chore(common): rm useless mutable

[bvanjoi]

No description provided.

[changeset-bot]

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Latest commit: e315a9a

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[codspeed-hq]

CodSpeed Performance Report

Merging #10405 will degrade performances by 2.4%

_{Comparing bvanjoi:pref-3 (e315a9a) with main (a0e89f0)}

Summary

⚡ 1 improvements
❌ 1 regressions
✅ 150 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	deserialization of serde	2.4 µs	2.4 µs	-2.4%
⚡	serialization of serde	2.8 µs	2.7 µs	+3.28%

[mischnic]

That clippy warning is probably gone as well then.

Suggested change

#[allow(clippy::wrong_self_convention)]

[kdy1]

I'll merge this when I'm going to make a breaking change of swc_common

[bvanjoi]

COMMENT: The reason I’d like to merge this PR since it shows a slight performance improvement in this report. However, I’m not entirely sure whether this is just noise or an actual improvement from these changes.

[kdy1]

I know, and it's expected to be faster because &mut is (very slightly) slower than &. Compiler cannot move in-between &mut-s, so & is likely to be faster.

But the problem is that this is a breaking change of swc_common meaning that nearly all SWC crates have to be published