Auto merge of #59370 - Centril:rollup, r=Centril

Rollup of 18 pull requests

Successful merges:

 - #59106 (Add peer_addr function to UdpSocket)
 - #59170 (Add const generics to rustdoc)
 - #59172 (Update and clean up several parts of CONTRIBUTING.md)
 - #59190 (consistent naming for Rhs type parameter in libcore/ops)
 - #59236 (Rename miri component to miri-preview)
 - #59266 (Do not complain about non-existing fields after parse recovery)
 - #59273 (some small HIR doc improvements)
 - #59291 (Make Option<ThreadId> no larger than ThreadId, with NonZeroU64)
 - #59297 (convert field/method confusion help to suggestions)
 - #59304 (Move some bench tests back from libtest)
 - #59309 (Add messages for different verbosity levels. Output copy actions.)
 - #59321 (Unify E0109, E0110 and E0111)
 - #59322 (Tweak incorrect escaped char diagnostic)
 - #59323 (use suggestions for "enum instead of variant" error)
 - #59327 (Add NAN test to docs)
 - #59329 (cleanup: Remove compile-fail-fulldeps directory again)
 - #59347 (Move one test from run-make-fulldeps to ui)
 - #59360 (Add tracking issue number for `seek_convenience`)

Failed merges:

r? @ghost

1 files changed, 11 insertions, 4 deletions

diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index 08f0aa2f0d2..d856f9b465e 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -163,6 +163,7 @@ use crate::ffi::{CStr, CString};
 use crate::fmt;
 use crate::io;
 use crate::mem;
+use crate::num::NonZeroU64;
 use crate::panic;
 use crate::panicking;
 use crate::str;
@@ -1036,7 +1037,7 @@ pub fn park_timeout(dur: Duration) {
 /// [`Thread`]: ../../std/thread/struct.Thread.html
 #[stable(feature = "thread_id", since = "1.19.0")]
 #[derive(Eq, PartialEq, Clone, Copy, Hash, Debug)]
-pub struct ThreadId(u64);
+pub struct ThreadId(NonZeroU64);
 
 impl ThreadId {
     // Generate a new unique thread ID.
@@ -1044,7 +1045,7 @@ impl ThreadId {
         // We never call `GUARD.init()`, so it is UB to attempt to
         // acquire this mutex reentrantly!
         static GUARD: mutex::Mutex = mutex::Mutex::new();
-        static mut COUNTER: u64 = 0;
+        static mut COUNTER: u64 = 1;
 
         unsafe {
             let _guard = GUARD.lock();
@@ -1058,7 +1059,7 @@ impl ThreadId {
             let id = COUNTER;
             COUNTER += 1;
 
-            ThreadId(id)
+            ThreadId(NonZeroU64::new(id).unwrap())
         }
     }
 }
@@ -1484,9 +1485,10 @@ fn _assert_sync_and_send() {
 mod tests {
     use super::Builder;
     use crate::any::Any;
+    use crate::mem;
     use crate::sync::mpsc::{channel, Sender};
     use crate::result;
-    use crate::thread;
+    use crate::thread::{self, ThreadId};
     use crate::time::Duration;
     use crate::u32;
 
@@ -1717,6 +1719,11 @@ mod tests {
     }
 
     #[test]
+    fn test_size_of_option_thread_id() {
+        assert_eq!(mem::size_of::<Option<ThreadId>>(), mem::size_of::<ThreadId>());
+    }
+
+    #[test]
     fn test_thread_id_equal() {
         assert!(thread::current().id() == thread::current().id());
     }