anchor.diff:              let store3 = stores.[comp3Name] :?> 'c3 Store
               let mutable i = 0
               while i < store.Length do
  -                world <- statement.Invoke (&store.[i], &store2.[i], &store3.[i], world)
  +                state <- statement.Invoke (&store.[i], &store2.[i], &store3.[i], state)
                   i <- inc i
  -        world
  +        state
   
       interface 'w Query with
           member this.CheckCompatibility system = this.CheckCompatibility system
  
positive.code: 
      member this.RegisterComponents (comp : 'c) (comp2 : 'c2) entityId world =
          this.RegisterNamedComponents typeof<'c>.Name comp typeof<'c2>.Name comp2 entityId world
  
      member this.Iterate (statement : Statement<'c, 'c2, 's>) state =
          let mutable state = state
  
negative.code:     member this.RegisterSystem (system : 'w System) =
          systems.Add (system.Id, system)
  
      member this.RegisterNamedComponent compName (comp : 'c) entityId world =
          ecs.RegisterNamedComponent compName comp entityId world
  
      member this.RegisterComponent (comp : 'c) entityId world =
          this.RegisterNamedComponent typeof<'c>.Name comp entityId world
  
      member this.UnregisterNamedComponent compName entityId world =
          ecs.UnregisterNamedComponent compName entityId world
  
      member this.UnregisterComponent<'c> entityId world =
          ecs.UnregisterComponent<'c> entityId world
  
      member this.Iterate (statement : Statement<'c, 's>) state =
          let mutable state = state
          for systemEntry in systems do
              let system = systemEntry.Value
              let stores = system.Stores
              let store = stores.[compName] :?> 'c Store
              let mutable i = 0
              while i < store.Length do
                  state <- statement.Invoke (&store.[i], state)
                  i <- inc i
          state
  
      interface 'w Query with
          member this.CheckCompatibility system = this.CheckCompatibility system
  