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dont lint unused parens on a pattern that came from a macro argument - #161728

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Albab-Hasan:unused-parens-macro-pat
Sep 26, 2026
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dont lint unused parens on a pattern that came from a macro argument#161728
rust-bors[bot] merged 2 commits into
rust-lang:mainfrom
Albab-Hasan:unused-parens-macro-pat

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@Albab-Hasan

@Albab-Hasan Albab-Hasan commented Aug 25, 2026

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fixes #86959

r? @folkertdev

@rustbot 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 Aug 25, 2026
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folkertdev commented Aug 26, 2026

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maybe

r? fmease

@rustbot rustbot assigned fmease and unassigned folkertdev Aug 26, 2026
@Albab-Hasan

Albab-Hasan commented Sep 10, 2026 •
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@rustbot reroll

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rustbot commented Sep 10, 2026

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Error: Failed to set assignee to reroll: invalid assignee

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@rustbot rustbot assigned nnethercote and unassigned fmease Sep 10, 2026
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nnethercote reviewed Sep 19, 2026
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Comment thread tests/ui/lint/unused-parens-macro-pat-issue-86959.rs
if_let_pat!(('a' | 'A'));
nested_pat!((1 | 2));
// A leading `..=` is rejected by both fragment specifiers. rust-lang/rust#120737
match_pat!((..='a' | 'z'));

@nnethercote nnethercote Sep 19, 2026 •
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Do we need additional testing to make sure the lint still triggers in the cases where it's supposed to?

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@Albab-Hasan Albab-Hasan Sep 19, 2026

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yes, there are three cases. one per leg of the gate. match_pat!(('a')) for a non-or pattern through a metavariable, body_or_pat!() for an or pattern written in the macro body and let (_x) = 1; as the no macro baseline. each one says what it guards in a comment above it.

one note. that leaves the struct field loop and ForLoop uncovered. struct field is easy. ForLoop costs an unrelated E0005 in the stderr since for ('a' | 'A') in "ab".chars() {} parses and lints before the refutable binding error lands. happy to add either or both.

@nnethercote nnethercote 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 Sep 19, 2026
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Albab-Hasan commented Sep 19, 2026

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@rustbot ready

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 19, 2026
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nnethercote commented Sep 22, 2026

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@bors r+

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rust-bors Bot commented Sep 22, 2026

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📌 Commit 917935b has been approved by nnethercote

It is now in the queue for this repository.

@rust-bors 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 Sep 22, 2026
@Albab-Hasan

Albab-Hasan commented Sep 22, 2026

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@nnethercote thanks!

jhpratt added a commit to jhpratt/rust that referenced this pull request Sep 22, 2026
@jhpratt
Rollup merge of rust-lang#161728 - Albab-Hasan:unused-parens-macro-pa…
d34a771 
…t, r=nnethercote

dont lint unused parens on a pattern that came from a macro argument

fixes rust-lang#86959

r? @folkertdev
@jhpratt jhpratt mentioned this pull request Sep 22, 2026
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jhpratt commented Sep 22, 2026

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@bors r- #163147 (comment)

@rust-bors rust-bors Bot 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 22, 2026
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This pull request was unapproved.

This PR was contained in a rollup (#163147), which was unapproved.

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@Albab-Hasan
dont lint unused parens on a pattern that came from a macro argument
a0de979 
parentheses around a pattern passed to a `macro_rules!` metavariable can be
required by the matcher even though they are redundant once expanded, so
suggesting their removal breaks the macro call. a `$p:pat_param` fragment never
accepts a top-level `|` and neither does `$p:pat` before edition 2021.

a metavariable keeps the call site syntax context while the code around it keeps
the macro definition context, so compare the two and reuse the existing
`avoid_or` flag when they differ. parens written inside a macro body share one
context and keep linting as before.
@Albab-Hasan
Albab-Hasan force-pushed the unused-parens-macro-pat branch from 917935b to ff63416 Compare September 26, 2026 11:16
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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.

@Albab-Hasan

Albab-Hasan commented Sep 26, 2026

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@rustbot ready

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 26, 2026
@Albab-Hasan

Albab-Hasan commented Sep 26, 2026

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@nnethercote rebased

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nnethercote commented Sep 26, 2026

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@bors r+

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📌 Commit ff63416 has been tentatively approved by nnethercote

It will be put into the queue for this repository once PR CI succeeds.

@rust-bors 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 Sep 26, 2026
@JonathanBrouwer JonathanBrouwer mentioned this pull request Sep 26, 2026
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rust-bors Bot pushed a commit that referenced this pull request Sep 26, 2026
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Auto merge of #163379 - JonathanBrouwer:rollup-TObNVuH, r=JonathanBro…
0b80633 
…uwer

Rollup of 3 pull requests

Successful merges:

 - #161728 (dont lint unused parens on a pattern that came from a macro argument)
 - #161791 (Make dropping an empty BTreeMap free)
 - #163283 (Update expect messages in rust_const_eval)
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rust-bors Bot merged commit f55900d into rust-lang:main Sep 26, 2026
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rust-bors Bot pushed a commit that referenced this pull request Sep 26, 2026
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Unrolled build for #161728 in rollup 163379
37f6968 
Rollup merge of #161728 - Albab-Hasan:unused-parens-macro-pat, r=nnethercote

dont lint unused parens on a pattern that came from a macro argument

fixes #86959

r? @folkertdev
@rustbot rustbot added this to the 1.101.0 milestone Sep 26, 2026
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Unnecessary parentheses warning for (A | B) as :pat in 2018 edition

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