anchor.diff:          let x = ()  // 9
           ()          // 10
   """
  -    => [ 2, 15, 10, 10
  -         6,  4, 10, 10
  -         6, 19, 10, 10 
  -         9,  8, 10, 10 ]
  +//    |> parseTree
  +    => [(2, 15, 10, 10)
  +        (3, 2, 4, 6)
  +        (5, 2, 10, 10)
  +        (6, 19, 10, 10)
  +        (8, 6, 10, 10) ]
            
   [<Test>]
   let ``computation expressions``() =
  
positive.code: 
  type Line = int
  type Col = int
  
  let (=>) (source: string) (expectedRanges: (Line * Col * Line * Col) list) =
      let ast = (parseSource source).ParseTree
  
negative.code: """
      => [ 2, 10, 10, 55
           8, 25, 10, 55
           (9, 15, 10, 55)
           (9, 27, 10, 55)]
  
  [<Test>]
  let ``type with a do block``() =
  