insertMany return type incompatible with document type

[ksyd9821]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the bug has not already been reported

Mongoose version

7.6.3

Node.js version

18.x

MongoDB server version

6.x

Typescript version (if applicable)

5.2.2

Description

This is the same issue previously reported in #13957 I have included the code that reproduces it below. Basically with the code below

import * as mongoose from "mongoose";

export class RepositoryBase<T> {
    protected model: mongoose.Model<T & mongoose.Document>;

    constructor(schemaModel: mongoose.Model<T & mongoose.Document>) {
        this.model = schemaModel;
    }

    async insertMany(elems: T[]): Promise<T[]> {
        elems = await this.model.insertMany(elems);
        return elems;
    }
}

the assignment inside the insertMany function generates the following error

Steps to Reproduce

https://github.com/ksyd9821/mongoose-insert-many-issue

Expected Behavior

No response

### Tasks

[vkarpov15]

Just remove the & Document and this script compiles fine:

import * as mongoose from "mongoose";

export class RepositoryBase<T> {
    protected model: mongoose.Model<T>;

    constructor(schemaModel: mongoose.Model<T>) {
        this.model = schemaModel;
    }

    async insertMany(elems: T[]): Promise<T[]> {
        elems = await this.model.insertMany(elems);
        return elems;
    }
}

As of Mongoose 7, we no longer support using extends Document in the DocType generic param to Model<>, and we recommend using the raw doc type instead. So don't use & Document.

[hardcodet]

Hi @vkarpov15

Just stumbled over this one. Is it possible that there is an overload missing here (we're on 8.0.0. currently)? Your snippet works, but not, if I provide an options object. See the inferred types in the screenshot here - bar here doesn't properly cast to T[], while foo works.

Let me know if you'd prefer a new issue. (I also don't know if you'll read this, since it's already closed, so I might open a new issue in a few days anyway).