react / react/react

React Compiler generates erroneous code when an app contains a component named `Symbol`

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#35,379 5 comments 1 reaction 0 assignees View on GitHub

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Status: Unconfirmed Type: Bug
Dominant language
JavaScript
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Description

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://playground.react.dev/#N4Igzg9grgTgxgUxALhAejQAgMIwQQwBcFN9M4IBbABwgDsE7DM79KEATTAZQE9KARhAA2AHToAzKHTiEAlvR78hwgBQBKTMHGZMeQrDqYAPBzkA3AHwBJUpVJLBI8lVoMmxtGasBucQF9xcQxMAFUwEjlmOSMAQWpqcQQAD1oYZg4ECXwoYWYpGXlFeOoNLR09BAMYI1UK3VMLS3rdEwALAEZLACUCWRxXOWEEGEwAISgAc0xe6hgIDihZBTpPTuajVoa+J2FMNA2tz29DzHU-On8QABoQCkk5SZQQORoIdMxCXmoSYEwABWEUxiAHlqEU6GBMP5MBJ5vYAOQCfACBDCAC01CBkxi6Lw+Fk6IoNCGIy8cjAhARF3Eqm0mwwxOoQyIKwAsgsEMhMKIQPhhGIQAFMGBWWAJHIEFDAcC6GCIWBzjdwG0IAB3axMEasYRgFDZXUIfxAA

Repro steps
  1. Configure a React app to run React Compiler.
  2. Create a component named Symbol.
  3. Run the app.

The issue relates to the fact that React Compiler generates output with a call to Symbol.for. As shown in the playground link, if a component is in scope with the name Symbol, the compiler-generated code tries to call the for method on the React component rather than globalThis.Symbol. This results in the runtime error "Symbol.for is not a function".

How often does this bug happen?

Every time

What version of React are you using?

19.2.3

What version of React Compiler are you using?

1.0.0

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the linked React Playground repro and inspect the React Compiler-generated JavaScript for the component named Symbol. Confirm the runtime failure, then trace the compiler entry point that emits the Symbol.for call; done means the same repro runs without the "Symbol.for is not a function" error.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
compilers, frontend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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