cat t.pl
use v6;

class C {
   has Int $.x is rw = 0;

   method foo (Int $i) { $!x += $i; return self; }
   method bar (Int $i) { $!x -= $i; return self; }
   }

C.new()\
 .foo(1)\
 .bar(2)\
 .say;
$ perl6 t.pl
C.new(x => -1)