Rollup of 9 pull requests

Successful merges:

 - #68700 (Add Wake trait for safe construction of Wakers.)
 - #69494 (Stabilize --crate-version option in rustdoc)
 - #70080 (rustc_mir: remove extra space when pretty-printing MIR.)
 - #70195 (Add test for issue #53275)
 - #70199 (Revised span-to-lines conversion to produce an empty vec on DUMMY_SP.)
 - #70299 (add err_machine_stop macro)
 - #70300 (Reword unused variable warning)
 - #70315 (Rename remaining occurences of Void to Opaque.)
 - #70318 (Split long derive lists into two derive attributes.)

Failed merges:

r? @ghost

Split long derive lists into two derive attributes.

Rename remaining occurences of Void to Opaque.

Two mentions of the type were missed when the type was renamed.

Reword unused variable warning

Fixes #66636

add err_machine_stop macro

We have that for all other error kinds, but here I somehow forgot it.

r? @oli-obk

Revised span-to-lines conversion to produce an empty vec on DUMMY_SP.

This required revising some of the client code to stop relying on the returned set of lines being non-empty.

Fix #68808

Add test for issue #53275

Fixes #53275

rustc_mir: remove extra space when pretty-printing MIR.

Stabilize --crate-version option in rustdoc

I don't see any reason to not stabilize it anymore, so let's go!

cc @kinnison @ehuss

r? @ollie27

Add Wake trait for safe construction of Wakers.

Currently, constructing a waker requires calling the unsafe `Waker::from_raw` API. This API requires the user to manually construct a vtable for the waker themself - which is both cumbersome and very error prone. This API would provide an ergonomic, straightforward and guaranteed memory-safe way of constructing a waker.

It has been our longstanding intention that the `Waker` type essentially function as an `Arc<dyn Wake>`, with a `Wake` trait as defined here. Two considerations prevented the original API from being shipped as simply an `Arc<dyn Wake>`:

- We want to support futures on embedded systems, which may not have an allocator, and in optimized executors for which this API may not be best-suited. Therefore, we have always explicitly supported the maximally-flexible (but also memory-unsafe) `RawWaker` API, and `Waker` has always lived in libcore.
- Because `Waker` lives in libcore and `Arc` lives in liballoc, it has not been feasible to provide a constructor for `Waker` from `Arc<dyn Wake>`.

Therefore, the Wake trait was left out of the initial version of the task waker API.

However, as Rust 1.41, it is possible under the more flexible orphan rules to implement `From<Arc<W>> for Waker where W: Wake` in liballoc. Therefore, we can now define this constructor even though `Waker` lives in libcore.

This PR adds these APIs:

- A `Wake` trait, which contains two methods
    - A required method `wake`, which is called by `Waker::wake`
    - A provided method `wake_by_ref`, which is called by `Waker::wake_by_ref` and which implementors can override if they can optimize this use case.
- An implementation of `From<Arc<W>> for Waker where W: Wake + Send + Sync + 'static`
- A similar implementation of `From<Arc<W>> for RawWaker`.

Co-Authored-By: NMazdak Farrokhzad <twingoow@gmail.com>

update miri

r? @ghost Cc @oli-obk

Fixes https://github.com/rust-lang/rust/issues/70220

Co-Authored-By: NAshley Mannix <ashleymannix@live.com.au>

Co-Authored-By: NAshley Mannix <ashleymannix@live.com.au>

Co-Authored-By: NAshley Mannix <ashleymannix@live.com.au>

Currently, constructing a waker requires calling the unsafe
`Waker::from_raw` API. This API requires the user to manually construct
a vtable for the waker themself - which is both cumbersome and very
error prone. This API would provide an ergonomic, straightforward and
guaranteed memory-safe way of constructing a waker.

It has been our longstanding intention that the `Waker` type essentially
function as an `Arc<dyn Wake>`, with a `Wake` trait as defined here. Two
considerations prevented the original API from being shipped as simply
an `Arc<dyn Wake>`:

- We want to support futures on embedded systems, which may not have an
  allocator, and in optimized executors for which this API may not be
  best-suited. Therefore, we have always explicitly supported the
  maximally-flexible (but also memory-unsafe) `RawWaker` API, and
  `Waker` has always lived in libcore.
- Because `Waker` lives in libcore and `Arc` lives in liballoc, it has
  not been feasible to provide a constructor for `Waker` from `Arc<dyn
  Wake>`.

Therefore, the Wake trait was left out of the initial version of the
task waker API.

However, as Rust 1.41, it is possible under the more flexible orphan
rules to implement `From<Arc<W>> for Waker where W: Wake` in liballoc.
Therefore, we can now define this constructor even though `Waker` lives
in libcore.

This PR adds these APIs:

- A `Wake` trait, which contains two methods
    - A required method `wake`, which is called by `Waker::wake`
    - A provided method `wake_by_ref`, which is called by
      `Waker::wake_by_ref` and which implementors can override if they
      can optimize this use case.
- An implementation of `From<Arc<W>> for Waker where W: Wake + Send +
  Sync + 'static`
- A similar implementation of `From<Arc<W>> for RawWaker`.

Tweak output for invalid negative impl errors

Follow up to #69722. Tweak negative impl errors emitted in the HIR:

```
error[E0192]: invalid negative impl
  --> $DIR/E0192.rs:9:6
   |
LL | impl !Trait for Foo { }
   |      ^^^^^^
   |
   = note: negative impls are only allowed for auto traits, like `Send` and `Sync`
```

Rollup of 8 pull requests

Successful merges:

 - #69080 (rustc_codegen_llvm: don't generate any type debuginfo for -Cdebuginfo=1.)
 - #69940 (librustc_codegen_llvm: Replace deprecated API usage)
 - #69942 (Increase verbosity when suggesting subtle code changes)
 - #69968 (rustc: keep upvars tupled in {Closure,Generator}Substs.)
 - #70123 (Ensure LLVM is in the link path for rustc tools)
 - #70159 (Update the bundled wasi-libc with libstd)
 - #70233 (resolve: Do not resolve visibilities on proc macro definitions twice)
 - #70286 (Miri error type: remove UbExperimental variant)

Failed merges:

r? @ghost

Miri error type: remove UbExperimental variant

In https://github.com/rust-lang/miri/pull/1250, I will move Miri away from that variant, and use a custom `MachineStop` exception instead.

resolve: Do not resolve visibilities on proc macro definitions twice

Fixes https://github.com/rust-lang/rust/issues/68921

Update the bundled wasi-libc with libstd

Brings in WebAssembly/wasi-libc#184 which can help standalone programs
with environment variables!

Ensure LLVM is in the link path for rustc tools

The build script for `rustc_llvm` outputs LLVM information in `cargo:rustc-link-lib` and `cargo:rustc-link-search` so the compiler can be linked correctly. However, while the lib is carried along in metadata, the search paths are not. So when cargo is invoked again later for rustc _tools_, they'll also try to link with LLVM, but the necessary paths may be left out.

Rustbuild can use the environment to set the LLVM link path for tools -- `LIB` for MSVC toolchains and `LIBRARY_PATH` for everyone else.

Fixes #68714.

rustc: keep upvars tupled in {Closure,Generator}Substs.

Previously, each closure/generator capture's (aka "upvar") type was tracked as one "synthetic" type parameter in the closure/generator substs, and figuring out where the parent `fn`'s generics end and the synthetics start involved slicing at `tcx.generics_of(def_id).parent_count`.

Needing to query `generics_of` limited @davidtwco (who wants to compute some `TypeFlags` differently for parent generics vs upvars, and `TyCtxt` is not available there), which is how I got started on this, but it's also possible that the `generics_of` queries are slowing down `{Closure,Generator}Substs` methods.

To give an example, for a `foo::<T, U>::{closure#0}` with captures `x: X` and `y: Y`, substs are:
* before this PR: `[T, U, /*kind*/, /*signature*/, X, Y]`
* after this PR: `[T, U, /*kind*/, /*signature*/, (X, Y)]`

You can see that, with this PR, no matter how many captures, the last 3 entries in the substs (or 5 for a generator) are always the "synthetic" ones, with the last one being the tuple of capture types.

r? @nikomatsakis cc @Zoxc

Increase verbosity when suggesting subtle code changes

Do not suggest changes that are actually quite small inline, to minimize the likelihood of confusion.

Fix #69243.

librustc_codegen_llvm: Replace deprecated API usage

rustc_codegen_llvm: don't generate any type debuginfo for -Cdebuginfo=1.

Works towards #69074 by adding more checks for `DebugInfo::Full` in a few places in `rustc_codegen_llvm`, bringing us in line with what `clang -g1` generates (no debuginfo types, nor debuginfo for `static`s).

<hr/>

My local build's (`debuginfo-level=1`, `debug-assertions=1`) `librustc_driver-*.so` went from just over 1GiB (1019MiB) down to 402MiB.

It's still bad, but the `.debug_*` sections themselves (as reported by `objdump`) went from something like 853MiB down to 236MiB, i.e. roughly a 3.6x reduction.

<hr/>

Sadly, I don't think this is enough to justify *shipping* all of this debuginfo, but now it's more plausible that we could at least *build* with `debuginfo-level=1` *then* strip it.
That would give us real backtraces for e.g. ICEs during builds, but I don't know how often that's relevant.

We could also look into split DWARF, and maybe have a `rustc-debuginfo` component in `rustup`.

There's also the possibility of making it slimmer by omitting parameters to functions, or perhaps some deduplication (I think right now there is no DWARF reuse across CGUs? maybe ThinLTO helps?).

r? @michaelwoerister cc @rust-lang/wg-codegen @alexcrichton @Mark-Simulacrum