React报错Function components cannot have string refs

// App.js
export default function App() {
  // A string ref has been found within a strict mode tree.
  // ⛔️ Function components cannot have string refs.
  // We recommend using useRef() instead.
  return (
    <div>
      <input type="text" id="message" ref="msg" />
    </div>
  );
}

// App.js
import {useEffect, useRef} from 'react';
export default function App() {
  const refContainer = useRef(null);
  useEffect(() => {
    // 👇️ this is reference to input element
    console.log(refContainer.current);
    refContainer.current.focus();
  }, []);
  return (
    <div>
      <input type="text" id="message" ref={refContainer} />
    </div>
  );
}

// App.js
import {useEffect, useRef} from 'react';
export default function App() {
  const refContainer = useRef(null);
  const refCounter = useRef(0);
  useEffect(() => {
    // 👇️ this is reference to input element
    console.log(refContainer.current);
    refContainer.current.focus();
    // 👇️ incrementing ref value does not cause re-render
    refCounter.current += 1;
    console.log(refCounter.current);
  }, []);
  return (
    <div>
      <input type="text" id="message" ref={refContainer} />
    </div>
  );
}