Commit Graph

235 Commits

Author SHA1 Message Date
Yuki Okushi
f4550a6edf
Rollup merge of - jyn514:stabilize-label-break-value, r=petrochenkov
Stabilize `#![feature(label_break_value)]`

See the stabilization report in https://github.com/rust-lang/rust/issues/48594#issuecomment-1186213313.
2022-08-25 08:50:54 +09:00
Joshua Nelson
31e39446ec Stabilize #![feature(label_break_value)]
# Stabilization proposal

The feature was implemented in https://github.com/rust-lang/rust/pull/50045 by est31 and has been in nightly since 2018-05-16 (over 4 years now).
There are [no open issues][issue-label] other than the tracking issue. There is a strong consensus that `break` is the right keyword and we should not use `return`.

There have been several concerns raised about this feature on the tracking issue (other than the one about tests, which has been fixed, and an interaction with try blocks, which has been fixed).
1. nrc's original comment about cost-benefit analysis: https://github.com/rust-lang/rust/issues/48594#issuecomment-422235234
2. joshtriplett's comments about seeing use cases: https://github.com/rust-lang/rust/issues/48594#issuecomment-422281176
3. withoutboats's comments that Rust does not need more control flow constructs: https://github.com/rust-lang/rust/issues/48594#issuecomment-450050630

Many different examples of code that's simpler using this feature have been provided:
- A lexer by rpjohnst which must repeat code without label-break-value: https://github.com/rust-lang/rust/issues/48594#issuecomment-422502014
- A snippet by SergioBenitez which avoids using a new function and adding several new return points to a function: https://github.com/rust-lang/rust/issues/48594#issuecomment-427628251. This particular case would also work if `try` blocks were stabilized (at the cost of making the code harder to optimize).
- Several examples by JohnBSmith: https://github.com/rust-lang/rust/issues/48594#issuecomment-434651395
- Several examples by Centril: https://github.com/rust-lang/rust/issues/48594#issuecomment-440154733
- An example by petrochenkov where this is used in the compiler itself to avoid duplicating error checking code: https://github.com/rust-lang/rust/issues/48594#issuecomment-443557569
- Amanieu recently provided another example related to complex conditions, where try blocks would not have helped: https://github.com/rust-lang/rust/issues/48594#issuecomment-1184213006

Additionally, petrochenkov notes that this is strictly more powerful than labelled loops due to macros which accidentally exit a loop instead of being consumed by the macro matchers: https://github.com/rust-lang/rust/issues/48594#issuecomment-450246249

nrc later resolved their concern, mostly because of the aforementioned macro problems.
joshtriplett suggested that macros could be able to generate IR directly
(https://github.com/rust-lang/rust/issues/48594#issuecomment-451685983) but there are no open RFCs,
and the design space seems rather speculative.

joshtriplett later resolved his concerns, due to a symmetry between this feature and existing labelled break: https://github.com/rust-lang/rust/issues/48594#issuecomment-632960804

withoutboats has regrettably left the language team.

joshtriplett later posted that the lang team would consider starting an FCP given a stabilization report: https://github.com/rust-lang/rust/issues/48594#issuecomment-1111269353

[issue-label]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+label%3AF-label_break_value+

 ## Report

+ Feature gate:
    - d695a497bb/src/test/ui/feature-gates/feature-gate-label_break_value.rs
+ Diagnostics:
    - 6b2d3d5f3c/compiler/rustc_parse/src/parser/diagnostics.rs (L2629)
    - f65bf0b2bb/compiler/rustc_resolve/src/diagnostics.rs (L749)
    - f65bf0b2bb/compiler/rustc_resolve/src/diagnostics.rs (L1001)
    - 111df9e6ed/compiler/rustc_passes/src/loops.rs (L254)
    - d695a497bb/compiler/rustc_parse/src/parser/expr.rs (L2079)
    - d695a497bb/compiler/rustc_parse/src/parser/expr.rs (L1569)
+ Tests:
    - https://github.com/rust-lang/rust/blob/master/src/test/ui/label/label_break_value_continue.rs
    - https://github.com/rust-lang/rust/blob/master/src/test/ui/label/label_break_value_unlabeled_break.rs
    - https://github.com/rust-lang/rust/blob/master/src/test/ui/label/label_break_value_illegal_uses.rs
    - https://github.com/rust-lang/rust/blob/master/src/test/ui/lint/unused_labels.rs
    - https://github.com/rust-lang/rust/blob/master/src/test/ui/run-pass/for-loop-while/label_break_value.rs

 ## Interactions with other features

Labels follow the hygiene of local variables.

label-break-value is permitted within `try` blocks:
```rust
let _: Result<(), ()> = try {
    'foo: {
        Err(())?;
        break 'foo;
    }
};
```

label-break-value is disallowed within closures, generators, and async blocks:
```rust
'a: {
    || break 'a
    //~^ ERROR use of unreachable label `'a`
    //~| ERROR `break` inside of a closure
}
```

label-break-value is disallowed on [_BlockExpression_]; it can only occur as a [_LoopExpression_]:
```rust
fn labeled_match() {
    match false 'b: { //~ ERROR block label not supported here
        _ => {}
    }
}

macro_rules! m {
    ($b:block) => {
        'lab: $b; //~ ERROR cannot use a `block` macro fragment here
        unsafe $b; //~ ERROR cannot use a `block` macro fragment here
        |x: u8| -> () $b; //~ ERROR cannot use a `block` macro fragment here
    }
}

fn foo() {
    m!({});
}
```

[_BlockExpression_]: https://doc.rust-lang.org/nightly/reference/expressions/block-expr.html
[_LoopExpression_]: https://doc.rust-lang.org/nightly/reference/expressions/loop-expr.html
2022-08-23 21:14:12 -05:00
finalchild
09d495cc15 Replace #[error(..)] etc. to #[diag(..)] 2022-08-22 01:24:47 +09:00
finalchild
e331ae57df Migrate forbidden_default and *_without_body 2022-08-22 01:11:59 +09:00
finalchild
b28cc097cf Support #[fatal(..)] 2022-08-22 01:11:55 +09:00
finalchild
bfefefbcfa Migrate fn_param_forbidden_self and rename others to have prefix fn_param_ 2022-08-22 00:57:22 +09:00
finalchild
07e0bc9600 Rename c_var_args_without_named_arg to c_var_args_is_sole_param 2022-08-22 00:57:22 +09:00
finalchild
c6903c04b1 Migrate doc_comment_on_fn_param, forbidden_attr_on_fn_param 2022-08-22 00:57:21 +09:00
finalchild
269c85390c Migrate forbidden_lifetime_bound, forbidden_non_lifetime_param, too_many_params, c_var_args_without_named_arg, c_var_args_not_last 2022-08-22 00:57:21 +09:00
finalchild
8d042f4483 Migrate trait_fn_const 2022-08-22 00:57:21 +09:00
finalchild
e3d4c4039a Migrate trait_fn_async 2022-08-22 00:57:21 +09:00
finalchild
88afae5d1a Tidy 2022-08-22 00:57:21 +09:00
finalchild
e144a2367a Migrate deprecated_where_clause_location, forbidden_assoc_constraint, keyword_lifetime, invalid_label, invalid_visibility 2022-08-22 00:57:21 +09:00
finalchild
d6fdf14eb7 Migrate forbidden_let 2022-08-22 00:57:21 +09:00
Christopher Durham
767239f740 Reenable early feature-gates as future-compat warnings 2022-08-17 06:53:18 -05:00
Mark Rousskov
154a09dd91 Adjust cfgs 2022-08-12 16:28:15 -04:00
Matthias Krüger
8237efc52d
Rollup merge of - nnethercote:simplify-visitors, r=cjgillot
Simplify visitors

By removing some unused arguments.

r? `@cjgillot`
2022-08-11 22:53:08 +02:00
Nicholas Nethercote
232bd80130 Simplify rustc_ast::visit::Visitor::visit_poly_trait_ref.
It is passed an argument that is never used.
2022-08-11 11:10:01 +10:00
Nicholas Nethercote
421125f30a Simplify rustc_ast::visit::Visitor::visit_enum_def.
It's passed three arguments that are never used.
2022-08-11 10:54:01 +10:00
Michael Goulet
a2b6744af0 Use &mut Diagnostic instead of &mut DiagnosticBuilder unless needed 2022-08-10 03:45:42 +00:00
Dylan DPC
1dc4858914
Rollup merge of - WaffleLapkin:rustc_default_body_unstable, r=Aaron1011
Implement `#[rustc_default_body_unstable]`

This PR implements a new stability attribute — `#[rustc_default_body_unstable]`.

`#[rustc_default_body_unstable]` controls the stability of default bodies in traits.
For example:
```rust
pub trait Trait {
    #[rustc_default_body_unstable(feature = "feat", isssue = "none")]
    fn item() {}
}
```
In order to implement `Trait` user needs to either
- implement `item` (even though it has a default implementation)
- enable `#![feature(feat)]`

This is useful in conjunction with [`#[rustc_must_implement_one_of]`](https://github.com/rust-lang/rust/pull/92164), we may want to relax requirements for a trait, for example allowing implementing either of `PartialEq::{eq, ne}`, but do so in a safe way — making implementation of only `PartialEq::ne` unstable.

r? `@Aaron1011`
cc `@nrc` (iirc you were interested in this wrt `read_buf`), `@danielhenrymantilla` (you were interested in the related `#[rustc_must_implement_one_of]`)
P.S. This is my first time working with stability attributes, so I'm not sure if I did everything right 😅
2022-08-09 17:34:50 +05:30
Esteban Küber
939c2b6313 Provide suggestion on missing let in binding statement
Fix .
2022-08-03 09:29:29 -07:00
Nicholas Nethercote
6dced80b86 Remove visit_name from the AST visitor.
Because the default is empty and it's never overridden. This means
`walk_ident` can also be removed, because it does nothing.
2022-07-29 15:28:32 +10:00
Maybe Waffle
177af47104 Implement #[rustc_default_body_unstable]
This attribute allows to mark default body of a trait function as
unstable. This means that implementing the trait without implementing
the function will require enabling unstable feature.

This is useful in conjunction with `#[rustc_must_implement_one_of]`,
we may want to relax requirements for a trait, for example allowing
implementing either of `PartialEq::{eq, ne}`, but do so in a safe way
-- making implementation of only `PartialEq::ne` unstable.
2022-07-26 15:38:03 +04:00
Deadbeef
9b75f2d498 Allow ~const on super traits 2022-07-23 14:25:55 +00:00
bors
9a7b7d5e50 Auto merge of - notriddle:notriddle/rustdoc-fn, r=petrochenkov,GuillaumeGomez
Improve the function pointer docs

This is  but for function pointers instead of tuples. The concept is basically the same.

* Reduce duplicate impls; show `fn (T₁, T₂, …, Tₙ)` and include a sentence saying that there exists up to twelve of them.
* Show `Copy` and `Clone`.
* Show auto traits like `Send` and `Sync`, and blanket impls like `Any`.

https://notriddle.com/notriddle-rustdoc-test/std/primitive.fn.html
2022-07-19 19:36:57 +00:00
Matthias Krüger
4815f94c51
Rollup merge of - TaKO8Ki:avoid-symbol-to-&str-conversions, r=nnethercote
Avoid `Symbol` to `&str` conversions

`Symbol::as_str` is a slowish operation, so this patch removes some usages of it.
2022-07-19 13:30:46 +02:00
Takayuki Maeda
a22934bea1 avoid Symbol to &str conversions 2022-07-18 14:25:34 +09:00
Yuki Okushi
f3a458f735
Rollup merge of - compiler-errors:issue-99331, r=fee1-dead
Do not ICE when we have `-Zunpretty=expanded` with invalid ABI

Fixes 
2022-07-18 08:40:00 +09:00
Michael Howell
1169832f2f rustdoc: extend #[doc(tuple_variadic)] to fn pointers
The attribute is also renamed `fake_variadic`.
2022-07-17 16:32:06 -07:00
Michael Goulet
26ecd44160 Do not ICE when we have -Zunpretty=expand with invalid ABI 2022-07-16 20:35:54 -07:00
Caio
3266460749 Stabilize let_chains 2022-07-16 20:17:58 -03:00
Maybe Waffle
40ae7b5b8e Parse closure binders
This is first step in implementing RFC 3216.
- Parse `for<'a>` before closures in ast
  - Error in lowering
- Add `closure_lifetime_binder` feature
2022-07-12 16:25:16 +04:00
Nixon Enraght-Moony
02fb345964 Suggest using block for extern "abi" fn with no body 2022-07-06 13:27:53 +01:00
Nixon Enraght-Moony
18ca2946e0 ast: Add span to Extern 2022-07-02 23:30:03 +01:00
bors
6ec3993ef4 Auto merge of - notriddle:notriddle/tuple-docs, r=jsha,GuillaumeGomez
Improve the tuple and unit trait docs

* Reduce duplicate impls; show only the `(T,)` and include a sentence saying that there exists ones up to twelve of them.
* Show `Copy` and `Clone`.
* Show auto traits like `Send` and `Sync`, and blanket impls like `Any`.

Here's the new version:

* <https://notriddle.com/notriddle-rustdoc-test/std/primitive.tuple.html>
* <https://notriddle.com/notriddle-rustdoc-test/std/primitive.unit.html>
2022-06-16 11:13:30 +00:00
Jacob Pratt
fb05b53745
Remove rustc_deprecated diagnostics 2022-06-14 19:46:13 -04:00
Takayuki Maeda
77d6176e69 remove unnecessary to_string and String::new 2022-06-13 15:48:40 +09:00
Michael Howell
9b31323b8f Fix incorrectly spelled "variadic" 2022-06-11 09:54:20 -07:00
Michael Howell
6950f144cf rustdoc: show tuple impls as impl Trait for (T, ...)
This commit adds a new unstable attribute, `#[doc(tuple_varadic)]`, that
shows a 1-tuple as `(T, ...)` instead of just `(T,)`, and links to a section
in the tuple primitive docs that talks about these.
2022-06-08 19:26:51 -07:00
bors
91cacb3faf Auto merge of - scottmcm:add-coldcc, r=nagisa,lcnr
Add support for emitting functions with `coldcc` to LLVM

The eventual goal is to try using this for things like the internal panicking stuff, to see whether it helps.
2022-06-07 08:12:45 +00:00
xFrednet
b5eee17088
Support the #[expect] attribute on fn parameters (RFC-2383) 2022-06-04 00:50:45 +02:00
Scott McMurray
e90be842fb Add support for emitting functions with coldcc in LLVM
The eventual goal is to try using this for things like the internal panicking stuff, to see whether it helps.
2022-05-30 00:19:23 -07:00
Matthias Krüger
5fc8a8e227 clippy::complexity fixes
clone_on_copy
useless_format
bind_instead_of_map
filter_map_identity
useless_conversion
map_flatten
unnecessary_unwrap
2022-05-26 13:14:24 +02:00
Jacob Pratt
8cece636b2
Remove feature: crate visibility modifier 2022-05-21 14:22:06 -04:00
Camille GILLOT
5953c57f27 Introduce LifetimeCtxt. 2022-05-20 12:25:05 +02:00
Vadim Petrochenkov
4fa24bcb54 rustc: Stricter checking for #[link] attributes 2022-05-15 02:45:47 +03:00
Scott McMurray
b317ec1697 Feature-gate do yeet inside cfgs too 2022-04-30 18:10:01 -07:00
Scott McMurray
e094ee5f10 Add do yeet expressions to allow experimentation in nightly
Using an obviously-placeholder syntax.  An RFC would still be needed before this could have any chance at stabilization, and it might be removed at any point.

But I'd really like to have it in nightly at least to ensure it works well with try_trait_v2, especially as we refactor the traits.
2022-04-30 17:40:27 -07:00
SparrowLii
38bd4fbdbd rename to BoundKind and add comments 2022-04-21 10:09:32 +08:00