The starting point for this was identical comments on two different
fields, in `ast::VariantData::Struct` and `hir::VariantData::Struct`:
```
// FIXME: investigate making this a `Option<ErrorGuaranteed>`
recovered: bool
```
I tried that, and then found that I needed to add an `ErrorGuaranteed`
to `Recovered::Yes`. Then I ended up using `Recovered` instead of
`Option<ErrorGuaranteed>` for these two places and elsewhere, which
required moving `ErrorGuaranteed` from `rustc_parse` to `rustc_ast`.
This makes things more consistent, because `Recovered` is used in more
places, and there are fewer uses of `bool` and
`Option<ErrorGuaranteed>`. And safer, because it's difficult/impossible
to set `recovered` to `Recovered::Yes` without having emitted an error.
Remove braces when fixing a nested use tree into a single item
[Back in 2019](https://github.com/rust-lang/rust/pull/56645) I added rustfix support for the `unused_imports` lint, to automatically remove them when running `cargo fix`. For the most part this worked great, but when removing all but one childs of a nested use tree it turned `use foo::{Unused, Used}` into `use foo::{Used}`. This is slightly annoying, because it then requires you to run `rustfmt` to get `use foo::Used`.
This PR automatically removes braces and the surrouding whitespace when all but one child of a nested use tree are unused. To get it done I had to add the span of the nested use tree to the AST, and refactor a bit the code I wrote back then.
A thing I noticed is, there doesn't seem to be any `//@ run-rustfix` test for fixing the `unused_imports` lint. I created a test in `tests/suggestions` (is that the right directory?) that for now tests just what I added in the PR. I can followup in a separate PR to add more tests for fixing `unused_lints`.
This PR is best reviewed commit-by-commit.
Some hir cleanups
It seemed odd to not put `AnonConst` in the arena, compared with the other types that we did put into an arena. This way we can also give it a `Span` without growing a lot of other HIR data structures because of the extra field.
r? compiler
Remove many `#[macro_use] extern crate foo` items
This requires the addition of more `use` items, which often make the code more verbose. But they also make the code easier to read, because `#[macro_use]` obscures where macros are defined.
r? `@fee1-dead`
Add StaticForeignItem and use it on ForeignItemKind
This is in preparation for unsafe extern blocks that adds a safe variant for functions inside extern blocks.
r? `@oli-obk`
cc `@compiler-errors`
Add a note to the ArbitraryExpressionInPattern error
The current "arbitrary expressions aren't allowed in patterns" error is confusing, as it fires for code where it *looks* like a pattern but the compiler still treats it as an expression. That this is due to the `:expr` fragment specifier forcing the expression-ness property on the code.
In the test suite, the "arbitrary expressions aren't allowed in patterns" error can only be found in combination with macro_rules macros that force expression-ness of their content, namely via `:expr` metavariables. I also can't come up with cases where there would be an expression instead of a pattern, so I think it's always coming from an `:expr`.
In order to make the error less confusing, this adds a note explaining the weird `:expr` fragment behaviour.
Fixes#99380
delegation: Support renaming, and async, const, extern "ABI" and C-variadic functions
Also allow delegating to functions with opaque types (`impl Trait`).
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created, which seems like a reasonable behavior.
(Such delegation items will cause query cycles when used in trait impls, but it can be fixed later.)
Part of https://github.com/rust-lang/rust/issues/118212.
Also allow `impl Trait` in delegated functions.
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created.
Don't inline integer literals when they overflow - new attempt
Basically #116633 but I implemented the suggested changes.
Fixes#115423. Fixes#116631.
This is my first contribution to this repo so please let me know if I'm supposed to change something :)
