diff --git a/tokio/src/macros/cfg.rs b/tokio/src/macros/cfg.rs
index 3836aa78b9d..b6beb3d6952 100644
--- a/tokio/src/macros/cfg.rs
+++ b/tokio/src/macros/cfg.rs
@@ -373,6 +373,16 @@ macro_rules! cfg_trace {
     };
 }
 
+macro_rules! cfg_unstable {
+    ($($item:item)*) => {
+        $(
+            #[cfg(tokio_unstable)]
+            #[cfg_attr(docsrs, doc(cfg(tokio_unstable)))]
+            $item
+        )*
+    };
+}
+
 macro_rules! cfg_not_trace {
     ($($item:item)*) => {
         $(
diff --git a/tokio/src/runtime/task/mod.rs b/tokio/src/runtime/task/mod.rs
index 15e36a0d897..2a492dc985d 100644
--- a/tokio/src/runtime/task/mod.rs
+++ b/tokio/src/runtime/task/mod.rs
@@ -135,6 +135,10 @@
 //! poll call will notice it when the poll finishes, and the task is cancelled
 //! at that point.
 
+// Some task infrastructure is here to support `JoinSet`, which is currently
+// unstable. This should be removed once `JoinSet` is stabilized.
+#![cfg_attr(not(tokio_unstable), allow(dead_code))]
+
 mod core;
 use self::core::Cell;
 use self::core::Header;
diff --git a/tokio/src/task/mod.rs b/tokio/src/task/mod.rs
index 7d254190148..d532155a1fe 100644
--- a/tokio/src/task/mod.rs
+++ b/tokio/src/task/mod.rs
@@ -300,8 +300,10 @@ cfg_rt! {
     mod unconstrained;
     pub use unconstrained::{unconstrained, Unconstrained};
 
-    mod join_set;
-    pub use join_set::JoinSet;
+    cfg_unstable! {
+        mod join_set;
+        pub use join_set::JoinSet;
+    }
 
     cfg_trace! {
         mod builder;
diff --git a/tokio/src/util/mod.rs b/tokio/src/util/mod.rs
index 41a3bce051f..618f5543802 100644
--- a/tokio/src/util/mod.rs
+++ b/tokio/src/util/mod.rs
@@ -44,8 +44,10 @@ pub(crate) mod linked_list;
 mod rand;
 
 cfg_rt! {
-    mod idle_notified_set;
-    pub(crate) use idle_notified_set::IdleNotifiedSet;
+    cfg_unstable! {
+        mod idle_notified_set;
+        pub(crate) use idle_notified_set::IdleNotifiedSet;
+    }
 
     mod wake;
     pub(crate) use wake::WakerRef;
diff --git a/tokio/tests/async_send_sync.rs b/tokio/tests/async_send_sync.rs
index c7e15c4775e..ea4445a27f1 100644
--- a/tokio/tests/async_send_sync.rs
+++ b/tokio/tests/async_send_sync.rs
@@ -434,13 +434,6 @@ async_assert_fn!(tokio::sync::watch::Receiver<YY>::changed(_): Send & Sync & !Un
 async_assert_fn!(tokio::sync::watch::Sender<NN>::closed(_): !Send & !Sync & !Unpin);
 async_assert_fn!(tokio::sync::watch::Sender<YN>::closed(_): !Send & !Sync & !Unpin);
 async_assert_fn!(tokio::sync::watch::Sender<YY>::closed(_): Send & Sync & !Unpin);
-
-async_assert_fn!(tokio::task::JoinSet<Cell<u32>>::join_one(_): Send & Sync & !Unpin);
-async_assert_fn!(tokio::task::JoinSet<Cell<u32>>::shutdown(_): Send & Sync & !Unpin);
-async_assert_fn!(tokio::task::JoinSet<Rc<u32>>::join_one(_): !Send & !Sync & !Unpin);
-async_assert_fn!(tokio::task::JoinSet<Rc<u32>>::shutdown(_): !Send & !Sync & !Unpin);
-async_assert_fn!(tokio::task::JoinSet<u32>::join_one(_): Send & Sync & !Unpin);
-async_assert_fn!(tokio::task::JoinSet<u32>::shutdown(_): Send & Sync & !Unpin);
 async_assert_fn!(tokio::task::LocalKey<Cell<u32>>::scope(_, Cell<u32>, BoxFuture<()>): !Send & !Sync & !Unpin);
 async_assert_fn!(tokio::task::LocalKey<Cell<u32>>::scope(_, Cell<u32>, BoxFutureSend<()>): Send & !Sync & !Unpin);
 async_assert_fn!(tokio::task::LocalKey<Cell<u32>>::scope(_, Cell<u32>, BoxFutureSync<()>): Send & !Sync & !Unpin);
@@ -458,10 +451,20 @@ assert_value!(tokio::task::JoinError: Send & Sync & Unpin);
 assert_value!(tokio::task::JoinHandle<NN>: !Send & !Sync & Unpin);
 assert_value!(tokio::task::JoinHandle<YN>: Send & Sync & Unpin);
 assert_value!(tokio::task::JoinHandle<YY>: Send & Sync & Unpin);
-assert_value!(tokio::task::JoinSet<YY>: Send & Sync & Unpin);
-assert_value!(tokio::task::JoinSet<YN>: Send & Sync & Unpin);
-assert_value!(tokio::task::JoinSet<NN>: !Send & !Sync & Unpin);
-assert_value!(tokio::task::LocalSet: !Send & !Sync & Unpin);
+#[cfg(tokio_unstable)]
+mod unstable {
+    use super::*;
+    async_assert_fn!(tokio::task::JoinSet<Cell<u32>>::join_one(_): Send & Sync & !Unpin);
+    async_assert_fn!(tokio::task::JoinSet<Cell<u32>>::shutdown(_): Send & Sync & !Unpin);
+    async_assert_fn!(tokio::task::JoinSet<Rc<u32>>::join_one(_): !Send & !Sync & !Unpin);
+    async_assert_fn!(tokio::task::JoinSet<Rc<u32>>::shutdown(_): !Send & !Sync & !Unpin);
+    async_assert_fn!(tokio::task::JoinSet<u32>::join_one(_): Send & Sync & !Unpin);
+    async_assert_fn!(tokio::task::JoinSet<u32>::shutdown(_): Send & Sync & !Unpin);
+    assert_value!(tokio::task::JoinSet<YY>: Send & Sync & Unpin);
+    assert_value!(tokio::task::JoinSet<YN>: Send & Sync & Unpin);
+    assert_value!(tokio::task::JoinSet<NN>: !Send & !Sync & Unpin);
+    assert_value!(tokio::task::LocalSet: !Send & !Sync & Unpin);
+}
 
 assert_value!(tokio::runtime::Builder: Send & Sync & Unpin);
 assert_value!(tokio::runtime::EnterGuard<'_>: Send & Sync & Unpin);
diff --git a/tokio/tests/task_join_set.rs b/tokio/tests/task_join_set.rs
index 574f216620e..66a2fbb021d 100644
--- a/tokio/tests/task_join_set.rs
+++ b/tokio/tests/task_join_set.rs
@@ -1,5 +1,5 @@
 #![warn(rust_2018_idioms)]
-#![cfg(feature = "full")]
+#![cfg(all(feature = "full", tokio_unstable))]
 
 use tokio::sync::oneshot;
 use tokio::task::JoinSet;