.p6

class C {
  has %!h{Pair};

  method m {
    %!h{a => 1} = 2;
  }

  method n {
    %!h{a => 2} = 3;
  }

  method o {
    say %!h;
  }

  method clone(*%twiddles) {
    my %h{Pair} = %!h.clone;
    my $result = callsame(|%twiddles);
    %!h = %h;
    $result;
  }
}

my $c = C.new();
$c.m;
$c.clone.n;
$c.o; # output: (a => 1) => 2, (a => 2) => 3