enable let_underscore_must_use lint

src/service/admin.rs

@@ -29,6 +29,7 @@ use ruma::{
 };
 use serde_json::value::to_raw_value;
 use tokio::sync::{mpsc, Mutex, RwLock};
+use tracing::warn;
 
 use crate::{
     api::client_server::{leave_all_rooms, AUTO_GEN_PASSWORD_LENGTH},
@@ -784,7 +785,9 @@ impl Service {
 
                     if leave_rooms {
                         for &user_id in &user_ids {
-                            let _ = leave_all_rooms(user_id).await;
+                            if let Err(error) = leave_all_rooms(user_id).await {
+                                warn!(%user_id, %error, "failed to leave one or more rooms");
+                            }
                         }
                     }
 

src/service/globals.rs

@@ -92,12 +92,12 @@ impl RotationHandler {
         let mut r = self.0.subscribe();
 
         async move {
-            let _ = r.recv().await;
+            r.recv().await.expect("should receive a message");
         }
     }
 
     pub(crate) fn fire(&self) {
-        let _ = self.0.send(());
+        self.0.send(()).expect("should be able to send message");
     }
 }
 

src/service/rooms/edus/typing.rs

@@ -1,6 +1,7 @@
 use ruma::{events::SyncEphemeralRoomEvent, OwnedRoomId, OwnedUserId, RoomId, UserId};
 use std::collections::BTreeMap;
 use tokio::sync::{broadcast, RwLock};
+use tracing::trace;
 
 use crate::{services, utils, Result};
 
@@ -29,7 +30,9 @@ impl Service {
             .write()
             .await
             .insert(room_id.to_owned(), services().globals.next_count()?);
-        let _ = self.typing_update_sender.send(room_id.to_owned());
+        if self.typing_update_sender.send(room_id.to_owned()).is_err() {
+            trace!("receiver found what it was looking for and is no longer interested");
+        }
         Ok(())
     }
 
@@ -45,7 +48,9 @@ impl Service {
             .write()
             .await
             .insert(room_id.to_owned(), services().globals.next_count()?);
-        let _ = self.typing_update_sender.send(room_id.to_owned());
+        if self.typing_update_sender.send(room_id.to_owned()).is_err() {
+            trace!("receiver found what it was looking for and is no longer interested");
+        }
         Ok(())
     }
 
@@ -86,7 +91,9 @@ impl Service {
                 .write()
                 .await
                 .insert(room_id.to_owned(), services().globals.next_count()?);
-            let _ = self.typing_update_sender.send(room_id.to_owned());
+            if self.typing_update_sender.send(room_id.to_owned()).is_err() {
+                trace!("receiver found what it was looking for and is no longer interested");
+            }
         }
         Ok(())
     }

src/service/rooms/event_handler.rs

@@ -1533,19 +1533,22 @@ impl Service {
 
             // Try to fetch keys, failure is okay
             // Servers we couldn't find in the cache will be added to `servers`
-            for pdu in &event.room_state.state {
-                let _ = self
+            for pdu in event
+                .room_state
+                .state
+                .iter()
+                .chain(&event.room_state.auth_chain)
+            {
+                if let Err(error) = self
                     .get_server_keys_from_cache(pdu, &mut servers, room_version, &mut pkm)
-                    .await;
-            }
-            for pdu in &event.room_state.auth_chain {
-                let _ = self
-                    .get_server_keys_from_cache(pdu, &mut servers, room_version, &mut pkm)
-                    .await;
+                    .await
+                {
+                    debug!(%error, "failed to get server keys from cache");
+                };
             }
 
             drop(pkm);
-        }
+        };
 
         if servers.is_empty() {
             info!("We had all keys locally");