chore: Prepare for Rust edition bump to 2024 (without autofix) (#27791)

Successor to #27779 - in this PR I've applied changes manually, without
futzing with if let lifetimes at all.

Release Notes:

- N/A

crates/client/src/client.rs

@@ -817,7 +817,7 @@ impl Client {
             | Status::Reauthenticating { .. }
             | Status::ReconnectionError { .. } => false,
             Status::Connected { .. } | Status::Connecting { .. } | Status::Reconnecting { .. } => {
-                return Ok(())
+                return Ok(());
             }
             Status::UpgradeRequired => return Err(EstablishConnectionError::UpgradeRequired)?,
         };
@@ -1024,7 +1024,7 @@ impl Client {
         &self,
         http: Arc<HttpClientWithUrl>,
         release_channel: Option<ReleaseChannel>,
-    ) -> impl Future<Output = Result<url::Url>> {
+    ) -> impl Future<Output = Result<url::Url>> + use<> {
         #[cfg(any(test, feature = "test-support"))]
         let url_override = self.rpc_url.read().clone();
 
@@ -1444,7 +1444,7 @@ impl Client {
     pub fn request<T: RequestMessage>(
         &self,
         request: T,
-    ) -> impl Future<Output = Result<T::Response>> {
+    ) -> impl Future<Output = Result<T::Response>> + use<T> {
         self.request_envelope(request)
             .map_ok(|envelope| envelope.payload)
     }
@@ -1476,7 +1476,7 @@ impl Client {
     pub fn request_envelope<T: RequestMessage>(
         &self,
         request: T,
-    ) -> impl Future<Output = Result<TypedEnvelope<T::Response>>> {
+    ) -> impl Future<Output = Result<TypedEnvelope<T::Response>>> + use<T> {
         let client_id = self.id();
         log::debug!(
             "rpc request start. client_id:{}. name:{}",
@@ -1501,7 +1501,7 @@ impl Client {
         &self,
         envelope: proto::Envelope,
         request_type: &'static str,
-    ) -> impl Future<Output = Result<proto::Envelope>> {
+    ) -> impl Future<Output = Result<proto::Envelope>> + use<> {
         let client_id = self.id();
         log::debug!(
             "rpc request start. client_id:{}. name:{}",

crates/client/src/telemetry.rs

@@ -273,14 +273,14 @@ impl Telemetry {
     }
 
     #[cfg(any(test, feature = "test-support"))]
-    fn shutdown_telemetry(self: &Arc<Self>) -> impl Future<Output = ()> {
+    fn shutdown_telemetry(self: &Arc<Self>) -> impl Future<Output = ()> + use<> {
         Task::ready(())
     }
 
     // Skip calling this function in tests.
     // TestAppContext ends up calling this function on shutdown and it panics when trying to find the TelemetrySettings
     #[cfg(not(any(test, feature = "test-support")))]
-    fn shutdown_telemetry(self: &Arc<Self>) -> impl Future<Output = ()> {
+    fn shutdown_telemetry(self: &Arc<Self>) -> impl Future<Output = ()> + use<> {
         telemetry::event!("App Closed");
         // TODO: close final edit period and make sure it's sent
         Task::ready(())

crates/client/src/user.rs

@@ -581,7 +581,7 @@ impl UserStore {
         })
     }
 
-    pub fn clear_contacts(&self) -> impl Future<Output = ()> {
+    pub fn clear_contacts(&self) -> impl Future<Output = ()> + use<> {
         let (tx, mut rx) = postage::barrier::channel();
         self.update_contacts_tx
             .unbounded_send(UpdateContacts::Clear(tx))