If I create an interface and attach arp entry to it, I can list it via "show ip arp"

When the interface is removed and I call the same command, vpp crashes. 

Example:

vat# 
vat# memif_create
created memif with sw_if_index 1
vat# ip_neighbor_add_del sw_if_index 1 dst 10.0.0.1 mac 00:00:00:00:00:01
vat# memif_delete sw_if_index 1

After this step, everything looks ok, I can perform any other changes (even re-create the memif and list arps). But if I just remove the memif and try to show arp entries, the VPP crashes. 
 
I haven't found any dump commands for ARPs (only for proxy arp) so the crash can only be reproduced via CLI.
 
VPP version:

vpp# sh ver
vpp v18.07-rc0~301-gdaff178

In older VPP versions the ARP would became dangling once the associated interface goes away. It wasn't possible to remove such entries anymore, unless they got re-attached to a new interface that recycled the same interface index, which is not desirable. I believe that automatic cleanup of dangling ARPs would probably fix the crash as well.