title: Rust: How do you pass an Option<trait> as a function parameter?
body: <p>I keep getting "Sized is not implemented". How do I get wp into the function foo? I thought boxing would give it a size, but I get the same error with or without it.</p>
  
  <pre><code>fn main() {
      let wp : Option&lt;Waypoint&gt;= new(45.1968, -75.1968);
      foo(box wp);
  }
  
  fn foo(wp: Box&lt;Option&lt;Coord&gt;&gt;) {
      println!("lat: {}, lon:{}", wp.lat(), wp.lon());
  }
  </code></pre>
  
  <p><a href="http://is.gd/sNTnk1" rel="nofollow">full code</a></p>