In particular this pulls in an update to the auto-deref
recursion_limit example, to no longer rely on the Freeze query.

This saves us both the Freeze/Unpin queries, and avoids placing
noalias attributes, which have a compile-time impact on LLVM
even in optnone builds (due to always_inline functions).

We don't have any known noalias bugs for LLVM 12 ... yet.

Such structures may contain self-references, in which case the
same location may be accessible through a pointer that is not
based-on the noalias pointer.

This is still grey area as far as language semantics are concerned,
but checking for !Unpin as an indicator for self-referential
sturctures seems like a good approach for the meantime.

When bumping the bootstrap version, the name of the generated LLVM
shared object file is changed, even though it's the same contents as
before. If bootstrap tries to use an older version, it will get linking
errors:

```
Building rustdoc for stage1 (x86_64-unknown-linux-gnu)
   Compiling rustdoc-tool v0.0.0 (/home/joshua/rustc/src/tools/rustdoc)
error: linking with `cc` failed: exit code: 1
  |
  = note: "cc" "-Wl,--as-needed" ... lots of args ...
  = note: /usr/bin/ld: cannot find -lLLVM-12-rust-1.53.0-nightly
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

error: could not compile `rustdoc-tool`
```

Currently, the print helper macro performs 'recollection' by doing
`token_stream.into_iter().collect()`. However, this will not affect
nonterminals that occur nested inside delimited groups, since the
wrapping delimited group will be left untouched.

This commit adds 'deep recollection', which recursively recollects every
delimited group in the token stream. As with normal recollection, we
only print out something if deep recollection results in a different
stringified token stream.

This is useful for catching bugs where we update the AST of a
nonterminal (which affects pretty-printing), but do not update the
attatched `TokenStream`

With this PR, we now lint for all cases where we perform some kind of
proc-macro back-compat hack.

The `js-sys` had an internal fix made to properly handle
`None`-delimited groups, so we need to manually check the version in the
filename. As a result, we no longer apply the back-compat hack to cases
where the version number is missing file the file path. This should not
affect any users of the `crates.io` crate.

make changes to liveness to use closure_min_captures

use different span

borrow check uses new structures

rename to CapturedPlace

stop using upvar_capture in regionck

remove the bridge

cleanup from rebase + remove the upvar_capture reference from mutability_errors.rs

remove line from livenes test

make our unused var checking more consistent

update tests

adding more warnings to the tests

move is_ancestor_or_same_capture to rustc_middle/ty

update names to reflect the closures

add FIXME

check that all captures are immutable borrows before returning

add surrounding if statement like the original

move var out of the loop and rename
Co-authored-by: NLogan Mosier <logmosier@gmail.com>
Co-authored-by: NRoxane Fruytier <roxane.fruytier@hotmail.com>

This is a continuation of https://github.com/rust-lang/llvm-project/pull/96
to continue to make progress on updating Rust's support for SIMD
intrinsics on WebAssembly to the latest version of the specification.

Unlike the other cases of this lint, there's no simple way to detect if
an old version of the relevant crate (`syn`) is in use. The `actix-web`
crate only depends on `pin-project` v1.0.0, so checking the version of
`actix-web` does not guarantee that a new enough version of
`pin-project` (and therefore `syn`) is in use.

Instead, we rely on the fact that virtually all of the regressed crates
are pinned to a pre-1.0 version of `pin-project`. When this is the case,
bumping the `actix-web` dependency will pull in the *latest* version of
`pin-project`, which has an explicit dependency on a newer v dependency
on a newer version of `syn`.

The lint message tells users to update `actix-web`, since that's what
they're most likely to have control over. We could potentially tell them
to run `cargo update -p syn`, but I think it's more straightforward to
suggest an explicit change to the `Cargo.toml`

The `actori-web` fork had its last commit over a year ago, and appears
to just be a renamed fork of `actix-web`. Therefore, I've removed the
`actori-web` check entirely - any crates that actually get broken can
simply update `syn` themselves.

async-pub check created a regression for default

Redirects `const? async? unsafe? pub` to `pub const? async? unsafe?`.

Fix #76437

Previously, there was no way to add a custom tool prefix, even if the tool
itself had registered a lint:

 ```
 #![feature(register_tool)]
 #![register_tool(xyz)]
 #![warn(xyz::my_lint)]
 ```

```
$ rustc unknown-lint.rs  --crate-type lib
error[E0710]: an unknown tool name found in scoped lint: `xyz::my_lint`
 --> unknown-lint.rs:3:9
  |
3 | #![warn(xyz::my_lint)]
  |         ^^^
```

This allows opting-in to lints from other tools using `register_tool`.