Auto merge of #120136 - matthiaskrgr:rollup-3zzb0z9, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #117561 (Stabilize `slice_first_last_chunk`)
 - #117662 ([rustdoc] Allows links in headings)
 - #119815 (Format sources into the error message when loading codegen backends)
 - #119835 (Exhaustiveness: simplify empty pattern logic)
 - #119984 (Change return type of unstable `Waker::noop()` from `Waker` to `&Waker`.)
 - #120009 (never_patterns: typecheck never patterns)
 - #120122 (Don't add needs-triage to A-diagnostics)
 - #120126 (Suggest `.swap()` when encountering conflicting borrows from `mem::swap` on a slice)
 - #120134 (Restrict access to the private field of newtype indexes)

Failed merges:

 - #119968 (Remove unused/unnecessary features)

r? `@ghost`
`@rustbot` modify labels: rollup

tests/pass/async-fn.rs

@@ -76,8 +76,7 @@ async fn uninhabited_variant() {
 fn run_fut<T>(fut: impl Future<Output = T>) -> T {
     use std::task::{Context, Poll, Waker};
 
-    let waker = Waker::noop();
-    let mut context = Context::from_waker(&waker);
+    let mut context = Context::from_waker(Waker::noop());
 
     let mut pinned = Box::pin(fut);
     loop {

tests/pass/dyn-star.rs

@@ -93,8 +93,7 @@ fn dispatch_on_pin_mut() {
     let mut fut = async_main();
 
     // Poll loop, just to test the future...
-    let waker = Waker::noop();
-    let ctx = &mut Context::from_waker(&waker);
+    let ctx = &mut Context::from_waker(Waker::noop());
 
     loop {
         match unsafe { Pin::new_unchecked(&mut fut).poll(ctx) } {

tests/pass/future-self-referential.rs

@@ -77,8 +77,7 @@ impl Future for DoStuff {
 }
 
 fn run_fut<T>(fut: impl Future<Output = T>) -> T {
-    let waker = Waker::noop();
-    let mut context = Context::from_waker(&waker);
+    let mut context = Context::from_waker(Waker::noop());
 
     let mut pinned = pin!(fut);
     loop {
@@ -90,8 +89,7 @@ fn run_fut<T>(fut: impl Future<Output = T>) -> T {
 }
 
 fn self_referential_box() {
-    let waker = Waker::noop();
-    let cx = &mut Context::from_waker(&waker);
+    let cx = &mut Context::from_waker(Waker::noop());
 
     async fn my_fut() -> i32 {
         let val = 10;

tests/pass/issues/issue-miri-2068.rs

@@ -6,8 +6,7 @@ use std::task::{Context, Poll, Waker};
 
 pub fn fuzzing_block_on<O, F: Future<Output = O>>(fut: F) -> O {
     let mut fut = std::pin::pin!(fut);
-    let waker = Waker::noop();
-    let mut context = Context::from_waker(&waker);
+    let mut context = Context::from_waker(Waker::noop());
     loop {
         match fut.as_mut().poll(&mut context) {
             Poll::Ready(v) => return v,

tests/pass/move-data-across-await-point.rs

@@ -56,8 +56,7 @@ fn data_moved() {
 fn run_fut<T>(fut: impl Future<Output = T>) -> T {
     use std::task::{Context, Poll, Waker};
 
-    let waker = Waker::noop();
-    let mut context = Context::from_waker(&waker);
+    let mut context = Context::from_waker(Waker::noop());
 
     let mut pinned = Box::pin(fut);
     loop {