C:\test>perl -MO=Deparse,p use 5.010; sub apple { say "apple" } sub banana { say "banana" } sub cherry { say "cherry" } apple && (banana || cherry) ^Z sub BEGIN { require 5.01; } sub apple { no feature; use feature ':5.10'; say 'apple'; } sub banana { no feature; use feature ':5.10'; say 'banana'; } sub cherry { no feature; use feature ':5.10'; say 'cherry'; } no feature; use feature ':5.10'; banana or cherry if apple ; - syntax OK