feat(linter): add unicorn/prefer-default-parameters rule

[re-taro]

This PR adds unicorn/prefer-default-parameters rule, issue #684

rule doc
rule source

[Copilot]

Pull request overview

This PR implements the unicorn/prefer-default-parameters linter rule, which encourages using default parameter syntax instead of reassignment patterns like foo = foo || 'bar'. The rule detects cases where function parameters are reassigned using logical operators with literal values and suggests using default parameters instead.

Key Changes

• Adds comprehensive logic to detect parameter reassignment patterns (foo = foo || 'bar' and const bar = foo || 'bar')
• Validates that the reassignment is the first statement in the function body and the parameter is the last one
• Includes extensive test coverage with 53 passing cases and 9 failing cases

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_linter/src/rules/unicorn/prefer_default_parameters.rs	Implements the complete rule logic with pattern detection, validation, and comprehensive tests
crates/oxc_linter/src/rules.rs	Registers the new rule in the linter's rule registry
crates/oxc_linter/src/snapshots/unicorn_prefer_default_parameters.snap	Adds snapshot test output for the rule's diagnostic messages

Comments suppressed due to low confidence (1)

crates/oxc_linter/src/rules/unicorn/prefer_default_parameters.rs:1

• The rule is inserted between prefer_bigint_literals and prefer_response_static_json, breaking the alphabetical ordering of the rules. It should be placed after prefer_date_now (line 474/1224) to maintain alphabetical order.

use oxc_ast::{

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[codspeed-hq]

CodSpeed Performance Report

Merging #16620 will not alter performance

_{Comparing re-taro:feat/prefer-default-params (e6c87db) with main (ce57612)¹}

Summary

✅ 4 untouched
⏩ 41 skipped²

Footnotes

1. No successful run was found on main (cb74fad) during the generation of this report, so ce57612 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 41 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[camc314]

Thanks for working on this! Unfortunately, it looks like the rulegen infra failed to port across some test cases. I've done them manually and updated the PR, however some tests cases are failing

[re-taro]

Thanks for working on this! Unfortunately, it looks like the rulegen infra failed to port across some test cases. I've done them manually and updated the PR, however some tests cases are failing

I'm sorry! Thank you!

[camc314]

Thank you!