title: Instatinating interface based object
body: <p>Having such a simple code:</p>
  <pre><code>interface int1 {
      aa: string,
      bb: number,
  }
  
  const obj1:int1 = {}  //#1
  
  function fun(param_obj:int1) {  //#2
  }
  </code></pre>
  <p>My question is why does the <em>compiler</em> shouts an error:</p>
  <p><code>Type '{}' is missing the following properties from type 'int1': aa, bb</code></p>
  <p>on line <em>#1</em> an does NOT show an error on line <em>#2</em> since on both lines the new object is being created?</p>