>perl -MO=Concise -e"@a=4"
9  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
8     <2> aassign[t3] vKS ->9
-        <1> ex-list lK ->5                <---
3           <0> pushmark s ->4
4           <$> const[IV 4] s ->5
-        <1> ex-list lK ->8                <---
5           <0> pushmark s ->6
7           <1> rv2av[t2] lKRM*/1 ->8
6              <#> gv[*a] s ->7
-e syntax OK