ReSharper.PossibleMultipleEnumeration.cs

using System;
using System.Linq;

static class Program
{
  static void Main(string[] args) {
    var lengths = args.Select(item => item.Length);
    // "lengths" can be enumerated a few times, depending on a size of "args".
    var xxx = args.Select(item => lengths.Select(x => x));
  }
}