And with one final incanation, the specific kind iterators were banished from ty::Generics, never to be seen again!

Begone lazy lifetime code!

Remove vestigial diverging !-coercion

Such conversions are no longer permitted. Fixes #50350.

r? @nikomatsakis

Update stdsimd module

to include https://github.com/rust-lang-nursery/stdsimd/commit/a19ca1cd91cf97777af8268a6136bd2e4648e189

Rustdoc improvements

Fixes #50658. (last commit)

A lot of small improvements.

r? @QuietMisdreavus

Ensure derive(PartialOrd) is no longer accidentally exponential

Previously, two comparison operations would be generated for each field, each of which could delegate to another derived PartialOrd. Now we use ordering and optional chaining to ensure each pair of fields is only compared once, addressing https://github.com/rust-lang/rust/issues/49650#issuecomment-379467572.

Closes #49505.

r? @Manishearth (sorry for changing it again so soon!)

Close #50755

Update clippy

r? @Manishearth

@bors p=1

typeck: Save the index of private fields

Save the index of all fields regardless of their visibility. Problems
could occur later when attempting to index fields in error recovery if
they are not inserted.

Fixes: #50493

rustc: don't trip an assertion for enums with present but uninhabited variants.

Fixes #50731.

r? @nikomatsakis

Update stdsimd module to include https://github.com/rust-lang-nursery/stdsimd/commit/a19ca1cd91cf97777af8268a6136bd2e4648e189

stabilize macro_lifetime_matcher

This stabilizes `:lifetime` which has completed FCP in #34303.

Fix volatile_store and nontemporal_store

Fixes #50371.

update libcompiler_builtins

let's OpenBSD to use libcompiler_rt.a from system library. it unbreaks
the build from source on OpenBSD.

see https://github.com/rust-lang-nursery/compiler-builtins/pull/241 for related PR

note this PR brings some other changes (on `floatdisf`/`floatundisf`) with compiler-builtins update.

r? @alexcrichton

Fix self referential impl Trait substitutions

A high impact bug because a lot of common traits use a `Self` substitution by default. Should be backported to beta.

There was a check for this which wasn't catching all cases, it was made more robust.

Fixes #49376
Fixes #50626

r? @petrochenkov

Reduce span highlighted code in unused_variables lint

Fixes #50472
- [X] reduce var span
- [ ] mark applicable

Before:
```
mut unused_mut_var
^^^^^^^^^^^^^^^^^^
```
After:
```
mut unused_mut_var
    ^^^^^^^^^^^^^^
```

Save the index of all fields regardless of their visibility. Problems
could occur later when attempting to index fields in error recovery if
they are not inserted.

Macros: Add a 'literal' fragment specifier

See: https://github.com/rust-lang/rust/issues/35625

```rust

macro_rules! test_literal {
    ($l:literal) => {
        println!("literal: {}", $l);
    };
    ($e:expr) => {
        println!("expr: {}", $e);
    };
}

fn main() {
    let a = 1;
    test_literal!(a);
    test_literal!(2);
    test_literal!(-3);
}
```

Output:

```
expr: 1
literal: 2
literal: -3
```

ToDo:

* [x] Feature gate
* [x] Basic tests
* [x] Tests for range patterns
* [x] Tests for attributes
* [x] Documentation
* [x] Fix for `true`/`false`
* [x] Fix for negative number literals

Implements RFC 1576.

See: https://github.com/rust-lang/rfcs/blob/master/text/1576-macros-literal-matcher.md

Changes are mostly in libsyntax, docs, and tests. Feature gate is
enabled for 1.27.0.

Many thanks to Vadim Petrochenkov for following through code reviews
and suggestions.

Example:

````rust

macro_rules! test_literal {
    ($l:literal) => {
        println!("literal: {}", $l);
    };
    ($e:expr) => {
        println!("expr: {}", $e);
    };
}

fn main() {
    let a = 1;
    test_literal!(a);
    test_literal!(2);
    test_literal!(-3);
}
```

Output:

```
expr: 1
literal: 2
literal: -3
```

This reverts commit a8809711.