perl -MO=Deparse -e 'sub a {}; my $r = \&a; sort $r (1,2)'                                                           
 sub a {

}
my $r = \&a;
sort $r 1, 2;

##</code><code>##

perl -MO=Deparse -e 'sub a {}; sort \&a (1,2)'
sub a {

}
sort \(&a(1, 2));