public void Select_SourceIsIReadOnlyCollection_CurrentIsDefaultOfTAfterEnumeration()
{
IReadOnlyCollection<int> source = new ReadOnlyCollection<int>(new List<int>() { 1 });
Func<int, int> selector = i => i + 1;
IEnumerable<int> query = source.Select(selector);
var enumerator = query.GetEnumerator();
while (enumerator.MoveNext()) ;
Assert.Equal(default(int), enumerator.Current);
}