Auto merge of #58446 - Centril:rollup, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #57451 (suggestion-diagnostics: as_ref improve snippet)
 - #57856 (Convert old first edition links to current edition one)
 - #57992 (Update the future/task API)
 - #58258 (Reduce the size of `hir::Expr`.)
 - #58267 (Tweak "incompatible match arms" error)
 - #58296 (Hidden suggestion support)
 - #58301 (Enable comparing fat pointers)
 - #58308 (Extract block to insert an intrinsic into its own function)

Failed merges:

r? @ghost

src/doc/guide-error-handling.md

@@ -1,4 +1,4 @@
 % Error Handling in Rust
 
 This content has moved into
-[the Rust Programming Language book](book/error-handling.html).
+[the Rust Programming Language book](book/ch09-00-error-handling.html).

src/doc/guide-ownership.md

@@ -1,4 +1,4 @@
 % The (old) Rust Ownership Guide
 
 This content has moved into
-[the Rust Programming Language book](book/ownership.html).
+[the Rust Programming Language book](book/ch04-00-understanding-ownership.html).

src/doc/guide-pointers.md

@@ -2,6 +2,6 @@
 
 This content has been removed, with no direct replacement. Rust only
 has two built-in pointer types now,
-[references](book/references-and-borrowing.html) and [raw
+[references](book/ch04-02-references-and-borrowing.html) and [raw
 pointers](book/raw-pointers.html). Older Rusts had many more pointer
 types, they’re gone now.

src/doc/guide-testing.md

@@ -1,4 +1,4 @@
 % The (old) Rust Testing Guide
 
 This content has moved into
-[the Rust Programming Language book](book/testing.html).
+[the Rust Programming Language book](book/ch11-00-testing.html).

src/liballoc/boxed.rs

@@ -71,7 +71,7 @@ use core::ops::{
     CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState
 };
 use core::ptr::{self, NonNull, Unique};
-use core::task::{LocalWaker, Poll};
+use core::task::{Waker, Poll};
 
 use crate::vec::Vec;
 use crate::raw_vec::RawVec;
@@ -896,7 +896,7 @@ impl<G: ?Sized + Generator> Generator for Pin<Box<G>> {
 impl<F: ?Sized + Future + Unpin> Future for Box<F> {
     type Output = F::Output;
 
-    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        F::poll(Pin::new(&mut *self), lw)
+    fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        F::poll(Pin::new(&mut *self), waker)
     }
 }

src/liballoc/lib.rs

@@ -132,10 +132,6 @@ mod macros;
 
 pub mod alloc;
 
-#[unstable(feature = "futures_api",
-           reason = "futures in libcore are unstable",
-           issue = "50547")]
-pub mod task;
 // Primitive types using the heaps above
 
 // Need to conditionally define the mod from `boxed.rs` to avoid

src/libcore/convert.rs

@@ -116,9 +116,6 @@ pub const fn identity<T>(x: T) -> T { x }
 /// - Use `Borrow` when the goal is related to writing code that is agnostic to
 ///   the type of borrow and whether it is a reference or value
 ///
-/// See [the book][book] for a more detailed comparison.
-///
-/// [book]: ../../book/first-edition/borrow-and-asref.html
 /// [`Borrow`]: ../../std/borrow/trait.Borrow.html
 ///
 /// **Note: this trait must not fail**. If the conversion can fail, use a
@@ -351,7 +348,7 @@ pub trait Into<T>: Sized {
 /// [`String`]: ../../std/string/struct.String.html
 /// [`Into<U>`]: trait.Into.html
 /// [`from`]: trait.From.html#tymethod.from
-/// [book]: ../../book/first-edition/error-handling.html
+/// [book]: ../../book/ch09-00-error-handling.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait From<T>: Sized {
     /// Performs the conversion.

src/libcore/future/future.rs

@@ -5,7 +5,7 @@
 use marker::Unpin;
 use ops;
 use pin::Pin;
-use task::{Poll, LocalWaker};
+use task::{Poll, Waker};
 
 /// A future represents an asynchronous computation.
 ///
@@ -19,13 +19,14 @@ use task::{Poll, LocalWaker};
 /// final value. This method does not block if the value is not ready. Instead,
 /// the current task is scheduled to be woken up when it's possible to make
 /// further progress by `poll`ing again. The wake up is performed using
-/// `cx.waker()`, a handle for waking up the current task.
+/// the `waker` argument of the `poll()` method, which is a handle for waking
+/// up the current task.
 ///
 /// When using a future, you generally won't call `poll` directly, but instead
 /// `await!` the value.
 #[must_use = "futures do nothing unless polled"]
 pub trait Future {
-    /// The result of the `Future`.
+    /// The type of value produced on completion.
     type Output;
 
     /// Attempt to resolve the future to a final value, registering
@@ -42,16 +43,16 @@ pub trait Future {
     /// Once a future has finished, clients should not `poll` it again.
     ///
     /// When a future is not ready yet, `poll` returns `Poll::Pending` and
-    /// stores a clone of the [`LocalWaker`] to be woken once the future can
+    /// stores a clone of the [`Waker`] to be woken once the future can
     /// make progress. For example, a future waiting for a socket to become
-    /// readable would call `.clone()` on the [`LocalWaker`] and store it.
+    /// readable would call `.clone()` on the [`Waker`] and store it.
     /// When a signal arrives elsewhere indicating that the socket is readable,
-    /// `[LocalWaker::wake]` is called and the socket future's task is awoken.
+    /// `[Waker::wake]` is called and the socket future's task is awoken.
     /// Once a task has been woken up, it should attempt to `poll` the future
     /// again, which may or may not produce a final value.
     ///
     /// Note that on multiple calls to `poll`, only the most recent
-    /// [`LocalWaker`] passed to `poll` should be scheduled to receive a
+    /// [`Waker`] passed to `poll` should be scheduled to receive a
     /// wakeup.
     ///
     /// # Runtime characteristics
@@ -67,44 +68,35 @@ pub trait Future {
     /// typically do *not* suffer the same problems of "all wakeups must poll
     /// all events"; they are more like `epoll(4)`.
     ///
-    /// An implementation of `poll` should strive to return quickly, and must
-    /// *never* block. Returning quickly prevents unnecessarily clogging up
+    /// An implementation of `poll` should strive to return quickly, and should
+    /// not block. Returning quickly prevents unnecessarily clogging up
     /// threads or event loops. If it is known ahead of time that a call to
     /// `poll` may end up taking awhile, the work should be offloaded to a
     /// thread pool (or something similar) to ensure that `poll` can return
     /// quickly.
     ///
-    /// # [`LocalWaker`], [`Waker`] and thread-safety
-    ///
-    /// The `poll` function takes a [`LocalWaker`], an object which knows how to
-    /// awaken the current task. [`LocalWaker`] is not `Send` nor `Sync`, so in
-    /// order to make thread-safe futures the [`LocalWaker::into_waker`] method
-    /// should be used to convert the [`LocalWaker`] into a thread-safe version.
-    /// [`LocalWaker::wake`] implementations have the ability to be more
-    /// efficient, however, so when thread safety is not necessary,
-    /// [`LocalWaker`] should be preferred.
+    /// An implementation of `poll` may also never cause memory unsafety.
     ///
     /// # Panics
     ///
     /// Once a future has completed (returned `Ready` from `poll`),
     /// then any future calls to `poll` may panic, block forever, or otherwise
-    /// cause bad behavior. The `Future` trait itself provides no guarantees
-    /// about the behavior of `poll` after a future has completed.
+    /// cause any kind of bad behavior expect causing memory unsafety.
+    /// The `Future` trait itself provides no guarantees about the behavior
+    /// of `poll` after a future has completed.
     ///
     /// [`Poll::Pending`]: ../task/enum.Poll.html#variant.Pending
     /// [`Poll::Ready(val)`]: ../task/enum.Poll.html#variant.Ready
-    /// [`LocalWaker`]: ../task/struct.LocalWaker.html
-    /// [`LocalWaker::into_waker`]: ../task/struct.LocalWaker.html#method.into_waker
-    /// [`LocalWaker::wake`]: ../task/struct.LocalWaker.html#method.wake
     /// [`Waker`]: ../task/struct.Waker.html
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output>;
+    /// [`Waker::wake`]: ../task/struct.Waker.html#method.wake
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output>;
 }
 
 impl<'a, F: ?Sized + Future + Unpin> Future for &'a mut F {
     type Output = F::Output;
 
-    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        F::poll(Pin::new(&mut **self), lw)
+    fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        F::poll(Pin::new(&mut **self), waker)
     }
 }
 
@@ -115,7 +107,7 @@ where
 {
     type Output = <<P as ops::Deref>::Target as Future>::Output;
 
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        Pin::get_mut(self).as_mut().poll(lw)
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        Pin::get_mut(self).as_mut().poll(waker)
     }
 }

src/libcore/marker.rs

@@ -78,7 +78,7 @@ impl<T: ?Sized> !Send for *mut T { }
 ///                         // be made into an object
 /// ```
 ///
-/// [trait object]: ../../book/first-edition/trait-objects.html
+/// [trait object]: ../../book/ch17-02-trait-objects.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[lang = "sized"]
 #[rustc_on_unimplemented(
@@ -518,7 +518,7 @@ macro_rules! impls{
 /// types. We track the Rust type using a phantom type parameter on
 /// the struct `ExternalResource` which wraps a handle.
 ///
-/// [FFI]: ../../book/first-edition/ffi.html
+/// [FFI]: ../../book/ch19-01-unsafe-rust.html#using-extern-functions-to-call-external-code
 ///
 /// ```
 /// # #![allow(dead_code)]

src/libcore/mem.rs

@@ -299,7 +299,7 @@ pub const fn size_of<T>() -> usize {
 /// then `size_of_val` can be used to get the dynamically-known size.
 ///
 /// [slice]: ../../std/primitive.slice.html
-/// [trait object]: ../../book/first-edition/trait-objects.html
+/// [trait object]: ../../book/ch17-02-trait-objects.html
 ///
 /// # Examples
 ///

src/libcore/task/mod.rs

@@ -8,4 +8,4 @@ mod poll;
 pub use self::poll::Poll;
 
 mod wake;
-pub use self::wake::{Waker, LocalWaker, UnsafeWake};
+pub use self::wake::{Waker, RawWaker, RawWakerVTable};