anchor.diff:  module ResizeArray =
       open System.Collections.Generic
   
  -
       //
       let [<NoDynamicInvocation>] inline length (resizeArray : ResizeArray<'T>) =
           resizeArray.Count
  +
  +    //
  +    let inline isEmpty (resizeArray : ResizeArray<'T>) =
  +        resizeArray.Count = 0
   
       //
       let [<NoDynamicInvocation>] inline add item (resizeArray : ResizeArray<'T>) =
  
positive.code:     /// Expands an array by creating a copy of it which has
      /// the specified number of empty elements appended to it.
      [<CompiledName("ExpandRight")>]
      let expandRight count (arr : 'T[]) =
          // Preconditions
          if count < 0 then
              invalidArg "count" "The number of elements to expand the array by is negative."
  
          // Create the new "expanded" array. Copy the elements from the original array
          // into the "left" side of the new array, then return the expanded array.
          let expandedArr = Array.zeroCreate (arr.Length + count)        
          Array.blit arr 0 expandedArr 0 arr.Length
          expandedArr
  
      /// Expands an array by creating a copy of it which has
      /// the specified number of empty elements prepended to it.
      [<CompiledName("ExpandLeft")>]
      let expandLeft count (arr : 'T[]) =
          // Preconditions
          if count < 0 then
              invalidArg "count" "The number of elements to expand the array by is negative."
  
          // Create the new "expanded" array. Copy the elements from the original array
          // into the "right" side of the new array, then return the expanded array.
          let expandedArr = Array.zeroCreate (arr.Length + count)
          Array.blit arr 0 expandedArr count arr.Length
          expandedArr
  
      //
  
negative.code: module TaggedArray =
      /// Similar to Array.mapi, but 'tags' the index values with a unit-of-measure
      /// type before applying them to the mapping function.
      [<CompiledName("MapIndexed")>]
      let mapi (mapping : int<'Tag> -> 'T -> 'U) (array : 'T[]) =
          // Preconditions
          checkNonNull "array" array
          
          let mapping = FSharpFunc<_,_,_>.Adapt mapping
          let len = array.Length
          let results = Array.zeroCreate len
  