--- @a before ---
$VAR1 = [
          'a',
          'b',
          'c',
          'd',
          'e'
        ];
--- %a before ---
$VAR1 = {
          'e' => 1,
          'c' => 1,
          'a' => 1,
          'b' => 1,
          'd' => 1
        };
--- @a after ---
$VAR1 = [
          'a',
          'b',
          'c',
          undef,
          'e'
        ];
--- %a after ---
$VAR1 = {
          'e' => undef,
          'c' => 1,
          'a' => 1,
          'b' => 1,
          'd' => 1
        };