[Compiler Bug]: Recursive functions seem to confuse the compiler

[snowystinger]

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-compiler (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/#N4Igzg9grgTgxgUxALhAHQHYDMobgFwEsIMACAFUIFsEYAhAQzAQBMBhCKgBxIQ3wAUXGBC5gAlKWCZSpOCTD5SMBFwQN8AUQBufJQF5SUZpqxYEBHXoEDJ+gHxSZs0sNFgAdCQBKq9YPEAbmdZZnxKGmhBW1IHJzIXWRU1DSt+W2CE2QBfABpSADYABiDnbNKMZwAbBCUAbRYIAHcMfLCAEWaMAF1Yo2YAZXwNBAEsBirmCtljBFNzAhs7R2ks0kIsUgFGlslVxNkAekPSRQYYJWT-MFIGLHxaUhYEKoYATxCXMIiEKKXYlbKPypXTpSR5UgARiKMPEn2yZQqzhU+FgZAEnwAPCxCNpSCQALLQZidFr6YAxOIdLoCfAwKAIcTZUiHezOCoIjAgXIgeTYQgAcxQIGoPAupHwbzUUlIAAUqlABYQMAB5LhEBSkZlYERUUgAcgARgxDS8ALRcBVKjBmlQMAhm+TcQg1GCHHGKfWZTACfYsw5OrgujTEDBE57IUhoEATKrRzDMsAhsBYQgIG7yxXKtUajASQLc8AAC2aAEl+LQMBMwChxpMENkgA

Repro steps

Open the repro link, the error will be on the side

Found 1 error:

Error: Cannot access variable before it is declared

repeatEvent is accessed before it is declared, which prevents the earlier access from updating when this value changes over time.

4 | props.onRepeat();
5 | setTimeout(() => {

6 | repeatEvent();
| ^^^^^^^^^^^ repeatEvent accessed before it is declared
7 | }, 60);
8 | });
9 |

1 |
2 | function TimerBasedComponent(props) {

3 | const repeatEvent = useEffectEvent(() => {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
4 | props.onRepeat();
| ^^^^^^^^^^^^^^^^^^^^^
5 | setTimeout(() => {
| ^^^^^^^^^^^^^^^^^^^^^
6 | repeatEvent();
| ^^^^^^^^^^^^^^^^^^^^^
7 | }, 60);
| ^^^^^^^^^^^^^^^^^^^^^
8 | });
| ^^^^^^ repeatEvent is declared here
9 |
10 | let [down, setDown] = useState(false);
11 | useEffect(() => {

How often does this bug happen?

Every time

What version of React are you using?

19.2

What version of React Compiler are you using?

7.0.0