Mixin function failed to compile when exported with --declaration

[vietthang]

TypeScript Version: 2.2.1

Code
Extract from official example:

// A *self-contained* demonstration of the problem follows...
export type Constructor<T> = new(...args: any[]) => T;

export function Tagged<T extends Constructor<{}>>(Base: T) {
  return class extends Base {
    _tag: string;
    constructor(...args: any[]) {
        super(...args);
        this._tag = "";
    }
  };
}

Expected behavior:
Code compiled fine.

Actual behavior:
This code fail to compile with --declaration options. The error is:

Return type of exported function has or is using private name '(Anonymous class)'.

It compiled fine without --declaration. Did I miss something?

[DanielRosenwasser]

Duplicate of #14209 and therefore #14075.