Fix inherited composite key (and some others I ran into)

use-after-free in tracing an outgoing pre-emptive ACKNACK message if security decides to drop the message
a harmless typo in the output of dynsub that today annoyed me too much 🙂
a potential use-after-free in my new non-assignability reason printer (bummer, well, it was caught quickly)
a crash on validating an empty struct with an unresolved base type

and, last but not least: the crash for an inherited composite key in a (non-mutable) type.

eclipse-cyclonedds / cyclonedds