anchor.diff:              | _ ->
                   let! items = getNavigableItems(document, options, cancellationToken)
                   let indexedItems = Index.build items
  +                itemsByDocumentId.Remove(document.Id) |> ignore
                   itemsByDocumentId.Add(document.Id, (textVersionHash, indexedItems))
                   return indexedItems
           }
  
positive.code:         entries.Sort(indexEntryComparer)
          { new IIndexedNavigableItems with
                member __.Find (searchValue) =
                    let result = ResizeArray()
                    if entries.Count > 0 then 
                       let entryToFind = IndexEntry(searchValue, 0, Unchecked.defaultof<_>, Unchecked.defaultof<_>)
                       
  
negative.code:                                  else NavigateToMatchKind.Prefix
                               else NavigateToMatchKind.Substring
                           let item = entry.Item
                           result.Add (NavigateToSearchResult(item, matchKind) :> INavigateToSearchResult) |> ignore
                      
                       // in case if there are multiple matching items binary search might return not the first one.
                       // in this case we'll walk backwards searching for the applicable answers
  