This increases the size of some important types, such as `ast::Expr` and
`mir::Statement`. However, it drastically reduces how much the interner
is used, and the fields are more natural sizes that don't require bit
operations to extract.

As a result, instruction counts drop across a range of workloads, by as
much as 12% for incremental "check" builds of `script-servo`.

Peak memory usage goes up a little for some cases, but down by more for
some other cases -- as much as 18% for non-incremental builds of
`packed-simd`.

The commit also:
- removes the `repr(packed)`, because it has negligible effect, but can
  cause undefined behaviour;
- replaces explicit impls of common traits (`Copy`, `PartialEq`, etc.)
  with derived ones.

It is now exactly equivalent to lookup_char_pos.

Implicit promotion on the other hand has very strict rules on what may be done

- Make links relative.
- Adjust links from old 2018-edition book.
- Fix broken link in `let` docs.

This commit implements the `{read,write}_vectored` methods on more types
in the standard library, namely:

* `std::fs::File`
* `std::process::ChildStd{in,out,err}`
* `std::io::Std{in,out,err}`
* `std::io::Std{in,out,err}Lock`
* `std::io::Std{in,out,err}Raw`

Where supported the OS implementations hook up to native support,
otherwise it falls back to the already-defaulted implementation.

It's useful to see the biggest variants first.

This implements RFC 2480:

* rust-lang/rfcs#2480
* https://github.com/rust-lang/rfcs/blob/master/text/2480-liballoc.md

Closes rust-lang#27783

…hton

Stabilize the `alloc` crate.

This implements RFC 2480:

* rust-lang/rfcs#2480
* https://github.com/rust-lang/rfcs/blob/master/text/2480-liballoc.md

Closes rust-lang#27783

…enkov

Increase `Span` from 4 bytes to 8 bytes.

This increases the size of some important types, such as `ast::Expr` and
`mir::Statement`. However, it drastically reduces how much the interner
is used, and the fields are more natural sizes that don't require bit
operations to extract.

As a result, instruction counts drop across a range of workloads, by as
much as 10% for `script-servo` incremental builds.

Peak memory usage goes up a little for some cases, but down by more for
some other cases -- as much as 18% for non-incremental builds of
`packed-simd`.

The commit also:
- removes the `repr(packed)`, because it has negligible effect, but can
  cause undefined behaviour;
- replaces explicit impls of common traits (`Copy`, `PartialEq`, etc.)
  with derived ones.

r? @petrochenkov

…-mut, r=pnkfelix

Mark variables captured by reference as mutable correctly

Closes rust-lang#59620

r? @pnkfelix

remove lookup_char_pos_adj

It is now exactly equivalent to lookup_char_pos.

…k, r=ehuss

Copy book.toml unstable book generator

Solves rust-lang#59554 and adds a book title to the unstable book.

I assume that [copy_recursive](https://github.com/rust-lang/rust/blob/acd8dd6a50d505057a7d7ad8d0d7a4c2bd274200/src/tools/unstable-book-gen/src/main.rs#L105) will take files regardless of their type (`.md` or `.toml`).

Although I had a hard time time testing it. A second pair of eyes is definitely needed.

Limit dylib symbols

This makes `windows-gnu` match the behavior of `windows-msvc`. It probably doesn't make sense to export these symbols on other platforms either.

Retire `IsNotConst` naming

This naming scheme caused a lot of confusion lately (including ICEs) due to misrefactored code. Also clean up the initialization code for said flag.

r? @eddyb

previous discussions: rust-lang#58784 (comment) rust-lang#58403 (comment)

Clean up jobserver integration

cc @alexcrichton

…cramertj

Eliminate `FnBox` usages from libstd.

Fix links on keyword docs.

- Make links relative.
- Adjust links from old 2018-edition book.
- Fix broken link in `let` docs.

…acrum

Re-export NonZero signed variant in std

Closes  rust-lang#59834 .

std: Add `{read,write}_vectored` for more types

This commit implements the `{read,write}_vectored` methods on more types
in the standard library, namely:

* `std::fs::File`
* `std::process::ChildStd{in,out,err}`
* `std::io::Std{in,out,err}`
* `std::io::Std{in,out,err}Lock`
* `std::io::Std{in,out,err}Raw`

Where supported the OS implementations hook up to native support,
otherwise it falls back to the already-defaulted implementation.

…-type-decl, r=QuietMisdreavus

Fix attributes position in type declaration

Fixes rust-lang#59797.

r? @rust-lang/rustdoc

…Centril

Make duplicate matcher bindings a hard error

r? @Centril

Closes rust-lang#57742

Use SecRandomCopyBytes instead of /dev/urandom on MacOS

SecRandomCopyBytes is [available since MacOS 10.7](https://developer.apple.com/documentation/security/1399291-secrandomcopybytes?language=objc) which is the minimum supported version and which was suggested in rust-lang#58901 (comment) is the earliest version currently in use.

This matches the behaviour of other platforms which have a random number generator syscall available.

…ize, r=pnkfelix

In `-Zprint-type-size` output, sort enum variants by size.

It's useful to see the biggest variants first.

r? @pnkfelix

MaybeUninit: remove deprecated functions