anchor.diff:  and [<AllowNullLiteral>] MathObject =
     inherit CO
   
  +  override x.ClassName = "Math"
  +
     new (env:Env) = {
       inherit CO(env, env.Maps.Base, env.Prototypes.Object)
     }
  
positive.code: and EO = ErrorObject
  and [<AllowNullLiteral>] ErrorObject =
    inherit CO
  
    new (env:Env) = {
      inherit CO(env, env.Maps.Base, env.Prototypes.Error)
  
negative.code: and NO = NumberObject
  and [<AllowNullLiteral>] NumberObject =
    inherit ValueObject
    
    override x.ClassName = "Number"
  
    new (env:Env) = {
      inherit ValueObject(env, env.Maps.Number, env.Prototypes.Number)
  