perf(es/parser): Remove start in State

[CPunisher]

Description:

The only use of start is in error span read_digits so I think it can be removed.

[changeset-bot]

🦋 Changeset detected

Latest commit: cf7c14e

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[codspeed-hq]

CodSpeed Performance Report

Merging #11201 will not alter performance

_{Comparing CPunisher:10-29-perf/remove-state-start (cf7c14e) with main (eda01e5)}

Summary

✅ 138 untouched

[Copilot]

Pull Request Overview

This PR removes the unused start field from the lexer's State struct and its associated getter method. The field was previously set but never actually used, making it redundant.

Key Changes

• Removed the start: BytePos field from the State struct
• Removed the start() getter method from the State implementation
• Removed assignments to self.state.start in next_token() and scan_jsx_token()
• Updated read_int_u32() to use self.cur_pos() instead of self.state().start()

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/swc_ecma_parser/src/lexer/state.rs	Removed the unused start field from State struct, its initialization, assignments, getter method, and commented-out debug code
crates/swc_ecma_parser/src/lexer/mod.rs	Updated read_int_u32() to call self.cur_pos() directly instead of accessing the removed start field via self.state().start()

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[github-actions]

Binary Sizes

File	Size
swc.linux-x64-gnu.node	31M (31933320 bytes)

Commit: dd41528