# perl -MO=Concise,-exec -e '$$a'
1  <0> enter
2  <;> nextstate(main 1 -e:1) v
3  <$> gvsv(*a) s
4  <1> rv2sv vK/1
5  <@> leave[t1] vKP/REFC
-e syntax OK
 perl -MO=Concise,-exec -e '${$a}'
1  <0> enter
2  <;> nextstate(main 2 -e:1) v
3  <$> gvsv(*a) s
4  <1> rv2sv vK/1
5  <@> leave[t1] vKP/REFC
-e syntax OK