>perl -MO=Concise -e"@in=@in[@idx]
e  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
d     <2> aassign[t7] vKS/COMMON ->e        <-- Note "COMMON"
-        <1> ex-list lK ->a
3           <0> pushmark s ->4
9           <@> aslice lK ->a
4              <0> pushmark s ->5
6              <1> rv2av[t6] lK/1 ->7
5                 <#> gv[*idx] s ->6
8              <1> rv2av[t4] sKR/1 ->9
7                 <#> gv[*in] s ->8
-        <1> ex-list lK ->d
a           <0> pushmark s ->b
c           <1> rv2av[t2] lKRM*/1 ->d
b              <#> gv[*in] s ->c

##</code><code>##

         1         995:     /* If there's a common identifier on both sides we have to take
         1         996:      * special care that assigning the identifier on the left doesn't
         1         997:      * clobber a value on the right that's used later in the list.
         1         998:      */
      5492 <<      999:     if (PL_op->op_private & (OPpASSIGN_COMMON)) {
      2062 <<     1000: 	EXTEND_MORTAL(lastrelem - firstrelem + 1);
      5492 <<     1001: 	for (relem = firstrelem; relem <= lastrelem; relem++) {
      5540 <<     1002: 	    if ((sv = *relem)) {
        18 << br  1003: 		TAINT_NOT;	/* Each item is independent */
      5492 <<     1004: 		*relem = sv_mortalcopy(sv);
        18 << br  1005: 	    }
      5492 <<     1006: 	}
         1        1007:     }
         1        1008: