anchor.diff:              val mutable public CodePrevTag : Option<'a>
               val mutable public CallCount : int
               val mutable public JumpDistance : int
  +            val mutable public IsDisposed : bool
   
               interface IFragment<'fragment> with
                   member x.Next = x.Next :> IFragment<_>
  
positive.code:                     relinkSet.Add prev |> ignore
  
                      // insert the new fragment in the linked list.
                      next.Prev <- fragment
                      fragment.Prev <- prev
                      fragment.Next <- next
                      prev.Next <- fragment
  
                      // finally return the new fragment
  
negative.code:                   Storage = None; Next = null; 
                    Prev = null; Tag = Some tag; 
                    Code = null; CodePrevTag = None
                    CallCount = 0; JumpDistance = 0; IsDisposed = false }
  
              new(context, storage) = 
                  { Context = context
                    Storage = Some storage; Next = null; 
                    Prev = null; Tag = None; 
                    Code = null; CodePrevTag = None
                    CallCount = 0; JumpDistance = 0; IsDisposed = false }
          end
  
      type Program<'i, 'k, 'instruction, 'fragment, 'a>
  