Classes static generic function return any type.

[lengyuxuan]

🔎 Search Terms

• Generics
• Scope

🕗 Version & Regression Information

• This is a crash
• This changed between versions 3.3.3 and nightly

⏯ Playground Link

https://www.typescriptlang.org/play?#code/MYGwhgzhAECyD2ATApiaBvAUNH0AOArgEYgCWw0EALmFedAGakB2iAQgJ4AKA1gDyxoyAB5VkrGAhQgAfAApSiAFyUqAJxYBzAJQrBAH2jMCINFlwXoa5FQJrmGbJecB6F9AB0Xj0+cBfaEg4AG5faD9MCMxQSBgAQSFRcURJJFRHC0UVag1mTVCLZhEqAEllVVzNaENjUwLcYHhmHIJgKng1OW0M50oCPGRO7XrnKgALUggPRWgAXmgAcmFlhZHLccmPItEyucWOA9WwiKjG5qpAvaKAd2g4rtCQG2hgO2tmUvKcrWqjEzR5mBpohQtcJk9oHJXmp3p9uuZcG5oAB1MYcaCTRZgZgcBYAfjCZ2oRjSeziHiYrE4vD4cXk0NhZWGYVIDEhAEJmGl4WELERrGAeGsIhYGeJPlc0ltimU1kjUeJoCVoNcNGJFmKPrt5lyUNKdohAjBvnkFtBxrQFjANJoxhdIpggA

💻 Code

class Model {
    public static findByPk<M extends Model>(id: string): M | null {
        return {
            // ....
        } as M;
    }
}

class A extends Model {
    id: string;
    nextId: string | null;
    constructor() {
        super();
        this.id = 'xxx';
        this.nextId = 'yyy';
    }
}

const a = new A();
let currentId: string | null = a.id;
while (currentId) {
    // Why is 'any'?
    const node = A.findByPk<A>(currentId);
    if (!node) {
        break;
    }
    currentId = node.nextId;
    // When I write 'currentId = node.nextId as string' that's right 
}

🙁 Actual behavior

Classes static generic function return any type.

🙂 Expected behavior

Classes static generic function return Model type.

Additional information about the issue

No response

[MartinJohns]

This is a crash.
This changed between versions 3.3.3 and nightly

This is neither a crash (means the compiler process crashes and can't produce a result, an error being a valid result) and it didn't change between version 3.3.3 and nightly (a comically large version range).

// Why is 'any'?

The error message tells you why it's any:

'node' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.

If you search for this error you will find many issues, e.g. this one: #43047 (comment)

[typescript-bot]

This issue has been marked as "Question" and has seen no recent activity. It has been automatically closed for house-keeping purposes.