> {
         // if let Some(task) = self.hash_set.get(key) {
         if let Some(task) = self.set().take(key) {
             unsafe {
-                if let Some(_) = (*task.future.get()).take() {
+                if (*task.future.get()).is_some() {
+                    task.future.get().write(None);
                     self.inner.unlink(Arc::as_ptr(&task.inner));
                     return true;
                 }