feat(eslint-plugin): [unbound-method] report property signatures with function types #11682

ronami · 2025-10-05T20:48:03Z

PR Checklist

Addresses an existing open issue: fixes [unbound-method] Should prevent conforming to a bound-style interface method with an unbound method #3503
That issue was marked as accepting prs
Steps in Contributing were taken

Overview

Waiting for resolution on #3503 (comment) before opening for review.

typescript-eslint · 2025-10-05T20:48:07Z

Thanks for the PR, @ronami!

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.

netlify · 2025-10-05T20:48:08Z

✅ Deploy Preview for typescript-eslint ready!

Name	Link
🔨 Latest commit	`3b98173`
🔍 Latest deploy log	https://app.netlify.com/projects/typescript-eslint/deploys/68e2d986cc985600081ffddd
😎 Deploy Preview	https://deploy-preview-11682--typescript-eslint.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 87 (🟢 up 9 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 your Netlify project configuration.

nx-cloud · 2025-10-05T20:49:41Z

View your CI Pipeline Execution ↗ for commit 3b98173

Command	Status	Duration	Result
`nx test eslint-plugin --coverage=false`	✅ Succeeded	5m 10s	View ↗
`nx run-many -t lint`	✅ Succeeded	3m 15s	View ↗
`nx run-many -t typecheck`	✅ Succeeded	2m 4s	View ↗
`nx test eslint-plugin-internal --coverage=false`	✅ Succeeded	5s	View ↗
`nx run types:build`	✅ Succeeded	5s	View ↗
`nx run integration-tests:test`	✅ Succeeded	3s	View ↗
`nx test typescript-estree --coverage=false`	✅ Succeeded	2s	View ↗
`nx run generate-configs`	✅ Succeeded	6s	View ↗
`Additional runs (29)`	✅ Succeeded	...	View ↗

☁️ Nx Cloud last updated this comment at 2025-10-05 20:59:43 UTC

ronami · 2025-10-05T20:53:48Z

packages/eslint-plugin/tests/rules/unbound-method.test.ts

-    'function foo({ unbound }: { unbound: () => void } = { unbound: () => {} }) {}',
+    `
+function foo(
+  { unbound }: { unbound: (this: void) => void } = { unbound: () => {} },


To my understanding, this previously valid test is in fact invalid without a this: void parameter type.

ronami · 2025-10-05T20:55:39Z

packages/eslint-plugin/tests/rules/unbound-method.test.ts

        {
          line: 5,
-          messageId: 'unbound',
+          messageId: 'unboundWithoutThisAnnotation',


This is interesting, it seems the rule iterates on union types and reports the first violation:

typescript-eslint/packages/eslint-plugin/src/rules/unbound-method.ts

Lines 263 to 275 in 7f5fed7

for (const intersectionPart of tsutils

.unionConstituents(services.getTypeAtLocation(node))

.flatMap(unionPart =>

tsutils.intersectionConstituents(unionPart),

)) {

const reported = checkIfMethodAndReport(

property.key,

intersectionPart.getProperty(property.key.name),

);

if (reported) {

break;

}

}

In this case, the union starts with { unbound: () => string }, with Foo being second. Currently, { unbound: () => string } doesn't report, which causes the report to come from Foo.

This PR made it so { unbound: () => string } does trigger a report, which changes the error message accordingly.

Somewhat related: #11683.

codecov · 2025-10-05T20:59:40Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.74%. Comparing base (cdd6384) to head (3b98173).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #11682   +/-   ##
=======================================
  Coverage   90.74%   90.74%           
=======================================
  Files         516      516           
  Lines       51989    51996    +7     
  Branches     8588     8591    +3     
=======================================
+ Hits        47176    47183    +7     
  Misses       4799     4799           
  Partials       14       14

Flag	Coverage Δ
unittest	`90.74% <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
packages/eslint-plugin/src/rules/unbound-method.ts	`99.10% <100.00%> (+0.02%)`	⬆️

... and 1 file with indirect coverage changes

🚀 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.

initial implementation

3b98173

ronami changed the title ~~feat(eslint-plugin): [unbound-method] Report property signatures with function types~~ feat(eslint-plugin): [unbound-method] report property signatures with function types Oct 5, 2025

ronami mentioned this pull request Oct 5, 2025

[unbound-method] Should prevent conforming to a bound-style interface method with an unbound method #3503

Open

3 tasks

ronami commented Oct 5, 2025

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

feat(eslint-plugin): [unbound-method] report property signatures with function types #11682

feat(eslint-plugin): [unbound-method] report property signatures with function types #11682

Uh oh!

ronami commented Oct 5, 2025 •

edited

Loading

Uh oh!

typescript-eslint bot commented Oct 5, 2025

Uh oh!

netlify bot commented Oct 5, 2025 •

edited

Loading

Uh oh!

nx-cloud bot commented Oct 5, 2025 •

edited

Loading

Uh oh!

ronami Oct 5, 2025

Uh oh!

ronami Oct 5, 2025 •

edited

Loading

Uh oh!

ronami Oct 5, 2025

Uh oh!

codecov bot commented Oct 5, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

	for (const intersectionPart of tsutils
	.unionConstituents(services.getTypeAtLocation(node))
	.flatMap(unionPart =>
	tsutils.intersectionConstituents(unionPart),
	)) {
	const reported = checkIfMethodAndReport(
	property.key,
	intersectionPart.getProperty(property.key.name),
	);
	if (reported) {
	break;
	}
	}

Uh oh!

feat(eslint-plugin): [unbound-method] report property signatures with function types #11682

Are you sure you want to change the base?

feat(eslint-plugin): [unbound-method] report property signatures with function types #11682

Uh oh!

Conversation

ronami commented Oct 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

PR Checklist

Overview

Uh oh!

typescript-eslint bot commented Oct 5, 2025

Uh oh!

netlify bot commented Oct 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

✅ Deploy Preview for typescript-eslint ready!

Uh oh!

nx-cloud bot commented Oct 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

ronami Oct 5, 2025

Choose a reason for hiding this comment

Uh oh!

ronami Oct 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

ronami Oct 5, 2025

Choose a reason for hiding this comment

Uh oh!

codecov bot commented Oct 5, 2025

Codecov Report

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

ronami commented Oct 5, 2025 •

edited

Loading

netlify bot commented Oct 5, 2025 •

edited

Loading

nx-cloud bot commented Oct 5, 2025 •

edited

Loading

ronami Oct 5, 2025 •

edited

Loading