Merge #831 #832

831: Add spin loop hints in tests for Miri r=taiki-e a=cbeuw

This is a better way to do #829 

Miri does not have a pre-emptive scheduler, so once the execution falls into a spin loop it'll hang forever: rust-lang/miri#1388

Similar measures (`yield_now()`) are already present in [some other tests](https://github.com/crossbeam-rs/crossbeam/blob/master/crossbeam-queue/tests/array_queue.rs), but it's missing here

832: Fix links to macro rules in docs r=taiki-e a=alygin

The fix provides explicit links to macro rules in docs because they [are not resolved globally anymore](rust-lang/rust#96676).


Co-authored-by: Andy Wang <[email protected]>
Co-authored-by: Andrew Lygin <[email protected]>

crossbeam-channel/src/channel.rs

@@ -233,6 +233,8 @@ pub fn at(when: Instant) -> Receiver<Instant> {
 ///
 /// Using a `never` channel to optionally add a timeout to [`select!`]:
 ///
+/// [`select!`]: crate::select!
+///
 /// ```
 /// use std::thread;
 /// use std::time::Duration;

crossbeam-channel/src/select.rs

@@ -519,6 +519,8 @@ pub(crate) fn select_deadline<'a>(
 /// The [`select!`] macro is a convenience wrapper around `Select`. However, it cannot select over a
 /// dynamically created list of channel operations.
 ///
+/// [`select!`]: crate::select!
+///
 /// Once a list of operations has been built with `Select`, there are two different ways of
 /// proceeding:
 ///

crossbeam-channel/src/select_macro.rs

@@ -993,7 +993,7 @@ macro_rules! crossbeam_channel_internal {
 /// An operation is considered to be ready if it doesn't have to block. Note that it is ready even
 /// when it will simply return an error because the channel is disconnected.
 ///
-/// The `select` macro is a convenience wrapper around [`Select`]. However, it cannot select over a
+/// The `select!` macro is a convenience wrapper around [`Select`]. However, it cannot select over a
 /// dynamically created list of channel operations.
 ///
 /// [`Select`]: super::Select

crossbeam-deque/tests/injector.rs

@@ -61,6 +61,8 @@ fn spsc() {
                         assert_eq!(i, v);
                         break;
                     }
+                    #[cfg(miri)]
+                    std::hint::spin_loop();
                 }
             }
 
@@ -102,6 +104,8 @@ fn mpmc() {
                             v[n].fetch_add(1, SeqCst);
                             break;
                         }
+                        #[cfg(miri)]
+                        std::hint::spin_loop();
                     }
                 }
             });

crossbeam-deque/tests/lifo.rs

@@ -87,6 +87,8 @@ fn spsc() {
                         assert_eq!(i, v);
                         break;
                     }
+                    #[cfg(miri)]
+                    std::hint::spin_loop();
                 }
             }