util: add `const fn` support for internal `LinkedList`. (#2805)

3 files changed, 6 insertions, 4 deletions

diff --git a/tokio/src/sync/batch_semaphore.rs b/tokio/src/sync/batch_semaphore.rs
index aad6c6f1..c48a911c 100644
--- a/tokio/src/sync/batch_semaphore.rs
+++ b/tokio/src/sync/batch_semaphore.rs
@@ -36,7 +36,7 @@ pub(crate) struct Semaphore {
 }
 
 struct Waitlist {
-    queue: LinkedList<Waiter>,
+    queue: LinkedList<Waiter, <Waiter as linked_list::Link>::Target>,
     closed: bool,
 }
 
diff --git a/tokio/src/sync/broadcast.rs b/tokio/src/sync/broadcast.rs
index a64774ec..9b3de530 100644
--- a/tokio/src/sync/broadcast.rs
+++ b/tokio/src/sync/broadcast.rs
@@ -273,7 +273,7 @@ struct Tail {
     closed: bool,
 
     /// Receivers waiting for a value
-    waiters: LinkedList<Waiter>,
+    waiters: LinkedList<Waiter, <Waiter as linked_list::Link>::Target>,
 }
 
 /// Slot in the buffer
diff --git a/tokio/src/sync/notify.rs b/tokio/src/sync/notify.rs
index 84a94823..def704f2 100644
--- a/tokio/src/sync/notify.rs
+++ b/tokio/src/sync/notify.rs
@@ -10,6 +10,8 @@ use std::ptr::NonNull;
 use std::sync::atomic::Ordering::SeqCst;
 use std::task::{Context, Poll, Waker};
 
+type WaitList = LinkedList<Waiter, <Waiter as linked_list::Link>::Target>;
+
 /// Notify a single task to wake up.
 ///
 /// `Notify` provides a basic mechanism to notify a single task of an event.
@@ -101,7 +103,7 @@ use std::task::{Context, Poll, Waker};
 #[derive(Debug)]
 pub struct Notify {
     state: AtomicU8,
-    waiters: Mutex<LinkedList<Waiter>>,
+    waiters: Mutex<WaitList>,
 }
 
 #[derive(Debug)]
@@ -285,7 +287,7 @@ impl Default for Notify {
     }
 }
 
-fn notify_locked(waiters: &mut LinkedList<Waiter>, state: &AtomicU8, curr: u8) -> Option<Waker> {
+fn notify_locked(waiters: &mut WaitList, state: &AtomicU8, curr: u8) -> Option<Waker> {
     loop {
         match curr {
             EMPTY | NOTIFIED => {