`impl` restriction lowering by CoCo-Japan-pan · Pull Request #153556 · rust-lang/rust

CoCo-Japan-pan · 2026-03-08T07:38:09Z

This PR is linked to a GSoC proposal and is part of the progress toward implementing impl restrictions proposed in RFC 3323.
This PR implements path resolution for impl restrictions. The resolution is performed in rustc_resolve/src/late.rs using smart_resolve_path.
This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s AncestorOnly error.

r? @Urgau
cc @jhpratt

Urgau

Looks pretty good. Only some nits.

View changes since this review

compiler/rustc_resolve/src/build_reduced_graph.rs

tests/ui/impl-restriction/restriction_resolution_errors.rs

tests/ui/impl-restriction/restriction_resolution_2018.rs

compiler/rustc_resolve/src/lib.rs

CoCo-Japan-pan · 2026-03-08T13:44:15Z

Thanks for the review!
@rustbot ready

Urgau

Looks mostly good, just need some positive tests now.

View changes since this review

tests/ui/impl-restriction/restriction_resolution_2018.rs

Urgau

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

View changes since this review

compiler/rustc_resolve/src/build_reduced_graph.rs

compiler/rustc_resolve/src/late.rs

compiler/rustc_middle/src/hir/map.rs

CoCo-Japan-pan · 2026-03-16T17:16:01Z

The current implementation uses smart_resolve_path.
I added a new variant, PathSource::Module.

I kept the ancestor check and pushed it into use_injections to keep the error emission order consistent with its occurrence.
Currently, the "too many leading super keywords" error is emitted first regardless of the occurrence order, but this seems to be a separate issue.
https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=05164a046abf4e1c123793c0037c06a7

@rustbot ready

tests/ui/impl-restriction/restriction_resolution_use.rs

tests/ui/impl-restriction/restriction_resolution_errors.rs

compiler/rustc_resolve/src/lib.rs

compiler/rustc_middle/src/ty/mod.rs

compiler/rustc_resolve/src/late.rs

petrochenkov · 2026-03-19T10:00:54Z

Thanks, this is good now.
r=me after addressing the remaining nit #153556 (comment) and updating the PR description.
@rustbot author

CoCo-Japan-pan · 2026-03-19T10:15:30Z

@rustbot ready

petrochenkov · 2026-03-19T10:18:27Z

@bors r+

rust-bors · 2026-03-19T10:18:31Z

📌 Commit 4a60dae has been approved by petrochenkov

It is now in the queue for this repository.

@Urgau

…wering, r=petrochenkov `impl` restriction lowering This PR is linked to a [GSoC proposal](https://github.com/rust-lang/google-summer-of-code?tab=readme-ov-file#implementing-impl-and-mut-restrictions) and is part of the progress toward implementing `impl` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). This PR implements path resolution for `impl` restrictions. The resolution is performed in `rustc_resolve/src/late.rs` using `smart_resolve_path`. This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s `AncestorOnly` error. r? @Urgau cc @jhpratt

…uwer Rollup of 9 pull requests Successful merges: - #153556 (`impl` restriction lowering) - #153992 (bootstrap: Optionally print a backtrace if a command fails) - #154019 (two smaller feature cleanups) - #154059 (tests: Activate `must_not_suspend` test for `MutexGuard` dropped before `await`) - #154075 (Rewrite `query_ensure_result`.) - #154082 (Updates derive_where and removes workaround) - #154084 (Preserve braces around `self` in use tree pretty printing) - #154086 (Insert space after float literal ending with `.` in pretty printer) - #154087 (Fix whitespace after fragment specifiers in macro pretty printing)

@Urgau

…wering, r=petrochenkov `impl` restriction lowering This PR is linked to a [GSoC proposal](https://github.com/rust-lang/google-summer-of-code?tab=readme-ov-file#implementing-impl-and-mut-restrictions) and is part of the progress toward implementing `impl` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). This PR implements path resolution for `impl` restrictions. The resolution is performed in `rustc_resolve/src/late.rs` using `smart_resolve_path`. This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s `AncestorOnly` error. r? @Urgau cc @jhpratt

@Urgau

…wering, r=petrochenkov `impl` restriction lowering This PR is linked to a [GSoC proposal](https://github.com/rust-lang/google-summer-of-code?tab=readme-ov-file#implementing-impl-and-mut-restrictions) and is part of the progress toward implementing `impl` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). This PR implements path resolution for `impl` restrictions. The resolution is performed in `rustc_resolve/src/late.rs` using `smart_resolve_path`. This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s `AncestorOnly` error. r? @Urgau cc @jhpratt

@Urgau

…wering, r=petrochenkov `impl` restriction lowering This PR is linked to a [GSoC proposal](https://github.com/rust-lang/google-summer-of-code?tab=readme-ov-file#implementing-impl-and-mut-restrictions) and is part of the progress toward implementing `impl` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). This PR implements path resolution for `impl` restrictions. The resolution is performed in `rustc_resolve/src/late.rs` using `smart_resolve_path`. This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s `AncestorOnly` error. r? @Urgau cc @jhpratt

@Urgau

…wering, r=petrochenkov `impl` restriction lowering This PR is linked to a [GSoC proposal](https://github.com/rust-lang/google-summer-of-code?tab=readme-ov-file#implementing-impl-and-mut-restrictions) and is part of the progress toward implementing `impl` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html). This PR implements path resolution for `impl` restrictions. The resolution is performed in `rustc_resolve/src/late.rs` using `smart_resolve_path`. This PR also checks whether the restricted module or crate is an ancestor. If it is not, it emits a restriction-specific counterpart to visibility’s `AncestorOnly` error. r? @Urgau cc @jhpratt

…uwer Rollup of 12 pull requests Successful merges: - #152909 (sess: `-Zbranch-protection` is a target modifier) - #153556 (`impl` restriction lowering) - #154048 (Don't emit rustdoc `missing_doc_code_examples` lint on impl items) - #153992 (bootstrap: Optionally print a backtrace if a command fails) - #154019 (two smaller feature cleanups) - #154059 (tests: Activate `must_not_suspend` test for `MutexGuard` dropped before `await`) - #154075 (Rewrite `query_ensure_result`.) - #154082 (Updates derive_where and removes workaround) - #154084 (Preserve braces around `self` in use tree pretty printing) - #154086 (Insert space after float literal ending with `.` in pretty printer) - #154087 (Fix whitespace after fragment specifiers in macro pretty printing) - #154109 (tests: Add regression test for async closures involving HRTBs)

Rollup of 15 pull requests Successful merges: - #152909 (sess: `-Zbranch-protection` is a target modifier) - #153556 (`impl` restriction lowering) - #154048 (Don't emit rustdoc `missing_doc_code_examples` lint on impl items) - #150935 (Introduce #[diagnostic::on_move(message)]) - #152973 (remove -Csoft-float) - #153862 (Rename `cycle_check` to `find_cycle`) - #153992 (bootstrap: Optionally print a backtrace if a command fails) - #154019 (two smaller feature cleanups) - #154059 (tests: Activate `must_not_suspend` test for `MutexGuard` dropped before `await`) - #154075 (Rewrite `query_ensure_result`.) - #154082 (Updates derive_where and removes workaround) - #154084 (Preserve braces around `self` in use tree pretty printing) - #154086 (Insert space after float literal ending with `.` in pretty printer) - #154087 (Fix whitespace after fragment specifiers in macro pretty printing) - #154109 (tests: Add regression test for async closures involving HRTBs)

rustbot assigned Urgau Mar 8, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 8, 2026

CoCo-Japan-pan changed the title ~~Impl restriction lowering~~ impl restriction lowering Mar 8, 2026

Urgau reviewed Mar 8, 2026

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Urgau added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 8, 2026

CoCo-Japan-pan force-pushed the impl-restriction-lowering branch 2 times, most recently from deed8e1 to 596133b Compare March 8, 2026 13:38

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CoCo-Japan-pan force-pushed the impl-restriction-lowering branch from 596133b to 40df631 Compare March 9, 2026 06:47

Urgau approved these changes Mar 9, 2026

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CoCo-Japan-pan force-pushed the impl-restriction-lowering branch from 40df631 to dcc1cf5 Compare March 10, 2026 16:52

CoCo-Japan-pan requested a review from Urgau March 10, 2026 17:51

Urgau assigned petrochenkov Mar 15, 2026

petrochenkov reviewed Mar 16, 2026

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CoCo-Japan-pan force-pushed the impl-restriction-lowering branch 2 times, most recently from f1ef729 to 020ae2b Compare March 16, 2026 17:01

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CoCo-Japan-pan added 2 commits March 19, 2026 19:05

Resolve paths for impl restrictions using smart_resolve_path

cec0a68

Add UI tests for path resolution errors of impl restrictions

4a60dae

CoCo-Japan-pan force-pushed the impl-restriction-lowering branch from 8cfbc47 to 4a60dae Compare March 19, 2026 10:11

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JonathanBrouwer mentioned this pull request Mar 19, 2026

Rollup of 9 pull requests #154102

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JonathanBrouwer mentioned this pull request Mar 19, 2026

Rollup of 12 pull requests #154116

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JonathanBrouwer mentioned this pull request Mar 19, 2026

Rollup of 12 pull requests #154117

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Zalathar mentioned this pull request Mar 20, 2026

Rollup of 15 pull requests #154123

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rust-bors bot merged commit 85b8c32 into rust-lang:main Mar 20, 2026
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rustbot added this to the 1.96.0 milestone Mar 20, 2026

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