问类型X是2个模块声明的一部分(Angular 2 RC5)

EN

import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { Routes, RouterModule }  from '@angular/router';
import { WelcomeModule } from './welcome/welcome.module';
import { AppComponent }  from './app.component';
import { 
    routing, 
    appRoutingProviders 
} from './app.routing';

@NgModule({
  imports:      [ 
  BrowserModule, 
  RouterModule, 
  WelcomeModule,
  routing
  ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ],
  providers:    [ appRoutingProviders ]
})
export class AppModule { }

import { 
    Routes,
    RouterModule 
} from '@angular/router';

import { welcomeRoutes } from './welcome/welcome.routing';

const appRoutes: Routes = [
     ...welcomeRoutes
];

export const appRoutingProviders: any[] = [];
export const routing = RouterModule.forRoot(appRoutes);

import { NgModule } from '@angular/core';

import { WelcomeComponent } from './welcome.component';

@NgModule({
    declarations: [ WelcomeComponent ]
})
export class WelcomeModule { }

import { 
    Routes,
    RouterModule 
} from '@angular/router';

import { WelcomeComponent } from './welcome.component';

export const welcomeRoutes: Routes = [
    { path: 'welcome', component: WelcomeComponent }
];

export const welcomeRoutingProviders: any[] = [];
export const welcomeRouting = RouterModule.forChild(welcomeRoutes);

import { WelcomeModule } from './welcome/welcome.module'