gistfile1.cs

foreach (string prop in props)
{
	if (prop == "Count")
	{
		var countMethod = (typeof(Enumerable)).GetMethods().First(m => m.Name == "Count").MakeGenericMethod(type);
		expr = Expression.Call(countMethod, expr);
		break;
	}

	PropertyInfo pi = type.GetProperty(prop);
	expr = Expression.Property(expr, pi);
	type = pi.PropertyType;
}