anchor.diff:  open Random
   open Microsoft.FSharp.Control
   open Microsoft.FSharp.Reflection
  + 
    
   type internal IGen = 
       abstract AsGenObject : Gen<obj>
  
positive.code:                     |> Array.to_list
                      |> sequence
                      |> (fun gen -> gen.Map List.to_array)
          check {config with name = t.Name+"."+m.Name} (forAll gen (fun g -> invokeMethod m g |> unbox<Property> ))) |>
      ignore
negative.code:                 yield Passed result.stamp
                  yield! test newSize resize rnd1 gen
              | Some (Lazy false) -> 
                  yield Falsified (result.arguments,result.exc)
                  yield! test newSize resize rnd1 gen
      }
  
  