This PR fixes a false positive in@typescript-eslint/no-base-to-string where.toString() calls on values typed as generic subclasses of ignored types, such asError, were being incorrectly reported. The rule previously only checked the type’s direct name, causing cases likeclass Boom<T> extends Error {} to be treated as unsafe, so this update adds recursive base-type checking with cycle protection to ensure that if a type or any of its ancestors matchignoredTypeNames, the call is allowed. A test is included to confirm.toString() is not reported for both direct and chained generic subclasses ofError, while preserving all existing rule behavior and configuration.

fix(eslint-plugin): honor ignored base types on generic classes

bef61e2

Copy link

Contributor

typescript-eslintbot commentedNov 19, 2025

Thanks for the PR,@OleksandraKordonets!

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!

🙏Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint.

Copy link

netlifybot commentedNov 19, 2025•
edited
Loading

✅ Deploy Preview fortypescript-eslint ready!

Name	Link
🔨 Latest commit	`52a4d74`
🔍 Latest deploy log	https://app.netlify.com/projects/typescript-eslint/deploys/69252c5ee7513a000898dafe
😎 Deploy Preview	https://deploy-preview-11767--typescript-eslint.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 94 (🔴 down 4 from production) Accessibility: 97 (no change from production) Best Practices: 100 (no change from production) SEO: 92 (no change from production) PWA: 80 (no change from production) View the detailed breakdown and full score reports

To edit notification comments on pull requests, go to yourNetlify project configuration.

Copy link

nx-cloudbot commentedNov 19, 2025•
edited
Loading

View yourCI Pipeline Execution ↗ for commit52a4d74

Command	Status	Duration	Result
`nx test eslint-plugin --coverage=false`	✅ Succeeded	5m 9s	View ↗
`nx run-many -t lint`	✅ Succeeded	3m 15s	View ↗
`nx run-many -t typecheck`	✅ Succeeded	2m 2s	View ↗
`nx test typescript-estree --coverage=false`	✅ Succeeded	2s	View ↗
`nx test eslint-plugin-internal --coverage=false`	✅ Succeeded	4s	View ↗
`nx run integration-tests:test`	✅ Succeeded	5s	View ↗
`nx run types:build`	✅ Succeeded	2s	View ↗
`nx run generate-configs`	✅ Succeeded	6s	View ↗
`Additional runs (29)`	✅ Succeeded	...	View ↗

☁️Nx Cloud last updated this comment at2025-11-25 04:22:22 UTC

Copy link

codecovbot commentedNov 19, 2025•
edited
Loading

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.49%. Comparing base (d26e9de) to head (52a4d74).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@##             main   #11767   +/-   ##=======================================  Coverage   90.49%   90.49%           =======================================  Files         522      522             Lines       53357    53362    +5       Branches     8909     8914    +5     =======================================+ Hits        48284    48289    +5  Misses       5057     5057             Partials       16       16

Flag	Coverage Δ
unittest	`90.49% <100.00%> (+<0.01%)`	⬆️

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

Files with missing lines	Coverage Δ
...kages/eslint-plugin/src/rules/no-base-to-string.ts	`99.07% <100.00%> (+0.01%)`	⬆️

🚀 New features to boost your workflow:

❄️Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

Merge branch 'main' into issue11758

3d0cf2a

JoshuaKGoldberg previously approved these changes

Nov 24, 2025

View reviewed changes

Copy link

Member

JoshuaKGoldberg left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others.Learn more.

LGTM, thanks! ✨

I just left a couple of stylistic nitpicks in case you're interested. No worries at all if you prefer the code as-is, I just like refactoring as a form of reading the code. Totally up to you. 🙂

packages/eslint-plugin/src/rules/no-base-to-string.tsShow resolvedHide resolved

packages/eslint-plugin/src/rules/no-base-to-string.ts Outdated

Comment on lines 258 to 264

		if(ignoredTypeNames.includes(typeName)){
		returntrue;
		}

		returngetBaseTypesForType(type).some(base=>
		isIgnoredTypeOrBase(base,seen),
		);

Copy link

Member

JoshuaKGoldbergNov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others.Learn more.

[Style] If you want to save a few lines 😄

Suggested change

	if(ignoredTypeNames.includes(typeName)){
	returntrue;
	}

	returngetBaseTypesForType(type).some(base=>
	isIgnoredTypeOrBase(base,seen),
	);
	return(
	ignoredTypeNames.includes(getTypeName(checker,type))\|\|
	getBaseTypesForType(type).some(base=>isIgnoredTypeOrBase(base,seen))
	);

Copy link

Member

JoshuaKGoldberg commentedNov 24, 2025•
edited
Loading

That issue was marked asaccepting prs

Btw, I wouldn't recommend sending PRs for issues that aren't yet marked as accepting prs. In this case it worked out because the issue was straightforward and accepted. But we've previously had to close PRs where the author put in a lot of work but the issue wasn't actually something that could be accepted. That feels bad for everyone.

https://typescript-eslint.io/docs/contributing