我在Select接口中定义了一个新的签名。签名告诉TypeScript类型检查对象是否具有该函数接口的键。

import { Knex, knex } from "knex"

type AnyToUnknown<T> = unknown extends T ? unknown : T;

type ArrayIfAlready<T1, T2> = AnyToUnknown<T1> extends any[] ? T2[] : T2;

declare module 'knex/types/index' {
  export namespace Knex {
    interface Select<TRecord extends {} = any, TResult = unknown[]>
      extends Knex.AliasQueryBuilder<TRecord, TResult>,
      Knex.ColumnNameQueryBuilder<TRecord, TResult> {

      <
        TResult2 = ArrayIfAlready<TResult, any>,
      >(
        obj: { [K in keyof TResult2]: string }
      ): Knex.QueryBuilder<TRecord, TResult2>;
    }
  }
}

export interface User {
  id: number;
  name: string;
  age: number;
}

const db = knex({});

const users = await db('user').select<User>({ id: 'id', name: 'id' });  // TypeScript should throw error: age is missing.
//   ^? let users: User
const users2 = await db('user').select<User>({}).first();  // TypeScript should throw error here: id, name, age is missing.
//   ^? let users: User | undefined

TypeScript应该会在这些例子中抛出错误，因为我传递给select函数的对象没有User接口的所有键。
为什么会这样？我的输入中缺少了什么？
如果我更改为以下代码，它就可以工作：

...
      <
        TResult2 = ArrayIfAlready<TResult, any>,
      >(
        obj: boolean
      ): Knex.QueryBuilder<TRecord, TResult2>;
....
const users2 = await db('user').select<User>(true).first();  // accept boolean, without it typescript throw error.

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