Add #[must_use] annotation to Result::ok

compiler/rustc_data_structures/src/jobserver.rs

@@ -47,7 +47,7 @@ fn default_client() -> Client {
     let client = Client::new(32).expect("failed to create jobserver");
 
     // Acquire a token for the main thread which we can release later
-    client.acquire_raw().ok();
+    let _ = client.acquire_raw().ok();
 
     client
 }
@@ -62,7 +62,7 @@ pub fn initialize_checked(report_warning: impl FnOnce(&'static str)) {
             default_client()
         }
     };
-    GLOBAL_CLIENT_CHECKED.set(client_checked).ok();
+    let _ = GLOBAL_CLIENT_CHECKED.set(client_checked);
 }
 
 const ACCESS_ERROR: &str = "jobserver check should have been called earlier";
@@ -72,9 +72,9 @@ pub fn client() -> Client {
 }
 
 pub fn acquire_thread() {
-    GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).acquire_raw().ok();
+    let _ = GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).acquire_raw();
 }
 
 pub fn release_thread() {
-    GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).release_raw().ok();
+    let _ = GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).release_raw();
 }

compiler/rustc_data_structures/src/sync/worker_local.rs

@@ -79,7 +79,7 @@ impl Registry {
                     drop(threads);
                     panic!("Thread already has a registry");
                 }
-                registry.set(self.clone()).ok();
+                let _ = registry.set(self.clone());
                 THREAD_DATA.with(|data| {
                     data.registry_id.set(self.id());
                     data.index.set(*threads);

compiler/rustc_query_system/src/query/caches.rs

@@ -99,7 +99,7 @@ where
 
     #[inline]
     fn complete(&self, _key: (), value: V, index: DepNodeIndex) {
-        self.cache.set((value, index)).ok();
+        let _ = self.cache.set((value, index));
     }
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {

library/core/src/result.rs

@@ -655,6 +655,7 @@ impl<T, E> Result<T, E> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_diagnostic_item = "result_ok_method"]
+    #[must_use]
     pub fn ok(self) -> Option<T> {
         match self {
             Ok(x) => Some(x),

library/std/src/collections/hash/set/tests.rs

@@ -446,14 +446,13 @@ fn test_extract_if_drop_panic_leak() {
 
     let mut set = (0..3).map(|i| D(i)).collect::<HashSet<_>>();
 
-    catch_unwind(move || {
+    let _ = catch_unwind(move || {
         set.extract_if(|_| {
             PREDS.fetch_add(1, Ordering::SeqCst);
             true
         })
         .for_each(drop)
-    })
-    .ok();
+    });
 
     assert_eq!(PREDS.load(Ordering::SeqCst), 2);
     assert_eq!(DROPS.load(Ordering::SeqCst), 3);
@@ -475,14 +474,13 @@ fn test_extract_if_pred_panic_leak() {
 
     let mut set: HashSet<_> = (0..3).map(|_| D).collect();
 
-    catch_unwind(AssertUnwindSafe(|| {
+    let _ = catch_unwind(AssertUnwindSafe(|| {
         set.extract_if(|_| match PREDS.fetch_add(1, Ordering::SeqCst) {
             0 => true,
             _ => panic!(),
         })
         .for_each(drop)
-    }))
-    .ok();
+    }));
 
     assert_eq!(PREDS.load(Ordering::SeqCst), 1);
     assert_eq!(DROPS.load(Ordering::SeqCst), 3);

library/std/src/panicking.rs

@@ -322,7 +322,7 @@ fn default_hook(info: &PanicHookInfo<'_>) {
 
     if let Ok(Some(local)) = try_set_output_capture(None) {
         write(&mut *local.lock().unwrap_or_else(|e| e.into_inner()));
-        try_set_output_capture(Some(local)).ok();
+        let _ = try_set_output_capture(Some(local));
     } else if let Some(mut out) = panic_output() {
         write(&mut out);
     }

src/tools/miri/src/shims/unix/fd.rs

@@ -88,7 +88,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             // If old_fd and new_fd point to the same description, then `dup_fd` ensures we keep the underlying file description alive.
             if let Some(old_new_fd) = this.machine.fds.fds.insert(new_fd_num, fd) {
                 // Ignore close error (not interpreter's) according to dup2() doc.
-                old_new_fd.close_ref(this.machine.communicate(), this)?.ok();
+                let _ = old_new_fd.close_ref(this.machine.communicate(), this)?;
             }
         }
         interp_ok(Scalar::from_i32(new_fd_num))