What does it do?

• Improve precompile set explicit list of security checks #2034 changed slightly the precompile macro to fully qualify PhantomData, avoiding a use at call site.
• Fix tuple encoding in precompiles return position #2068 added a new expansion test for tuples
• since it was based on master before Improve precompile set explicit list of security checks #2034 was merged, it doesn't include the expansion change
• thus after merging Fix tuple encoding in precompiles return position #2068 in master, the test no longer pas

Is there something left for follow-up PRs?

Is there some way to protect against this kind of issues?