>perl -MO=Concise -e"1 for ($a,$b)"
d  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
3     <;> nextstate(main 1 -e:1) v ->4
c     <2> leaveloop vK/2 ->d
8        <{> enteriter(next->9 last->c redo->9) lK/8 ->a
-           <0> ex-pushmark s ->4
-           <1> ex-list lKPM ->7       <-- lvalue list
4              <0> pushmark sM ->5
-              <1> ex-rv2sv sKM/1 ->6
5                 <#> gvsv[*a] s ->6
-              <1> ex-rv2sv sKM/1 ->-
6                 <#> gvsv[*b] s ->7
7           <#> gv[*_] s ->8
-        <1> null vK/1 ->c
b           <|> and(other->9) vK/1 ->c
a              <0> iter s ->b
-              <@> lineseq vK ->-
-                 <0> ex-const v ->9
9                 <0> unstack v ->a
-e syntax OK