Access to Modified Closure error

I was LINQ-ing today and had this obscure error that didn't have much meaning to until I trolled the tubes and came up with Franc Bouma's blog.

Franc's blog

I realized the error and would like to point out that LINQ doesn't like empty or null values in the WHERE clause. Be careful unless you like to get a generic LINQ error and go bonkers and waste countless hours scratching your head wondering what went wrong.

  245         private void DoNothing(List<SomeObject.SomeClass> someList1, List<SomeObject.RoomRateType> someList2)

  246         {

  247             string rphValue = String.Empty;

  248             List<SomeClass> someClassList = new List<SomeClass>();

  249             SomeClass someObjectVar = new SomeClass();

  250 

  251             foreach (SomeObject.SomeClass someObjectVar in someList1)

  252             {

  253                 if (someObjectVar.RPHSpecified)

  254                 {

  255                     rphValue = someObjectVar.RPH.ToString();

  256                     var linqQuery = from rrl in someList2

  257                                     where (rrl.RatePlanCode == rphValue) && (rrl.Rates[0].Base.AdditionalFeesExcludedIndicator == true)

  258                                     select rrl.RoomRateDescription.Name;

  259 

  260                     foreach (var linqItem in linqQuery)

  261                     {

  262                         someObjectVar.MoreDescription += linqItem;

  263                     }

  264 

  265                     someObjectVar.RphCode = someObjectVar.RPH;

  266                 }

  267             }

  268         }

the "rphValue" variable can be null or empty and although I know that what I am doing may not cause any trouble, I am sure in some more complex situation, the results will be dire