MaxOrDefault sem catch

gistfile1.cs

public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource> source)
    where TSource : IComparable
{
    return source.MaxOrDefault(default(TSource));
}

public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource> source, TSource defaultValue)
    where TSource : IComparable
{
    var enumerator = source.GetEnumerator(); 
    if (!enumerator.MoveNext()) return defaultValue;

    TSource max = enumerator.Current;
    while (enumerator.MoveNext())
    {
        var current = enumerator.Current;
        if (current != null && current.CompareTo(max) > 0)
            max = current;
    }
    return max;
}

public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource?> source)
    where TSource : struct, IComparable
{
    return source.MaxOrDefault(default(TSource));
}

public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource?> source, TSource defaultValue)
    where TSource : struct, IComparable
{
    return source.Where(x => x != null).Select(x => x ?? default(TSource)).MaxOrDefault(defaultValue);
}