Add correct suggestion for multi-references for self type in method #146305

Kivooeo · 2025-09-07T18:32:15Z

Currently the suggestion for this code

fn main() {}

struct A {
    field: i32,
}

impl A {
    fn f(&&self) {}
}

looks like this, which is incorrect and missleading

   Compiling playground v0.0.1 (/playground)
error: expected one of `!`, `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
 --> src/main.rs:8:16
  |
8 |     fn f(&&self) {}
  |                ^ expected one of 9 possible tokens
  |
  = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: explicitly ignore the parameter name
  |
8 |     fn f(_: &&self) {}
  |          ++

So this fixes it and make more correct suggestions

error: expected one of `!`, `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
 --> /home/gh-Kivooeo/test_/src/main.rs:8:16
  |
8 |     fn f(&&self) {}
  |                ^ expected one of 9 possible tokens
  |
help: `self` should be `self`, `&self` or `&mut self`, please remove extra references
  |
8 -     fn f(&&self) {}
8 +     fn f(&self) {}

Implementation is pretty self-documenting, but if you have suggestions on how to improve this (according to current test, which may be not fully covering all cases, this is works very well) or have some funny edge cases to show, I would appreciate it

r? compiler

compiler/rustc_parse/src/parser/diagnostics.rs

petrochenkov · 2025-09-25T17:26:20Z

I'm not sure if it's useful to give a special suggestion for this.
I guess &&self specifically is possible in practice as a typo, but anything more than that, especially intentionally? Very unlikely.
@rustbot author

Kivooeo · 2025-09-25T18:50:04Z

Let's try this one, I removed second suggestion with self: Self

Not sure what to do with cases where there is more than two references, but I'd keep it as it just because current suggestion is even worse and not correct in any way

Kivooeo · 2025-11-08T00:04:00Z

r? compiler

compiler/rustc_parse/src/parser/diagnostics.rs

JonathanBrouwer · 2025-11-08T08:27:43Z

@rustbot author

rustbot · 2025-11-08T13:46:11Z

⚠️ Warning ⚠️

This PR is based on an upstream commit that is older than 28 days.

It's recommended to update your branch according to the rustc-dev-guide.

JonathanBrouwer · 2025-11-08T14:02:38Z

r=me after rebasing & ci green

Kivooeo · 2025-11-08T14:59:12Z

Forget about rebase but I guess it shouldn't be a problem?

JonathanBrouwer · 2025-11-08T15:55:21Z

There's an increased risk of soft-conflicts if you have an old base, but given how isolated this change is it should be fine.
@bors r+ rollup

bors · 2025-11-08T15:55:24Z

📌 Commit 7298174 has been approved by JonathanBrouwer

It is now in the queue for this repository.

Rollup of 22 pull requests Successful merges: - #128666 (Add `overflow_checks` intrinsic) - #146305 (Add correct suggestion for multi-references for self type in method) - #147179 ([DebugInfo] Fix container types failing to find template args) - #147743 (Show packed field alignment in mir_transform_unaligned_packed_ref) - #148079 (Rename `downcast_[ref|mut]_unchecked` -> `downcast_unchecked_[ref|mut]`) - #148084 (Optimize path components iteration on platforms that don't have prefixes) - #148126 (Fix rust stdlib build failing for VxWorks) - #148204 (Modify contributor email entries in .mailmap) - #148279 (rustc_builtin_macros: rename bench parameter to avoid collisions with user-defined function names) - #148333 (constify result unwrap unchecked) - #148539 (Add Allocator proxy impls for Box, Rc, and Arc) - #148601 (`invalid_atomic_ordering`: also lint `update` & `try_update`) - #148612 (Add note for identifier with attempted hygiene violation) - #148613 (Switch hexagon targets to rust-lld) - #148619 (Enable std locking functions on AIX) - #148644 ([bootstrap] Make `--open` option work with `doc src/tools/error_index_generator`) - #148649 (don't completely reset `HeadUsages`) - #148673 (Remove a remnant of `dyn*` from the parser) - #148675 (Remove eslint-js from npm dependencies) - #148680 (Recover `[T: N]` as `[T; N]`) - #148688 (Remove unused argument `features` from `eval_config_entry`) - #148711 (Use the current lint note id when parsing `cfg!()`) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #146305 - Kivooeo:a-lot-of-references-in-self, r=JonathanBrouwer Add correct suggestion for multi-references for self type in method Currently the suggestion for this code ```rust fn main() {} struct A { field: i32, } impl A { fn f(&&self) {} } ``` looks like this, which is incorrect and missleading ```rust Compiling playground v0.0.1 (/playground) error: expected one of `!`, `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)` --> src/main.rs:8:16 | 8 | fn f(&&self) {} | ^ expected one of 9 possible tokens | = note: anonymous parameters are removed in the 2018 edition (see RFC 1685) help: explicitly ignore the parameter name | 8 | fn f(_: &&self) {} | ++ ``` So this fixes it and make more correct suggestions ```rust error: expected one of `!`, `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)` --> /home/gh-Kivooeo/test_/src/main.rs:8:16 | 8 | fn f(&&self) {} | ^ expected one of 9 possible tokens | help: `self` should be `self`, `&self` or `&mut self`, please remove extra references | 8 - fn f(&&self) {} 8 + fn f(&self) {} ``` Implementation is pretty self-documenting, but if you have suggestions on how to improve this (according to current test, which may be not fully covering all cases, this is works very well) or have some funny edge cases to show, I would appreciate it r? compiler

rustbot assigned petrochenkov Sep 7, 2025

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 Sep 7, 2025

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add parser check for multi-reference self

7298174

rust-cloud-vms bot force-pushed the a-lot-of-references-in-self branch from cd574ab to 7298174 Compare November 8, 2025 13:46

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Zalathar mentioned this pull request Nov 9, 2025

Rollup of 22 pull requests #148721

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bors merged commit 0a74011 into rust-lang:master Nov 9, 2025
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rustbot added this to the 1.93.0 milestone Nov 9, 2025

Add correct suggestion for multi-references for self type in method #146305

Add correct suggestion for multi-references for self type in method #146305

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