With this code sample:

import 'package:flutter/material.dart';

void main() => runApp(const MaterialApp(home: Home()));

class Home extends StatefulWidget {
  const Home({super.key});

  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {
  @override
  Widget build(BuildContext context) {
    return const Scaffold();
  }
}

Place the cursor under either Home or _HomeState and with the quick-fix to "Move [it] to file" move it to a new file say a.dart.

After that, place the cursor in the second class and do the same (same file). It will (currently) tell you that the file already exists and ask if you want to replace it. After pressing "yes", it does nothing.

logs.zip