feat(minifier): compress return void foo() => foo(); return

[sapphi-red]

Compress return void foo() => foo(); return.
return void 0 and return undefined was handled but this wasn't.

[sapphi-red]

• perf(minifier): exit early in is_closest_function_scope_an_async_generator #13273
• feat(minifier): compress return void foo() => foo(); return #13271 👈 (View in Graphite)
• main

---

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

• 0-merge - adds this PR to the back of the merge queue
• hotfix - for urgent hot fixes, skip the queue and merge this PR next

You must have a Graphite account in order to use the merge queue. Sign up using this link.

An organization admin has enabled the Graphite Merge Queue in this repository.

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

This stack of pull requests is managed by Graphite. Learn more about stacking.

[Copilot]

Pull Request Overview

This PR implements a minification optimization that transforms return void foo() to foo(); return when the expression evaluates to undefined. This builds on existing optimizations for return void 0 and return undefined patterns.

• Adds logic to detect return statements with arguments that evaluate to undefined and have side effects
• Transforms these statements by extracting the side-effect expression and creating a bare return
• Updates test expectations to reflect the new optimization behavior

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
crates/oxc_minifier/src/peephole/minimize_statements.rs	Implements the core optimization logic for return void foo() transformation
crates/oxc_minifier/src/peephole/substitute_alternate_syntax.rs	Updates test case to expect the new optimized output
tasks/minsize/minsize.snap	Minor improvement in gzip size measurement for typescript.js

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #13271 will not alter performance

_{Comparing 08-23-feat_minifier_compress_return_void_foo_foo_return_ (cae222c) with main (a1b6ad4)¹}

Summary

✅ 34 untouched benchmarks

Footnotes

1. No successful run was found on main (cae222c) during the generation of this report, so a1b6ad4 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[Boshen]

Merge activity

• Aug 24, 1:09 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Aug 24, 1:09 AM UTC: Boshen added this pull request to the Graphite merge queue.
• Aug 24, 1:17 AM UTC: The Graphite merge queue couldn't merge this PR because it was not satisfying all requirements (Failed CI: 'Test NAPI', 'Conformance').
• Aug 24, 4:37 AM UTC: Merged by the Graphite merge queue.