in which the unused-parens lint comes to cover function and method args by zackmdavis · Pull Request #46980 · rust-lang/rust

error: unnecessary parentheses around function argument
--> src\librustc_apfloat\ieee.rs:1437:56
|
1437 | let exp_change = cmp::min(cmp::max(exp as i32, (-max_change - 1)), max_change);
| ^^^^^^^^^^^^^^^^^ help: remove these parentheses
|
note: lint level defined here
--> src\librustc_apfloat\lib.rs:45:9
|
45 | #![deny(warnings)]
| ^^^^^^^^
= note: #[deny(unused_parens)] implied by #[deny(warnings)]
Compiling rustc_binaryen v0.0.0 (file:///C:/projects/rust/src/librustc_binaryen)
error: aborting due to previous error
error: Could not compile `rustc_apfloat`.

zackmdavis · 2017-12-31T03:46:31Z

Yes, with regrets, it turns out that the "Eh, this looks right; I don't have to tie up my cores running the tests locally because Travis will catch any needed fixes for me without wasting any reviewer-minutes" PR strategy is less effective when Travis is broken. Force-push bff573c is more likely to be what we want (although my local test build is unrelatedly flaking late in the test process, after the ui/run-pass/compile-fail tests have apparently succeeded).

petrochenkov · 2017-12-31T11:03:04Z

@bors r+

bors · 2017-12-31T11:03:05Z

📌 Commit 6dee797 has been approved by petrochenkov

bors · 2018-01-06T20:24:04Z

📌 Commit 8a94e4c has been approved by petrochenkov

kennytm · 2018-01-06T20:54:22Z

@bors r-

Something’s wrong with the new cargo @rust-lang/cargo.

[00:34:36] Cargo Book (x86_64-unknown-linux-gnu) - cargo
[00:34:36] thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 30, message: "Read-only file system" } }', libcore/result.rs:916:5
[00:34:36] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:34:36] [00:34:36] [00:34:36] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/rustbook" "build" "/checkout/src/tools/cargo/src/doc/book" "-d" "/checkout/obj/build/x86_64-unknown-linux-gnu/doc/cargo"

bors · 2018-01-10T03:56:05Z

☔ The latest upstream changes (presumably #47248) made this pull request unmergeable. Please resolve the merge conflicts.

petrochenkov · 2018-01-14T10:32:41Z

Blocked on #47280

Resolvesrust-lang#46137.

zackmdavis · 2018-01-18T16:37:06Z

no. 47280 has landed; rebased

petrochenkov · 2018-01-18T22:40:13Z

@bors r+

bors · 2018-01-18T22:40:13Z

📌 Commit 14982db has been approved by petrochenkov

bors · 2018-01-20T15:06:47Z

⌛ Testing commit 14982db with merge 15a1e28...

…nthesized_arguments, r=petrochenkov in which the unused-parens lint comes to cover function and method args Resolves#46137.

bors · 2018-01-20T17:51:51Z

☀️ Test successful - status-appveyor, status-travis
Approved by: petrochenkov
Pushing 15a1e28 to master...

In rust-lang#46980 ("in which the unused-parens lint..." (14982db)), the unused-parens lint was made to check function and method arguments, which it previously did not (seemingly due to oversight rather than willful design). However, in rust-lang#47775 and discussion thereon, user–developers of Geal/nom and graphql-rust/juniper reported that the lint was seemingly erroneously triggering on certain complex macros in those projects. While this doesn't seem like a bug in the lint in the particular strict sense that the expanded code would, in fact, contain unncecessary parentheses, it also doesn't seem like the sort of thing macro authors should have to think about: the spirit of the unused-parens lint is to prevent needless clutter in code, not to give macro authors extra heartache in the handling of token trees. We propose the expediency of declining to lint unused parentheses in function or method args inside of nested expansions: we believe that this should eliminate the petty, troublesome lint warnings reported in the issue, without forgoing the benefits of the lint in simpler macros. It seemed like too much duplicated code for the `Call` and `MethodCall` match arms to duplicate the nested-macro check in addition to each having their own `for` loop, so this occasioned a slight refactor so that the function and method cases could share code—hopefully the overall intent is at least no less clear to the gentle reader. This is concerning rust-lang#47775.

…ssary_unnecessary_parens, r=nikomatsakis decline to lint technically-unnecessary parens in function or method arguments inside of nested macros In rust-lang#46980 ("in which the unused-parens lint..." (14982db)), the unused-parens lint was made to check function and method arguments, which it previously did not (seemingly due to oversight rather than willful design). However, in rust-lang#47775 and discussion thereon, user–developers of Geal/nom and graphql-rust/juniper reported that the lint was seemingly erroneously triggering on certain complex macros in those projects. While this doesn't seem like a bug in the lint in the particular strict sense that the expanded code would, in fact, contain unncecessary parentheses, it also doesn't seem like the sort of thing macro authors should have to think about: the spirit of the unused-parens lint is to prevent needless clutter in code, not to give macro authors extra heartache in the handling of token trees. We propose the expediency of declining to lint unused parentheses in function or method args inside of nested expansions: we believe that this should eliminate the petty, troublesome lint warnings reported in the issue, without forgoing the benefits of the lint in simpler macros. It seemed like too much duplicated code for the `Call` and `MethodCall` match arms to duplicate the nested-macro check in addition to each having their own `for` loop, so this occasioned a slight refactor so that the function and method cases could share code—hopefully the overall intent is at least no less clear to the gentle reader. This is concerning rust-lang#47775.

rust-highfive assigned arielb1 Dec 24, 2017

zackmdavis force-pushed the and_the_case_of_the_needlessly_parenthesized_arguments branch from 92e9c0d to b7739f3Compare December 24, 2017 04:23

rust-highfive assigned petrochenkov and unassigned arielb1 Dec 24, 2017

petrochenkov added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Dec 24, 2017

bors added a commit that referenced this pull request Dec 27, 2017
Auto merge of#46980- zackmdavis:and_the_case_of_the_needlessly_pare…
5ccdeea
…nthesized_arguments, r=petrochenkov in which the unused-parens lint comes to cover function and method args Resolves#46137.

kennytm 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 Dec 27, 2017

zackmdavis force-pushed the and_the_case_of_the_needlessly_parenthesized_arguments branch from b7739f3 to bff573cCompare December 31, 2017 03:41

zackmdavis force-pushed the and_the_case_of_the_needlessly_parenthesized_arguments branch from bff573c to 6dee797Compare December 31, 2017 05:25

kennytm added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Dec 31, 2017

kennytm added S-blocked Status: Blocked on something else such as an RFC or other implementation work. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jan 6, 2018

in which the unused-parens lint comes to cover function and method args
14982db
Resolvesrust-lang#46137.

zackmdavis force-pushed the and_the_case_of_the_needlessly_parenthesized_arguments branch from 8a94e4c to 14982dbCompare January 18, 2018 16:36

kennytm added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-blocked Status: Blocked on something else such as an RFC or other implementation work. labels Jan 18, 2018

petrochenkov 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 Jan 18, 2018

bors added a commit that referenced this pull request Jan 20, 2018
Auto merge of#46980- zackmdavis:and_the_case_of_the_needlessly_pare…
15a1e28
…nthesized_arguments, r=petrochenkov in which the unused-parens lint comes to cover function and method args Resolves#46137.

bors merged commit 14982db into rust-lang:masterJan 20, 2018

zackmdavis deleted the and_the_case_of_the_needlessly_parenthesized_arguments branch January 20, 2018 23:24

zackmdavis mentioned this pull request Jan 27, 2018
Wrong "unnecessary parentheses around function argument"-warning #47775
Closed

zackmdavis mentioned this pull request Jan 31, 2018
decline to lint technically-unnecessary parens in function or method arguments inside of nested macros #47896
Merged

Mark-Simulacrum mentioned this pull request Mar 4, 2018
Unnecessary parentheses around argument lint #48717
Closed

zackmdavis mentioned this pull request Mar 9, 2018
unused_parens false positive on cfg_attr(..., derive(..., ...)) #48871
Closed

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