effect-needs-cleanup false positive for React 19 callback ref cleanups

[simPod]

Summary

react-doctor@0.9.14 reports react-doctor/effect-needs-cleanup for a React 19 callback ref that returns its ResizeObserver cleanup.

Reproduction

import { useCallback } from 'react';

export const useContainerWidth = () => {
  const containerRef = useCallback((node: HTMLDivElement | null) => {
    if (node === null) {
      return;
    }

    const observer = new ResizeObserver(() => {});
    observer.observe(node);

    return () => observer.disconnect();
  }, []);

  return containerRef;
};

Actual result

React Doctor reports effect-needs-cleanup at observer.observe(node).

Expected result

No diagnostic. React 19 supports callback refs that return a cleanup function. React calls that cleanup when the referenced element detaches.

The callback's null branch owns no observer. Returning void there is valid according to the React ref callback type, which permits void | (() => void).

Environment

• react-doctor: 0.9.14
• react: 19.3.0
• TypeScript

[react-doctor-evals]

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