The Box in liballoc always has a field for the allocator. It is quite
hard to support both the old and new definition of Box in cg_clif so
this change uses the new definition in this test too.

Bump portable-simd to shadow Ord

Yon usual bump.
Summary for reference:
- We are moving away from the subjective "directional" nomenclature, so `horizontal_*` becomes `reduce_*`, et cetera.
- In addition, `Simd<Int, N>` now has methods which shadow Ord's methods directly, making those methods behave like the already "overloaded" float methods do.

Queryify `is_doc_hidden`

It came up hot on some profiling of rustdoc I did, so hopefully turning
it into a query will help.

Fix sidebar elements display

The bug can be seen more easily when the javascript is disabled:

![Screenshot from 2022-02-24 12-18-28](https://user-images.githubusercontent.com/3050060/155514578-cbefd3dd-f006-47e9-bc76-7c26d7e823e8.png)

r? `@jsha`

Remove unneeded conversions in bootstrapping code

Fixes warnings from `clippy::useless_conversion` in `src/bootstrap`.

update Miri

Fixes https://github.com/rust-lang/rust/issues/94871

Rollup of 3 pull requests

Successful merges:

 - #94867 (Add regression test for `<i32 as Iterator>::count`)
 - #94886 (Update browser-ui-test version used in CI)
 - #94894 (Remove needless use of `Into`)

Failed merges:

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

* add test from issue rust-lang/portable-simd#253

It came up hot on some profiling of rustdoc I did, so hopefully turning
it into a query will help.

Remove needless use of `Into`

Update browser-ui-test version used in CI

I realized that the extension of `assert-text*` commands was generated not completely valid (it stopped at first "success" and moved instead of running all checks). It was fixed in [this PR](https://github.com/GuillaumeGomez/browser-UI-test/pull/280).

We don't use this feature currently in the rustdoc GUI tests, but just in case...

r? ``@notriddle``

Add regression test for `<i32 as Iterator>::count`

Closes #84495

Fix exposing fields marked unstable or doc hidden

Closes https://github.com/rust-lang/rust/issues/89837

Work towards https://github.com/rust-lang/rust/issues/89554

Filter fields that are marked `doc(hidden)` or are unstable with that feature turned off. This brings structs and enums into alignment behavior-wise when emitting warning/errors about pattern exhaustiveness/reachability.

cc `@Nadrieril`

diagnostics: single colon within `<>` probably, not type ascription

Fixes #94812

Return early to fix ICE

This fixes #94627, ICE happens because compiler tries to suggest constraining type parameter but the only constraint is implicit `std::Sized` one, so it gets removed and there is nothing to suggest resulting in ICE.

Co-authored-by: NCamille Gillot <gillot.camille@gmail.com>

Fix ICE when using Box<T, A>, again

Sequel to #94043, fixes #94835.

diagnostics: do not spurriously claim something is "not an iterator"

Fixes a minor regression caused by #94746, where `iter::Filter` is spurriously declared "not an iterator."

Rollup of 3 pull requests

Successful merges:

 - #94150 (rustdoc-json: Include GenericParamDefKind::Type::synthetic in JSON)
 - #94833 ([2/2] Implement macro meta-variable expression)
 - #94863 (Remove redundant slicing of whole ranges in `bootstrap`)

Failed merges:

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

Remove redundant slicing of whole ranges in `bootstrap`

Found with `clippy::redundant_slicing`.

[2/2] Implement macro meta-variable expression

Final part of https://github.com/rust-lang/rust/pull/93545#issuecomment-1050963295

r? `@petrochenkov`

rustdoc-json: Include GenericParamDefKind::Type::synthetic in JSON

The rustdoc JSON for

```
pub fn f(_: impl Clone) {}
```

will effectively be

```
pub fn f<impl Clone: Clone>(_: impl Clone) {}
```

where a synthetic generic parameter called `impl Clone` with generic trait bound
`Clone` is added to the function declaration.

The generated HTML filters out these generic parameters by doing
`self.params.iter().filter(|p| !p.is_synthetic_type_param())`, because the
synthetic generic paramter is not of interest to regular users.

For the same reason, we should expose whether or not a generic parameter is
synthetic or not also in the rustdoc JSON, so that rustdoc JSON clients can also
have the option to hide syntehtic generic parameters.

`@rustbot` modify labels: +A-rustdoc-json

Improve `AdtDef` interning.

This commit makes `AdtDef` use `Interned`. Much of the commit is tedious
changes to introduce getter functions. The interesting changes are in
`compiler/rustc_middle/src/ty/adt.rs`.

r? `@fee1-dead`