[compiler] Enable additional lints by default by josephsavona · Pull Request #33752 · facebook/react

josephsavona · 2025-07-10T05:11:13Z

Enable more validations to help catch bad patterns, but only in the linter. These rules are already enabled by default in the compiler if violations could produce unsafe output.

Stack created with Sapling. Best reviewed with ReviewStack.

) * Error for `eval()` * More specific error message for `with (expr) { ... }` syntax * More specific error message for class declarations --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33746). * #33752 * #33751 * #33750 * #33748 * #33747 * __->__ #33746

Supports inline enum declarations in both Flow and TS by treating the node as pass-through (enums can't capture values mutably). Related, this PR extends the set of type-related declarations that we ignore. Previously we threw a todo for things like DeclareClass or DeclareVariable, but these are type related and can simply be dropped just like we dropped TypeAlias. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33747). * #33753 * #33752 * #33751 * #33750 * #33748 * __->__ #33747

…atements (#33748) import, export, and TS namespace statements can only be used at the top-level of a module, which is enforced by parsers already. Here we add a backup validation of that. As of this PR, we now have only major statement type (class declarations) listed as a todo. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33748). * #33753 * #33752 * #33751 * #33750 * __->__ #33748

We use this variant for syntax we intentionally don't support: with statements, eval, and inline class declarations. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33750). * #33753 * #33752 * #33751 * __->__ #33750 * #33748

) * Error for `eval()` * More specific error message for `with (expr) { ... }` syntax * More specific error message for class declarations --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33746). * #33752 * #33751 * #33750 * #33748 * #33747 * __->__ #33746 DiffTrain build for [4a3ff8e](4a3ff8e)

We use this variant for syntax we intentionally don't support: with statements, eval, and inline class declarations. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33750). * #33753 * #33752 * #33751 * __->__ #33750 * #33748 DiffTrain build for [96c61b7](96c61b7)

react-sizebot · 2025-07-10T15:24:48Z

Comparing: 5020d48...1517c63

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.js	=	6.68 kB	6.68 kB	+0.05%	1.83 kB	1.83 kB
oss-stable/react-dom/cjs/react-dom-client.production.js	=	530.70 kB	530.70 kB	=	93.70 kB	93.70 kB
oss-experimental/react-dom/cjs/react-dom.production.js	=	6.69 kB	6.69 kB	=	1.83 kB	1.83 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js	=	655.25 kB	655.25 kB	=	115.40 kB	115.40 kB
facebook-www/ReactDOM-prod.classic.js	=	675.13 kB	675.13 kB	=	118.75 kB	118.75 kB
facebook-www/ReactDOM-prod.modern.js	=	665.56 kB	665.56 kB	=	117.11 kB	117.12 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 1517c63

josephsavona · 2025-07-11T23:16:23Z

I ran the latest linter against our internal codebase, Meta folks can check at P1867417094. This really just confirms that we're not seeing unexpected cases beyond what we anticipated in the test coverage.

mofeiZ · 2025-07-24T19:07:24Z

compiler/packages/eslint-plugin-react-compiler/src/rules/ReactCompilerRule.ts

    validateRefAccessDuringRender: false,
+    validateNoSetStateInRender: true,
+    validateNoSetStateInEffects: true,
+    validateNoJSXInTryStatements: true,


Makes sense, even for potentially valid code like the following, we can just direct devs to move the JSX creation out of the try statement

function Component(); try { const value = tryGetData(); return <Foo value={value} />; } catch { return <Fallback />; } }

Enable more validations to help catch bad patterns, but only in the linter. These rules are already enabled by default in the compiler _if_ violations could produce unsafe output.

--- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33753). * #33981 * #33777 * #33767 * #33765 * #33760 * #33759 * #33758 * #33751 * #33752 * __->__ #33753

Work in progress, i'm experimenting with revamping our diagnostic infra. Starting with a better format for representing errors, with an ability to point ot multiple locations, along with better printing of errors. Of course, Babel still controls the printing in the majority case so this still needs more work. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33751). * #33981 * #33777 * #33767 * #33765 * #33760 * #33759 * #33758 * __->__ #33751 * #33752 * #33753

Enable more validations to help catch bad patterns, but only in the linter. These rules are already enabled by default in the compiler _if_ violations could produce unsafe output. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/33752). * #33981 * #33777 * #33767 * #33765 * #33760 * #33759 * #33758 * #33751 * __->__ #33752 * #33753 DiffTrain build for [0d39496](0d39496)

facebook-github-bot added the CLA Signed label Jul 10, 2025

github-actions bot added the React Core Team Opened by a member of the React Core Team label Jul 10, 2025

josephsavona force-pushed the pr33752 branch from 924fd7e to 8812f26 Compare July 10, 2025 05:20

josephsavona mentioned this pull request Jul 10, 2025

[compiler] Validate against setState in all effect types #33753

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josephsavona force-pushed the pr33752 branch from 8812f26 to 20a38b8 Compare July 10, 2025 05:22

josephsavona force-pushed the pr33752 branch from 20a38b8 to 8ada325 Compare July 10, 2025 05:28

josephsavona force-pushed the pr33752 branch 2 times, most recently from 737dd9c to 7f64e97 Compare July 10, 2025 15:21

josephsavona force-pushed the pr33752 branch 2 times, most recently from ce0e8f7 to 6750584 Compare July 10, 2025 17:18

This was referenced Jul 10, 2025

[compiler] Improve more error messages #33758

Merged

[compiler] Update diagnostics for ValidatePreservedManualMemoization #33759

Merged

[compiler] Use new diagnostics for core inference errors #33760

Merged

[compiler] Cleanup diagnostic messages #33765

Merged

josephsavona mentioned this pull request Jul 12, 2025

[compiler] Use new diagnostic printing in playground #33767

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josephsavona mentioned this pull request Jul 12, 2025

[compiler][rfc] Enable more validations in playground. #33777

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josephsavona mentioned this pull request Jul 24, 2025

[compiler] Use diagnostic for "found suppression" error #33981

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mofeiZ reviewed Jul 24, 2025

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mofeiZ approved these changes Jul 24, 2025

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josephsavona added 2 commits July 24, 2025 14:43

[compiler] Validate against setState in all effect types

5fbe88a

[compiler] Enable additional lints by default

1517c63

Enable more validations to help catch bad patterns, but only in the linter. These rules are already enabled by default in the compiler _if_ violations could produce unsafe output.

josephsavona force-pushed the pr33752 branch from 6750584 to 1517c63 Compare July 24, 2025 21:50

josephsavona merged commit 0d39496 into main Jul 24, 2025
260 of 285 checks passed

nextjs-bot mentioned this pull request Jul 25, 2025

Upgrade React from 3d14fcf0-20250724 to 19baee81-20250725 vercel/next.js#82063

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[compiler] Enable additional lints by default#33752

[compiler] Enable additional lints by default#33752
josephsavona merged 2 commits intomainfrom
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