sub foo {
    print "foo @_\n";
    for (0..2) {
        print join('|', caller($_)), "\n" if caller($_);
    }
    print "\n";
}

my $r1 = sub { foo("bar", @_) };
my $r2 = sub { unshift @_, "bar"; goto &foo };


foo();
$r1->('baz');    # This call has an extra frame in the call stack. 
$r2->('baz', 'qux');