role EXR { method foo { } };
class EX { method foo { } };

role XR {
  has Int @!x;
  method TWEAK { @!x = Nil xx 100; }
  method set($i, $v) { @!x[$i] = $v; }
};

class X {
  has $!cap is built;
  has Int @!x;
  method TWEAK { @!x = Nil xx $!cap }
  method set($i, $v) { @!x[$i] = $v; }
}

sub exr { my EXR $x .= new; for ^1_000_000 { $x.foo } }
sub ex { my EX $x .= new; for ^1_000_000 { $x.foo } }
sub xr { my XR $x .= new(); for ^1_000_000 { $x.set(0, $_) } }
sub x { my X $x .= new(cap => 100); for ^1_000_000 { $x.set(0, $_) } }

use Bench;
for (|(10 xx 5), 500) -> $iters { # warmup
  my $b = Bench.new;
  $b.cmpthese($iters, { :&xr, :&x, :&ex, :&exr });
}