Problem with declaration file generated from generic extended function

[nayish]

I have code like so:

export class A<T> {
	//
}
export type Constructor<T> = new (...args: any[]) => T;

export function foo<T extends Constructor<{}>>(Base: T): T & Constructor<{}> {
	return class extends Base {};
}

export class B<T> extends foo<Constructor<A<T>>>(A) {}

(This is an over simplified version of real code just to show the problem)

The generated .d.ts file does not compile

export declare class A<T> {}

export declare type Constructor<T> = new (...args: any[]) => T;

export declare function foo<T extends Constructor<{}>>(Base: T): T & Constructor<{}>;

declare const B_base: Constructor<A<T>> & Constructor<{}>;

export declare class B<T> extends B_base {}

As you can see the extending function is compiled to a const B_Base and since consts can not be generic this line throws an error when using the definition file.

[weswigham]

This is now an error, as per #17922