There is no meaningful distinction between types and expressions at the serice level; collapse those packages.
Add a types registry to the types registry service (!)
Now that types registry is a service, it needs to be wired all over the place, particularly in unit tests.
Startup is delicate.
Make test setup more explicit.
Add a simple test for registry basics.
Make the names for INT match adapter and MySQL itself.
Tighten up when things have a charset and collation.
Delay creation of cloner until service started.
Add test flag to check types.
More charset and collation problems.
Update tests for stricter APIs.
Legal collation.