anchor.diff:  
   open NUnit.Framework
   open System.IO
  -open Microsoft.FSharp.Compiler
   open Microsoft.FSharp.Compiler.SourceCodeServices
   open FSharpVSPowerTools
  -open System.Threading
  -open FSharpVSPowerTools.AsyncMaybe
  -open TestHelpers.LanguageServiceTestHelper
   
   //[<Literal>]
   //let DataFolderName = __SOURCE_DIRECTORY__ + "/../data/"
  
positive.code:     { opts with LoadTime = System.DateTime.UtcNow }
  
  let (=>) (source, line, col) (expected: (int * ((int * int) list)) list) = 
      let opts = opts source
  
      let getSymbol line col lineStr =
          Lexer.getSymbol source line col lineStr SymbolLookupKind.Fuzzy LanguageServiceTestHelper.args Lexer.queryLexState
      
      let sourceLines = String.getLines source
  
      let lexer = 
          { new LexerBase() with
              member __.GetSymbolFromTokensAtLocation (_tokens, line, col) =
  
negative.code:         }
          |> Async.RunSynchronously
          |> Option.getOrElse [||]
          |> Array.toList
          |> List.groupBy (fun su -> su.RangeAlternate.StartLine)
          |> List.map (fun (line, sus) ->    
              line, sus |> List.map (fun su -> su.RangeAlternate.StartColumn, su.RangeAlternate.EndColumn))
          |> List.sortBy (fun (line, _) -> line)
  
      let expected = 
          expected 
          |> List.map (fun (line, sus) -> line, List.sort sus)
          |> List.sortBy (fun (line, _) -> line)
      
      try actual |> Collection.assertEquiv expected
      with _ -> 
          debug "AST: %A" results.ParseTree
          for x in actual do
              debug "Actual: %A" x
          reraise()
  
  [<Test>]
  let ``should find usages of module let bindings``() =
      ("""
  let helloWorld = string1 + " " + string2
  let substring = helloWorld.[0..6]
  let string5 =
      let helloWorld = "Hello F# world"
      helloWorld
  """, 2, 5)
      => [ 2, [ 4, 14 ]
           3, [ 16, 26 ]]
  
  //[<Test>]
  //let ``should find usages of arrays``() =
  