package tests { public class TestDeclarationInterface { public function run(): MyIFace { var i:MyIFace = null; var n:int = 2; switch(n) { case 0: i = new MyClass(); break; case 1: i = new MyClass2(); break; } return i; } } } interface MyIFace { } class MyClass implements MyIFace { } class MyClass2 implements MyIFace { }