Formerly `-Zterminal-width`, `--terminal-width` allows the user or build
tool to inform rustc of the width of the terminal so that diagnostics
can be truncated.

Signed-off-by: David Wood <[email protected]>

Rename the `--terminal-width` flag to `--output-width` as the behaviour
doesn't just apply to terminals (and so is slightly less accurate).

Signed-off-by: David Wood <[email protected]>

Rename the `--output-width` flag to `--diagnostic-width` as this appears
to be the preferred name within the compiler team.

Signed-off-by: David Wood <[email protected]>

This lint seems to have been broken by rust-lang#98446

…esolve_region, and remove RootEmptyRegion

…ion, r=oli-obk

sess: stabilize `--terminal-width` as `--diagnostic-width`

Formerly `-Zterminal-width`, `--terminal-width` allows the user or build
tool to inform rustc of the width of the terminal so that diagnostics
can be truncated.

Pending agreement to stabilize, see tracking issue at rust-lang#84673.

r? ``@oli-obk``

…stebank

Fix last `let_chains` blocker

In order to forbid things like `let x = (let y = 1);` or `if let a = 1 && { let x = let y = 1; } {}`, the parser **HAS** to know the context of `let`.

This context thing is not a surprise in the parser because you can see **a lot** of ad hoc fixes mixing parsing logic with validation logic creating code that looks more like spaghetti with tomato sauce.

To make things even greater, a new ad hoc fix was added to only allow `let`s in a valid `let_chains` context by checking the previously processed token. This was the only solution I could think of and believe me, I thought about it for a long time 👍

In the long term, it should be preferable to segregate different responsibilities or create a more robust and cleaner parser framework.

cc rust-lang#94927
cc rust-lang#53667

…r=yaahc

Stabilize `into_future`

rust-lang#67644 has been labeled with [S-tracking-ready-to-stabilize](https://github.com/rust-lang/rust/labels/S-tracking-ready-to-stabilize) - which mentions someone needs to file a stabilization PR. So hence this PR! ✨ Thanks!

Closes rust-lang#67644

r? `@joshtriplett`

…anup, r=compiler-errors

A few cleanups

Each commit is (mostly) self-explanatory. These changes have come as I try to remove `ReEmpty` (rust-lang#98559).

Add doc comments in `rustc_middle::mir`

Add test for and fix rust-lang/rust-clippy#9131

This lint seems to have been broken by rust-lang#98446 -- but of course, there was no clippy test for this case at the time.

`expr.span.ctxt().outer_expn_data()` now has `MacroKind::Derive` instead of `MacroKind::Attr` for something like:

```
#[derive(Clone, Debug)]
pub struct UnderscoreInStruct {
    _foo: u32,
}
```

---

changelog: none

closes: rust-lang/rust-clippy#9131