DB<30> x @_
0  1
1  2
  DB<31> x ($a,$b,$c,$d) = (@_, ("D1".."D4")[@_..3])
0  1
1  2
2  'D3'
3  'D4'
  DB<32>

##</code><code>##

  DB<32> @DEF= ("D1".."D4")

  DB<33> x ($a,$b,$c,$d) = (@_, @DEF[@_..$#DEF])
0  1
1  2
2  'D3'
3  'D4'
  DB<34>

##</code><code>##

use v5.12.0;
use warnings;
use Data::Dump qw/pp dd/;


sub test {
    my ($x, $y, $z) =
      ( @_,
        ("X","Y","Z")[@_..42]
      );

    pp ($x, $y, $z);
}

test(1..$_) for 0..3

##</code><code>##

("X", "Y", "Z")
(1, "Y", "Z")
(1, 2, "Z")
(1, 2, 3)