我有一个代码片段，以前是在TypeScript 4.6中编译的，但从TypeScript 4.7（4.7，4.8，4.9）开始编译失败。如果有问题的语句不是return语句，或者lambda函数只有一个参数，而不是两个参数，那么问题就解决了。
Playground链接

import { EventEmitter } from 'node:events';

// Simplified from discord.js https://github.com/discordjs/discord.js licence Apache 2.0
interface ClientEvents {
  warn: [message: string];
  shardDisconnect: [closeEvent: CloseEvent, shardId: number];
}

class BaseClient extends EventEmitter {
  public constructor() {
    super();
  };
}

type Awaitable<T> = PromiseLike<T> | T;

declare class Client extends BaseClient {
  public on<K extends keyof ClientEvents>(event: K, listener: (...args: ClientEvents[K]) => Awaitable<void>): this;
  public on<S extends string | symbol>(
    event: Exclude<S, keyof ClientEvents>,
    listener: (...args: any[]) => Awaitable<void>,
  ): this;
}

// Demonstrative code
const bot = new Client();
// Return statement. Fails to compile, thinks that event is a union type of all first arguments (string | CloseEvent), but hovering over `event` shows just CloseEvent.
bot.on("shardDisconnect", (event, shard) => console.log(`Shard ${shard} disconnected (${event.code},${event.wasClean}): ${event.reason}`));
// Not a return statement. Compiles.
bot.on("shardDisconnect", (event, shard) => {
  console.log(`Shard ${shard} disconnected (${event.code},${event.wasClean}): ${event.reason}`);
});
// Return statement. Compiles.
bot.on("shardDisconnect", event => console.log(`${event.code} ${event.wasClean} ${event.reason}`))