How to add/send ancillary info from CallSites to Binders? #280

I am experimenting with the dlr by writing a toy language. I've based some of it on the examples given by the Sympl code in the dlr repo. I'm keeping it fairly simple - runtime objects are instances of a class derived from DynamicObject. Callable methods are also classes derived from DynamicObject (leveraging the TryGet/TrySet/TryInvoke features).

I would like to make source line number information available so that if something goes wrong and my runtime throws an exception, it can include the source line # in the error message.
I have used a custom field on my custom binders (deriving from GetMemberBinder, InvokeBinder, etc), but I suspect this is not the correct way to do it as that would prevent these binders from being re-used across call sites.

I had hoped that perhaps I could derive a custom class from CallInfo, but that is sealed.

How should/could this be done? Where might I find examples of something similar in another language's implementation on the dlr?
TIA