You're right about numbers up front. I should have tried this to begin with:
[jim@krakatoa perl]$ cat use23Skidoo.pl
use warnings FATAL => 'all';
[jim@krakatoa perl]$ ./use23Skidoo.pl
syntax error at ./use23Skidoo.pl line 8, near "use 23"
Execution of ./use23Skidoo.pl aborted due to compilation errors.
It helps to remember that the primary goal is to drain the swamp even when you are hip-deep in alligators.