Commit Graph

45999 Commits

Author SHA1 Message Date
Nicholas Nethercote
e37c367482 Improve pretty printing of if/else.
By removing some of the over-indenting. AST pretty printing now looks
correct. HIR pretty printing is better, but still over-indents some.
2025-04-25 14:33:16 +10:00
Nicholas Nethercote
ee43aa356a Fix some pretty printing indents.
Indents for `cbox` and `ibox` are 0 or `INDENT_UNIT` (4) except for a
couple of places which are `INDENT_UNIT - 1` for no clear reason.

This commit changes the three space indents to four spaces.
2025-04-25 14:33:16 +10:00
bors
dc8fe1f81c Auto merge of #140239 - matthiaskrgr:rollup-75felo8, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - #134446 (Stabilize the `cell_update` feature)
 - #139307 (std: Add performance warnings to HashMap::get_disjoint_mut)
 - #139450 (Impl new API `std::os::unix::fs::mkfifo` under feature `unix_fifo`)
 - #139809 (Don't warn about `v128` in wasm ABI transition)
 - #139852 (StableMIR: Implement `CompilerInterface`)
 - #139945 (Extend HIR to track the source and syntax of a lifetime)
 - #140028 (`deref_patterns`: support string and byte string literals in explicit `deref!("...")` patterns)
 - #140181 (Remove `synstructure::Structure::underscore_const` calls.)
 - #140232 (Remove unnecessary clones)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-24 08:50:48 +00:00
Matthias Krüger
986750ded4
Rollup merge of #140232 - nnethercote:rm-unnecessary-clones, r=SparrowLii
Remove unnecessary clones

r? `@SparrowLii`
2025-04-24 08:13:01 +02:00
Matthias Krüger
1254559404
Rollup merge of #140181 - nnethercote:rm-underscore_const, r=compiler-errors
Remove `synstructure::Structure::underscore_const` calls.

The `synstructure` docs say "This method is a no-op, underscore consts are used by default now." The behaviour change occurred going from `synstructure` version 0.13.0 to 0.13.1.

r? ``@SparrowLii``
2025-04-24 08:13:00 +02:00
Matthias Krüger
5d52b37a81
Rollup merge of #140028 - dianne:lit-deref-pats-p1, r=oli-obk
`deref_patterns`: support string and byte string literals in explicit `deref!("...")` patterns

When `deref_patterns` is enabled, this allows string literal patterns to be used where `str` is expected and byte string literal patterns to be used where `[u8]` or `[u8; N]` is expected. This lets them be used in explicit `deref!("...")` patterns to match on `String`, `Box<str>`, `Vec<u8>`, `Box<[u8;N]>`, etc. (as well as to match on slices and arrays obtained through other means). Implementation-wise, this follows up on #138992: similar to how byte string literals matching on `&[u8]` is implemented, this changes the type of the patterns as determined by HIR typeck, which informs const-to-pat on how to translate them to THIR (though strings needed a bit of extra work since we need references to call `<str as PartialEq>::eq` in the MIR lowering for string equality tests).

This PR does not add support for implicit deref pattern syntax (e.g. `"..."` matching on `String`, as `string_deref_patterns` allows). I have that implemented locally, but I'm saving it for a follow-up PR[^1].

This also does not add support for using named or associated constants of type `&str` where `str` is expected (nor likewise with named byte string constants). It'd be possible to add that if there's an appetite for it, but I figure it's simplest to start with literals.

This is gated by the `deref_patterns` feature since it's motivated by deref patterns. That said, its impact reaches outside of deref patterns; it may warrant a separate experiment and feature gate, particularly factoring in the follow-up[^1]. Even without deref patterns, I think there's probably motivation for these changes.

The update to the unstable book added by this will conflict with #140022, so they shouldn't be merged at the same time.

Tracking issue for deref patterns: #87121

r? ``@oli-obk``
cc ``@Nadrieril``

[^1]: The piece missing from this PR to support implicit deref pattern syntax is to allow string literal patterns to implicitly dereference their scrutinees before matching (see #44849). As a consequence, it also makes examples like the one in that issue work (though it's still gated by `deref_patterns`). I can provide more information on how I've implemented it or open a draft if it'd help in reviewing this PR.
2025-04-24 08:13:00 +02:00
Matthias Krüger
2ba3a5c909
Rollup merge of #139945 - shepmaster:hir-lifetime-syntax-source, r=nnethercote
Extend HIR to track the source and syntax of a lifetime

An upcoming lint will want to be able to know if a lifetime is hidden (e.g. `&u8`, `ContainsLifetime`) or anonymous: (e.g. `&'_ u8`, `ContainsLifetime<'_>`). It will also want to know if the lifetime is related to a reference (`&u8`) or a path (`ContainsLifetime`).

r? ``@nnethercote``
2025-04-24 08:12:59 +02:00
Matthias Krüger
2a07f998d0
Rollup merge of #139852 - makai410:smir-refactor, r=celinval
StableMIR: Implement `CompilerInterface`

This PR implements part of [the document](https://hackmd.io/``@celinaval/H1lJBGse0).``

With `TablesWrapper` wrapped by `CompilerInterface`, the stable-mir's TLV stores a pointer to `CompilerInterface`, while the rustc-specific TLV stores a pointer to tables.
2025-04-24 08:12:58 +02:00
Matthias Krüger
32b2428c8b
Rollup merge of #139809 - alexcrichton:wasm-simd-safe, r=RalfJung
Don't warn about `v128` in wasm ABI transition

The `-Zwasm-c-abi=spec` mode of `extern "C"` does not actually change the meaning of `v128`  meaning that the FCW lint firing is a false positive.

cc https://github.com/rust-lang/rust/issues/138762#issuecomment-2801709483
2025-04-24 08:12:58 +02:00
bors
7f695232a8 Auto merge of #140168 - joshlf:no-nfas, r=jswrenn
transmute: Mark edges by byte sets, not byte values

This leads to drastic performance improvements. For example, on the author's 2024 MacBook Pro, the time to convert the `Tree` representation of a `u64` to its equivalent DFA representation drops from ~8.5ms to ~1us, a reduction of ~8,500x. See `bench_dfa_from_tree`.

Similarly, the time to execute a transmutability query from `u64` to `u64` drops from ~35us to ~1.7us, a reduction of ~20x. See `bench_transmute`.

r? `@jswrenn`
2025-04-24 05:36:38 +00:00
Nicholas Nethercote
af8047789d Refactor StableMir to avoid some clones.
Pass `args` to `run` instead of storing it in a field. This avoids the
need to clone it within `run`.

Also, change `args` from `Vec<String>` to `&[String]`, avoiding the need
for some vecs and clones.
2025-04-24 11:12:34 +10:00
Nicholas Nethercote
055a27da2a Remove some unnecessary clones.
I found these by grepping for `&[a-z_\.]*\.clone()`, i.e. expressions
like `&a.b.clone()`, which are sometimes unnecessary clones, and also
looking at clones nearby to cases like that.
2025-04-24 11:12:34 +10:00
bors
c02a4f0852 Auto merge of #139309 - RalfJung:abi_unsupported_vector_types, r=fee1-dead,traviscross
make abi_unsupported_vector_types a hard error

Fixes https://github.com/rust-lang/rust/issues/116558 by completing the transition; see that issue for context. The lint was introduced with Rust 1.84 and this has been shown in cargo's future breakage reports since Rust 1.85, released 6 weeks ago, and so far we got 0 complaints by users. There's not even a backlink on the tracking issue. We did a [crater run](https://github.com/rust-lang/rust/pull/127731#issuecomment-2286736295) when the lint was originally added and found no breakage. So I don't think we need another crater run now, but I can do one if the team prefers that.

https://github.com/rust-lang/rust/issues/131800 is done, so for most current targets (in particular, all tier 1 and tier 2 targets) we have the information to implement this check (modulo the targets where we don't properly support SIMD vectors yet, see the sub-issues of https://github.com/rust-lang/rust/issues/116558). If a new target gets added in the future, it will default to reject all SIMD vector types until proper information is added, which is the default we want.

This will need approval by for `@rust-lang/lang.` Cc `@workingjubilee` `@veluca93`

try-job: test-various
try-job: armhf-gnu
try-job: dist-i586-gnu-i586-i686-musl
2025-04-24 00:44:40 +00:00
bors
fa58ce343a Auto merge of #138845 - compiler-errors:stall-generators, r=lcnr
Properly stall coroutine witnesses in new solver

TODO: write description

r? lcnr
2025-04-23 21:35:15 +00:00
Jake Goulding
2a5c349f42 Extend HIR to track the source and syntax of a lifetime
An upcoming lint will want to be able to know if a lifetime is
hidden (e.g. `&u8`, `ContainsLifetime`) or anonymous: (e.g. `&'_ u8`,
`ContainsLifetime<'_>`). It will also want to know if the lifetime is
related to a reference (`&u8`) or a path (`ContainsLifetime`).
2025-04-23 16:37:39 -04:00
Joshua Liebow-Feeser
4326a44e6f transmutability: Mark edges by ranges, not values
In the `Tree` and `Dfa` representations of a type's layout, store byte
ranges rather than needing to separately store each byte value. This
permits us to, for example, represent a `u8` using a single 0..=255 edge
in the DFA rather than using 256 separate edges.

This leads to drastic performance improvements. For example, on the
author's 2024 MacBook Pro, the time to convert the `Tree` representation
of a `u64` to its equivalent DFA representation drops from ~8.5ms to
~1us, a reduction of ~8,500x. See `bench_dfa_from_tree`.

Similarly, the time to execute a transmutability query from `u64` to
`u64` drops from ~35us to ~1.7us, a reduction of ~20x. See
`bench_transmute`.
2025-04-23 11:45:00 -07:00
bors
553600e0f5 Auto merge of #140180 - ChrisDenton:rollup-5pvs08u, r=ChrisDenton
Rollup of 7 pull requests

Successful merges:

 - #140142 (Some more graphviz tweaks)
 - #140146 (Update `compiler_builtins` to 0.1.156)
 - #140147 (Clean: rename `open_braces` to `open_delimiters` in lexer and move `make_unclosed_delims_error` into `diagnostics.rs`.)
 - #140160 (Use `is_lang_item` and `as_lang_item` instead of handrolling their logic)
 - #140163 (Validate extension in `PathBuf::add_extension`)
 - #140173 (Ping Mara when touching format_args!() internals.)
 - #140175 (`rc""` more clear error message)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-23 15:12:33 +00:00
Michael Goulet
f943f73db4 More 2025-04-23 15:09:25 +00:00
Makai
5b390cdc58 Make SmirInterface pub(crate) and rename Context to SmirContext
Co-authored-by: Celina G. Val <celinval@amazon.com>
2025-04-23 12:28:14 +08:00
Nicholas Nethercote
51088fdcee Remove synstructure::Structure::underscore_const calls.
The `synstructure` docs say "This method is a no-op, underscore consts
are used by default now." The behaviour change occurred going from
`synstructure` version 0.13.0 to 0.13.1.
2025-04-23 11:14:27 +10:00
Chris Denton
ecb9775438
Rollup merge of #140175 - Kivooeo:new-fix-one, r=compiler-errors
`rc""` more clear error message

here is small fix that provides better error message when user is trying to use `rc""` the same way it was made for `rb""`

example of it's work

```rust
  |
2 |     rc"\n";
  |     ^^ unknown prefix
  |
  = note: prefixed identifiers and literals are reserved since Rust 2021
help: use `cr` for a raw C-string
  |
2 -     rc"\n";
2 +     cr"\n";
  |
```

**related issue**
fixes #140170

cc `@cyrgani` (issue author)
2025-04-23 00:43:08 +00:00
Chris Denton
b03267fc11
Rollup merge of #140160 - oli-obk:lang-items, r=jieyouxu
Use `is_lang_item` and `as_lang_item` instead of handrolling their logic

Various cleanups and deduplication. Most notably `if is_lang_item(foo, bar) {} else if is_lang_item...` chains are turned into matches. No behaviour changes intended beyond turning ICEs into fatal "lang item not found" errors
2025-04-23 00:43:07 +00:00
Chris Denton
090f6a9629
Rollup merge of #140147 - xizheyin:issue-138401-1, r=compiler-errors
Clean: rename `open_braces` to `open_delimiters` in lexer and move `make_unclosed_delims_error` into `diagnostics.rs`.

Clean code prepared for resolving #138401. To avoid having too many extraneous changes in one PR, I cleaned up some of the naming and method placement in lexer in this PR.
1. For the make_unclosed_delims_error function defined in mod.rs is only used in lexer, so moved into lexer, which enhances encapsulation.
2. For open_braces in TokenTreeDiagInfo the naming is not canonical, as Brace refers to `{...} ` and this variable can store all kinds of different Delimiters. so I named it open_delimiters.

r? `@chenyukang`
2025-04-23 00:43:06 +00:00
Chris Denton
1b9e11ed3b
Rollup merge of #140142 - nnethercote:some-graphviz-tweaks-2, r=compiler-errors
Some more graphviz tweaks

A follow-up to #132346.

r? `@davidtwco`
2025-04-23 00:43:05 +00:00
Kivooeo
44b19e5fe7 rc and cr more clear error message 2025-04-23 03:15:43 +05:00
Alex Crichton
19e44d463b Don't warn about v128 in wasm ABI transition
This has other warnings if necessary and doesn't need extra warnings
from this FCW.

cc #138762
2025-04-22 15:11:23 -07:00
dianne
32503440cd make [u8] and [u8;N] literal patterns usable in deref patterns
Specifically, this allows byte string literal patterns to be used where
a `[u8]` or `[u8;N]` is expected when `deref_patterns` is enabled.
2025-04-22 13:19:20 -07:00
dianne
61840254c5 make str literal patterns usable in deref patterns
Specifically, this allows string literal patterns to be used where a
`str` is expected when `deref_patterns` is enabled.
2025-04-22 13:19:17 -07:00
Michael Goulet
7c1661f945 Consider Copy/Clone too 2025-04-22 17:05:15 +00:00
Michael Goulet
1727badf77 Don't compute query unless in new solver 2025-04-22 17:04:59 +00:00
Michael Goulet
a922983393 Eagerly instantiate coroutine witness in new solver 2025-04-22 16:50:38 +00:00
Michael Goulet
169955f3be Properly drain pending obligations for coroutines 2025-04-22 16:50:38 +00:00
Michael Goulet
67df5b9cfa Collect and resolve ambiguous obligations from normalizing in writeback 2025-04-22 16:50:38 +00:00
Chris Denton
15f8847a25
Rollup merge of #140144 - nnethercote:fix-140098, r=petrochenkov
Handle another negated literal in `eat_token_lit`.

Extends the change from #139653, which was on expressions, to literals.

Fixes #140098.

r? ``@petrochenkov``
2025-04-22 15:24:08 +00:00
Chris Denton
264249fbe1
Rollup merge of #140104 - Shourya742:2025-04-21-auto-diff-fails-on-impl-block, r=ZuseZ4
Fix auto diff failing on inherent impl blocks

closes: #139557

r? ``@ZuseZ4``
2025-04-22 15:24:07 +00:00
Chris Denton
107f04daa8
Rollup merge of #140072 - folkertdev:miri-fn-align, r=RalfJung
handle function alignment in miri

tracking issue: https://github.com/rust-lang/rust/issues/82232
Fixes https://github.com/rust-lang/miri/issues/4282

The `#[repr(align(N))]` attribute on functions was ignored when using miri. For such a function, its address should be a multiple of `N`.

There is some further discussion in the thread [#t-compiler/const-eval > function address alignment](https://rust-lang.zulipchat.com/#narrow/channel/146212-t-compiler.2Fconst-eval/topic/function.20address.20alignment) on how `dyn Fn` should be handled. The behavior there appears to be consistent between miri and nightly, though both may be incorrect. In any case, that can be resolved separately.
2025-04-22 15:24:06 +00:00
Chris Denton
8089e317b5
Rollup merge of #139921 - Kivooeo:master, r=WaffleLapkin
improve diagnostic for raw pointer field access with ->

This PR enhances the error messages emitted by the Rust compiler when users attempt to use the `->` operator for field access on raw pointers or when dereferencing is needed. The changes aim to provide clearer guidance, by suggesting the correct use of the `.` operator and explicit dereferencing.

**Before:**
```
help: `xs` is a raw pointer; try dereferencing it
   |
LL |         (*xs)->count += 1;
   |         ++  +
```

**Now:**
```
help: use `.` on a dereferenced raw pointer instead
   |
LL -         xs->count += 1;
LL +         (*xs).count += 1;
   |
```

I added extra clarification in the message. Since this error occurs in the parser, we can't be certain that the type is a raw pointer. That's why the message includes only a small note in brackets. (In contrast, the message above is emitted in HIR, where we *can* check whether it's a raw pointer.)

**Before:**
```
  --> main.rs:11:11
   |
11 |         xs->count += 1;
   |           ^^
   |
   = help: the . operator will dereference the value if needed
```
**After:**
```
--> main.rs:11:11
   |
11 |         xs->count += 1;
   |           ^^
   |
   = help: the `.` operator will automatically dereference the value, except if the value is a raw pointer
```
2025-04-22 15:24:05 +00:00
Oli Scherer
5d2952100f Use is_lang_item and as_lang_item instead of handrolling their logic 2025-04-22 11:02:37 +00:00
Ralf Jung
47a1278841
add comment for "Other" case 2025-04-22 11:40:48 +02:00
bors
8bf5a8d12f Auto merge of #132833 - est31:stabilize_let_chains, r=fee1-dead
Stabilize let chains in the 2024 edition

# Stabilization report

This proposes the stabilization of `let_chains` ([tracking issue], [RFC 2497]) in the [2024 edition] of Rust.

[tracking issue]: https://github.com/rust-lang/rust/issues/53667
[RFC 2497]: https://github.com/rust-lang/rfcs/pull/2497
[2024 edition]: https://doc.rust-lang.org/nightly/edition-guide/rust-2024/index.html

## What is being stabilized

The ability to `&&`-chain `let` statements inside `if` and `while` is being stabilized, allowing intermixture with boolean expressions. The patterns inside the `let` sub-expressions can be irrefutable or refutable.

```Rust
struct FnCall<'a> {
    fn_name: &'a str,
    args: Vec<i32>,
}

fn is_legal_ident(s: &str) -> bool {
    s.chars()
        .all(|c| ('a'..='z').contains(&c) || ('A'..='Z').contains(&c))
}

impl<'a> FnCall<'a> {
    fn parse(s: &'a str) -> Option<Self> {
        if let Some((fn_name, after_name)) = s.split_once("(")
            && !fn_name.is_empty()
            && is_legal_ident(fn_name)
            && let Some((args_str, "")) = after_name.rsplit_once(")")
        {
            let args = args_str
                .split(',')
                .map(|arg| arg.parse())
                .collect::<Result<Vec<_>, _>>();
            args.ok().map(|args| FnCall { fn_name, args })
        } else {
            None
        }
    }
    fn exec(&self) -> Option<i32> {
        let iter = self.args.iter().copied();
        match self.fn_name {
            "sum" => Some(iter.sum()),
            "max" => iter.max(),
            "min" => iter.min(),
            _ => None,
        }
    }
}

fn main() {
    println!("{:?}", FnCall::parse("sum(1,2,3)").unwrap().exec());
    println!("{:?}", FnCall::parse("max(4,5)").unwrap().exec());
}
```

The feature will only be stabilized for the 2024 edition and future editions. Users of past editions will get an error with a hint to update the edition.

closes #53667

## Why 2024 edition?

Rust generally tries to ship new features to all editions. So even the oldest editions receive the newest features. However, sometimes a feature requires a breaking change so much that offering the feature without the breaking change makes no sense. This occurs rarely, but has happened in the 2018 edition already with `async` and `await` syntax. It required an edition boundary in order for `async`/`await` to become keywords, and the entire feature foots on those keywords.

In the instance of let chains, the issue is the drop order of `if let` chains. If we want `if let` chains to be compatible with `if let`, drop order makes it hard for us to [generate correct MIR]. It would be strange to have different behaviour for `if let ... {}` and `if true && let ... {}`. So it's better to [stay consistent with `if let`].

In edition 2024, [drop order changes] have been introduced to make `if let` temporaries be lived more shortly. These changes also affected `if let` chains. These changes make sense even if you don't take the `if let` chains MIR generation problem into account. But if we want to use them as the solution to the MIR generation problem, we need to restrict let chains to edition 2024 and beyond: for let chains, it's not just a change towards more sensible behaviour, but one required for correct function.

[generate correct MIR]: https://github.com/rust-lang/rust/issues/104843
[stay consistent with `if let`]: https://github.com/rust-lang/rust/pull/103293#issuecomment-1293408574
[drop order changes]: https://github.com/rust-lang/rust/issues/124085

## Introduction considerations

As edition 2024 is very new, this stabilization PR only makes it possible to use let chains on 2024 without that feature gate, it doesn't mark that feature gate as stable/removed. I would propose to continue offering the `let_chains` feature (behind a feature gate) for a limited time (maybe 3 months after stabilization?) on older editions to allow nightly users to adopt edition 2024 at their own pace. After that, the feature gate shall be marked as *stabilized*, not removed, and replaced by an error on editions 2021 and below.

## Implementation history

* History from before March 14, 2022 can be found in the [original stabilization PR] that was reverted.
* https://github.com/rust-lang/rust/pull/94927
* https://github.com/rust-lang/rust/pull/94951
* https://github.com/rust-lang/rust/pull/94974
* https://github.com/rust-lang/rust/pull/95008
* https://github.com/rust-lang/rust/pull/97295
* https://github.com/rust-lang/rust/pull/98633
* https://github.com/rust-lang/rust/pull/99731
* https://github.com/rust-lang/rust/pull/102394
* https://github.com/rust-lang/rust/pull/100526
* https://github.com/rust-lang/rust/pull/100538
* https://github.com/rust-lang/rust/pull/102998
* https://github.com/rust-lang/rust/pull/103405
* https://github.com/rust-lang/rust/pull/103293
* https://github.com/rust-lang/rust/pull/107251
* https://github.com/rust-lang/rust/pull/110568
* https://github.com/rust-lang/rust/pull/115677
* https://github.com/rust-lang/rust/pull/117743
* https://github.com/rust-lang/rust/pull/117770
* https://github.com/rust-lang/rust/pull/118191
* https://github.com/rust-lang/rust/pull/119554
* https://github.com/rust-lang/rust/pull/129394
* https://github.com/rust-lang/rust/pull/132828
* https://github.com/rust-lang/reference/pull/1179
* https://github.com/rust-lang/reference/pull/1251
* https://github.com/rust-lang/rustfmt/pull/5910

[original stabilization PR]: https://github.com/rust-lang/rust/pull/94927

## Adoption history

### In the compiler

* History before March 14, 2022 can be found in the [original stabilization PR].
* https://github.com/rust-lang/rust/pull/115983
* https://github.com/rust-lang/rust/pull/116549
* https://github.com/rust-lang/rust/pull/116688

### Outside of the compiler

* https://github.com/rust-lang/rust-clippy/pull/11750
* [rspack](https://github.com/web-infra-dev/rspack)
* [risingwave](https://github.com/risingwavelabs/risingwave)
* [dylint](https://github.com/trailofbits/dylint)
* [convex-backend](https://github.com/get-convex/convex-backend)
* [tikv](https://github.com/tikv/tikv)
* [Daft](https://github.com/Eventual-Inc/Daft)
* [greptimedb](https://github.com/GreptimeTeam/greptimedb)

## Tests

<details>

### Intentional restrictions

[`partially-macro-expanded.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/partially-macro-expanded.rs), [`macro-expanded.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/macro-expanded.rs): it is possible to use macros to expand to both the pattern and the expression inside a let chain, but not to the entire `let pat = expr` operand.
[`parens.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/parens.rs): `if (let pat = expr)` is not allowed in chains
[`ensure-that-let-else-does-not-interact-with-let-chains.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs): `let...else` doesn't support chaining.

### Overlap with match guards

[`move-guard-if-let-chain.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs): test for the `use moved value` error working well in match guards. could maybe be extended with let chains that have more than one `let`
[`shadowing.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/shadowing.rs): shadowing in if let guards works as expected
[`ast-validate-guards.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.rs): let chains in match guards require the match guards feature gate

### Simple cases from the early days

PR #88642 has added some tests with very simple usages of `let else`, mostly as regression tests to early bugs.

[`then-else-blocks.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/then-else-blocks.rs)
[`ast-lowering-does-not-wrap-let-chains.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs)
[`issue-90722.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-90722.rs)
[`issue-92145.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-92145.rs)

### Drop order/MIR scoping tests

[`issue-100276.rs`](4adafcf40a/tests/ui/drop/issue-100276.rs): let expressions on RHS aren't terminating scopes
[`drop_order.rs`](4adafcf40a/tests/ui/drop/drop_order.rs): exhaustive temporary drop order test for various Rust constructs, including let chains
[`scope.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/scope.rs): match guard scoping test
[`drop-scope.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/drop-scope.rs): another match guard scoping test, ensuring that temporaries in if-let guards live for the arm
[`drop_order_if_let_rescope.rs`](4adafcf40a/tests/ui/drop/drop_order_if_let_rescope.rs): if let rescoping on edition 2024, including chains
[`mir_let_chains_drop_order.rs`](4adafcf40a/tests/ui/mir/mir_let_chains_drop_order.rs): comprehensive drop order test for let chains, distinguishes editions 2021 and 2024.
[`issue-99938.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-99938.rs), [`issue-99852.rs`](4adafcf40a/tests/ui/mir/issue-99852.rs) both bad MIR ICEs fixed by #102394

### Linting

[`irrefutable-lets.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.rs): trailing and leading irrefutable let patterns get linted for, others don't. The lint is turned off for `else if`.
[`issue-121070-let-range.rs`](4adafcf40a/tests/ui/lint/issue-121070-let-range.rs): regression test for false positive of the unused parens lint, precedence requires the `()`s here

### Parser: intentional restrictions

[`disallowed-positions.rs`](2128d8df0e/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs): `let` in expression context is rejected everywhere except at the top level
[`invalid-let-in-a-valid-let-context.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs): nested `let` is not allowed (let's are no legal expressions just because they are allowed in `if` and `while`).

### Parser: recovery

[`issue-103381.rs`](4adafcf40a/tests/ui/parser/issues/issue-103381.rs): Graceful recovery of incorrect chaining of `if` and `if let`
[`semi-in-let-chain.rs`](4adafcf40a/tests/ui/parser/semi-in-let-chain.rs): Ensure that stray `;`s in let chains give nice errors (`if_chain!` users might be accustomed to `;`s)
[`deli-ident-issue-1.rs`](4adafcf40a/tests/ui/parser/deli-ident-issue-1.rs), [`brace-in-let-chain.rs`](4adafcf40a/tests/ui/parser/brace-in-let-chain.rs): Ensure that stray unclosed `{`s in let chains give nice errors and hints

### Misc

[`conflicting_bindings.rs`](4adafcf40a/tests/ui/pattern/usefulness/conflicting_bindings.rs): the conflicting bindings check also works in let chains. Personally, I'd extend it to chains with multiple let's as well.
[`let-chains-attr.rs`](4adafcf40a/tests/ui/expr/if/attrs/let-chains-attr.rs): attributes work on let chains

### Tangential tests with `#![feature(let_chains)]`

[`if-let.rs`](4adafcf40a/tests/coverage/branch/if-let.rs): MC/DC coverage tests for let chains
[`logical_or_in_conditional.rs`](4adafcf40a/tests/mir-opt/building/logical_or_in_conditional.rs): not really about let chains, more about dropping/scoping behaviour of `||`
[`stringify.rs`](4adafcf40a/tests/ui/macros/stringify.rs): exhaustive test of the `stringify` macro
[`expanded-interpolation.rs`](4adafcf40a/tests/ui/unpretty/expanded-interpolation.rs), [`expanded-exhaustive.rs`](4adafcf40a/tests/ui/unpretty/expanded-exhaustive.rs): Exhaustive test of `-Zunpretty`
[`diverges-not.rs`](4adafcf40a/tests/ui/rfcs/rfc-0000-never_patterns/diverges-not.rs): Never type, mostly tangential to let chains

</details>

## Possible future work

* There is proposals to allow `if let Pat(bindings) = expr {}` to be written as `if expr is Pat(bindings) {}` ([RFC 3573]). `if let` chains are a natural extension of the already existing `if let` syntax, and I'd argue orthogonal towards `is` syntax.
  * https://github.com/rust-lang/lang-team/issues/297
* One could have similar chaining inside `let ... else` statements. There is no proposed RFC for this however, nor is it implemented on nightly.
* Match guards have the `if` keyword as well, but on stable Rust, they don't support `let`. The functionality is available via an unstable feature ([`if_let_guard` tracking issue]). Stabilization of let chains affects this feature in so far as match guards containing let chains now only need the `if_let_guard` feature gate be present instead of also the `let_chains` feature (NOTE: this PR doesn't implement this simplification, it's left for future work).

[RFC 3573]: https://github.com/rust-lang/rfcs/pull/3573
[`if_let_guard` tracking issue]: https://github.com/rust-lang/rust/issues/51114

## Open questions / blockers

- [ ] bad recovery if you don't put a `let` (I don't think this is a blocker): [#117977](https://github.com/rust-lang/rust/issues/117977)
- [x] An instance where a temporary lives shorter than with nested ifs, breaking compilation: [#103476](https://github.com/rust-lang/rust/issues/103476). Personally I don't think this is a blocker either, as it's an edge case. Edit: turns out to not reproduce in edition 2025 any more, due to let rescoping. regression test added in #133093
- [x] One should probably extend the tests for `move-guard-if-let-chain.rs` and `conflicting_bindings.rs` to have chains with multiple let's: done in 133093
- [x] Parsing rejection tests: addressed by https://github.com/rust-lang/rust/pull/132828
- [x] [Style](https://rust-lang.zulipchat.com/#narrow/channel/346005-t-style/topic/let.20chains.20stabilization.20and.20formatting): https://github.com/rust-lang/rust/pull/139456
- [x] https://github.com/rust-lang/rust/issues/86730 explicitly mentions `let_else`. I think we can live with `let pat = expr` not evaluating as `expr` for macro_rules macros, especially given that `let pat = expr` is not a legal expression anywhere except inside `if` and `while`.
- [x] Documentation in the reference: https://github.com/rust-lang/reference/pull/1740
- [x] Add chapter to the Rust 2024 [edition guide]: https://github.com/rust-lang/edition-guide/pull/337
- [x] Resolve open questions on desired drop order.

[original reference PR]: https://github.com/rust-lang/reference/pull/1179
[edition guide]: https://github.com/rust-lang/edition-guide
2025-04-22 07:54:10 +00:00
xizheyin
dce5d99ce8 Rename open_brace to open_delimiters
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-04-22 14:37:26 +08:00
xizheyin
e827b17ddb Move make_unclosed_delims_error to lexer/diagonostics.rs
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-04-22 14:37:26 +08:00
Nicholas Nethercote
6be270be0c Handle another negated literal in eat_token_lit.
Extends the change from #139653, which was on expressions, to literals.

Fixes #140098.
2025-04-22 15:08:32 +10:00
bors
9bfa31f632 Auto merge of #140138 - ChrisDenton:rollup-zw7jibi, r=ChrisDenton
Rollup of 5 pull requests

Successful merges:

 - #139981 (Don't compute name of associated item if it's an RPITIT)
 - #140077 (Construct OutputType using macro and print [=FILENAME] help info)
 - #140081 (Update `libc` to 0.2.172)
 - #140094 (Improve diagnostics for pointer arithmetic += and -= (fixes #137391))
 - #140128 (Use correct annotation for CSS pseudo elements)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-22 04:44:13 +00:00
Chris Denton
8f42ac0043
Rollup merge of #140094 - Kivooeo:raw-pointer-assignment-suggestion, r=compiler-errors
Improve diagnostics for pointer arithmetic += and -= (fixes #137391)

**Description**:

This PR improves the diagnostic message for cases where a binary assignment operation like `ptr += offset` or `ptr -= offset` is attempted on `*mut T`. These operations are not allowed, and the compiler previously suggested calling `.add()` or `.wrapping_add()`, which is misleading if not assigned.

This PR updates the diagnostics to suggest assigning the result of `.wrapping_add()` or `.wrapping_sub()` back to the pointer, e.g.:

**Examples**

For this code
```rust
let mut arr = [0u8; 10];
let mut ptr = arr.as_mut_ptr();

ptr += 2;
```
it will say:
```rust
10 |     ptr += 2;
   |     ---^^^^^
   |     |
   |     cannot use `+=` on type `*mut u8`
   |
help: consider replacing `ptr += offset` with `ptr = ptr.wrapping_add(offset)` or `ptr.add(offset)`
   |
10 -     ptr += 2;
10 +     ptr = ptr.wrapping_add(2);
```

**Related issue**: #137391
cc `@nabijaczleweli` for context (issue author)
2025-04-22 01:22:13 +00:00
Chris Denton
2fff8257ad
Rollup merge of #140077 - xizheyin:issue-139805, r=jieyouxu
Construct OutputType using macro and print [=FILENAME] help info

Closes #139805

Use define_output_types to define variants of OutputType, as well as refactor all of its methods for clarity. This way no variant is missed when pattern matching or output help messages.

On top of that, I optimized for `emit` help messages.

r? ```@jieyouxu```
2025-04-22 01:22:12 +00:00
Chris Denton
32862fba47
Rollup merge of #139981 - compiler-errors:name-2, r=nnethercote
Don't compute name of associated item if it's an RPITIT

Another simple fix for an RPITIT name ICE.

Fixes https://github.com/rust-lang/rust/issues/139941
Fixes #140084

r? nnethercote
2025-04-22 01:22:11 +00:00
bors
fae7785b60 Auto merge of #139897 - nnethercote:rm-OpenDelim-CloseDelim, r=petrochenkov
Remove `token::{Open,Close}Delim`

By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.

PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.

This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
  pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
  `Delimiter` values to `TokenKind`.

Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
-   } else if self.token != token::CloseDelim(Delimiter::Brace) {
+   } else if self.token != token::CloseBrace {
```

r? `@petrochenkov`
2025-04-22 01:15:06 +00:00
Nicholas Nethercote
521b379705 Remove unnecessary lifetime on ResultsVisitor. 2025-04-22 10:08:05 +10:00
Nicholas Nethercote
3bd1e1484f Remove unused ResultsCursor methods. 2025-04-22 09:46:24 +10:00