Added loom test

.github/workflows/ci.yaml

@@ -71,3 +71,21 @@ jobs:
         run: >
           cargo +nightly miri test --lib
           queue::test::concurrent_enqueues_work
+
+  loom:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 30
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Run Loom model
+        env:
+          RUSTFLAGS: --cfg loom
+        run: >
+          cargo test --release --lib
+          queue::test::loom_concurrent_enqueues_work

Cargo.toml

@@ -18,3 +18,9 @@ static_assertions = "1"
 
 [dev-dependencies]
 tokio = { version = "1", features = ["full"] }
+
+[target.'cfg(loom)'.dependencies]
+loom = "0.7"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(loom)'] }

src/queue.rs

@@ -2,14 +2,15 @@ use std::{
     cell::UnsafeCell,
     mem::{ManuallyDrop, MaybeUninit},
     ops::Not,
-    sync::{
-        Arc, Weak,
-        atomic::{AtomicBool, AtomicPtr, Ordering},
-    },
+    sync::{Arc, Weak},
     task::Waker,
 };
 
 use futures::task::AtomicWaker;
+#[cfg(loom)]
+use loom::sync::atomic::{AtomicBool, AtomicPtr, Ordering};
+#[cfg(not(loom))]
+use std::sync::atomic::{AtomicBool, AtomicPtr, Ordering};
 
 /// Receiver handle for a [`Queue`].
 ///
@@ -358,6 +359,37 @@ mod test {
 
     use crate::queue::Receiver;
 
+    #[cfg(loom)]
+    #[test]
+    fn loom_concurrent_enqueues_work() {
+        loom::model(|| {
+            let mut receiver = Receiver::default();
+            let queue = receiver.queue().clone();
+            let first = queue.create(1);
+            let second = queue.create(2);
+
+            let first_sender = loom::thread::spawn(move || first.enqueue());
+            let second_sender = loom::thread::spawn(move || second.enqueue());
+
+            let mut values = Vec::new();
+            while values.len() < 2 {
+                let Some(node) = receiver.dequeue() else {
+                    loom::thread::yield_now();
+                    continue;
+                };
+                values.push(*node.get().value());
+            }
+
+            first_sender.join().unwrap();
+            second_sender.join().unwrap();
+
+            assert!(receiver.dequeue().is_none());
+
+            values.sort_unstable();
+            assert_eq!(values, [1, 2]);
+        });
+    }
+
     #[tokio::test(flavor = "multi_thread", worker_threads = 5)]
     async fn snapshots_work() {
         const SENDERS: usize = 4;