This idea came up in conversation with @tritao. Just thought I'd open an issue about it so we can work towards a nice implementation for either this or a similar technique.

The idea for this came out of wanting to make caching and garbage collection a bit easier.

For the typeID, we could do something similar to the SourceId where the first ‘n’ bits specify the TypeEngineId that the type isn’t stored within.
I guess we should also do this for the DeclEngines and ParsedDeclEngines as well.

Would this also make having a single workspaces collection of Engines possible as mentioned in #5856?