fix(eslint-plugin): [prefer-readonly-parameter-types] ignore tagged primitives

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes [prefer-readonly-parameter-types] false positive with tagged primitive type #1790
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

Adds a special-case exemption for an intersection of a literal and an object, as suggested in #1790 (comment).

I think Codecov is wrong to complain. The new functions are hit. We're just not merging coverage reports.

💖

[typescript-eslint]

Thanks for the PR, @JoshuaKGoldberg!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit bea544c

Command	Status	Duration	Result
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nx run-many -t lint	✅ Succeeded	3m 20s	View ↗
nx run-many -t typecheck	✅ Succeeded	2m 3s	View ↗
nx test eslint-plugin-internal --coverage=false	✅ Succeeded	11s	View ↗
nx run types:build	✅ Succeeded	5s	View ↗
nx test typescript-estree --coverage=false	✅ Succeeded	2s	View ↗
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Additional runs (29)	✅ Succeeded	...	View ↗

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☁️ Nx Cloud last updated this comment at 2025-10-06 12:27:49 UTC

[codecov]

Codecov Report

❌ Patch coverage is 9.52381% with 38 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.67%. Comparing base (7f5fed7) to head (bea544c).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
...ackages/type-utils/src/isTypeBrandedLiteralLike.ts	7.31%	38 Missing ⚠️

❌ Your patch status has failed because the patch coverage (9.52%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #11660      +/-   ##
==========================================
- Coverage   90.74%   90.67%   -0.07%     
==========================================
  Files         516      517       +1     
  Lines       51987    52028      +41     
  Branches     8588     8588              
==========================================
+ Hits        47174    47177       +3     
- Misses       4799     4837      +38     
  Partials       14       14              

Flag	Coverage Δ
unittest	90.67% <9.52%> (-0.07%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...lugin/src/rules/prefer-readonly-parameter-types.ts	100.00% <100.00%> (ø)
...ackages/type-utils/src/isTypeBrandedLiteralLike.ts	7.31% <7.31%> (ø)

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[ronami]

Looking great! Just a few questions/nits from me 🚀🚀🚀

[ronami]

🚀🚀🚀 Looking good!

I added a couple of comments, mostly around a case I missed on the last review (my apologies).

[ronami]

🤩