How to give `BotType` to the scene?

[mirismaili]

const greetingScene = new Scene('greeting').step('message', (context) => {
  // Here `context` type, isn't aware of `bot.derive`s, etc.
})

[mirismaili]

I wrote this utility:

type ExtendSceneContext<T extends AnyScene> =
  T extends Scene<infer P, infer E, infer S, infer SceneDerives>
    ? BotType extends Bot<any, infer BotDerives>
      ? Scene<P, E, S, SceneDerives & BotDerives>
      : never
    : never

Where BotType is type of my bot:

const bot = new Bot().derive(...)
type BotType = typeof bot

And then I used it this way:

const greetingScene = new Scene('greeting')

const scene = greetingScene as ExtendSceneContext<typeof greetingScene>

scene.step('message', async (ctx) => {
  // `ctx` is aware of `BotType` here
})