Lint unused parentheses around method receiver

[chenyukang]

Extends the unused_parens lint to detect unnecessary parentheses around method receivers like (x).method().

Fixes #151985

[rustbot]

compiler-builtins is developed in its own repository. If possible, consider making this change to rust-lang/compiler-builtins instead.

cc @tgross35

[rustbot]

r? @jieyouxu

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[rustbot]

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  • c1b3bf0

[chenyukang]

seems better add parens for unsafe block?

[rust-log-analyzer]

The job x86_64-gnu-miri failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

REPOSITORY                                   TAG       IMAGE ID       CREATED      SIZE
ghcr.io/dependabot/dependabot-updater-core   latest    bcec0b4e062b   6 days ago   783MB
=> Removing docker images...
Deleted Images:
untagged: ghcr.io/dependabot/dependabot-updater-core:latest
untagged: ghcr.io/dependabot/dependabot-updater-core@sha256:b662be51f7b8ef7e2c8464428f14e49cb79c36aa9afb7ecb9221dfe0f507050c
deleted: sha256:bcec0b4e062b5ffe11cc1c2729558c0cd96621c0271ab5e97ff3a56e0c25045a
deleted: sha256:64e147d5e54d9be8b8aa322e511cda02296eda4b8b8d063c6a314833aca50e29
deleted: sha256:5cba409bb463f4e7fa1a19f695450170422582c1bc7c0e934d893b4e5f558bc6
deleted: sha256:cddc6ebd344b0111eaab170ead1dfda24acdfe865ed8a12599a34d338fa8e28b
deleted: sha256:2412c3f334d79134573cd45e657fb6cc0abd75bef3881458b0d498d936545c8d
---
tests/pass/shims/x86/rounding-error.rs ... ok
tests/pass/shims/x86/intrinsics-x86-gfni.rs ... ok

FAILED TEST: tests/pass/u128.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-p1BMJS" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/pass" "tests/pass/u128.rs" "--edition" "2021"

error: test got exit status: 1, but expected 0
 = note: compilation failed, but was expected to succeed

error: no output was expected
Execute `./miri test --bless` to update `tests/pass/u128.stderr` to the actual output
+++ <stderr output>
error: unnecessary parentheses around method receiver
##[error]  --> tests/pass/u128.rs:60:16
   |
LL |     assert_eq!((z).checked_mul(z), Some(0x734C_C2F2_A521));
   |                ^ ^
   |
   = note: `-D unused-parens` implied by `-D unused`
   = help: to override `-D unused` add `#[allow(unused_parens)]`
help: remove these parentheses
   |
LL -     assert_eq!((z).checked_mul(z), Some(0x734C_C2F2_A521));
LL +     assert_eq!(z .checked_mul(z), Some(0x734C_C2F2_A521));
   |

error: unnecessary parentheses around method receiver
##[error]  --> tests/pass/u128.rs:61:16
   |
LL |     assert_eq!((k).checked_mul(k), None);
   |                ^ ^
   |
help: remove these parentheses
   |
LL -     assert_eq!((k).checked_mul(k), None);
LL +     assert_eq!(k .checked_mul(k), None);
   |

error: aborting due to 2 previous errors



full stderr:
error: unnecessary parentheses around method receiver
##[error]  --> tests/pass/u128.rs:60:16
   |
LL |     assert_eq!((z).checked_mul(z), Some(0x734C_C2F2_A521));
   |                ^ ^
   |
   = note: `-D unused-parens` implied by `-D unused`
   = help: to override `-D unused` add `#[allow(unused_parens)]`
help: remove these parentheses
   |
LL -     assert_eq!((z).checked_mul(z), Some(0x734C_C2F2_A521));
LL +     assert_eq!(z .checked_mul(z), Some(0x734C_C2F2_A521));
   |

error: unnecessary parentheses around method receiver
##[error]  --> tests/pass/u128.rs:61:16
   |
LL |     assert_eq!((k).checked_mul(k), None);
   |                ^ ^
   |
help: remove these parentheses
   |
LL -     assert_eq!((k).checked_mul(k), None);
LL +     assert_eq!(k .checked_mul(k), None);
   |

error: aborting due to 2 previous errors


---
Location:
   /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/ui_test-0.30.3/src/lib.rs:365

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   1: <color_eyre[c347bb8439eedf52]::config::EyreHook>::into_eyre_hook::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   2: <eyre[b6a35a05bd5c1b8b]::Report>::from_adhoc::<&str><unknown>
      at <unknown source file>:<unknown line>
   3: ui_test[4e0397377b429e93]::run_tests_generic::<ui_test[4e0397377b429e93]::default_file_filter, ui[7bc7edd0f8f5024a]::run_tests::{closure#1}, alloc[d3205064c01c8e3c]::boxed::Box<dyn ui_test[4e0397377b429e93]::status_emitter::StatusEmitter>><unknown>
      at <unknown source file>:<unknown line>
   4: ui[7bc7edd0f8f5024a]::ui<unknown>
      at <unknown source file>:<unknown line>
   5: ui[7bc7edd0f8f5024a]::main<unknown>
      at <unknown source file>:<unknown line>
   6: std[f28e0ef05a2fcfdc]::sys::backtrace::__rust_begin_short_backtrace::<fn() -> core[9864d63c68801c6d]::result::Result<(), eyre[b6a35a05bd5c1b8b]::Report>, core[9864d63c68801c6d]::result::Result<(), eyre[b6a35a05bd5c1b8b]::Report>><unknown>
      at <unknown source file>:<unknown line>
   7: std[f28e0ef05a2fcfdc]::rt::lang_start::<core[9864d63c68801c6d]::result::Result<(), eyre[b6a35a05bd5c1b8b]::Report>>::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   8: std[f28e0ef05a2fcfdc]::rt::lang_start_internal<unknown>
      at <unknown source file>:<unknown line>
   9: main<unknown>
      at <unknown source file>:<unknown line>
  10: __libc_start_main<unknown>
      at <unknown source file>:<unknown line>
  11: _start<unknown>
      at <unknown source file>:<unknown line>

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.
Run with RUST_BACKTRACE=full to include source snippets.
error: test failed, to rerun pass `--test ui`

Caused by:
  process didn't exit successfully: `/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/deps/ui-399d57cbacaa656d` (exit status: 1)
Bootstrap failed while executing `test --stage 2 src/tools/miri src/tools/miri/cargo-miri`
Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo test -Zwarnings --target x86_64-unknown-linux-gnu -Zbinary-dep-depinfo -j 4 -Zroot-dir=/checkout --locked --color=always --profile=release --manifest-path /checkout/src/tools/miri/Cargo.toml -- [workdir=/checkout]` failed with exit code 1
Created at: src/bootstrap/src/core/build_steps/tool.rs:191:21
Executed at: src/bootstrap/src/core/build_steps/test.rs:738:19

Command has failed. Rerun with -v to see more details.
Build completed unsuccessfully in 0:40:48
  local time: Mon Feb  2 15:12:55 UTC 2026
  network time: Mon, 02 Feb 2026 15:12:55 GMT
##[error]Process completed with exit code 1.
##[group]Run echo "disk usage:"