anchor.diff:          let airship = ecs.RegisterJunctioned airshipSystem.Name Unchecked.defaultof<Airship> Gen.id
   
           // invoke update behavior
  -        let world = ecs.Publish EcsEvents.Update () ecs.GlobalSystem world
  -
  -        // fin
  -        world+        ecs.Publish EcsEvents.Update () ecs.GlobalSystem world
positive.code:         let airshipSystem = ecs.RegisterSystem (SystemJunctioned<Airship, World> ())
  
          // define our airship system's update behavior
          let subId = ecs.Subscribe EcsEvents.Update (fun _ _ _ world ->
              for i = 0 to airshipSystem.Components.Length - 1 do
                  let comp = &airshipSystem.Components.[i]
                  comp.Transform.Value.Enabled <- i % 2 = 0
  
negative.code: open Nu
  module EcsTests =
  
      type [<NoEquality; NoComparison; Struct>] Skin =
          { mutable RefCount : int
            mutable Color : Vector4 }
          interface Component with
  