NotNull runtime guard

Ensure.cs

public static class Ensure
{
    public static TValue NotNull<TValue>(Expression<Func<TValue>> parameterExpression)
    {
        var possibleNull = parameterExpression.Compile().Invoke();

        if (possibleNull == null)
        {
            var paramName = GetVariableName(parameterExpression);
            throw new ArgumentNullException(paramName);
        }

        return possibleNull;
    }

    private static string GetVariableName<TValue>(Expression<Func<TValue>> parameterExpression)
    {
        var body = (MemberExpression) parameterExpression.Body;
        return body.Member.Name;
    }
}