Parse `impl` restrictions by CoCo-Japan-pan · Pull Request #152943 · rust-lang/rust

CoCo-Japan-pan · 2026-02-21T17:55:19Z

This PR implements the parsing logic for impl restrictions (e.g., pub impl(crate) trait Foo {}) as proposed in RFC 3323.
As the first step of the RFC implementation, this PR focuses strictly on the parsing phase. The new syntax is guarded by the #![feature(impl_restriction)] feature gate.
This implementation basically follows the pattern used in #141754.

r? @jhpratt

rustbot · 2026-02-21T17:55:23Z

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Kivooeo · 2026-02-21T18:27:49Z

since this is more a compiler related change, I'll reroll from @jhpratt

r? compiler

Urgau · 2026-02-21T18:31:46Z

This PR is linked to a GSOC idea/proposal, where I and @jhpratt are mentors, we will both review it.

r? Urgau

CoCo-Japan-pan · 2026-02-22T02:48:26Z

It turns out the CI is failing because I was printing impl in rustfmt even when no restrictions are present. I’ll push a fix for this shortly.

compiler/rustc_ast_pretty/src/pprust/state/item.rs

compiler/rustc_parse/src/parser/item.rs

compiler/rustc_parse/src/errors.rs

src/tools/clippy/clippy_utils/src/ast_utils/mod.rs

tests/ui/impl-restriction/feature-gate-impl-restriction.rs

compiler/rustc_parse/src/errors.rs

CoCo-Japan-pan · 2026-02-22T16:48:07Z

@Urgau Thanks for the feedback! I've addressed all the comments. Ready for another look!

Urgau

Look good to me. I will let @jhpratt do the final review.

View changes since this review

Urgau · 2026-02-22T20:06:16Z

Btw, 17 commits is a bit too much, it would be great if you could squash them to max 2/3 commits.

compiler/rustc_parse/src/parser/item.rs

…h) trait`

rustbot · 2026-02-28T05:16:14Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

jhpratt · 2026-03-03T06:28:08Z

LGTM! @Urgau Any particular preference regarding this?

it would be great if you could squash them to max 2/3 commits.

The current commits (10) all seem reasonable to me; I reviewed commit-by-commit. A couple could reasonably be folded into their preceding commit, but I don't think it's egregious or anything.

r=me (and you, of course) at your preference.

Urgau · 2026-03-03T06:34:56Z

I'm fine with the 10 commits as they currently are. Let's merge it.

@bors r=Urgau,jhpratt

rust-bors · 2026-03-03T06:34:58Z

📌 Commit 3dcefa3 has been approved by Urgau,jhpratt

It is now in the queue for this repository.

@jhpratt

…rse, r=Urgau,jhpratt Parse `impl` restrictions This PR implements the parsing logic for `impl` restrictions (e.g., `pub impl(crate) trait Foo {}`) as proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). As the first step of the RFC implementation, this PR focuses strictly on the parsing phase. The new syntax is guarded by the `#![feature(impl_restriction)]` feature gate. This implementation basically follows the pattern used in rust-lang#141754. r? @jhpratt

…uwer Rollup of 4 pull requests Successful merges: - #152164 (Lint unused features) - #152943 (Parse `impl` restrictions) - #153184 (Replace CodegenResults with CompiledModules) - #153319 (Comments and docs: add missing periods to "ie.")

…uwer Rollup of 6 pull requests Successful merges: - #153336 (stdarch subtree update) - #152943 (Parse `impl` restrictions) - #153184 (Replace CodegenResults with CompiledModules) - #153285 (Update call-llvm-intrinsics test for Rust 1.94.0 IR) - #153319 (Comments and docs: add missing periods to "ie.") - #153326 (Make `rustc_with_all_queries!` pass query modifiers as named values)

@jhpratt

Rollup merge of #152943 - CoCo-Japan-pan:impl-restriction-parse, r=Urgau,jhpratt Parse `impl` restrictions This PR implements the parsing logic for `impl` restrictions (e.g., `pub impl(crate) trait Foo {}`) as proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). As the first step of the RFC implementation, this PR focuses strictly on the parsing phase. The new syntax is guarded by the `#![feature(impl_restriction)]` feature gate. This implementation basically follows the pattern used in #141754. r? @jhpratt

…uwer Rollup of 6 pull requests Successful merges: - rust-lang/rust#153336 (stdarch subtree update) - rust-lang/rust#152943 (Parse `impl` restrictions) - rust-lang/rust#153184 (Replace CodegenResults with CompiledModules) - rust-lang/rust#153285 (Update call-llvm-intrinsics test for Rust 1.94.0 IR) - rust-lang/rust#153319 (Comments and docs: add missing periods to "ie.") - rust-lang/rust#153326 (Make `rustc_with_all_queries!` pass query modifiers as named values)

rustbot assigned jhpratt Feb 21, 2026

rustbot assigned petrochenkov and unassigned jhpratt Feb 21, 2026

rustbot assigned Urgau and unassigned petrochenkov Feb 21, 2026

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CoCo-Japan-pan force-pushed the impl-restriction-parse branch from 1ad4b8a to 0345b89 Compare February 22, 2026 03:29

Urgau reviewed Feb 22, 2026

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CoCo-Japan-pan force-pushed the impl-restriction-parse branch from 14453b8 to 13e1685 Compare February 22, 2026 13:52

Urgau reviewed Feb 22, 2026

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fmease reviewed Feb 22, 2026

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compiler/rustc_parse/src/parser/item.rs Show resolved Hide resolved

fmease mentioned this pull request Feb 22, 2026

Parse impl restrictions fmease/rasur#28

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CoCo-Japan-pan force-pushed the impl-restriction-parse branch from 7d71945 to 50d182e Compare February 23, 2026 03:35

CoCo-Japan-pan changed the title ~~Introduce impl restriction to AST~~ Parse impl restrictions Feb 23, 2026

CoCo-Japan-pan requested a review from fmease February 23, 2026 04:39

CoCo-Japan-pan force-pushed the impl-restriction-parse branch from 286fff4 to 5c157c0 Compare February 23, 2026 05:20

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CoCo-Japan-pan added 2 commits February 28, 2026 13:56

Add impl_restriction feature

a0ccef6

Introduce impl restriction to AST

3232d99

CoCo-Japan-pan added 8 commits February 28, 2026 13:59

Parse impl restriction on trait definitions

f55f6b4

Handle ambiguity between const unsafe fn and `const unsafe impl(pat…

2b39bea

…h) trait`

Pretty print impl restriction

65aef77

Discard impl restrictions during HIR lowering for now

2a48c19

Add eq_impl_restriction to clippy_utils

9bf2494

rustfmt impl restriction

f40881d

Add ui tests

26d4291

Trait aliases cannot be impl-restricted

3dcefa3

CoCo-Japan-pan force-pushed the impl-restriction-parse branch from 5c157c0 to 3dcefa3 Compare February 28, 2026 05:16

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 3, 2026

JonathanBrouwer mentioned this pull request Mar 3, 2026

Rollup of 4 pull requests #153334

Closed

JonathanBrouwer mentioned this pull request Mar 3, 2026

Rollup of 6 pull requests #153344

Merged

rust-bors bot merged commit bef489b into rust-lang:main Mar 3, 2026
11 checks passed

rustbot added this to the 1.96.0 milestone Mar 3, 2026

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CoCo-Japan-pan commented Feb 21, 2026 •

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