AngularJS/TypeScript由于服务导致模块实例化失败

I have a service:

我有一个服务:

module app {
    export interface ISomeService {
        doSomething(): string;
    }

    export class SomeService implements ISomeService {
        doSomething() {
            return "haaay.";
        };
    }

    angular.module('app').service('someService', SomeService);
}
module app {