While preparing the NAV 2009 SP1 training for developers in The Netherlands I came accross this new feature.
If you compile one or multiple objects in this version you will get an error list like in real dev. environments.
Another feature that is added is warnings. Until this release NAV only had compile errors. This version warns you if you implement stuff that won't work in the service tier.
If you import the objects from my contribution to the good old Christmas Contest on Mibuso you will get a codeunit amongst other things.
When you compile the codeunit you will get this screen.
Sorry for the Dutch, waarschuwing means Warning.
What it says is that BEEP is not supported in the service tier.
If you compile multiple objects you will get all warnings and errors from all objects and if you push design it will flip to the code.
The data is stored in a new internal table, 2000000070 Error List
There is a downside. If you compile a codeunit with f11 while in the object you will get the warnings in a messagebox as well. Mr. Microsoft, can you please remove that? Or does someone disagree?
I thing this might be more what you are looking for?