anchor.diff:  /// to each of the elements of the array. The integer index passed to the
   /// function indicates the index of element being transformed.
   [<CompiledName("MapIndexed")>]
  -let mapi (mapping : int -> 'T -> 'U) (resizeArray : ResizeArray<'T>) =
  +let mapi (mapping : int -> 'T -> 'U) (resizeArray : ResizeArray<'T>) : ResizeArray<'U> =
       // Preconditions
       checkNonNull "resizeArray" resizeArray
   
  
positive.code:         state <- folder.Invoke (state, resizeArray.[i])
      state
  
  //
  [<CompiledName("FoldIndexed")>]
  let foldi (folder : int -> 'State -> 'T -> 'State) state (resizeArray : ResizeArray<'T>) =
      // Preconditions
      checkNonNull "resizeArray" resizeArray
  
  
negative.code: 
  /// Apply the given function to each element of the array.
  [<CompiledName("Iter")>]
  let iter (action : 'T -> unit) (resizeArray : ResizeArray<'T>) : unit =
      // Preconditions
      checkNonNull "resizeArray" resizeArray
  
  