IEnumerable ForEach safety extensions

gistfile1.cs

namespace System.Collections.Generic
{
	using System.Linq;

	public static class IEnumerableExtensions
	{
    
                // Why ForEach extension is not included on IEnumerable<T> by default http://blogs.msdn.com/b/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx
        
		public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
		{
                        Guard.Against(action == null, new ArgumentNullException("action"));
			if(source == null) return;
			foreach (T t in source)
			{
				action(t);
			}
		}

		public static void ForEachSkipNull<T>(this IEnumerable<T> source, Action<T> action)
		{
			Guard.Against(action == null, new ArgumentNullException("action"));
                        if(source == null) return;
			foreach (T t in source.Where(t => !ReferenceEquals(t, null)))
			{
				action(t);
			}
		}

		public static void ForEachThrowOnNull<T>(this IEnumerable<T> source, Action<T> action)
		{
                        Guard.Against(action == null, new ArgumentNullException("action"));
                        if(source == null) return;
			foreach (T t in source)
			{
				if (ReferenceEquals(t, null))
				{
					throw new InvalidOperationException("Item is null");
				}
				action(t);
			}
		}
	}
}