basic sink context working

sink.pl

my $SV = 0;
class A {
    method sink() {
        say "sunk $SV";
    }
}
sub f($x) { $SV = $x; A };
my $x = do {
    f(1);
    f(2);
    f(3);
};
# ./perl6 --sink sink-test.pl
# sunk 1
# sunk 2