Would there be issues with IEnumerables deferred execution?
e.g.
var xs = new List<int>{1, 2, 3, 4, 5};
xs.Select(Inc)
.Where(IsEven);
If I run that, nothing happens, neither Inc or IsEven is called... Its not until the results are realised that they will be called. If Select was writing back to xs, would this break?
