Dylan DPC
3ad81e0dd8
Rollup merge of #93628 - est31:stabilize_let_else, r=joshtriplett
...
Stabilize `let else`
🎉 **Stabilizes the `let else` feature, added by [RFC 3137](https://github.com/rust-lang/rfcs/pull/3137 ).** 🎉
Reference PR: https://github.com/rust-lang/reference/pull/1156
closes #87335 (`let else` tracking issue)
FCP: https://github.com/rust-lang/rust/pull/93628#issuecomment-1029383585
----------
## Stabilization report
### Summary
The feature allows refutable patterns in `let` statements if the expression is
followed by a diverging `else`:
```Rust
fn get_count_item(s: &str) -> (u64, &str) {
let mut it = s.split(' ');
let (Some(count_str), Some(item)) = (it.next(), it.next()) else {
panic!("Can't segment count item pair: '{s}'");
};
let Ok(count) = u64::from_str(count_str) else {
panic!("Can't parse integer: '{count_str}'");
};
(count, item)
}
assert_eq!(get_count_item("3 chairs"), (3, "chairs"));
```
### Differences from the RFC / Desugaring
Outside of desugaring I'm not aware of any differences between the implementation and the RFC. The chosen desugaring has been changed from the RFC's [original](https://rust-lang.github.io/rfcs/3137-let-else.html#reference-level-explanations ). You can read a detailed discussion of the implementation history of it in `@cormacrelf` 's [summary](https://github.com/rust-lang/rust/pull/93628#issuecomment-1041143670 ) in this thread, as well as the [followup](https://github.com/rust-lang/rust/pull/93628#issuecomment-1046598419 ). Since that followup, further changes have happened to the desugaring, in #98574 , #99518 , #99954 . The later changes were mostly about the drop order: On match, temporaries drop in the same order as they would for a `let` declaration. On mismatch, temporaries drop before the `else` block.
### Test cases
In chronological order as they were merged.
Added by df9a2e0687#87688 ):
* [`ui/pattern/usefulness/top-level-alternation.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/pattern/usefulness/top-level-alternation.rs ) to ensure the unreachable pattern lint visits patterns inside `let else`.
Added by 5b95df4bdc#87688 ):
* [`ui/let-else/let-else-bool-binop-init.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-bool-binop-init.rs ) to ensure that no lazy boolean expressions (using `&&` or `||`) are allowed in the expression, as the RFC mandates.
* [`ui/let-else/let-else-brace-before-else.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-brace-before-else.rs ) to ensure that no `}` directly preceding the `else` is allowed in the expression, as the RFC mandates.
* [`ui/let-else/let-else-check.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-check.rs ) to ensure that `#[allow(...)]` attributes added to the entire `let` statement apply for the `else` block.
* [`ui/let-else/let-else-irrefutable.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-irrefutable.rs ) to ensure that the `irrefutable_let_patterns` lint fires.
* [`ui/let-else/let-else-missing-semicolon.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-missing-semicolon.rs ) to ensure the presence of semicolons at the end of the `let` statement.
* [`ui/let-else/let-else-non-diverging.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-non-diverging.rs ) to ensure the `else` block diverges.
* [`ui/let-else/let-else-run-pass.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-run-pass.rs ) to ensure the feature works in some simple test case settings.
* [`ui/let-else/let-else-scope.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-scope.rs ) to ensure the bindings created by the outer `let` expression are not available in the `else` block of it.
Added by bf7c32a447#89965 ):
* [`ui/let-else/issue-89960.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/issue-89960.rs ) as a regression test for the ICE-on-error bug #89960 . Later in 102b9125e1856541963c#89974 ):
* [`ui/let-else/let-else-if.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-if.rs ) to test for the improved error message that points out that `let else if` is not possible.
Added by 9b45713b6chttps://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-allow-unused.rs ) as a regression test for #89807 , to ensure that `#[allow(...)]` attributes added to the entire `let` statement apply for bindings created by the `let else` pattern.
Added by 61bcd8d307#89841 ):
* [`ui/let-else/let-else-non-copy.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-non-copy.rs ) to ensure that a copy is performed out of non-copy wrapper types. This mirrors `if let` behaviour. The test case bases on rustc internal changes originally meant for #89933 but then removed from the PR due to the error prior to the improvements of #89841 .
* [`ui/let-else/let-else-source-expr-nomove-pass.rs `](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs ) to ensure that while there is a move of the binding in the successful case, the `else` case can still access the non-matching value. This mirrors `if let` behaviour.
Added by 102b9125e1#89841 ):
* [`ui/let-else/let-else-ref-bindings.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-ref-bindings.rs ) and [`ui/let-else/let-else-ref-bindings-pass.rs `](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-ref-bindings-pass.rs ) to check `ref` and `ref mut` keywords in the pattern work correctly and error when needed.
Added by 2715c5f984#89841 ):
* Match ergonomic tests adapted from the `rfc2005` test suite.
Added by fec8a507a2#89841 ):
* [`ui/let-else/let-else-deref-coercion-annotated.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-deref-coercion-annotated.rs ) and [`ui/let-else/let-else-deref-coercion.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-deref-coercion.rs ) to check deref coercions.
#### Added since this stabilization report was originally written (2022-02-09)
Added by 76ea566677#94211 ):
* [`ui/let-else/let-else-destructuring.rs`](https://github.com/rust-lang/rust/blob/1.63.0/src/test/ui/let-else/let-else-destructuring.rs ) to give a nice error message if an user tries to do an assignment with a (possibly refutable) pattern and an `else` block, like asked for in #93995 .
Added by e7730dcb7e#94208 ):
* [`ui/let-else/let-else-allow-in-expr.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-allow-in-expr.rs ) to test whether `#[allow(unused_variables)]` works in the expr, as well as its non presence, as well as putting it on the entire `let else` *affects* the expr, too. This was adding a missing test as pointed out by the stabilization report.
* Expansion of `ui/let-else/let-else-allow-unused.rs` and `ui/let-else/let-else-check.rs` to ensure that non-presence of `#[allow(unused)]` does issue the unused lint. This was adding a missing test case as pointed out by the stabilization report.
Added by 5bd71063b3#94208 ):
* [`ui/let-else/let-else-slicing-error.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-slicing-error.rs ), a regression test for #92069 , which got fixed without addition of a regression test. This resolves a missing test as pointed out by the stabilization report.
Added by 5374688e1d#98574 ):
* [`src/test/ui/async-await/async-await-let-else.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/async-await/async-await-let-else.rs ) to test the interaction of async/await with `let else`
Added by 6c529ded86#98574 ):
* [`src/test/ui/let-else/let-else-temporary-lifetime.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs ) as a (partial) regression test for #98672
Added by 9b56640106#99518 ):
* [`src/test/ui/let-else/let-else-temp-borrowck.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs ) as a regression test for #93951
* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a partial regression test for #98672 (especially regarding `else` drop order)
Added by baf9a7cb57#99518 ):
* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a partial regression test for #93951 , similar to `let-else-temp-borrowck.rs`
Added by 60be2de8b7#99518 ):
* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a program that can now be compiled thanks to borrow checker implications of #99518
Added by 47a7a91c96#100132 ):
* [`src/test/ui/let-else/issue-100103.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-100103.rs ), as a regression test for #100103 , to ensure that there is no ICE when doing `Err(...)?` inside else blocks.
Added by e3c5bd617d#100443 ):
* [`src/test/ui/let-else/let-else-then-diverge.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-then-diverge.rs ), to verify that there is no unreachable code error with the current desugaring.
Added by 981852677c#100443 ):
* [`src/test/ui/let-else/issue-94176.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-94176.rs ), to make sure that a correct span is emitted for a missing trailing expression error. Regression test for #94176 .
Added by e182d12a84#100434 ):
* [src/test/ui/unpretty/pretty-let-else.rs](https://github.com/rust-lang/rust/blob/master/src/test/ui/unpretty/pretty-let-else.rs ), as a regression test to ensure pretty printing works for `let else` (this bug surfaced in many different ways)
Added by e26285603c#99954 ):
* [`src/test/ui/let-else/let-else-temporary-lifetime.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs ) extended to contain & borrows as well, as this was identified as an earlier issue with the desugaring: https://github.com/rust-lang/rust/issues/98672#issuecomment-1200196921
Added by 2d8460ef43#99291 ):
* [`src/test/ui/let-else/let-else-drop-order.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-drop-order.rs ) a matrix based test for various drop order behaviour of `let else`. Especially, it verifies equality of `let` and `let else` drop orders, [resolving](https://github.com/rust-lang/rust/pull/93628#issuecomment-1238498468 ) a [stabilization blocker](https://github.com/rust-lang/rust/pull/93628#issuecomment-1055738523 ).
Added by 1b87ce0d40#101410 ):
* Edit to `src/test/ui/let-else/let-else-temporary-lifetime.rs` to add the `-Zvalidate-mir` flag, as a regression test for #99228
Added by af591ebe4d#101410 ):
* [`src/test/ui/let-else/issue-99975.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-99975.rs ) as a regression test for the ICE #99975 .
Added by this PR:
* `ui/let-else/let-else.rs`, a simple run-pass check, similar to `ui/let-else/let-else-run-pass.rs`.
### Things not currently tested
* ~~The `#[allow(...)]` tests check whether allow works, but they don't check whether the non-presence of allow causes a lint to fire.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~There is no `#[allow(...)]` test for the expression, as there are tests for the pattern and the else block.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~`let-else-brace-before-else.rs` forbids the `let ... = {} else {}` pattern and there is a rustfix to obtain `let ... = ({}) else {}`. I'm not sure whether the `.fixed` files are checked by the tooling that they compile. But if there is no such check, it would be neat to make sure that `let ... = ({}) else {}` compiles.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~#92069 got closed as fixed, but no regression test was added. Not sure it's worth to add one.~~ → *test added by 5bd71063b3810d977aa376d1e6dd7cec359330cc*
* ~~consistency between `let else` and `if let` regarding lifetimes and drop order: https://github.com/rust-lang/rust/pull/93628#issuecomment-1055738523~~ → *test added by 2d8460ef43d902f34ba2133fe38f66ee8d2fdafc*
Edit: they are all tested now.
### Possible future work / Refutable destructuring assignments
[RFC 2909](https://rust-lang.github.io/rfcs/2909-destructuring-assignment.html ) specifies destructuring assignment, allowing statements like `FooBar { a, b, c } = foo();`.
As it was stabilized, destructuring assignment only allows *irrefutable* patterns, which before the advent of `let else` were the only patterns that `let` supported.
So the combination of `let else` and destructuring assignments gives reason to think about extensions of the destructuring assignments feature that allow refutable patterns, discussed in #93995 .
A naive mapping of `let else` to destructuring assignments in the form of `Some(v) = foo() else { ... };` might not be the ideal way. `let else` needs a diverging `else` clause as it introduces new bindings, while assignments have a default behaviour to fall back to if the pattern does not match, in the form of not performing the assignment. Thus, there is no good case to require divergence, or even an `else` clause at all, beyond the need for having *some* introducer syntax so that it is clear to readers that the assignment is not a given (enums and structs look similar). There are better candidates for introducer syntax however than an empty `else {}` clause, like `maybe` which could be added as a keyword on an edition boundary:
```Rust
let mut v = 0;
maybe Some(v) = foo(&v);
maybe Some(v) = foo(&v) else { bar() };
```
Further design discussion is left to an RFC, or the linked issue.
2022-09-17 15:31:06 +05:30
Rageking8
d433efa649
more simple formatting
2022-09-16 19:07:42 +08:00
est31
173eb6f407
Only enable the let_else feature on bootstrap
...
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
2022-09-15 21:06:45 +02:00
bors
750bd1a7ff
Auto merge of #101313 - SparrowLii:mk_attr_id, r=cjgillot
...
make `mk_attr_id` part of `ParseSess`
Updates #48685
The current `mk_attr_id` uses the `AtomicU32` type, which is not very efficient and adds a lot of lock contention in a parallel environment.
This PR refers to the task list in #48685 , uses `mk_attr_id` as a method of the `AttrIdGenerator` struct, and adds a new field `attr_id_generator` to `ParseSess`.
`AttrIdGenerator` uses the `WorkerLocal`, which has two advantages: 1. `Cell` is more efficient than `AtomicU32`, and does not increase any lock contention. 2. We put the index of the work thread in the first few bits of the generated `AttrId`, so that the `AttrId` generated in different threads can be easily guaranteed to be unique.
cc `@cjgillot`
2022-09-14 20:52:18 +00:00
bors
6153d3cbe6
Auto merge of #101212 - eholk:dyn-star, r=compiler-errors
...
Initial implementation of dyn*
This PR adds extremely basic and incomplete support for [dyn*](https://smallcultfollowing.com/babysteps//blog/2022/03/29/dyn-can-we-make-dyn-sized/ ). The goal is to get something in tree behind a flag to make collaboration easier, and also to make sure the implementation so far is not unreasonable. This PR does quite a few things:
* Introduce `dyn_star` feature flag
* Adds parsing for `dyn* Trait` types
* Defines `dyn* Trait` as a sized type
* Adds support for explicit casts, like `42usize as dyn* Debug`
* Including const evaluation of such casts
* Adds codegen for drop glue so things are cleaned up properly when a `dyn* Trait` object goes out of scope
* Adds codegen for method calls, at least for methods that take `&self`
Quite a bit is still missing, but this gives us a starting point. Note that this is never intended to become stable surface syntax for Rust, but rather `dyn*` is planned to be used as an implementation detail for async functions in dyn traits.
Joint work with `@nikomatsakis` and `@compiler-errors.`
r? `@bjorn3`
2022-09-14 18:10:51 +00:00
bors
a0d1df4a5d
Auto merge of #101709 - nnethercote:simplify-visitors-more, r=cjgillot
...
Simplify visitors more
A successor to #100392 .
r? `@cjgillot`
2022-09-14 05:21:14 +00:00
SparrowLii
bfc4f2e189
add debug assertion for max attr_id
2022-09-14 08:49:12 +08:00
SparrowLii
1a3ecbdb6a
make mk_attr_id part of ParseSess
2022-09-14 08:49:10 +08:00
Matthias Krüger
8fa8021451
Rollup merge of #101752 - GuillaumeGomez:improve-attr-docs, r=lqd
...
Improve Attribute doc methods
r? `@lqd`
2022-09-13 22:25:35 +02:00
Dylan DPC
db75d7e14b
Rollup merge of #101602 - nnethercote:AttrTokenStream, r=petrochenkov
...
Streamline `AttrAnnotatedTokenStream`
r? ```@petrochenkov```
2022-09-13 16:51:31 +05:30
Eric Holk
eff35e59c6
Introduce dyn_star feature flag
...
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.
2022-09-12 16:55:55 -07:00
Guillaume Gomez
c4559ebfde
Improve Attribute doc methods
2022-09-12 21:18:59 +02:00
bors
52e003a6e9
Auto merge of #99334 - NiklasJonsson:84447/error-privacy, r=oli-obk
...
rustc_error, rustc_private: Switch to stable hash containers
Relates https://github.com/rust-lang/rust/issues/84447
2022-09-12 15:57:37 +00:00
Dylan DPC
d7bad03cab
Rollup merge of #101668 - chenyukang:fix-101626, r=TaKO8Ki
...
Suggest pub instead of public for const type item
Fixes #101626
2022-09-12 15:21:31 +05:30
Dylan DPC
93177758fc
Rollup merge of #100767 - kadiwa4:escape_ascii, r=jackh726
...
Remove manual <[u8]>::escape_ascii
`@rustbot` label: +C-cleanup
2022-09-12 15:21:30 +05:30
Nicholas Nethercote
925363f13d
Remove unused span argument from walk_fn.
2022-09-12 13:24:27 +10:00
Nicholas Nethercote
6568ef338e
Remove path_span argument to the visit_path_segment methods.
...
The `visit_path_segment` method of both the AST and HIR visitors has a
`path_span` argument that isn't necessary. This commit removes it.
There are two very small and inconsequential functional changes.
- One call to `NodeCollector::insert` now is passed a path segment
identifier span instead of a full path span. This span is only used in
a panic message printed in the case of an internal compiler bug.
- Likewise, one call to `LifetimeCollectVisitor::record_elided_anchor`
now uses a path segment identifier span instead of a full path span.
This span is used to make some `'_` lifetimes.
2022-09-12 13:24:25 +10:00
yukang
975dd6cdea
fix #101626 , suggest pub instead of public for const type item
2022-09-11 08:29:38 +08:00
Niklas Jonsson
8d3c30c004
rustc_error, rustc_private, rustc_ast: Switch to stable hash containers
2022-09-10 11:49:12 +02:00
Dylan DPC
ae4973281b
Rollup merge of #101573 - lcnr:param-kind-ord, r=BoxyUwU
...
update `ParamKindOrd`
https://github.com/rust-lang/rust/pull/90207#discussion_r767160854 😁
writing comments "for future prs" sure works well :3
r? `@BoxyUwU`
2022-09-09 22:02:18 +05:30
lcnr
5db6907498
review
2022-09-09 14:28:57 +02:00
Nicholas Nethercote
d2df07c425
Rename {Create,Lazy}TokenStream as {To,Lazy}AttrTokenStream.
...
`To` is better than `Create` for indicating that this is a non-consuming
conversion, rather than creating something out of nothing.
And the addition of `Attr` is because the current names makes them sound
like they relate to `TokenStream`, but really they relate to
`AttrTokenStream`.
2022-09-09 17:25:38 +10:00
Nicholas Nethercote
f6c9e1df59
Inline and remove TokenStream::opt_from_ast.
2022-09-09 16:53:17 +10:00
Nicholas Nethercote
81eaf877d6
Tweak some formatting.
2022-09-09 16:40:25 +10:00
Nicholas Nethercote
208ca93cda
Change return type of Attribute::tokens.
...
The `AttrTokenStream` is always immediately turned into a `TokenStream`.
2022-09-09 16:25:31 +10:00
Nicholas Nethercote
a56d345490
Rename AttrAnnotatedToken{Stream,Tree}.
...
These two type names are long and have long matching prefixes. I find
them hard to read, especially in combinations like
`AttrAnnotatedTokenStream::new(vec![AttrAnnotatedTokenTree::Token(..)])`.
This commit renames them as `AttrToken{Stream,Tree}`.
2022-09-09 12:45:26 +10:00
Nicholas Nethercote
890e759ffc
Move Spacing out of AttrAnnotatedTokenStream.
...
And into `AttrAnnotatedTokenTree::Token`.
PR #99887 did the same thing for `TokenStream`.
2022-09-09 12:00:46 +10:00
Michael Goulet
5be30f9d79
Make async fn in traits work
2022-09-09 01:31:45 +00:00
lcnr
b79a2b3f73
update ParamKindOrd
2022-09-08 16:50:44 +02:00
bors
512bd84f51
Auto merge of #94075 - mikebenfield:wip-enum, r=oli-obk
...
Use niche-filling optimization even when multiple variants have data.
Fixes #46213
2022-09-07 23:40:06 +00:00
Michael Benfield
d7a750b504
Use niche-filling optimization even when multiple variants have data.
...
Fixes #46213
2022-09-07 20:12:45 +00:00
Guillaume Gomez
88fa621bab
Add documentation for Attr::is_doc_comment
2022-09-07 15:34:16 +02:00
bors
a594044533
Auto merge of #101362 - compiler-errors:unnecessary-let, r=cjgillot
...
Suggest removing unnecessary prefix let in patterns
Helps with #101291 , though I think `@estebank` probably wants this:
> Finally, I think it'd be nice if we could detect that we don't know for sure and "just" swallow the rest of the expression (find the next ; accounting for nested braces) or the end of the item (easier).
... to be implemented before we close that issue out completely.
2022-09-06 08:49:54 +00:00
bors
6c358c67d4
Auto merge of #101241 - camsteffen:refactor-binding-annotations, r=cjgillot
...
`BindingAnnotation` refactor
* `ast::BindingMode` is deleted and replaced with `hir::BindingAnnotation` (which is moved to `ast`)
* `BindingAnnotation` is changed from an enum to a tuple struct e.g. `BindingAnnotation(ByRef::No, Mutability::Mut)`
* Associated constants added for convenience `BindingAnnotation::{NONE, REF, MUT, REF_MUT}`
One goal is to make it more clear that `BindingAnnotation` merely represents syntax `ref mut` and not the actual binding mode. This was especially confusing since we had `ast::BindingMode`->`hir::BindingAnnotation`->`thir::BindingMode`.
I wish there were more symmetry between `ByRef` and `Mutability` (variant) naming (maybe `Mutable::Yes`?), and I also don't love how long the name `BindingAnnotation` is, but this seems like the best compromise. Ideas welcome.
2022-09-06 03:16:29 +00:00
Dylan DPC
5d55009b79
Rollup merge of #101142 - nnethercote:improve-hir-stats, r=davidtwco
...
Improve HIR stats
#100398 improve the AST stats collection done by `-Zhir-stats`. This PR does the same for HIR stats collection.
r? `@davidtwco`
2022-09-05 14:15:51 +05:30
Michael Goulet
91674cc56c
Suggest removing unnecessary prefix let in patterns
2022-09-03 05:39:46 +00:00
Cameron Steffen
02ba216e3c
Refactor and re-use BindingAnnotation
2022-09-02 12:55:05 -05:00
Oli Scherer
ee3c835018
Always import all tracing macros for the entire crate instead of piecemeal by module
2022-09-01 14:54:27 +00:00
bors
eac6c33bc6
Auto merge of #100869 - nnethercote:replace-ThinVec, r=spastorino
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Replace `rustc_data_structures::thin_vec::ThinVec` with `thin_vec::ThinVec`
`rustc_data_structures::thin_vec::ThinVec` looks like this:
```
pub struct ThinVec<T>(Option<Box<Vec<T>>>);
```
It's just a zero word if the vector is empty, but requires two
allocations if it is non-empty. So it's only usable in cases where the
vector is empty most of the time.
This commit removes it in favour of `thin_vec::ThinVec`, which is also
word-sized, but stores the length and capacity in the same allocation as
the elements. It's good in a wider variety of situation, e.g. in enum
variants where the vector is usually/always non-empty.
The commit also:
- Sorts some `Cargo.toml` dependency lists, to make additions easier.
- Sorts some `use` item lists, to make additions easier.
- Changes `clean_trait_ref_with_bindings` to take a
`ThinVec<TypeBinding>` rather than a `&[TypeBinding]`, because this
avoid some unnecessary allocations.
r? `@spastorino`
2022-09-01 08:01:06 +00:00
Matthias Krüger
e5356712b9
Rollup merge of #101165 - ldm0:drain_to_iter, r=cjgillot
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Use more `into_iter` rather than `drain(..)`
Clearer semantic.
2022-08-31 21:30:13 +02:00
Donough Liu
97b1a6146c
Use more into_iter rather than drain(..)
2022-08-30 04:42:03 +01:00
Nilstrieb
d1ef8180f9
Revert let_chains stabilization
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This reverts commit 3266460749#100538 .
2022-08-29 19:34:11 +02:00
Nicholas Nethercote
78f83f0b46
Inline attrs.
2022-08-29 20:25:48 +10:00
Nicholas Nethercote
b38106b6d8
Replace rustc_data_structures::thin_vec::ThinVec with thin_vec::ThinVec.
...
`rustc_data_structures::thin_vec::ThinVec` looks like this:
```
pub struct ThinVec<T>(Option<Box<Vec<T>>>);
```
It's just a zero word if the vector is empty, but requires two
allocations if it is non-empty. So it's only usable in cases where the
vector is empty most of the time.
This commit removes it in favour of `thin_vec::ThinVec`, which is also
word-sized, but stores the length and capacity in the same allocation as
the elements. It's good in a wider variety of situation, e.g. in enum
variants where the vector is usually/always non-empty.
The commit also:
- Sorts some `Cargo.toml` dependency lists, to make additions easier.
- Sorts some `use` item lists, to make additions easier.
- Changes `clean_trait_ref_with_bindings` to take a
`ThinVec<TypeBinding>` rather than a `&[TypeBinding]`, because this
avoid some unnecessary allocations.
2022-08-29 15:42:13 +10:00
Nicholas Nethercote
854219d2ad
Expand the HIR (and AST) size assertions.
2022-08-29 06:35:14 +10:00
Yuki Okushi
d4a5ec17a7
Rollup merge of #100978 - nnethercote:fix-100948, r=petrochenkov
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Handle `Err` in `ast::LitKind::to_token_lit`.
Fixes #100948 .
r? ``@petrochenkov``
2022-08-26 09:51:46 +09:00
Nicholas Nethercote
b997af95fc
Handle Err in ast::LitKind::to_token_lit.
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Fixes #100948 .
2022-08-25 10:50:39 +10:00
Yuki Okushi
f4550a6edf
Rollup merge of #99332 - jyn514:stabilize-label-break-value, r=petrochenkov
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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)]
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# 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.rs6b2d3d5f3c/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)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
Dylan DPC
28ead17745
Rollup merge of #100909 - nnethercote:minor-ast-LitKind-improvement, r=petrochenkov
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Minor `ast::LitKind` improvements
r? `@petrochenkov`
2022-08-23 20:40:09 +05:30
