anchor.diff:            else
               this.Insert(~~~index, k, v)
               ~~~index
  -    finally
  -      exitLockIf syncRoot entered
  +    //finally
  +    exitLockIf syncRoot entered
  +    ret
   
     member this.Add(key, value) : unit =
       if isKeyReferenceType && EqualityComparer<'K>.Default.Equals(key, Unchecked.defaultof<'K>) then 
  
positive.code:   /// Sets the value to the key position and returns the index of the key
    member internal this.SetWithIndex(k, v) =
      let entered = enterLockIf syncRoot isSynchronized
      try
        // first/last optimization (only last here)
        if this.size = 0 then
          this.Insert(0, k, v)
  
negative.code:           if valueComparer.Compare(value,this.values.[res]) = 0 then
                found <- true
            else res <- res + 1
        exitLockIf syncRoot entered
        if found then res else -1
      //finally
        
  
  
    member this.First
  