Bug: set-state-in-use-effect false negative when there are multiple instances

[roryabraham]

This code correctly produces a lint error:

function MyComponent() {
    const [loading, setLoading] = useState(false);
    useEffect(() => {
        setLoading(true);  // ✅ ESLint correctly flags this (1 error)
    }, []);
    // commented out code...
    return null;
}

But this code does not:

function MyComponent() {
    const [loading, setLoading] = useState(false);
    useEffect(() => {
        setLoading(true);  // ❌ BUG: Error no longer reported (should still be flagged!)
    }, []);
    const [firstName, setFirstName] = useState<string>('');
    const [lastName, setLastName] = useState<string>('');
    const [fullName, setFullName] = useState<string>('');
    useEffect(() => {
        setFullName(`${firstName} ${lastName}`);  // ❌ BUG: Also not reported
    }, [firstName, lastName]);
    return null;
}

React version: ^19.2.1

Steps To Reproduce

Created a minimal reproduction repo: https://github.com/roryabraham/set-state-in-effect-bug

The current behavior

In the second code snippet provided, no lint errors are thrown.

The expected behavior

Lint errors should be thrown for both setState calls in useEffect callbacks.