Cannot compile @Injectable in angular 6

Question

recently I upgraded to:

• angular-cli 6.0.7
• angular 6.0.3

I have generated a new project and wanted to use the new Injectable decorator. When decorating a class:

  @Injectable({
      providedIn: 'root'
   })
   export class SomeService {
       constructor() { }
   }

I get following compile error:

Argument type {providedIn: "root"} is not assignable to parameter type {providedIn: Type | "root" | null} & InjectableProvider Checks TypeScript called function parameters , return values , assigned expressions to be of correct type.

When I write the class like:

 @Injectable
 export class SomeService {
    constructor() { }
 }

I get a runtime error with the same message.

Any ideas?