This is needed for my Ubuntu 22.04 box due to a slight change in gdb
output. The fix is similar to the fix in rust-lang#95063.

Improves the compiler error backtrace information, as shown in rust-lang#99363,
by using `span_bug` instead of `bug`.

New output:

```
build/aarch64-apple-darwin/stage1/bin/rustc /tmp/test.rs --edition=2021
error: internal compiler error: compiler/rustc_middle/src/ty/closure.rs:185:25: Unexpected type Opaque(DefId(0:5 ~ test[db0f]::main::T::{opaque#0}), []) for `Field` projection
  --> /tmp/test.rs:11:27
   |
11 |         let Foo((a, b)) = foo;
   |                           ^^^

thread 'rustc' panicked at 'Box<dyn Any>', /Users/jmq/src/forked/rust/compiler/rustc_errors/src/lib.rs:1331:9
stack backtrace:
```

(Remainder of output truncated.)

The restriction that success ordering must be at least as strong as its
failure ordering in compare-exchange operations was lifted in rust-lang#98383.

wf-check generators

fixes rust-lang#90409

We should not rely on generators being well formed by construction now that they can get used via type alias impl trait (and thus users can choose generic arguments that are invalid). This can cause surprising behaviour if (definitely unsound) transmutes are used, and it's generally saner to just check for well formedness.

…estebank

Mention first and last macro in backtrace

Slight improvement to diagnostic mentioning what macro an error originates from. Not sure if it's worthwhile.

Use split_once in FromStr docs

Current implementation:

```rust
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let coords: Vec<&str> = s.trim_matches(|p| p == '(' || p == ')' )
                                 .split(',')
                                 .collect();

        let x_fromstr = coords[0].parse::<i32>()?;
        let y_fromstr = coords[1].parse::<i32>()?;

        Ok(Point { x: x_fromstr, y: y_fromstr })
    }
```

Creating the vector is not necessary, `split_once` does the job better.

Alternatively we could also remove `trim_matches` with `strip_prefix` and `strip_suffix`:

```rust
        let (x, y) = s
            .strip_prefix('(')
            .and_then(|s| s.strip_suffix(')'))
            .and_then(|s| s.split_once(','))
            .unwrap();
```

The question is how much 'correctness' is too much and distracts from the example. In a real implementation you would also not unwrap (or originally access the vector without bounds checks), but implementing a custom Error and adding a `From<ParseIntError>` and implementing the `Error` trait adds a lot of code to the example which is not relevant to the `FromStr` trait.

…al-def-id, r=oli-obk

Use `LocalDefId` in `OpaqueTypeKey`

Addresses a `// FIXME(oli-obk): make this a LocalDefId`

r? ``@oli-obk``

…pnkfelix

Fix debuginfo tests.

This is needed for my Ubuntu 22.04 box due to a slight change in gdb
output. The fix is similar to the fix in rust-lang#95063.

Use span_bug for unexpected field projection type

Improves the compiler error backtrace information, as shown in rust-lang#99363,
by using `span_bug` instead of `bug`.

New output:

```
build/aarch64-apple-darwin/stage1/bin/rustc /tmp/test.rs --edition=2021
error: internal compiler error: compiler/rustc_middle/src/ty/closure.rs:185:25: Unexpected type Opaque(DefId(0:5 ~ test[db0f]::main::T::{opaque#0}), []) for `Field` projection
  --> /tmp/test.rs:11:27
   |
11 |         let Foo((a, b)) = foo;
   |                           ^^^

thread 'rustc' panicked at 'Box<dyn Any>', /Users/jmq/src/forked/rust/compiler/rustc_errors/src/lib.rs:1331:9
stack backtrace:
```

(Remainder of output truncated.)

Update invalid atomic ordering lint

The restriction that success ordering must be at least as strong as its
failure ordering in compare-exchange operations was lifted in rust-lang#98383.

…=scottmcm

Fix `Skip::next` for non-fused inner iterators

`iter.skip(n).next()` will currently call `nth` and `next` in succession on `iter`, without checking whether `nth` exhausts the iterator. Using `?` to propagate a `None` value returned by `nth` avoids this.