This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

…s output

Add some inlines to trivial methods of IpAddr
Closes rust-lang#77583

…tc` is set

 ## Motivation

This avoids having to rebuild bootstrap and tidy each time you rebase
over master. In particular, it makes rebasing and running `x.py fmt` on
each commit in a branch significantly faster. It also avoids having to
rebuild bootstrap after setting `download-rustc = true`.

 ## Implementation

Instead of extracting the CI artifacts directly to `stage0/`, extract
them to `ci-rustc/` instead. Continue to copy them to the proper
sysroots as necessary for all stages except stage 0.

This also requires `bootstrap.py` to download both stage0 and CI
artifacts and distinguish between the two when checking stamp files.

Note that since tools have to be built by the same compiler that built
`rustc-dev` and the standard library, the downloaded artifacts can't be
reused when building with the beta compiler. To make sure this is still
a good user experience, warn when building with the beta compiler, and
default to building with stage 2.

Fixes rust-lang#83852

r? `@GuillaumeGomez`

This prevents us from warning on links such as `<hello@example.com>`.
Note that we still warn on links such as `<hello@localhost>` because
they have no dots in them. However, the links will still work, even
though a warning is reported.

Previously, the types looked like this:

- None means this is not an associated item (but may be a variant field)
- Some(Err) means this is known to be an error. I think the only way that can happen is if it resolved and but you had your own anchor.
- Some(Ok(_, None)) was impossible.

Now, this returns a nested Option and does the error handling and
fiddling with the side channel in the caller. As a side-effect, it also
removes duplicate error handling.

This has one small change in behavior, which is that
`resolve_primitive_associated_item` now goes through `variant_field` if
it fails to resolve something.  This is not ideal, but since it will be
quickly rejected anyway, I think the performance hit is worth the
cleanup.

This also fixes a bug where struct fields would forget to set the side
channel.

Now the family name is Source Serif 4 (upstream issue 77) instead of
Source Serif Pro.

…rk-Simulacrum

Use the beta compiler for building bootstrap tools when `download-rustc` is set

 ## Motivation

This avoids having to rebuild bootstrap and tidy each time you rebase
over master. In particular, it makes rebasing and running `x.py fmt` on
each commit in a branch significantly faster. It also avoids having to
rebuild bootstrap after setting `download-rustc = true`.

 ## Implementation

Instead of extracting the CI artifacts directly to `stage0/`, extract
them to `ci-rustc/` instead. Continue to copy them to the proper
sysroots as necessary for all stages except stage 0.

This also requires `bootstrap.py` to download both stage0 and CI
artifacts and distinguish between the two when checking stamp files.

Note that since tools have to be built by the same compiler that built
`rustc-dev` and the standard library, the downloaded artifacts can't be
reused when building with the beta compiler. To make sure this is still
a good user experience, warn when building with the beta compiler, and
default to building with stage 2.

I tested this by rebasing this PR from edeee91 over 1c77a1f and confirming that only the bootstrap library itself had to be rebuilt, not any dependencies and not `tidy`. I also tested that a clean build with `x.py build` builds rustdoc exactly once and does no other work, and that `touch src/librustdoc/lib.rs && x.py build` works. `x.py check` still behaves as before (checks using the beta compiler, even if there are changes to `compiler/`).

Helps with rust-lang#81930.

r? `@Mark-Simulacrum`

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ```````@Mark-Simulacrum``````` cc ```````@camelid```````

…eGomez

Update Source Serif to release 4.004

Now the family name is Source Serif 4 (upstream issue 77) instead of Source Serif Pro.

…order-shuffle, r=jyn514

List trait impls before deref methods in doc's sidebar

This PR is acting directly on a suggestion made by ``````@jyn514`````` in rust-lang#83133. I've tested the changes locally, and can confirm that it does in fact properly achieve what he thought it would. This PR also in turn closes rust-lang#83133.

…ine-for-ip, r=m-ou-se

Add `#[inline]` to IpAddr methods

Add some inlines to trivial methods of IpAddr
Closes rust-lang#77583

rustdoc: Cleanup handling of associated items for intra-doc links

Helps with rust-lang#83761 (right now the uses of the resolver are all intermingled with uses of the tyctxt). Best reviewed one commit at a time.

r? ```@bugadani``` maybe? Feel free to reassign :)

Render destructured struct function param names as underscore

Fixes rust-lang#83852

r? ```@GuillaumeGomez```

Don't report disambiguator error if link would have been ignored

Fixes rust-lang#83859.

This prevents us from warning on links such as `<hello@example.com>`.
Note that we still warn on links such as `<hello@localhost>` because
they have no dots in them. However, the links will still work, even
though a warning is reported.

r? ```@jyn514```