It took me a while to address an awful IDE crash issue. If you install a design time package which uses RTTI to populate custom attributes declared in the package, recompiling it will make the IDE fatal failed and have to be killed. (Even you don't save references to them) Tested in Win10/7, from "Seattle" to "Tokyo".

It took me a while to address an awful IDE crash issue. If you install a design time package which uses RTTI to populate custom attributes declared in the package, recompiling it will make the IDE fatal failed and have to be killed. (Even you don't save references to them) Tested in Win10/7, from "Seattle" to "Tokyo".

[Fatal Error] Access violation at address 5005F8A8 in module 'rtl250.bpl'. Read of address 2B571F7C (see https://quality.embarcadero.com/browse/RSP-18600)

This is caused by a "design defect" of the RTTI. Those live rtti objects in the shared pool will not be immediately freed when unloading a package. Instead it will be freed when you retrieve rtti next time. But this will be a problem for user-defined attributes as their containing packages have been unloaded...

Later I also found similar issue reported in 2015 (https://quality.embarcadero.com/browse/RSP-11620) I think this should be marked as a high priority issue. It might have impact for third-parties (component vendors) and user experience.
https://quality.embarcadero.com/browse/RSP-11620