Main.as

package
{
	import flash.display.*;

	public class Main extends Sprite implements MyTrait
	{
		public function Main()
		{
			addChild(this.q3());
		}
	}
}

MyTrait.as

package
{
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.DisplayObject;

	[Trait]
	public interface MyTrait
	{
		function q1(s : String, i : int, complexType : Bitmap) : void
		{
			trace("q1");
		}

		function q2(s : String) : void
		{
			throw new Error("q2!!!");
		}
		
		function q3 () : DisplayObject
		{
			return  new Bitmap(new BitmapData(100, 100, false, 0xFF0000));
		}
	}
}