anchor.diff:                      match stream with
                       | :? StreamPluggable as stream ->
                           let world =
  -                            Stream.monitor (fun evt world ->
  -                                match (evt.Data : Expr option) with
  +                            Stream.monitor (fun (evt : Event<Expr option, _>) world ->
  +                                match evt.Data with
                                   | Some expr ->
                                       match World.tryGetSimulantProperty propertyName simulant world with
                                       | Some prop ->
  
positive.code:             | struct ([|_; Violation _ as v|], world) -> struct (v, world)
              | struct ([|Single x; Single y|], world) -> struct (Pluggable { Vector2 = Vector2 (x, y) }, world)
              | struct ([|_; _|], world) -> struct (Violation (["InvalidArgumentType"; String.capitalize fnName], "Application of " + fnName + " requires a Single for the both arguments.", originOpt), world)
              | struct (_, world) -> struct (Violation (["InvalidArgumentCount"; String.capitalize fnName], "Incorrect number of arguments for application of '" + fnName + "'; 2 arguments required.", originOpt), world)
  
          static member internal evalIndexV2Extrinsic fnName exprs originOpt world =
              match World.evalManyInternal exprs world with
  
negative.code:             | struct ([|String propertyName; value|], world)
              | struct ([|Keyword propertyName; value|], world) -> World.evalSet fnName propertyName None value originOpt world
              | struct ([|_; _|], world) -> struct (Violation (["InvalidArgumentType"; String.capitalize fnName], "Application of " + fnName + " requires a String or Keyword for the first argument, a value for the second, and an optional Relation for the third.", originOpt), world)
              | struct (_, world) -> struct (Violation (["InvalidArgumentCount"; String.capitalize fnName], "Incorrect number of arguments for '" + fnName + "'; 2 or 3 arguments required.", originOpt), world)
  
          static member internal evalSetAsStreamExtrinsic fnName exprs originOpt world =
              match World.evalManyInternal exprs world with
  