Previously we were suggesting stuff like `fn f( &u32) {}`

To avoid circular link time dependency between core and compiler
builtins when building with `-Zshare-generics`.

Signed-off-by: Yuki Okushi <jtitor@2k36.org>

…ntation, r=dtolnay

os str capacity documentation

This is based on rust-lang#95394 , with expansion and consolidation
to address comments from `@dtolnay` and other `@rust-lang/libs-api` team members.

…ions, r=compiler-errors

Fix suggestions for `&a: T` parameters

I've accidentally discovered that we have broken suggestions for `&a: T` parameters:
```rust
fn f(&mut bar: u32) {}

fn main() {
    let _ = |&mut a| ();
}
```
```text
error[E0308]: mismatched types
 --> ./t.rs:1:6
  |
1 | fn f(&mut bar: u32) {}
  |      ^^^^^^^^-----
  |      |         |
  |      |         expected due to this
  |      expected `u32`, found `&mut _`
  |      help: did you mean `bar`: `&u32`
  |
  = note:           expected type `u32`
          found mutable reference `&mut _`

error[E0308]: mismatched types
 --> ./t.rs:4:23
  |
4 |     let _: fn(u32) = |&mut a| ();
  |                       ^^^^^--
  |                       |    |
  |                       |    expected due to this
  |                       expected `u32`, found `&mut _`
  |                       help: did you mean `a`: `&u32`
  |
  = note:           expected type `u32`
          found mutable reference `&mut _`
```

It's hard to see, but
1. The help span is overlapping with "expected" spans
2. It suggests `fn f( &u32) {}` (no `mut` and lost parameter name) and `|&u32 ()` (no closing `|` and lost parameter name)

I've tried to fix this.

r? ``@compiler-errors``

…n-ice, r=notriddle

Fix generic impl rustdoc json output

Fixes rust-lang#97986.

The problem in case of generic trait impl is that the trait's items are the same for all the types afterward. But since they're the same, it's safe for rustdoc-json to just ignore them.

A little representation of what's going on:

```rust
trait T {
    fn f(); // <- defid 0
}

impl<Y> T for Y {
    fn f() {} // <- defid 1
}

struct S; // <- defid 1 (since it matches `impl<Y> T for Y`
```

cc ```@Urgau```

r? ```@CraftSpider```

…=Amanieu

Inline `const_eval_select`

To avoid circular link time dependency between core and compiler
builtins when building with `-Zshare-generics`.

r? ```@Amanieu```

…pand-collapse, r=notriddle

Fix sidebar items expand collapse

The collapse/expand event was not working for the items in the source code viewer sidebar (talking about these items:

![Screenshot from 2022-06-14 11-21-58](https://user-images.githubusercontent.com/3050060/173543346-af056928-e921-458f-b918-60f6fd0ecbde.png)

).

This PR fixes it and adds a GUI test to prevent another regression.

r? ```@notriddle```

…or, r=estebank

Refactor path segment parameter error

This PR attempts to rewrite the error handling for an unexpected parenthesised type parameters to:
- Use provided data instead of re-parsing the whole span
- Add a multipart suggestion to reflect on the changes with an underline
- Remove the unnecessary "if" nesting

…iler-errors

Add regression test for rust-lang#93775

Closes rust-lang#93775, also closes rust-lang#93022 as it should have the same root cause
r? ```@compiler-errors```

Signed-off-by: Yuki Okushi <jtitor@2k36.org>