Clean up code

Before this change, the suggestion was `std::panic::panic_any(123]`,
changing the opening brace but not the closing one.

An attempt to compute HIR stats for crates with nested foreign items results in an ICE.

```
fn main() {
    extern "C" { fn f(); }
}
```

```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```

Provide required implementation of visitor method.

Changes from 81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.

A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.

Update conflict_errors.rs

Add deref definition location

Fix rust-lang#82290, fix rust-lang#82250.

Co-authored-by: Joshua Nelson <joshua@yottadb.com>

Fixes rust-lang#81918
Fixes rust-lang#82326 (duplicate)
Fixes rust-lang#82325

I left some of them so this change doesn't balloon in size and because
removing the RefCell in `DocContext.resolver` would require compiler
changes.

Thanks to `@jyn514` for making this a lot easier with rust-lang#82020!

…1011

Point out implicit deref coercions in borrow

Fixes rust-lang#81365

`@Aaron1011` I'm not sure why my code shows the note even in an implicit `Deref` call. See the output for `issue-81365-8.rs`.

Improve non_fmt_panic lint.

This change:
- fixes the span used by this lint in the case the panic argument is a single macro expansion (e.g. `panic!(a!())`);
- adds a suggestion for `panic!(format!(..))` to remove `format!()` instead of adding `"{}", ` or using `panic_any` like it does now; and
- fixes the incorrect suggestion to replace `panic![123]` by `panic_any(123]`.

Fixes rust-lang#82109.
Fixes rust-lang#82110.
Fixes rust-lang#82111.

Example output:
```
warning: panic message is not a string literal
 --> src/main.rs:8:12
  |
8 |     panic!(format!("error: {}", "oh no"));
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(non_fmt_panic)]` on by default
  = note: this is no longer accepted in Rust 2021
  = note: the panic!() macro supports formatting, so there's no need for the format!() macro here
help: remove the `format!(..)` macro call
  |
8 |     panic!("error: {}", "oh no");
  |           --                  --

```

r? `@estebank`

Implement -Z hir-stats for nested foreign items

An attempt to compute HIR stats for crates with nested foreign items results in an ICE.

```rust
fn main() {
    extern "C" { fn f(); }
}
```

```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```

Provide required implementation of visitor method.

Support `pub` on `macro_rules`

This rebases and updates `since` version of rust-lang#78166 from ``@petrochenkov``

r? ``@nikomatsakis``

Consider auto derefs before warning about write only fields

Changes from rust-lang#81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.

A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.

Closes rust-lang#81626.

Remove many RefCells from DocContext

I left some of them so this change doesn't balloon in size and because
removing the RefCell in `DocContext.resolver` would require compiler
changes.

Thanks to `@jyn514` for making this a lot easier with rust-lang#82020!

r? `@jyn514`

Lower condition of `if` expression before it's "then" block

Fix rust-lang#82290, fix rust-lang#82250.

…s, r=jyn514

Jsondocck improvements

Adds 2 new commands, ```@is``` and ```@set`.``

```@is``` works like ```@has`,`` except instead of checking if any value matches, it checks that there is exactly one value, and it matches. This allows more precise testing.

```@set``` gets a value, and saves it to be used later. This makes it possible to check that an item appears in the correct module.

Once this lands, the rest of the test suite can be upgraded to use these.

cc ``@CraftSpider``

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

Fix mir-cfg dumps

Fixes rust-lang#81918
Fixes rust-lang#82326 (duplicate)
Fixes rust-lang#82325

---

r? ``@oli-obk``

disable atomic_max/min tests in Miri

Disable some tests that currently [fail in Miri](https://travis-ci.com/github/RalfJung/miri-test-libstd/builds/217788631).