Static method on abstract class with generic this parameter causes "excessively deep" error when called on concrete class

🔎 Search Terms

• abstract class
• static method
• this parameter
• excessively deep
• concrete class
• generic

🕗 Version & Regression Information

This is broken in 5.6, 5.7, and nightly at least.

⏯ Playground Link

https://www.typescriptlang.org/play/?target=99&ts=5.8.0-dev.20250117&ssl=6&ssc=12&pln=6&pc=15#code/IYIwzgLgTsDGEAJYBthjAgguacIGFV0AeAEQD4EBvAKAXoQHMBTRAE2AmAAoBKALgSlqdBmKisArlAB21AL4I0CSTIDWMgPYB3OctKj68moYSROAS1gIAHgE8AXsQAqCZjYjMZbDBDsAHZk0AMywcGHhCNDBiYBk7cnJuUzEIAAsLMEFnABoUhg4ubLcPLx8EP0CQsMgIgiIYixlg5ighSgB+IQRBGWYAN1bTXgUaYxoUaIR8TRlYCU8o9BLPbwxsWrwlmNqmxkpaMZMZuYXmbYA6ewduAEYAJgBmXiA

💻 Code

abstract class AbstractClass<D> {
    get data(): D {
        return {} as unknown as D
    }

    static xyz<T extends typeof AbstractClass<any>>(
        this: T,
        data: T extends typeof AbstractClass<infer D> ? D : never
    ) {}
}

class ConcreteClass extends AbstractClass<string> {

}

ConcreteClass.xyz(123)

🙁 Actual behavior

The ConcreteClass.xyz results in Type instantiation is excessively deep and possibly infinite. and as a result infers D as never.

🙂 Expected behavior

This to work fine. A similar case, but where InstanceType<T> extends AbstractClass<infer D> ? D : never works fine: https://www.typescriptlang.org/play/?target=99&ts=5.8.0-dev.20250117#code/IYIwzgLgTsDGEAJYBthjAgguacIGFV0AeAEQD4EBvAKAXoQHMBTRAE2AmAAoBKALgSlqdBmKisArlAB21AL4I0CSTIDWMgPYB3OctKj68moYSROAS1gIAHgE8AXsQAqCZjYjMZbDBDsAHZk0AMywcGHhCNDBiYBk7cnJuUzEIAAsLMEFnABoUhg4uQQBJGXMZWGZnAOYXSndPbwxsSAiCIhiLGWDmKCFKAH4hBEEZZgA3XtNeBRpjGhRohHxNColPKPQ3Dy8fMNa8TZjWrsZKWjmTFbXWZiOAOnsHbgBGACYAZl4gA

Additional information about the issue

No response

まず、提供された TypeScript Playground の再現例を実行し、動作する InstanceType バリアントと比較します。コンパイラーが static this パラメーターと条件型の推論をどのように処理するかを追跡します。ConcreteClass.xyz が過度に深いインスタンス化エラーを報告せず、意図した型を推論できれば完了です。