Merge #875 #876

875: Miri: Fix thread leaks in doctests in utils r=taiki-e a=taiki-e



876: Fix clippy::explicit_auto_deref warning r=taiki-e a=taiki-e

```
warning: deref which would be done by auto-deref
    --> crossbeam-epoch/src/atomic.rs:1715:43
     |
1715 |         let arr: &[MaybeUninit<usize>] = &*owned;
     |                                           ^^^^^^ help: try this: `owned`
     |
     = note: `#[warn(clippy::explicit_auto_deref)]` on by default
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref

warning: deref which would be done by auto-deref
    --> crossbeam-skiplist/src/base.rs:1045:21
     |
1045 |                     (*n).refs_and_height
     |                     ^^^^ help: try this: `n`
     |
     = note: `#[warn(clippy::explicit_auto_deref)]` on by default
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref
```

Co-authored-by: Taiki Endo <te316e89@gmail.com>

ci/miri.sh

@@ -9,8 +9,7 @@ echo
 
 export RUSTFLAGS="${RUSTFLAGS:-} -Z randomize-layout"
 
-# -Zmiri-ignore-leaks is needed because we use detached threads in tests/docs: https://github.com/rust-lang/miri/issues/1371
-MIRIFLAGS="-Zmiri-symbolic-alignment-check -Zmiri-disable-isolation -Zmiri-ignore-leaks" \
+MIRIFLAGS="-Zmiri-symbolic-alignment-check -Zmiri-disable-isolation" \
     cargo miri test \
     -p crossbeam-queue \
     -p crossbeam-utils 2>&1 | ts -i '%.s  '

crossbeam-epoch/src/atomic.rs

@@ -1712,7 +1712,7 @@ mod tests {
     #[test]
     fn array_init() {
         let owned = Owned::<[MaybeUninit<usize>]>::init(10);
-        let arr: &[MaybeUninit<usize>] = &*owned;
+        let arr: &[MaybeUninit<usize>] = &owned;
         assert_eq!(arr.len(), 10);
     }
 }

crossbeam-skiplist/src/base.rs

@@ -1042,7 +1042,7 @@ where
                     }
 
                     // Installation failed. Decrement the reference count.
-                    (*n).refs_and_height
+                    n.refs_and_height
                         .fetch_sub(1 << HEIGHT_BITS, Ordering::Relaxed);
 
                     // We don't have the most up-to-date search results. Repeat the search.

crossbeam-utils/src/backoff.rs

@@ -201,6 +201,7 @@ impl Backoff {
     /// assert_eq!(ready.load(SeqCst), false);
     /// spin_wait(&ready);
     /// assert_eq!(ready.load(SeqCst), true);
+    /// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371
     /// ```
     ///
     /// [`AtomicBool`]: std::sync::atomic::AtomicBool
@@ -269,6 +270,7 @@ impl Backoff {
     /// assert_eq!(ready.load(SeqCst), false);
     /// blocking_wait(&ready);
     /// assert_eq!(ready.load(SeqCst), true);
+    /// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371
     /// ```
     ///
     /// [`AtomicBool`]: std::sync::atomic::AtomicBool

crossbeam-utils/src/sync/parker.rs

@@ -44,6 +44,7 @@ use std::time::{Duration, Instant};
 ///
 /// // Wakes up when `u.unpark()` provides the token.
 /// p.park();
+/// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371
 /// ```
 ///
 /// [`park`]: Parker::park
@@ -241,6 +242,7 @@ impl Unparker {
     ///
     /// // Wakes up when `u.unpark()` provides the token.
     /// p.park();
+    /// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371
     /// ```
     ///
     /// [`park`]: Parker::park