[Types] "new generic({ properties })" does not work anymore since 5.13.4

[hasezoey]

Do you want to request a feature or report a bug?
types / bug

What is the current behavior?
since 5.13.4 new genericModel({ properties }) does not work anymore when in an generic context (even if restricted to extend from a class with the properties)

Re: #10475
Commit introducing the issue: 060039d

If the current behavior is a bug, please provide the steps to reproduce.

// NodeJS: 16.6.0
// MongoDB: 4.2-bionic (Docker)
import * as mongoose from "mongoose"; // [email protected]

// when the "AnyKeys" in mongoose is replaced with this, it works
// type AnyKeys<T> = { [P in keyof T]?: T[P] | any };

class Testy {
  public prop1!: string;
  public prop2?: string;
}

// the following 2 functions should be the same in types, so they both have the error
function test1<U extends typeof Testy>(arg1: mongoose.Model<mongoose.Document & InstanceType<U>>) {
  const t = new arg1({ prop2: "hello" }); // error here
}
function test2<U extends Testy>(arg1: mongoose.Model<mongoose.Document & U>) {
  const t = new arg1({ prop2: "hello" }); // error here
}

// working, both of these blocks should be equal in types
const sch = new mongoose.Schema({ prop1: String, prop2: String });
sch.loadClass(Testy);
{
  const model: mongoose.Model<mongoose.Document<any, any> & InstanceType<typeof Testy>> = mongoose.model("testy1", sch);

  const t = new model({ prop2: "hello" });
}
{
  const model: mongoose.Model<mongoose.Document<any, any> & Testy> = mongoose.model("testy2", sch);

  const t = new model({ prop2: "hello" });
}

Note: the new AnyKeys type is basically like the one existing already, but removed the need for Partial, because it directly integrates ?, and the | undefined part (from Partial) should not be needed anymore, because it already has | any

Error (for both mentioned times):

Argument of type '{ prop2: string; }' is not assignable to parameter of type 'Partial<{ [P in keyof (Document<any, any, any> & InstanceType<U>)]: any; }> & AnyObject'.
  Type '{ prop2: string; }' is not assignable to type 'Partial<{ [P in keyof (Document<any, any, any> & InstanceType<U>)]: any; }>'.ts(2345)

tsconfig:

{
    "compileOnSave": true,
    "typeAcquisition": {
        "enable": true
    },
    "compilerOptions": {
        "experimentalDecorators": true,
        "emitDecoratorMetadata": true,
        "declarationMap": true,
        "outDir": "lib",
        "moduleResolution": "node",
        "target": "es6",
        "module": "commonjs",
        "newLine": "LF",
        "sourceMap": true,
        "removeComments": true,
        "strict": true,
        "allowUnreachableCode": false,
        "pretty": true,
        "declaration": true,
        "incremental": true,
        "tsBuildInfoFile": ".tsbuildinfo",
        "lib": [
            "esnext"
        ]
    },
    "include": [
        "src/**/*"
    ]
}

Reproduction Repository & branch: https://github.com/typegoose/typegoose-testing/tree/mongooseNewIssue
Reproduction File: https://github.com/typegoose/typegoose-testing/blob/mongooseNewIssue/src/test.ts

What is the expected behavior?
to not give an error

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
mongoose 5.13.4 / 5.13.5

---

PS: because this took some time to find out and sometimes the types were too complex, #10525 came from it

[vkarpov15]

Thanks for finding this - apparently { [P in keyof T]?: T[P] | any } is different from Partial<{ [P in keyof T]: T[P] | any }>, although I haven't been able to figure out why. The below also fails:

  type __Partial<T> = {
    [P in keyof T]?: T[P];
  };
  type AnyKeys<T> = __Partial<{ [P in keyof T]: any }>;

So it doesn't look like an issue with Partial<> (https://www.typescriptlang.org/docs/handbook/advanced-types.html), maybe just a quirk with TypeScript not being able to handle nested definitions using [P in keyof T]?

Either way, your suggestion works so we'll use it 👍