[Ferm] Subchain confusion

[Kiss Gabor (Bitman)]

Check this quite legal configuration snippet:

------------------------------
domain (ip ip6) {
    table filter {
        chain INPUT { 
            policy DROP;
            proto tcp dport ssh @subchain "ssh" {
                @subchain "fail2ban-SSH" { RETURN; }
                ACCEPT saddr (
                    @ipfilter((192.0.2.0/24 2001:db8::/32))
                    host1.example.com
                );
            }
        }
    }
}
------------------------------

Then run command
ferm -n -l --domain ip subchain.ferm

Expected output:

------------------------------
# Generated by ferm 2.2 on Thu Aug 24 09:38:15 2017
*filter
:FORWARD ACCEPT [0:0]
:INPUT DROP [0:0]
:OUTPUT ACCEPT [0:0]
:fail2ban-SSH - [0:0]
:ssh - [0:0]
-A INPUT --protocol tcp --dport ssh --jump ssh
-A fail2ban-SSH --jump RETURN
-A ssh --jump fail2ban-SSH
-A ssh --jump ACCEPT --source 192.0.2.0/24
-A ssh --jump ACCEPT --source host1.example.com
COMMIT
------------------------------

Barely acceptable output:
(See also http://lists.lunar-linux.org/pipermail/ferm/2013-July/000123.html)
------------------------------
# Generated by ferm 2.2 on Thu Aug 24 09:38:15 2017
*filter
:FORWARD ACCEPT [0:0]
:INPUT DROP [0:0]
:OUTPUT ACCEPT [0:0]
:fail2ban-SSH - [0:0]
:ssh - [0:0]
-A INPUT --protocol tcp --dport ssh --jump ssh
-A fail2ban-SSH --protocol tcp --jump RETURN
-A ssh --protocol tcp --jump fail2ban-SSH
-A ssh --protocol tcp --jump ACCEPT --source 192.0.2.0/24
-A ssh --protocol tcp --jump ACCEPT --source host1.example.com
COMMIT
------------------------------

Real output:
------------------------------
Error in subchain.ferm line 12:
        chain INPUT 
        { 
            proto tcp dport ssh @subchain "ssh" 
            { 
                @subchain <--
No rule specified before $jumpkey
------------------------------

Gabor