Fix eslint-parser AST definition of AccessorProperty by jpradelle · Pull Request #18257 · babel/babel

jpradelle · 2026-09-28T15:06:54Z

Q	A
Fixed Issues?	Fixes #18230
Patch: Bug Fix?	Yes
Major: Breaking Change?	Fixes AccessorProperty quasis ranges to be consistent with PropertyDefinition, might break stuff made based on wrong values ?
Minor: New Feature?	No
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?	No
License	MIT

Fixes template quasis parsing for AccessorProperty. For example this was wrongly parsed:

class Test {
  accessor foo = html`
    <foo-baz icon="${' '}"></foo-baz>
  `;
}

See ticket #18230 for more details and samples.

github-actions · 2026-09-28T15:07:06Z

Thanks for opening this pull request! 🎉

We really appreciate you taking the time to contribute, @jpradelle.

A maintainer will take a look as soon as they can. In the meantime, please make sure that:

the description explains what changed and why
any related issues are linked
existing tests still pass

If anything needs adjusting we'll leave comments here. Thanks again!

babel-bot · 2026-09-28T15:09:09Z

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/62196

JLHwung · 2026-09-28T15:11:00Z

    // AST Types that are not presented in Babel AST
    const newTypes = {
+      AccessorProperty: ["decorators", "typeAnnotation"].concat(
+        ESLINT_VISITOR_KEYS.PropertyDefinition,


Suggested change

ESLINT_VISITOR_KEYS.PropertyDefinition,

ESLINT_VISITOR_KEYS.AccessorProperty,

There is no guarantee that the shape of these two AST types will always be exactly the same.

There is nothing in ESLINT_VISITOR_KEYS that looks like to be something for AccessorProperty.
I can replace with (which is the computed values of PropertyDefinition)

AccessorProperty: ["decorators", "typeAnnotation", "value", "key"],

I kept typeAnnotation copied from PropertyDefinition, but I'm not sure about the use, and I don't get why this was added here https://github.com/babel/babel/pull/13752/changes#diff-76e55da3b712c3967c9951e46430e7c52680d3de9baf60f803c742233b181b2dR16

decorators I found it in node when parsing this code

class T { @foo() accessor a; }

For the fix of this issue specifically, only this is needed.

AccessorProperty: ["value"],

I'm not completely sure of the impact of the rest.

I think we should go with at least

AccessorProperty: ["decorators", "value", "key"],

Fair enough. The accessor is still stage 2.7 so espree does not support this syntax. In that case the AccessorProperty basically follows what Babel defines ClassAccessorProperty, in that case we can just pull the visitor keys from types.VISITOR_KEYS.ClassAccessorProperty.

Update: never mind, the ClassAccessorProperty will not have value anyway. At this point I agree with you and we can just put AccessorProperty: ["decorators", "typeAnnotation", "value", "key"], here.

JLHwung · 2026-09-28T15:13:27Z

+      const ast = parseForESLint("class T { accessor a = `x${y}z`; }", {
+        eslintVisitorKeys: true,
+        eslintScopeManager: true,
+        babelOptions: BABEL_OPTIONS,
+      }).ast;
+
+      const accessor = ast.body[0].body.body[0];
+      expect(accessor.type).toBe("AccessorProperty");
+
+      const quasis = accessor.value.quasis;
+      expect(quasis.map(q => q.range)).toEqual([
+        [23, 27], // `x${
+        [28, 31], // }z`
+      ]);
+    });


Suggested change

const ast = parseForESLint("class T { accessor a = `x${y}z`; }", {

eslintVisitorKeys: true,

eslintScopeManager: true,

babelOptions: BABEL_OPTIONS,

}).ast;

const accessor = ast.body[0].body.body[0];

expect(accessor.type).toBe("AccessorProperty");

const quasis = accessor.value.quasis;

expect(quasis.map(q => q.range)).toEqual([

[23, 27], // `x${

[28, 31], // }z`

]);

});

parseAndAssertSame("class T { accessor a = `x${y}z`; }");

parseAndAssertSame would have caught the quasis mismatches.

Doing so throws an exception

Babel and Espree > templates > template element ranges inside accessor property #18230 SyntaxError: Unexpected token a at Espree.raise (/home/jpradelle/workspace/babel/node_modules/espree/dist/espree.cjs:892:6) at Espree.unexpected (/home/jpradelle/workspace/babel/node_modules/espree/dist/espree.cjs:942:10) at Espree.pp$9.semicolon (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:776:68) at Espree.pp$8.parseClassField (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:1680:10) at Espree.pp$8.parseClassElement (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:1612:12) at Espree.pp$8.parseClass (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:1528:26) at Espree.pp$8.parseStatement (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:989:19) at Espree.pp$8.parseTopLevel (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:856:23) at Espree.parseTopLevel (/home/jpradelle/workspace/babel/node_modules/espree/dist/espree.cjs:879:18) at Espree.parse (/home/jpradelle/workspace/babel/node_modules/acorn/dist/acorn.js:611:17)

accessor keyword is not parsed properly by Espree

I didn't commit this test I firstly used, that's more in the spirit of comparing things like that, but I didn't find it relevant

it("accessor property template ranges match property template ranges #18230", () => { const collectQuasiRanges = ast => { const ranges = []; const walk = node => { if (!node || typeof node !== "object") return; if (node.type === "TemplateElement") { ranges.push([node.range[0], node.range[1]]); } for (const key of Object.keys(node)) { const value = node[key]; if (Array.isArray(value)) { value.forEach(walk); } else if (value && typeof value === "object" && value.type) { walk(value); } } }; walk(ast); return ranges; }; const options = { eslintVisitorKeys: true, eslintScopeManager: true, babelOptions: BABEL_OPTIONS, }; const withAccessor = parseForESLint( `class Test { /**/accessor foo = \`\${' '}\`; }`, options, ).ast; const withoutAccessor = parseForESLint( `class Test { /*accessor*/ foo = \`\${' '}\`; }`, options, ).ast; expect(collectQuasiRanges(withAccessor)).toEqual( collectQuasiRanges(withoutAccessor), ); });

I am glad that you have not committed that test, which is too complex for merely AST comparision. Could you move the parseAndAssertSame test to the typescript-estree.test.js? I believe typescript-estree should support parsing accessor property very well.

Working as expected in typescript-estree.test.js, thanks 👍

pkg-pr-new · 2026-09-28T15:18:48Z

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commit: e5a6e70

JLHwung

Thanks.

nicolo-ribaudo

Thank you!

Fix eslint-parser AccessorProperty template parsing (babel#18230)

8e0c9fa

JLHwung reviewed Sep 28, 2026

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Fix for pull request babel#18257

e5a6e70

JLHwung approved these changes Sep 29, 2026

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nicolo-ribaudo added the PR: Bug Fix 🐛 A type of pull request used for our changelog categories label Sep 30, 2026

nicolo-ribaudo approved these changes Sep 30, 2026

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nicolo-ribaudo changed the title ~~Fix eslint-parser AccessorProperty template parsing (#18230)~~ Fix eslint-parser AST definition of AccessorProperty Sep 30, 2026

nicolo-ribaudo merged commit b6bb564 into babel:main Sep 30, 2026
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Fix eslint-parser AST definition of AccessorProperty - #18257

Fix eslint-parser AST definition of AccessorProperty#18257
nicolo-ribaudo merged 2 commits into
babel:mainfrom
jpradelle:18230

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	ESLINT_VISITOR_KEYS.PropertyDefinition,
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jpradelle commented Sep 28, 2026

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