[breaking change] Validate crate name in `--extern` [MCP 650]
Reject non-ASCII-identifier crate names passed to the CLI option `--extern` (`rustc`, `rustdoc`).
Implements [MCP 650](https://github.com/rust-lang/compiler-team/issues/650) (except that we only allow ASCII identifiers not arbitrary Rust identifiers).
Fixes#113035.
[As mentioned on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Disallow.20non-identifier-valid.20--extern.20cr.E2.80.A6.20compiler-team.23650/near/376826988), doing a crater run probably doesn't make sense since it wouldn't yield anything. Most users don't interact with `rustc` directly but only ever through Cargo which always passes a valid crate name to `--extern` when it invokes `rustc` and `rustdoc`. In any case, the user wouldn't be able to use such a crate name in the source code anyway.
Note that I'm not using [`rustc_session::output::validate_crate_name`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_session/output/fn.validate_crate_name.html) (used for `--crate-name` and `#![crate_name]`) since the latter doesn't reject non-ASCII crate names and ones that start with a digit.
As an aside, I've also thought about getting rid of `validate_crate_name` entirely in a separate PR (with another MCP) in favor of `is_ascii_ident` to reject more weird `--crate-name`s, `#![crate_name]`s and file names but I think that would lead to a lot of actual breakage, namely because of file names starting with a digit. In `tests/ui` 9 tests would be impacted for example.
CC `@estebank`
r? `@est31`
adjust how closure/generator types are printed
I saw `&[closure@$DIR/issue-20862.rs:2:5]` and I thought it is a slice type, because that's usually what `&[_]` is... it took me a while to realize that this is just a confusing printer and actually there's no slice. Let's use something that cannot be mistaken for a regular type.
Allow `-Z treat-err-as-bug=0`
Makes `-Z treat-err-as-bug=0` behave as if the option wasn't present instead of asking the value to be ⩾ 1. This enables a quick on/off of the option, as you only need to change one character instead of removing the whole `-Z`.
Also update some text, e.g.
```bash
$ rustc -Z help | grep treat-err-as-bug
-Z treat-err-as-bug=val -- treat error number `val` that occurs as bug
```
where the value could be interpreted as an error code instead of an ordinal.
- Some comment fixes.
- Make some functions unsafe.
- Make helpers module private.
- Rebase on master
- Update r-efi to v4.2.0
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
- Make BootServices unavailable if ExitBootServices event is signaled.
- Use thread locals for SystemTable and ImageHandle
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
give FutureIncompatibilityReason variants more explicit names
Also make the `reason` field mandatory when declaring a lint, to make sure this is a deliberate decision.
tests/ui: Split large_moves.rs and move to lint/large_assignments
To make failing tests easier to debug with `--emit=mir`, etc.
Don't bother with `revisions: attribute option` for both tests though. Seems sufficient to just have that on one of the tests.
`git show -M --find-renames=40%` makes the diff easier to review. Or note that before this change we had one test with 4 errors, now we have 2 tests with 2 errors each.
r? `@oli-obk`
Part of https://github.com/rust-lang/rust/issues/83518
Command: also print removed env vars
There is no real shell syntax for unsetting an env var so easily, so we have to make one up. But we already do that for showing the 'program' name so I hope that's okay here, too. No strong opinion on what that should look like, I went with `unset(VAR_NAME)` for now.
