This saves a lot of time compiling.

This allows implementing traits that require a raw FD on Arc and Box.

Previously, you'd have to add the function to the trait itself:

```rust
trait MyTrait {
    fn as_raw_fd(&self) -> RawFd;
}

impl<T: MyTrait> MyTrait for Arc<T> {
    fn as_raw_fd(&self) -> RawFd {
        (**self).as_raw_fd()
    }
}
```

4 commits in 4d92f07f34ba7fb7d7f207564942508f46c225d3..8d42b0e8794ce3787c9f7d6d88b02ae80ebe8d19
2022-06-10 01:11:04 +0000 to 2022-06-17 16:46:26 +0000
- Use specific terminology for sparse HTTP-based registry (rust-lang/cargo#10764)
- chore: Upgrade to clap 3.2 (rust-lang/cargo#10753)
- Improve testing framework for http registries (rust-lang/cargo#10738)
- doc: Improve example of using the links field (rust-lang/cargo#10728)

 * no-sequences
 * no-throw-literal

`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`

This allows implementing traits that require a raw FD on Arc and Box.

Previously, you'd have to add the function to the trait itself:

```rust
trait MyTrait {
    fn as_raw_fd(&self) -> RawFd;
}

impl<T: MyTrait> MyTrait for Arc<T> {
    fn as_raw_fd(&self) -> RawFd {
        (**self).as_raw_fd()
    }
}
```

In particular, this leads to lots of "multiple applicable items in scope" errors because you have to disambiguate `MyTrait::as_raw_fd` from `AsRawFd::as_raw_fd` at each call site. In generic contexts, when passing the type to a function that takes `impl AsRawFd` it's also sometimes required to use `T: MyTrait + AsRawFd`, which wouldn't be necessary if I could write `MyTrait: AsRawFd`.

After this PR, the code can be simpler:
```rust
trait MyTrait: AsRawFd {}

impl<T: MyTrait> MyTrait for Arc<T> {}
```

…imulacrum

Don't build the compiler before building rust-demangler

This saves a lot of time compiling, since rust-demangler doesn't actually use any unstable features.

This is not quite ideal because it uses ToolStd, not ToolBootstrap, so rust-demangler would be able to add unstable library features in the future. But it's a lot better than before, and `builder.cargo` doesn't currently know how to handle stages other than 0.

… r=m-ou-se

once cell renamings

This PR does the renamings proposed in rust-lang#74465 (comment)

- Move/rename `lazy::{OnceCell, Lazy}` to `cell::{OnceCell, LazyCell}`
- Move/rename `lazy::{SyncOnceCell, SyncLazy}` to `sync::{OnceLock, LazyLock}`

(I used `Lazy...` instead of `...Lazy` as it seems to be more consistent, easier to pronounce, etc)

``@rustbot`` label +T-libs-api -T-libs

Update cargo

4 commits in 4d92f07f34ba7fb7d7f207564942508f46c225d3..8d42b0e8794ce3787c9f7d6d88b02ae80ebe8d19
2022-06-10 01:11:04 +0000 to 2022-06-17 16:46:26 +0000
- Use specific terminology for sparse HTTP-based registry (rust-lang/cargo#10764)
- chore: Upgrade to clap 3.2 (rust-lang/cargo#10753)
- Improve testing framework for http registries (rust-lang/cargo#10738)
- doc: Improve example of using the links field (rust-lang/cargo#10728)

…an-DPC

Add new eslint checks

r? ``@Dylan-DPC``