Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std by estebank · Pull Request #149795 · rust-lang/rust

estebank · 2025-12-09T00:10:42Z

Split off #148837.

rustbot · 2025-12-09T00:10:46Z

rustbot has assigned @Mark-Simulacrum.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

workingjubilee

some of these format kinda weirdly.

View changes since this review

workingjubilee · 2025-12-09T03:02:48Z

- if let Some(new_secs) = secs.checked_add(1) {
- secs = new_secs;
- } else {
- return None;
- }
+ let Some(new_secs) = secs.checked_add(1) else { return None };
+ secs = new_secs;


I feel it is much harder to read the control flow in this case because we have hidden the return off to the right.

workingjubilee · 2025-12-09T03:03:36Z

- } else {
- return Err(FromUtf16Error(()));
- }
+ let Ok(c) = c else { return Err(FromUtf16Error(())) };


This also loses clarity due to let-else, IMO.

Would you be ok with the let...else if the return block was on its own line?

basically yes.

workingjubilee · 2025-12-09T04:01:18Z

- let (ptr, layout) = if let Some(mem) = unsafe { self.current_memory(elem_layout) } {
- mem
- } else {
+ let Some((ptr, layout)) = (unsafe { self.current_memory(elem_layout) }) else {


this is obviously fine, to be clear.

…f let ... else return` in std

workingjubilee · 2025-12-10T03:02:36Z

it's so weird to me that that matters. oh well.

workingjubilee · 2025-12-10T03:03:13Z

@bors r+ rollup

bors · 2025-12-10T03:03:16Z

📌 Commit 0488690 has been approved by workingjubilee

It is now in the queue for this repository.

…bilee Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std Split off rust-lang#148837.

Rollup of 12 pull requests Successful merges: - #147602 (Deduplicate higher-ranked lifetime capture errors in impl Trait) - #147725 (Remove -Zoom=panic) - #148294 (callconv: fix mips64 aggregate argument passing for C FFI) - #148491 ( Correctly provide suggestions when encountering `async fn` with a `dyn Trait` return type) - #149417 (tidy: Detect outdated workspaces in workspace list) - #149458 (Run clippy on cg_gcc in CI) - #149679 (Restrict spe_acc to PowerPC SPE targets) - #149781 (Don't suggest wrapping attr in unsafe if it may come from proc macro) - #149795 (Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std) - #149816 (Make typo in field and name suggestions verbose) - #149824 (Add a regression test for issue 145748) - #149826 (compiletest: tidy up `adb_path`/`adb_test_dir` handling) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 10 pull requests Successful merges: - #147725 (Remove -Zoom=panic) - #148294 (callconv: fix mips64 aggregate argument passing for C FFI) - #148491 ( Correctly provide suggestions when encountering `async fn` with a `dyn Trait` return type) - #149458 (Run clippy on cg_gcc in CI) - #149679 (Restrict spe_acc to PowerPC SPE targets) - #149781 (Don't suggest wrapping attr in unsafe if it may come from proc macro) - #149795 (Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std) - #149816 (Make typo in field and name suggestions verbose) - #149824 (Add a regression test for issue 145748) - #149826 (compiletest: tidy up `adb_path`/`adb_test_dir` handling) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #149795 - estebank:let-else-std, r=workingjubilee Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std Split off #148837.

Rollup of 10 pull requests Successful merges: - rust-lang/rust#147725 (Remove -Zoom=panic) - rust-lang/rust#148294 (callconv: fix mips64 aggregate argument passing for C FFI) - rust-lang/rust#148491 ( Correctly provide suggestions when encountering `async fn` with a `dyn Trait` return type) - rust-lang/rust#149458 (Run clippy on cg_gcc in CI) - rust-lang/rust#149679 (Restrict spe_acc to PowerPC SPE targets) - rust-lang/rust#149781 (Don't suggest wrapping attr in unsafe if it may come from proc macro) - rust-lang/rust#149795 (Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std) - rust-lang/rust#149816 (Make typo in field and name suggestions verbose) - rust-lang/rust#149824 (Add a regression test for issue 145748) - rust-lang/rust#149826 (compiletest: tidy up `adb_path`/`adb_test_dir` handling) r? `@ghost` `@rustbot` modify labels: rollup

rustbot assigned Mark-Simulacrum Dec 9, 2025

rustbot added O-windows Operating system: Windows S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Dec 9, 2025

workingjubilee reviewed Dec 9, 2025
View reviewed changes

estebank force-pushed the let-else-std branch from 698ff18 to 0ab59e7Compare December 9, 2025 23:22

This comment has been minimized.
Sign in to view

Use let...else instead of match foo { ... _ => return }; and `i…
0488690
…f let ... else return` in std

estebank force-pushed the let-else-std branch from 0ab59e7 to 0488690Compare December 9, 2025 23:35

bors 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 Dec 10, 2025

Zalathar mentioned this pull request Dec 10, 2025
Rollup of 13 pull requests #149828
Closed

Zalathar mentioned this pull request Dec 10, 2025
Rollup of 12 pull requests #149830
Closed

matthiaskrgr mentioned this pull request Dec 10, 2025
Rollup of 10 pull requests #149836
Merged

bors merged commit 3a3c7b5 into rust-lang:mainDec 10, 2025
11 checks passed

rustbot added this to the 1.94.0 milestone Dec 10, 2025

rust-timer added a commit that referenced this pull request Dec 10, 2025
Unrolled build for#149795
c2d36f8
Rollup merge of #149795 - estebank:let-else-std, r=workingjubilee Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std Split off #148837.

github-actionsBot mentioned this pull request Dec 12, 2025
Toolchain upgrade to nightly-2026-02-09 flux-rs/flux#1345
Closed

Navigation Menu

Uh oh!

Uh oh!

Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std - #149795

Use `let`...`else` instead of `match foo { ... _ => return };` and `if let ... else return` in std#149795
bors merged 1 commit into
rust-lang:mainfrom
estebank:let-else-std

estebank commented Dec 9, 2025•
edited by rustbot
Loading

Uh oh!

rustbot commented Dec 9, 2025

Uh oh!

workingjubilee left a comment •
edited by rustbot
Loading

Uh oh!

workingjubileeDec 9, 2025

Uh oh!

workingjubileeDec 9, 2025

Uh oh!

estebankDec 9, 2025

Uh oh!

workingjubileeDec 10, 2025

Uh oh!

workingjubileeDec 9, 2025

Uh oh!

This comment has been minimized.

workingjubilee commented Dec 10, 2025•
edited
Loading

Uh oh!

workingjubilee commented Dec 10, 2025

Uh oh!

bors commented Dec 10, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

Uh oh!

Uh oh!

Conversation

estebank commented Dec 9, 2025• edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rustbot commented Dec 9, 2025

Uh oh!

workingjubilee left a comment • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

workingjubileeDec 9, 2025

Choose a reason for hiding this comment

Uh oh!

workingjubileeDec 9, 2025

Choose a reason for hiding this comment

Uh oh!

estebankDec 9, 2025

Choose a reason for hiding this comment

Uh oh!

workingjubileeDec 10, 2025

Choose a reason for hiding this comment

Uh oh!

workingjubileeDec 9, 2025

Choose a reason for hiding this comment

Uh oh!

This comment has been minimized.

workingjubilee commented Dec 10, 2025• edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

workingjubilee commented Dec 10, 2025

Uh oh!

bors commented Dec 10, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

estebank commented Dec 9, 2025•
edited by rustbot
Loading

workingjubilee left a comment •
edited by rustbot
Loading

workingjubilee commented Dec 10, 2025•
edited
Loading