title: Angular Injectable decorator - Expected 0 arguments but got 1
body: <p>I am just getting started with the base tutorial for Angular but I face a small compilation issue.</p>
  
  <p>I am following the tutorial on Angular's website. I am stuck with the dependency injection part because it doesn't want to compile.</p>
  
  <p>In the tutorial they ask to create a service with :</p>
  
  <pre><code>ng generate service hero
  </code></pre>
  
  <p>In this generated service you have a decorator like this :</p>
  
  <pre><code>@Injectable()
  </code></pre>
  
  <p>Then they ask to add a parameter to that decorator like this :</p>
  
  <pre><code>@Injectable({
    providedIn: 'root'
  })
  </code></pre>
  
  <p>When I try to do so I have a TypeScript error telling me :</p>
  
  <blockquote>
    <p>error TS2554: Expected 0 arguments, but got 1.
    The versions I use are those ones :</p>
  </blockquote>
  
  <pre><code>Angular CLI: 1.7.4
  Node: 9.5.0
  OS: win32 x64
  Angular: 5.2.10
  ... animations, common, compiler, compiler-cli, core, forms
  ... http, language-service, platform-browser
  ... platform-browser-dynamic, router
  
  @angular/cli: 1.7.4
  @angular-devkit/build-optimizer: 0.3.2
  @angular-devkit/core: 0.3.2
  @angular-devkit/schematics: 0.3.2
  @ngtools/json-schema: 1.2.0
  @ngtools/webpack: 1.10.2
  @schematics/angular: 0.3.2
  @schematics/package-update: 0.3.2
  typescript: 2.5.3
  webpack: 3.11.0
  </code></pre>
  
  <p>Any idea why it doesn't accept the parameter ?</p>
  
  <p>Thanks in advance !</p>