This greatly reduces round-trips to fetch relevant extra information about the
token in proc macro code, and avoids RPC messages to create Group tokens.

This greatly reduces round-trips to fetch relevant extra information about the
token in proc macro code, and avoids RPC messages to create Punct tokens.

proc_macro/bridge: cache static spans in proc_macro's client thread-local state

This is the second part of https://github.com/rust-lang/rust/pull/86822, split off as requested in https://github.com/rust-lang/rust/pull/86822#pullrequestreview-1008655452. This patch removes the RPC calls required for the very common operations of `Span::call_site()`, `Span::def_site()` and `Span::mixed_site()`.

Some notes:

This part is one of the ones I don't love as a final solution from a design standpoint, because I don't like how the spans are serialized immediately at macro invocation. I think a more elegant solution might've been to reserve special IDs for `call_site`, `def_site`, and `mixed_site` at compile time (either starting at 1 or from `u32::MAX`) and making reading a Span handle automatically map these IDs to the relevant values, rather than doing extra serialization.

This would also have an advantage for potential future work to allow `proc_macro` to operate more independently from the compiler (e.g. to reduce the necessity of `proc-macro2`), as methods like `Span::call_site()` could be made to function without access to the compiler backend.

That was unfortunately tricky to do at the time, as this was the first part I wrote of the patches. After the later part (#98188, #98189), the other uses of `InternedStore` are removed meaning that a custom serialization strategy for `Span` is easier to implement.

If we want to go that path, we'll still need the majority of the work to split the bridge object and introduce the `Context` trait for free methods, and it will be easier to do after `Span` is the only user of `InternedStore` (after #98189).

Rollup of 11 pull requests

Successful merges:

 - #97140 (std: use an event-flag-based thread parker on SOLID)
 - #97295 ([rustc_parse] Forbid `let`s in certain places)
 - #97743 (make const_err show up in future breakage reports)
 - #97908 (Stabilize NonZero* checked operations constness.)
 - #98297 (Transform help popup into a pocket menu)
 - #98428 (macros: use typed identifiers in diag and subdiag derive)
 - #98528 (Respect --color when building rustbuild itself)
 - #98535 (Add regression test for generic const in rustdoc)
 - #98538 (Add a ui test for issue #91883)
 - #98540 (Add regression test for #87558)
 - #98541 (Update `std::alloc::System` doc example code style)

Failed merges:

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

Update `std::alloc::System` doc example code style

`return` on the last line of a block is unidiomatic so I don't think the example should be using that here

Add regression test for #87558

Fixes #87558

Add a ui test for issue #91883

closes #91883

Add regression test for generic const in rustdoc

Fixes #92859.

r? ```@lcnr```

Respect --color when building rustbuild itself

Separated out from https://github.com/rust-lang/rust/pull/95503.

macros: use typed identifiers in diag and subdiag derive

Using typed identifiers instead of strings with the Fluent identifiers in the diagnostic and subdiagnostic derives - this enables the diagnostic derive to benefit from the compile-time validation that comes with typed identifiers, namely that use of a non-existent Fluent identifier will not compile.

r? `````@oli-obk`````

Transform help popup into a pocket menu

Just like we moved the settings menu into a "pocket menu", it's doing the same to the help popup.

You can test it [here](https://rustdoc.crud.net/imperio/help-pocket-menu/doc/foo/index.html) and here is a screenshot:

![Screenshot from 2022-06-20 20-58-29](https://user-images.githubusercontent.com/3050060/174663718-538e9d11-3bf9-48b2-8909-f9bfe75af135.png)

r? ``````````@jsha``````````

Stabilize NonZero* checked operations constness.

Partial stabilization for #97547 (continued).

make const_err show up in future breakage reports

As tracked in https://github.com/rust-lang/rust/issues/71800, const_err should become a hard error Any Day Now (TM). I'd love to move forward with that sooner rather than later; it has been deny-by-default for many years and a future incompat lint since https://github.com/rust-lang/rust/pull/80394 (landed more than a year ago). Some CTFE errors are already hard errors since https://github.com/rust-lang/rust/pull/86194. But before we truly make it a hard error in all cases, we now have one more intermediate step we can take -- to make it show up in future breakage reports.

Cc `````@rust-lang/wg-const-eval`````

[rustc_parse] Forbid `let`s in certain places

Currently only forbids in locals to resolve https://github.com/rust-lang/rust/pull/94927#issuecomment-1099605024 but feel free to point any other places.

std: use an event-flag-based thread parker on SOLID

`Mutex` and `Condvar` are being replaced by more efficient implementations, which need thread parking themselves (see #93740). Therefore, the generic `Parker` needs to be replaced on all platforms where the new lock implementation will be used, which, after #96393, are SOLID, SGX and Hermit (more PRs coming soon).

SOLID, conforming to the [μITRON specification](http://www.ertl.jp/ITRON/SPEC/FILE/mitron-400e.pdf), has event flags, which are a thread parking primitive very similar to `Parker`. However, they do not make any atomic ordering guarantees (even though those can probably be assumed) and necessitate a system call even when the thread token is already available. Hence, this `Parker`, like the Windows parker, uses an extra atomic state variable.

I future-proofed the code by wrapping the event flag in a `WaitFlag` structure, as both SGX and Hermit can share the Parker implementation, they just have slightly different primitives (SGX uses signals and Hermit has a thread blocking API).

`````@kawadakk````` I assume you are the target maintainer? Could you test this for me?

Improve `derive(Debug)`

r? `@ghost`

update Miri

Fixes https://github.com/rust-lang/rust/issues/98493 (this is a flaky test, that's why the toolstate already says Miri is fixed)
r? `@ghost` Cc `@rust-lang/miri`

Rollup of 8 pull requests

Successful merges:

 - #98371 (Fix printing `impl trait` under binders)
 - #98385 (Work around llvm 12's memory ordering restrictions.)
 - #98474 (x.py: Support systems with only `python3` not `python`)
 - #98488 (Bump RLS to latest master on rust-lang/rls)
 - #98491 (Fix backtrace UI test when panic=abort is used)
 - #98502 (Fix source sidebar hover in ayu theme)
 - #98509 (diagnostics: consider parameter count when suggesting smart pointers)
 - #98513 (Fix LLVM rebuild with download-ci-llvm.)

Failed merges:

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

Fix LLVM rebuild with download-ci-llvm.

This fixes an issue where updating a local checkout that includes a change in `src/version` causes a linking failure.

The cause is that the `rustc_llvm` build script uses `rerun-if-changed` of `llvm-config` to know if it needs to rerun. Cargo only compares the timestamp of the last time the build script to the file. However, extracting the tar files retains the timestamps in the tarball which may be some time in the past. Since `src/version` is included in the LLVM `.so` filename, `rustc` attempts to load the wrong shared library since the `rustc_llvm` build script doesn't rerun.

https://github.com/rust-lang/cargo/issues/10791 contains a more detailed explanation.

The solution here is a hack which updates the timestamp of `llvm-config` to the current time when it is extracted.

This is a bit of a hack, but seems to be the best solution I can think of until https://github.com/rust-lang/cargo/issues/10791 is fixed. There are likely several other situations where this is a problem (such as using system LLVM), and this isn't really a complete fix.

Note that apple platforms are not directly affected by this problem because they don't have a version in the dylib filename.

How to test this:

1. On a linux host, enable download-ci-llvm
2. Check out 7036449c (the commit just before the last version bump)
3. `./x.py build library/std`
4. Check out 5f015a24 (the commit that bumped the version)
5. `./x.py build library/std`

Fixes #98495

diagnostics: consider parameter count when suggesting smart pointers

Fixes #96834

Fix source sidebar hover in ayu theme

In the screenshot below, `rc.rs` should be orange:

![Screenshot from 2022-06-25 22-24-06](https://user-images.githubusercontent.com/3050060/175789532-99e8781d-2e62-43f7-bbd9-1b1151e1f8c1.png)

It's because the CSS selector was not precise enough and was "overloaded" with another one. This PR fixes it and adds a test for the colors in the source sidebar.

cc `@jsha`
r? `@notriddle`

Fix backtrace UI test when panic=abort is used

The function `contains_verbose_expected` is only used when the panic strategy is not abort, so it caused a warning when it was abort, which made the UI test failed on stderr comparison.

Bump RLS to latest master on rust-lang/rls

Of primary interest, this merges
rust-lang/rls@ece09b88c0365947af79c0ffdeea02bc6c1eec25 into rust-lang/rust,
which brings in the changes that fix RLS tests broken by #97853. #97853 already
introduced that commit's changes (under
rust-lang/rls@27f4044df03d15c7c38a483c3e4635cf4f51807d) but without putting those changes on
rust-lang/rls as a branch, so we ended up with an orphan commit that caused
trouble when updating submodules in rust-lang/rust.

This commit, once merged into rust-lang/rust, should continue to let RLS tests
to pass on rust-lang/rust's side and move us back into a healthy state where tip
of the submodule points to a valid master commit in the rust-lang/rls
repository.

cc https://github.com/rust-lang/rust/issues/98451, but not marking as fixed as I believe we need to add verification to prevent future oversights.

x.py: Support systems with only `python3` not `python`

Fixes #71818 without the pitfalls so far described in previous attempts.

Work around llvm 12's memory ordering restrictions.

Older llvm has the pre-C++17 restriction on success and failure memory ordering, requiring the former to be at least as strong as the latter. So, for llvm 12, this upgrades the success ordering to a stronger one if necessary.

See https://github.com/rust-lang/rust/issues/68464

Fix printing `impl trait` under binders

Before, we would render `impl for<'a> Trait<'a>` like `impl Trait<for<'a> 'a>`, lol.

compiletest: strip debuginfo by default for mode=ui

This reduces occupied disk space, for example for src/test/ui it drops from 1972mb to 132mb (x86_64-pc-windows-msvc).

Individual tests that require debuginfo/symbols should turn this option off (as in fixed tests).

Fully remove submodule handling from bootstrap.py

These submodules were previously updated in python because Cargo gives a hard error if toml files
are missing from the workspace:

```
error: failed to load manifest for workspace member `/home/jnelson/rust-lang/rust/src/tools/rls`

Caused by:
  failed to read `/home/jnelson/rust-lang/rust/src/tools/rls/Cargo.toml`

Caused by:
  No such file or directory (os error 2)
failed to run: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/bin/cargo build --manifest-path /home/jnelson/rust-lang/rust/src/bootstrap/Cargo.toml
```

However, bootstrap doesn't actually need to be part of the workspace.
Remove it so we can move submodule handling fully to Rust, avoiding duplicate code between Rust and Python.

Note that this does break `cargo run`; it has to be `cd src/bootstrap && cargo run` now.
Given that we're planning to make the main entrypoint a shell script (or rust binary),
I think this is a good tradeoff for reduced complexity in bootstrap.py.

To get this working, I also had to remove support for vendoring when using the git sources, because `cargo vendor` requires all submodules to be checked out. I think this is ok; people who care about this are likely already using the pre-vendored `rustc-src` tarball.

Fixes https://github.com/rust-lang/rust/issues/90764. Helps with #94829