TypeScript:指定导出静态部分的接口class?

TypeScript: Specify the interface of the static part of an export class?

我尝试使用手册“Difference between static/instance side of class”部分下的技巧为 class:

的静态端(即函数)指定接口
export interface StaticInterface {
    info: string;
}
class _X {
    static info = 'something';
    ...
}
export var X: StaticInterface = _X;

但是当我试图在另一个文件中 extend theModule.X 时,编译器说:

error TS2305: Module '"..."' has no exported member 'X'.

这是一个基于 TypeScript 手册的工作示例:

module Example {
    export interface ClockStatic {
        new (hour: number, minute: number);
    }

    class Clock {
        currentTime: Date;
        constructor(h: number, m: number) { }
    }

    export var cs: ClockStatic = Clock;
}

var newClock = new Example.cs(7, 30);

导出接口很重要,class 正确实现接口。