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jsx: react-jsxdev passes this to jsxDEV before super() returns #65415
Description
🔎 Search Terms
react-jsxdev super this, jsxDEV self before super, Must call super constructor jsx
🕗 Version & Regression Information
Not a regression; jsx: react-jsx is correct.
- Fails: 6.0.3, 7.0.2, 7.1.0-dev.20261107.1, 7.1.0-dev.20261109.1
⏯ Playground Link
(Playground v2, 6.0.3; press Run. The project uses a six-line local jsx-dev-runtime with React's jsxDEV signature, so no packages are needed.)
💻 Code
/** @jsxImportSource ./rt */
class Base { constructor(public content: { type: unknown }) {} }
class Card extends Base {
constructor(title: string) {
super(<h2>{title}</h2>);
}
}
console.log(new Card("Hello").content.type);🙁 Actual behavior
The emit passes this as the self argument of _jsxDEV(...) inside the super(...) arguments, so the constructor throws ReferenceError: Must call super constructor in derived class before accessing 'this'. There is no compile error, and jsx: react-jsx works.
🙂 Expected behavior
h2 is printed: pass undefined for self when this is not yet available (before super() in a derived constructor), as Babel and esbuild do for the same case.
This was found with an AI-assisted differential testing tool; the repros and outputs above were re-run on the listed versions.
Activity
yamaankhan20 commentedon Nov 13, 2026
Hi, I'd like to work on this issue. I'll investigate how the JSX transformer emits the self argument for jsxDEV inside super() calls, and add regression tests alongside the fix.