title: Type Script decorator error TS1241: Unable to resolve signature of method decorator when called as an expression
body: <p>i'm learning the decorator in the javascript. I use the typescrip for compile
  Below is the code :</p>
  
  <pre><code>class Greeter {
      greeting: string;
      constructor(message: string) {
          this.greeting = message;
      }
  
      @enumerable(false)
      greet() {
          return "Hello, " + this.greeting;
      }
  }
  
  
  function enumerable(value: boolean) {
      return 
      function(target:any,propertyKey:string,descriptor:PropertyDescriptor) {
      descriptor.enumerable = value;
      };
  }
  </code></pre>
  
  <p>Actually the code is from <a href="http://www.typescriptlang.org/docs/handbook/decorators.html" rel="nofollow noreferrer">http://www.typescriptlang.org/docs/handbook/decorators.html</a>
  When use tsc to compile the file , below error occurred:</p>
  
  <p><strong>first.ts:39:5 - error TS1241: Unable to resolve signature of method decorator when called as an expression.
  39     @enumerable(false)</strong>
  What should I do for this issue</p>