anchor.diff:          world
   
       member this.TryClear world =
  -        if Seq.isEmpty allocated then
  +        if allocated.Count = 0 then
               let mutable world = world
               for entityIdInv in unallocated do
                   let entityId = UInt64.MaxValue - entityIdInv
  
positive.code:             let indexOpt4 = system4.TryIndexCorrelatedToI entityId
              if indexOpt > -1 && indexOpt2 > -1 && indexOpt3 > -1 && indexOpt4 > -1 then
                  let systemIds = ecs.IndexSystemIds entityId
                  if not (systemIds.IsSupersetOf excluding)
                  then cache.[entityId] <- struct (indexOpt, indexOpt2, indexOpt3, indexOpt4)
                  else cache.Remove entityId |> ignore<bool>
              elif indexOpt > -1 || indexOpt2 > -1 || indexOpt3 > -1 || indexOpt4 > -1 then // OPTIMIZATION: make sure it exists and needs removing
  
negative.code:         world
  
      member this.TryClear world =
          if allocated.Count = 0 then
              let mutable world = world
              for entityIdInv in unallocated do
                  let entityId = UInt64.MaxValue - entityIdInv
  