>perl -MO=Concise -e"f()" 2>&1 | find "entersub"
5     <1> entersub[t2] vKS/TARG,1 ->6
                       ^
                       |
                       void

>perl -MO=Concise -e"0+f()" 2>&1 | find "entersub"
6        <1> entersub[t2] sKS/TARG,1 ->7
                          ^
                          |
                          scalar

>perl -MO=Concise -e"print f()" 2>&1 | find "entersub"
6        <1> entersub[t2] lKS/TARG,1 ->7
                          ^
                          |
                          list

>perl -MO=Concise -e"return f()" 2>&1 | find "entersub"
6        <1> entersub[t2] KS/TARG,1 ->7
                          ^
                          |
                          unknown at compile-time