address review: remove several #[allow(dead_code)]

Author: mox692

tokio/src/runtime/driver/op.rs

@@ -9,10 +9,13 @@ use std::task::Poll;
 use std::task::Waker;
 use std::{io, mem};
 
-#[allow(dead_code)]
 #[derive(Debug)]
 pub(crate) enum CancelData {
-    Open(Open),
+    Open(
+        // This field isn't accessed directly, but it holds cancellation data,
+        // so `#[allow(dead_code)]` is needed.
+        #[allow(dead_code)] Open,
+    ),
 }
 
 #[derive(Debug)]
@@ -25,15 +28,17 @@ pub(crate) enum Lifecycle {
 
     /// The submitter no longer has interest in the operation result. The state
     /// must be passed to the driver and held until the operation completes.
-    #[allow(dead_code)]
-    Cancelled(CancelData),
+    Cancelled(
+        // This field isn't accessed directly, but it holds cancellation data,
+        // so `#[allow(dead_code)]` is needed.
+        #[allow(dead_code)] CancelData,
+    ),
 
     /// The operation has completed with a single cqe result
     Completed(io_uring::cqueue::Entry),
 }
 
 pub(crate) enum State {
-    #[allow(dead_code)]
     Initialize(Option<Entry>),
     Polled(usize),
     Complete,
@@ -53,7 +58,6 @@ impl<T: Cancellable> Op<T> {
     ///
     /// Callers must ensure that parameters of the entry (such as buffer) are valid and will
     /// be valid for the entire duration of the operation, otherwise it may cause memory problems.
-    #[allow(dead_code)]
     pub(crate) unsafe fn new(entry: Entry, data: T) -> Self {
         let handle = Handle::current();
         Self {
@@ -87,7 +91,6 @@ impl<T: Cancellable> Drop for Op<T> {
 
 /// A single CQE result
 pub(crate) struct CqeResult {
-    #[allow(dead_code)]
     pub(crate) result: io::Result<u32>,
 }
 

tokio/src/runtime/io/driver/uring.rs

@@ -181,7 +181,6 @@ impl Drop for UringContext {
 }
 
 impl Handle {
-    #[allow(dead_code)]
     fn add_uring_source(&self, uringfd: RawFd) -> io::Result<()> {
         let mut source = SourceFd(&uringfd);
         self.registry
@@ -276,8 +275,6 @@ impl Handle {
         Ok(index)
     }
 
-    // TODO: Remove this annotation when operations are actually supported
-    #[allow(unused_variables, unreachable_code)]
     pub(crate) fn cancel_op<T: Cancellable>(&self, index: usize, data: Option<T>) {
         let mut guard = self.get_uring().lock();
         let ctx = &mut *guard;