Revert "review comment: Remove AST AnonTy"
This reverts commit 020cca8d36.
Revert "Ensure macros are not affected"
This reverts commit 12d18e4031.
Revert "Emit fewer errors on patterns with possible type ascription"
This reverts commit c847a01a3b.
Revert "Teach parser to understand fake anonymous enum syntax"
This reverts commit 2d82420665.
Teach parser to understand fake anonymous enum syntax
Parse `Ty | OtherTy` in function argument and return types.
Parse type ascription in top level patterns.
Minimally address #100741.
Rollup of 9 pull requests
Successful merges:
- #104531 (Provide a better error and a suggestion for `Fn` traits with lifetime params)
- #105899 (`./x doc library --open` opens `std`)
- #106190 (Account for multiple multiline spans with empty padding)
- #106202 (Trim more paths in obligation types)
- #106234 (rustdoc: simplify settings, help, and copy button CSS by not reusing)
- #106236 (docs/test: add docs and a UI test for `E0514` and `E0519`)
- #106259 (Update Clippy)
- #106260 (Fix index out of bounds issues in rustdoc)
- #106263 (Formatter should not try to format non-Rust files)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Currently, given `Fn`-family traits with lifetime params like
`Fn<'a>(&'a str) -> bool`, many unhelpful errors show up. These are a
bit confusing.
This commit allows these situations to suggest simply using
higher-ranked trait bounds like `for<'a> Fn(&'a str) -> bool`.
`MacArgs` is an enum with three variants: `Empty`, `Delimited`, and `Eq`. It's
used in two ways:
- For representing attribute macro arguments (e.g. in `AttrItem`), where all
three variants are used.
- For representing function-like macros (e.g. in `MacCall` and `MacroDef`),
where only the `Delimited` variant is used.
In other words, `MacArgs` is used in two quite different places due to them
having partial overlap. I find this makes the code hard to read. It also leads
to various unreachable code paths, and allows invalid values (such as
accidentally using `MacArgs::Empty` in a `MacCall`).
This commit splits `MacArgs` in two:
- `DelimArgs` is a new struct just for the "delimited arguments" case. It is
now used in `MacCall` and `MacroDef`.
- `AttrArgs` is a renaming of the old `MacArgs` enum for the attribute macro
case. Its `Delimited` variant now contains a `DelimArgs`.
Various other related things are renamed as well.
These changes make the code clearer, avoids several unreachable paths, and
disallows the invalid values.
Recover wrong-cased keywords that start items
(_this pr was inspired by [this tweet](https://twitter.com/Azumanga/status/1552982326409367561)_)
r? `@estebank`
We've talked a bit about this recovery, but I just wanted to make sure that this is the right approach :)
For now I've only added the case insensitive recovery to `use`s, since most other items like `impl` blocks, modules, functions can start with multiple keywords which complicates the matter.
The primary purpose of this commit is to introduce the
dyn_star flag so we can begin experimenting with implementation.
In order to have something to do in the feature gate test, we also add
parser support for `dyn* Trait` objects. These are currently treated
just like `dyn Trait` objects, but this will change in the future.
Note that for now `dyn* Trait` is experimental syntax to enable
implementing some of the machinery needed for async fn in dyn traits
without fully supporting the feature.
Recover keywords in trait bounds
(_this pr was inspired by [this tweet](https://twitter.com/Azumanga/status/1552982326409367561)_)
Recover keywords in trait bound, motivational example:
```rust
fn f(_: impl fn()) {} // mistyped, meant `Fn`
```
<details><summary>Current nightly (3 needless and confusing errors!)</summary>
<p>
```text
error: expected identifier, found keyword `fn`
--> ./t.rs:1:15
|
1 | fn _f(_: impl fn()) {}
| ^^ expected identifier, found keyword
|
help: escape `fn` to use it as an identifier
|
1 | fn _f(_: impl r#fn()) {}
| ++
error: expected one of `:` or `|`, found `)`
--> ./t.rs:1:19
|
1 | fn _f(_: impl fn()) {}
| ^ expected one of `:` or `|`
error: expected one of `!`, `(`, `)`, `,`, `?`, `for`, `~`, lifetime, or path, found keyword `fn`
--> ./t.rs:1:15
|
1 | fn _f(_: impl fn()) {}
| -^^ expected one of 9 possible tokens
| |
| help: missing `,`
error: at least one trait must be specified
--> ./t.rs:1:10
|
1 | fn _f(_: impl fn()) {}
| ^^^^
```
</p>
</details>
This PR:
```text
error: expected identifier, found keyword `fn`
--> ./t.rs:1:15
|
1 | fn _f(_: impl fn()) {}
| ^^ expected identifier, found keyword
|
help: escape `fn` to use it as an identifier
|
1 | fn _f(_: impl r#fn()) {}
| ++
error[E0405]: cannot find trait `r#fn` in this scope
--> ./t.rs:1:15
|
1 | fn _f(_: impl fn()) {}
| ^^ help: a trait with a similar name exists (notice the capitalization): `Fn`
|
::: /home/waffle/projects/repos/rust/library/core/src/ops/function.rs:74:1
|
74 | pub trait Fn<Args>: FnMut<Args> {
| ------------------------------- similarly named trait `Fn` defined here
```
It would be nice to have suggestion in the first error like "have you meant `Fn` trait", instead of a separate error, but the recovery is deep inside ident parsing, which makes it a lot harder to do.
r? `@compiler-errors`
Move conditions out of recover/report functions.
`Parser` has six recover/report functions that are passed a boolean, and
nothing is done if the boolean has a particular value.
This PR moves the tests outside the functions. This has the following effects.
- The number of lines of code goes down.
- Some `use` items become shorter.
- Avoids the strangeness whereby 11 out of 12 calls to
`maybe_recover_from_bad_qpath` pass `true` as the second argument.
- Makes it clear at the call site that only one of
`maybe_recover_from_bad_type_plus` and `maybe_report_ambiguous_plus` will be
run.
r? `@estebank`
Swift has specific syntax that desugars to `Option<T>` similar to our
`?` operator, which means that people might try to use it in Rust. Parse
it and gracefully recover.
