This reverts commit faac70b.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

I believe this was changed a while ago in rust-lang/promote-release#14.

When using `symlink_dir`, it first removes the existing link with `remove_dir`.
However, if the path isn't a link and contains files, `remove_dir` fails
with "DirectoryNotEmpty", which causes the symbolic linking to fail as well.
We have this problem on linking 'rustlib/rust' because it contains files as an
actual directory.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

If `codegen-backends` is missing "cranelift" and "gcc" (which is common),
bootstrap will now only show this warning during `dist` and `install` steps,
or if codegen-backends was explicitly called for build.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

This is already handled from bootstrap at
https://github.com/rust-lang/rust/blob/a1ca449981e3b8442e358026437b7bedb9a1458e/src/bootstrap/src/utils/helpers.rs#L504-L506.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

So we can omit the `token::` qualifier, which gives more space to some
cramped code.

Merge `PatParam`/`PatWithOr`, and `Expr`/`Expr2021`, for a few reasons.

- It's conceptually nice, because the two pattern kinds and the two
  expression kinds are very similar.

- With expressions in particular, there are several places where both
  expression kinds get the same treatment.

- It removes one unreachable match arm.

- Most importantly, for rust-lang#124141 I will need to introduce a new type
  `MetaVarKind` that is very similar to `NonterminalKind`, but records a
  couple of extra fields for expression metavars. It's nicer to have a
  single `MetaVarKind::Expr` expression variant to hold those extra
  fields instead of duplicating them across two variants
  `MetaVarKind::{Expr,Expr2021}`. And then it makes sense for patterns
  to be treated the same way, and for `NonterminalKind` to also be
  treated the same way.

I also clarified the comments, because I have long found them a little
hard to understand.

…-Simulacrum

tidy: skip submodules if not present for non-CI environments

Right now tidy requires rustc-perf to be fetched as it checks its license, but this doesn't make sense for most contributors since rustc-perf is a dist-specific tool and its license will not change frequently, especially during compiler development. This PR makes tidy to skip rustc-perf if it's not fetched and if it's not running in CI.

Applies rust-lang#126225 (comment) and reverts rust-lang#126225.

…k-Simulacrum

Update outdated README in build-manifest.

I believe this was changed a while ago in rust-lang/promote-release#14.

…imulacrum

less bootstrap warnings

This is how the build logs looks like currently:

```sh
$ x build
Building bootstrap
   Compiling bootstrap v0.0.0 (/home/nimda/devspace/onur-ozkan/rust/src/bootstrap)
    Finished `dev` profile [unoptimized] target(s) in 3.43s
WARNING: no codegen-backends config matched the requested path to build a codegen backend. HELP: add backend to codegen-backends in config.toml.
WARNING: creating symbolic link `/home/nimda/devspace/.other/rustc-builds/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/rustc-src/rust` to `/home/nimda/devspace/onur-ozkan/rust` failed with File exists (os
error 17)
Creating a sysroot for stage2 compiler (use `rustup toolchain link 'name' build/host/stage2`)
WARNING: creating symbolic link `/home/nimda/devspace/.other/rustc-builds/build/x86_64-unknown-linux-gnu/ci-rustc-sysroot/lib/rustlib/rustc-src/rust` to `/home/nimda/devspace/onur-ozkan/rust` failed with File e
xists (os error 17)
Building tool rustdoc (stage1 -> stage2, x86_64-unknown-linux-gnu)
   Compiling rustdoc v0.0.0 (/home/nimda/devspace/onur-ozkan/rust/src/librustdoc)
   Compiling rustdoc-tool v0.0.0 (/home/nimda/devspace/onur-ozkan/rust/src/tools/rustdoc)
    Finished `release` profile [optimized + debuginfo] target(s) in 13.57s
Build completed successfully in 0:00:17
```

This PR removes artifact linking warnings and only shows the codegen-backend warning if explicitly called or during Dist or Install steps.

…mulacrum

remove `GIT_DIR` handling in pre-push hook

This is already handled from bootstrap: https://github.com/rust-lang/rust/blob/a1ca449981e3b8442e358026437b7bedb9a1458e/src/bootstrap/src/utils/helpers.rs#L504-L506

…iler-errors

make unsized_fn_params an internal feature

As suggested [here](rust-lang#123894 (comment)).
r? `@compiler-errors`

Fixes rust-lang#123887 (kind of -- ICEs on internal features are considered acceptable so this issue is not-a-bug once this PR lands)

…compiler-errors

don't ICE when encountering an extern type field during validation

"extern type" is a pain that keeps on giving...

Fixes rust-lang#126814

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

…errors

delegation: Do not crash on qpaths without a trait

Fixes rust-lang#126742

…r=compiler-errors

Rework pattern and expression nonterminal kinds.

Some tweaks to `NonterminalKind` that will assist with rust-lang#124141. Details in the individual commits.

r? compiler-errors
cc ```@eholk```

Add needs-symlink directive to compiletest

This is an alternative to rust-lang#126846 that allows running symlink tests on Windows in CI but will ignore them locally if symlinks aren't available. A future improvement would be to check that the `needs-symlink` directive is used in rmake files that call `create_symlink` but this is just a quick PR to unblock Windows users who want to run tests locally without enabling symlinks.