[Compiler Bug]: Compiler breaks JSX pragma handling for Oxc/SWC/TS

[swandir]

What kind of issue is this?

• React Compiler core (the JS output is incorrect, or your app works incorrectly after optimization)
• babel-plugin-react-compiler (build issue installing or using the Babel plugin)
• eslint-plugin-react-hooks (build issue installing or using the eslint plugin)
• react-compiler-healthcheck (build issue installing or using the healthcheck script)

Link to repro

https://stackblitz.com/edit/vitejs-vite-9eantx6h

Repro steps

React Compiler adds an import declaration to the top of the module, before leading comments.

React Compiler playground

While this works file with Babel's JSX transform (playground), other tools don't respect JSX pragma (e.g. @jsxImportSource) comments that come after any code statement, including imports.

Oxc playground

SWC playground

TypeScript playground

It's common to integrate React Compiler into a build process that handles JSX transform using Oxc/SWC. And current compiler's behavior prevents code with JSX pragmas from working in such a setup.

React Compiler should probably keep JSX pragmas and other leading comments/directives at the top.

How often does this bug happen?

Every time

What version of React are you using?

19.2.6

What version of React Compiler are you using?

1.0.0

[swandir]

Note: it seems that, despite what the playground shows, in an actual build pipeline babel-plugin-react-compiler adds a line break after the import declaration.

SWC then handles the pragma fine.

While Oxc and TypeScript don't.