$ perl -MXML::LibXML -MData::Dumper -MStorable -e   '
    $a = XML::LibXML->load_xml(string => "<a></a>");
    print Dumper $a;
    store($a, "tmp");
    $b = retrieve "tmp";
    print Dumper $b;
  '
$VAR1 = bless( do{\(my $o = 2150785512)}, 'XML::LibXML::Document' );
$VAR1 = bless( do{\(my $o = 2150785512)}, 'XML::LibXML::Document' );
PmmREFCNT_dec: REFCNT decremented below 0 for 803261e8! during global destruction.
Aborted (core dumped)