Error    2    Property or indexer 'AnonymousType#1.MyAnnoymousP' cannot be assigned to -- it is read only  

Why did this became like this as we go from Beta 1 to Beta 2?

This code generated the above error

var q = from x in y
             where x.d = 1
             select new {MyAnnoymousP = x.L, x.J};

q.MyAnnoymousP = Something;

in beta 1 this was valid, but in Beta 2 it became ReadOnly. Why? Will this change? Is this a bug in Beta 2?