terminator is one of the rarer fakeywords that we use for indicating that the program on the target platform will unconditionally terminate. For example, the
exit functions in PHP, or
fatalError in Swift.
By declaring that a scope will terminate the program execution, we can excuse behaviour that would otherwise be invalid, such as constructors in derived classes failing to call a super constructor.
Sempiler will overlook what would otherwise be a violation only if the constructor contains a terminator function that will unconditionally be hit.
Additionally, Sempiler will allow us to adorn a constructor with the
terminator fakeyword even though constructors generally do not have a return type annotation.
This is necessary if you are sempiling to Swift because you must indicate that a constructor may terminate when invoked.